From 9cd3c840876b1f3ea79ab810a5b00d9931749631 Mon Sep 17 00:00:00 2001 From: Zheng Da Date: Tue, 15 Jun 2010 16:20:24 +0200 Subject: implement get_random_bytes() with random() in libc --- libdde_linux26/contrib/drivers/char/random.c | 1691 ------------------------- libdde_linux26/lib/src/Makefile | 3 +- libdde_linux26/lib/src/drivers/char/random.c | 1709 ++++++++++++++++++++++++++ libddekit/include/ddekit/resources.h | 1 + libddekit/resources.c | 6 + 5 files changed, 1718 insertions(+), 1692 deletions(-) delete mode 100644 libdde_linux26/contrib/drivers/char/random.c create mode 100644 libdde_linux26/lib/src/drivers/char/random.c diff --git a/libdde_linux26/contrib/drivers/char/random.c b/libdde_linux26/contrib/drivers/char/random.c deleted file mode 100644 index 7c13581c..00000000 --- a/libdde_linux26/contrib/drivers/char/random.c +++ /dev/null @@ -1,1691 +0,0 @@ -/* - * random.c -- A strong random number generator - * - * Copyright Matt Mackall , 2003, 2004, 2005 - * - * Copyright Theodore Ts'o, 1994, 1995, 1996, 1997, 1998, 1999. All - * rights reserved. - * - * Redistribution and use in source and binary forms, with or without - * modification, are permitted provided that the following conditions - * are met: - * 1. Redistributions of source code must retain the above copyright - * notice, and the entire permission notice in its entirety, - * including the disclaimer of warranties. - * 2. Redistributions in binary form must reproduce the above copyright - * notice, this list of conditions and the following disclaimer in the - * documentation and/or other materials provided with the distribution. - * 3. The name of the author may not be used to endorse or promote - * products derived from this software without specific prior - * written permission. - * - * ALTERNATIVELY, this product may be distributed under the terms of - * the GNU General Public License, in which case the provisions of the GPL are - * required INSTEAD OF the above restrictions. (This clause is - * necessary due to a potential bad interaction between the GPL and - * the restrictions contained in a BSD-style copyright.) - * - * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED - * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES - * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, ALL OF - * WHICH ARE HEREBY DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE - * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR - * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT - * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR - * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF - * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT - * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE - * USE OF THIS SOFTWARE, EVEN IF NOT ADVISED OF THE POSSIBILITY OF SUCH - * DAMAGE. - */ - -/* - * (now, with legal B.S. out of the way.....) - * - * This routine gathers environmental noise from device drivers, etc., - * and returns good random numbers, suitable for cryptographic use. - * Besides the obvious cryptographic uses, these numbers are also good - * for seeding TCP sequence numbers, and other places where it is - * desirable to have numbers which are not only random, but hard to - * predict by an attacker. - * - * Theory of operation - * =================== - * - * Computers are very predictable devices. Hence it is extremely hard - * to produce truly random numbers on a computer --- as opposed to - * pseudo-random numbers, which can easily generated by using a - * algorithm. Unfortunately, it is very easy for attackers to guess - * the sequence of pseudo-random number generators, and for some - * applications this is not acceptable. So instead, we must try to - * gather "environmental noise" from the computer's environment, which - * must be hard for outside attackers to observe, and use that to - * generate random numbers. In a Unix environment, this is best done - * from inside the kernel. - * - * Sources of randomness from the environment include inter-keyboard - * timings, inter-interrupt timings from some interrupts, and other - * events which are both (a) non-deterministic and (b) hard for an - * outside observer to measure. Randomness from these sources are - * added to an "entropy pool", which is mixed using a CRC-like function. - * This is not cryptographically strong, but it is adequate assuming - * the randomness is not chosen maliciously, and it is fast enough that - * the overhead of doing it on every interrupt is very reasonable. - * As random bytes are mixed into the entropy pool, the routines keep - * an *estimate* of how many bits of randomness have been stored into - * the random number generator's internal state. - * - * When random bytes are desired, they are obtained by taking the SHA - * hash of the contents of the "entropy pool". The SHA hash avoids - * exposing the internal state of the entropy pool. It is believed to - * be computationally infeasible to derive any useful information - * about the input of SHA from its output. Even if it is possible to - * analyze SHA in some clever way, as long as the amount of data - * returned from the generator is less than the inherent entropy in - * the pool, the output data is totally unpredictable. For this - * reason, the routine decreases its internal estimate of how many - * bits of "true randomness" are contained in the entropy pool as it - * outputs random numbers. - * - * If this estimate goes to zero, the routine can still generate - * random numbers; however, an attacker may (at least in theory) be - * able to infer the future output of the generator from prior - * outputs. This requires successful cryptanalysis of SHA, which is - * not believed to be feasible, but there is a remote possibility. - * Nonetheless, these numbers should be useful for the vast majority - * of purposes. - * - * Exported interfaces ---- output - * =============================== - * - * There are three exported interfaces; the first is one designed to - * be used from within the kernel: - * - * void get_random_bytes(void *buf, int nbytes); - * - * This interface will return the requested number of random bytes, - * and place it in the requested buffer. - * - * The two other interfaces are two character devices /dev/random and - * /dev/urandom. /dev/random is suitable for use when very high - * quality randomness is desired (for example, for key generation or - * one-time pads), as it will only return a maximum of the number of - * bits of randomness (as estimated by the random number generator) - * contained in the entropy pool. - * - * The /dev/urandom device does not have this limit, and will return - * as many bytes as are requested. As more and more random bytes are - * requested without giving time for the entropy pool to recharge, - * this will result in random numbers that are merely cryptographically - * strong. For many applications, however, this is acceptable. - * - * Exported interfaces ---- input - * ============================== - * - * The current exported interfaces for gathering environmental noise - * from the devices are: - * - * void add_input_randomness(unsigned int type, unsigned int code, - * unsigned int value); - * void add_interrupt_randomness(int irq); - * - * add_input_randomness() uses the input layer interrupt timing, as well as - * the event type information from the hardware. - * - * add_interrupt_randomness() uses the inter-interrupt timing as random - * inputs to the entropy pool. Note that not all interrupts are good - * sources of randomness! For example, the timer interrupts is not a - * good choice, because the periodicity of the interrupts is too - * regular, and hence predictable to an attacker. Disk interrupts are - * a better measure, since the timing of the disk interrupts are more - * unpredictable. - * - * All of these routines try to estimate how many bits of randomness a - * particular randomness source. They do this by keeping track of the - * first and second order deltas of the event timings. - * - * Ensuring unpredictability at system startup - * ============================================ - * - * When any operating system starts up, it will go through a sequence - * of actions that are fairly predictable by an adversary, especially - * if the start-up does not involve interaction with a human operator. - * This reduces the actual number of bits of unpredictability in the - * entropy pool below the value in entropy_count. In order to - * counteract this effect, it helps to carry information in the - * entropy pool across shut-downs and start-ups. To do this, put the - * following lines an appropriate script which is run during the boot - * sequence: - * - * echo "Initializing random number generator..." - * random_seed=/var/run/random-seed - * # Carry a random seed from start-up to start-up - * # Load and then save the whole entropy pool - * if [ -f $random_seed ]; then - * cat $random_seed >/dev/urandom - * else - * touch $random_seed - * fi - * chmod 600 $random_seed - * dd if=/dev/urandom of=$random_seed count=1 bs=512 - * - * and the following lines in an appropriate script which is run as - * the system is shutdown: - * - * # Carry a random seed from shut-down to start-up - * # Save the whole entropy pool - * echo "Saving random seed..." - * random_seed=/var/run/random-seed - * touch $random_seed - * chmod 600 $random_seed - * dd if=/dev/urandom of=$random_seed count=1 bs=512 - * - * For example, on most modern systems using the System V init - * scripts, such code fragments would be found in - * /etc/rc.d/init.d/random. On older Linux systems, the correct script - * location might be in /etc/rcb.d/rc.local or /etc/rc.d/rc.0. - * - * Effectively, these commands cause the contents of the entropy pool - * to be saved at shut-down time and reloaded into the entropy pool at - * start-up. (The 'dd' in the addition to the bootup script is to - * make sure that /etc/random-seed is different for every start-up, - * even if the system crashes without executing rc.0.) Even with - * complete knowledge of the start-up activities, predicting the state - * of the entropy pool requires knowledge of the previous history of - * the system. - * - * Configuring the /dev/random driver under Linux - * ============================================== - * - * The /dev/random driver under Linux uses minor numbers 8 and 9 of - * the /dev/mem major number (#1). So if your system does not have - * /dev/random and /dev/urandom created already, they can be created - * by using the commands: - * - * mknod /dev/random c 1 8 - * mknod /dev/urandom c 1 9 - * - * Acknowledgements: - * ================= - * - * Ideas for constructing this random number generator were derived - * from Pretty Good Privacy's random number generator, and from private - * discussions with Phil Karn. Colin Plumb provided a faster random - * number generator, which speed up the mixing function of the entropy - * pool, taken from PGPfone. Dale Worley has also contributed many - * useful ideas and suggestions to improve this driver. - * - * Any flaws in the design are solely my responsibility, and should - * not be attributed to the Phil, Colin, or any of authors of PGP. - * - * Further background information on this topic may be obtained from - * RFC 1750, "Randomness Recommendations for Security", by Donald - * Eastlake, Steve Crocker, and Jeff Schiller. - */ - -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include - -#include -#include -#include -#include - -/* - * Configuration information - */ -#define INPUT_POOL_WORDS 128 -#define OUTPUT_POOL_WORDS 32 -#define SEC_XFER_SIZE 512 - -/* - * The minimum number of bits of entropy before we wake up a read on - * /dev/random. Should be enough to do a significant reseed. - */ -static int random_read_wakeup_thresh = 64; - -/* - * If the entropy count falls under this number of bits, then we - * should wake up processes which are selecting or polling on write - * access to /dev/random. - */ -static int random_write_wakeup_thresh = 128; - -/* - * When the input pool goes over trickle_thresh, start dropping most - * samples to avoid wasting CPU time and reduce lock contention. - */ - -static int trickle_thresh __read_mostly = INPUT_POOL_WORDS * 28; - -static DEFINE_PER_CPU(int, trickle_count); - -/* - * A pool of size .poolwords is stirred with a primitive polynomial - * of degree .poolwords over GF(2). The taps for various sizes are - * defined below. They are chosen to be evenly spaced (minimum RMS - * distance from evenly spaced; the numbers in the comments are a - * scaled squared error sum) except for the last tap, which is 1 to - * get the twisting happening as fast as possible. - */ -static struct poolinfo { - int poolwords; - int tap1, tap2, tap3, tap4, tap5; -} poolinfo_table[] = { - /* x^128 + x^103 + x^76 + x^51 +x^25 + x + 1 -- 105 */ - { 128, 103, 76, 51, 25, 1 }, - /* x^32 + x^26 + x^20 + x^14 + x^7 + x + 1 -- 15 */ - { 32, 26, 20, 14, 7, 1 }, -#if 0 - /* x^2048 + x^1638 + x^1231 + x^819 + x^411 + x + 1 -- 115 */ - { 2048, 1638, 1231, 819, 411, 1 }, - - /* x^1024 + x^817 + x^615 + x^412 + x^204 + x + 1 -- 290 */ - { 1024, 817, 615, 412, 204, 1 }, - - /* x^1024 + x^819 + x^616 + x^410 + x^207 + x^2 + 1 -- 115 */ - { 1024, 819, 616, 410, 207, 2 }, - - /* x^512 + x^411 + x^308 + x^208 + x^104 + x + 1 -- 225 */ - { 512, 411, 308, 208, 104, 1 }, - - /* x^512 + x^409 + x^307 + x^206 + x^102 + x^2 + 1 -- 95 */ - { 512, 409, 307, 206, 102, 2 }, - /* x^512 + x^409 + x^309 + x^205 + x^103 + x^2 + 1 -- 95 */ - { 512, 409, 309, 205, 103, 2 }, - - /* x^256 + x^205 + x^155 + x^101 + x^52 + x + 1 -- 125 */ - { 256, 205, 155, 101, 52, 1 }, - - /* x^128 + x^103 + x^78 + x^51 + x^27 + x^2 + 1 -- 70 */ - { 128, 103, 78, 51, 27, 2 }, - - /* x^64 + x^52 + x^39 + x^26 + x^14 + x + 1 -- 15 */ - { 64, 52, 39, 26, 14, 1 }, -#endif -}; - -#define POOLBITS poolwords*32 -#define POOLBYTES poolwords*4 - -/* - * For the purposes of better mixing, we use the CRC-32 polynomial as - * well to make a twisted Generalized Feedback Shift Reigster - * - * (See M. Matsumoto & Y. Kurita, 1992. Twisted GFSR generators. ACM - * Transactions on Modeling and Computer Simulation 2(3):179-194. - * Also see M. Matsumoto & Y. Kurita, 1994. Twisted GFSR generators - * II. ACM Transactions on Mdeling and Computer Simulation 4:254-266) - * - * Thanks to Colin Plumb for suggesting this. - * - * We have not analyzed the resultant polynomial to prove it primitive; - * in fact it almost certainly isn't. Nonetheless, the irreducible factors - * of a random large-degree polynomial over GF(2) are more than large enough - * that periodicity is not a concern. - * - * The input hash is much less sensitive than the output hash. All - * that we want of it is that it be a good non-cryptographic hash; - * i.e. it not produce collisions when fed "random" data of the sort - * we expect to see. As long as the pool state differs for different - * inputs, we have preserved the input entropy and done a good job. - * The fact that an intelligent attacker can construct inputs that - * will produce controlled alterations to the pool's state is not - * important because we don't consider such inputs to contribute any - * randomness. The only property we need with respect to them is that - * the attacker can't increase his/her knowledge of the pool's state. - * Since all additions are reversible (knowing the final state and the - * input, you can reconstruct the initial state), if an attacker has - * any uncertainty about the initial state, he/she can only shuffle - * that uncertainty about, but never cause any collisions (which would - * decrease the uncertainty). - * - * The chosen system lets the state of the pool be (essentially) the input - * modulo the generator polymnomial. Now, for random primitive polynomials, - * this is a universal class of hash functions, meaning that the chance - * of a collision is limited by the attacker's knowledge of the generator - * polynomail, so if it is chosen at random, an attacker can never force - * a collision. Here, we use a fixed polynomial, but we *can* assume that - * ###--> it is unknown to the processes generating the input entropy. <-### - * Because of this important property, this is a good, collision-resistant - * hash; hash collisions will occur no more often than chance. - */ - -/* - * Static global variables - */ -static DECLARE_WAIT_QUEUE_HEAD(random_read_wait); -static DECLARE_WAIT_QUEUE_HEAD(random_write_wait); -static struct fasync_struct *fasync; - -#if 0 -static int debug; -module_param(debug, bool, 0644); -#define DEBUG_ENT(fmt, arg...) do { \ - if (debug) \ - printk(KERN_DEBUG "random %04d %04d %04d: " \ - fmt,\ - input_pool.entropy_count,\ - blocking_pool.entropy_count,\ - nonblocking_pool.entropy_count,\ - ## arg); } while (0) -#else -#define DEBUG_ENT(fmt, arg...) do {} while (0) -#endif - -/********************************************************************** - * - * OS independent entropy store. Here are the functions which handle - * storing entropy in an entropy pool. - * - **********************************************************************/ - -struct entropy_store; -struct entropy_store { - /* read-only data: */ - struct poolinfo *poolinfo; - __u32 *pool; - const char *name; - int limit; - struct entropy_store *pull; - - /* read-write data: */ - spinlock_t lock; - unsigned add_ptr; - int entropy_count; - int input_rotate; -}; - -static __u32 input_pool_data[INPUT_POOL_WORDS]; -static __u32 blocking_pool_data[OUTPUT_POOL_WORDS]; -static __u32 nonblocking_pool_data[OUTPUT_POOL_WORDS]; - -static struct entropy_store input_pool = { - .poolinfo = &poolinfo_table[0], - .name = "input", - .limit = 1, - .lock = __SPIN_LOCK_UNLOCKED(&input_pool.lock), - .pool = input_pool_data -}; - -static struct entropy_store blocking_pool = { - .poolinfo = &poolinfo_table[1], - .name = "blocking", - .limit = 1, - .pull = &input_pool, - .lock = __SPIN_LOCK_UNLOCKED(&blocking_pool.lock), - .pool = blocking_pool_data -}; - -static struct entropy_store nonblocking_pool = { - .poolinfo = &poolinfo_table[1], - .name = "nonblocking", - .pull = &input_pool, - .lock = __SPIN_LOCK_UNLOCKED(&nonblocking_pool.lock), - .pool = nonblocking_pool_data -}; - -/* - * This function adds bytes into the entropy "pool". It does not - * update the entropy estimate. The caller should call - * credit_entropy_bits if this is appropriate. - * - * The pool is stirred with a primitive polynomial of the appropriate - * degree, and then twisted. We twist by three bits at a time because - * it's cheap to do so and helps slightly in the expected case where - * the entropy is concentrated in the low-order bits. - */ -static void mix_pool_bytes_extract(struct entropy_store *r, const void *in, - int nbytes, __u8 out[64]) -{ - static __u32 const twist_table[8] = { - 0x00000000, 0x3b6e20c8, 0x76dc4190, 0x4db26158, - 0xedb88320, 0xd6d6a3e8, 0x9b64c2b0, 0xa00ae278 }; - unsigned long i, j, tap1, tap2, tap3, tap4, tap5; - int input_rotate; - int wordmask = r->poolinfo->poolwords - 1; - const char *bytes = in; - __u32 w; - unsigned long flags; - - /* Taps are constant, so we can load them without holding r->lock. */ - tap1 = r->poolinfo->tap1; - tap2 = r->poolinfo->tap2; - tap3 = r->poolinfo->tap3; - tap4 = r->poolinfo->tap4; - tap5 = r->poolinfo->tap5; - - spin_lock_irqsave(&r->lock, flags); - input_rotate = r->input_rotate; - i = r->add_ptr; - - /* mix one byte at a time to simplify size handling and churn faster */ - while (nbytes--) { - w = rol32(*bytes++, input_rotate & 31); - i = (i - 1) & wordmask; - - /* XOR in the various taps */ - w ^= r->pool[i]; - w ^= r->pool[(i + tap1) & wordmask]; - w ^= r->pool[(i + tap2) & wordmask]; - w ^= r->pool[(i + tap3) & wordmask]; - w ^= r->pool[(i + tap4) & wordmask]; - w ^= r->pool[(i + tap5) & wordmask]; - - /* Mix the result back in with a twist */ - r->pool[i] = (w >> 3) ^ twist_table[w & 7]; - - /* - * Normally, we add 7 bits of rotation to the pool. - * At the beginning of the pool, add an extra 7 bits - * rotation, so that successive passes spread the - * input bits across the pool evenly. - */ - input_rotate += i ? 7 : 14; - } - - r->input_rotate = input_rotate; - r->add_ptr = i; - - if (out) - for (j = 0; j < 16; j++) - ((__u32 *)out)[j] = r->pool[(i - j) & wordmask]; - - spin_unlock_irqrestore(&r->lock, flags); -} - -static void mix_pool_bytes(struct entropy_store *r, const void *in, int bytes) -{ - mix_pool_bytes_extract(r, in, bytes, NULL); -} - -/* - * Credit (or debit) the entropy store with n bits of entropy - */ -static void credit_entropy_bits(struct entropy_store *r, int nbits) -{ - unsigned long flags; - int entropy_count; - - if (!nbits) - return; - - spin_lock_irqsave(&r->lock, flags); - - DEBUG_ENT("added %d entropy credits to %s\n", nbits, r->name); - entropy_count = r->entropy_count; - entropy_count += nbits; - if (entropy_count < 0) { - DEBUG_ENT("negative entropy/overflow\n"); - entropy_count = 0; - } else if (entropy_count > r->poolinfo->POOLBITS) - entropy_count = r->poolinfo->POOLBITS; - r->entropy_count = entropy_count; - - /* should we wake readers? */ - if (r == &input_pool && entropy_count >= random_read_wakeup_thresh) { - wake_up_interruptible(&random_read_wait); - kill_fasync(&fasync, SIGIO, POLL_IN); - } - spin_unlock_irqrestore(&r->lock, flags); -} - -/********************************************************************* - * - * Entropy input management - * - *********************************************************************/ - -/* There is one of these per entropy source */ -struct timer_rand_state { - cycles_t last_time; - long last_delta, last_delta2; - unsigned dont_count_entropy:1; -}; - -#ifndef CONFIG_SPARSE_IRQ - -static struct timer_rand_state *irq_timer_state[NR_IRQS]; - -static struct timer_rand_state *get_timer_rand_state(unsigned int irq) -{ - return irq_timer_state[irq]; -} - -static void set_timer_rand_state(unsigned int irq, - struct timer_rand_state *state) -{ - irq_timer_state[irq] = state; -} - -#else - -static struct timer_rand_state *get_timer_rand_state(unsigned int irq) -{ - struct irq_desc *desc; - - desc = irq_to_desc(irq); - - return desc->timer_rand_state; -} - -static void set_timer_rand_state(unsigned int irq, - struct timer_rand_state *state) -{ - struct irq_desc *desc; - - desc = irq_to_desc(irq); - - desc->timer_rand_state = state; -} -#endif - -static struct timer_rand_state input_timer_state; - -/* - * This function adds entropy to the entropy "pool" by using timing - * delays. It uses the timer_rand_state structure to make an estimate - * of how many bits of entropy this call has added to the pool. - * - * The number "num" is also added to the pool - it should somehow describe - * the type of event which just happened. This is currently 0-255 for - * keyboard scan codes, and 256 upwards for interrupts. - * - */ -static void add_timer_randomness(struct timer_rand_state *state, unsigned num) -{ - struct { - cycles_t cycles; - long jiffies; - unsigned num; - } sample; - long delta, delta2, delta3; - - preempt_disable(); - /* if over the trickle threshold, use only 1 in 4096 samples */ - if (input_pool.entropy_count > trickle_thresh && - (__get_cpu_var(trickle_count)++ & 0xfff)) - goto out; - - sample.jiffies = jiffies; - sample.cycles = get_cycles(); - sample.num = num; - mix_pool_bytes(&input_pool, &sample, sizeof(sample)); - - /* - * Calculate number of bits of randomness we probably added. - * We take into account the first, second and third-order deltas - * in order to make our estimate. - */ - - if (!state->dont_count_entropy) { - delta = sample.jiffies - state->last_time; - state->last_time = sample.jiffies; - - delta2 = delta - state->last_delta; - state->last_delta = delta; - - delta3 = delta2 - state->last_delta2; - state->last_delta2 = delta2; - - if (delta < 0) - delta = -delta; - if (delta2 < 0) - delta2 = -delta2; - if (delta3 < 0) - delta3 = -delta3; - if (delta > delta2) - delta = delta2; - if (delta > delta3) - delta = delta3; - - /* - * delta is now minimum absolute delta. - * Round down by 1 bit on general principles, - * and limit entropy entimate to 12 bits. - */ - credit_entropy_bits(&input_pool, - min_t(int, fls(delta>>1), 11)); - } -out: - preempt_enable(); -} - -void add_input_randomness(unsigned int type, unsigned int code, - unsigned int value) -{ - static unsigned char last_value; - - /* ignore autorepeat and the like */ - if (value == last_value) - return; - - DEBUG_ENT("input event\n"); - last_value = value; - add_timer_randomness(&input_timer_state, - (type << 4) ^ code ^ (code >> 4) ^ value); -} -EXPORT_SYMBOL_GPL(add_input_randomness); - -void add_interrupt_randomness(int irq) -{ - struct timer_rand_state *state; - - state = get_timer_rand_state(irq); - - if (state == NULL) - return; - - DEBUG_ENT("irq event %d\n", irq); - add_timer_randomness(state, 0x100 + irq); -} - -#ifdef CONFIG_BLOCK -void add_disk_randomness(struct gendisk *disk) -{ - if (!disk || !disk->random) - return; - /* first major is 1, so we get >= 0x200 here */ - DEBUG_ENT("disk event %d:%d\n", - MAJOR(disk_devt(disk)), MINOR(disk_devt(disk))); - - add_timer_randomness(disk->random, 0x100 + disk_devt(disk)); -} -#endif - -#define EXTRACT_SIZE 10 - -/********************************************************************* - * - * Entropy extraction routines - * - *********************************************************************/ - -static ssize_t extract_entropy(struct entropy_store *r, void *buf, - size_t nbytes, int min, int rsvd); - -/* - * This utility inline function is responsible for transfering entropy - * from the primary pool to the secondary extraction pool. We make - * sure we pull enough for a 'catastrophic reseed'. - */ -static void xfer_secondary_pool(struct entropy_store *r, size_t nbytes) -{ - __u32 tmp[OUTPUT_POOL_WORDS]; - - if (r->pull && r->entropy_count < nbytes * 8 && - r->entropy_count < r->poolinfo->POOLBITS) { - /* If we're limited, always leave two wakeup worth's BITS */ - int rsvd = r->limit ? 0 : random_read_wakeup_thresh/4; - int bytes = nbytes; - - /* pull at least as many as BYTES as wakeup BITS */ - bytes = max_t(int, bytes, random_read_wakeup_thresh / 8); - /* but never more than the buffer size */ - bytes = min_t(int, bytes, sizeof(tmp)); - - DEBUG_ENT("going to reseed %s with %d bits " - "(%d of %d requested)\n", - r->name, bytes * 8, nbytes * 8, r->entropy_count); - - bytes = extract_entropy(r->pull, tmp, bytes, - random_read_wakeup_thresh / 8, rsvd); - mix_pool_bytes(r, tmp, bytes); - credit_entropy_bits(r, bytes*8); - } -} - -/* - * These functions extracts randomness from the "entropy pool", and - * returns it in a buffer. - * - * The min parameter specifies the minimum amount we can pull before - * failing to avoid races that defeat catastrophic reseeding while the - * reserved parameter indicates how much entropy we must leave in the - * pool after each pull to avoid starving other readers. - * - * Note: extract_entropy() assumes that .poolwords is a multiple of 16 words. - */ - -static size_t account(struct entropy_store *r, size_t nbytes, int min, - int reserved) -{ - unsigned long flags; - - /* Hold lock while accounting */ - spin_lock_irqsave(&r->lock, flags); - - BUG_ON(r->entropy_count > r->poolinfo->POOLBITS); - DEBUG_ENT("trying to extract %d bits from %s\n", - nbytes * 8, r->name); - - /* Can we pull enough? */ - if (r->entropy_count / 8 < min + reserved) { - nbytes = 0; - } else { - /* If limited, never pull more than available */ - if (r->limit && nbytes + reserved >= r->entropy_count / 8) - nbytes = r->entropy_count/8 - reserved; - - if (r->entropy_count / 8 >= nbytes + reserved) - r->entropy_count -= nbytes*8; - else - r->entropy_count = reserved; - - if (r->entropy_count < random_write_wakeup_thresh) { - wake_up_interruptible(&random_write_wait); - kill_fasync(&fasync, SIGIO, POLL_OUT); - } - } - - DEBUG_ENT("debiting %d entropy credits from %s%s\n", - nbytes * 8, r->name, r->limit ? "" : " (unlimited)"); - - spin_unlock_irqrestore(&r->lock, flags); - - return nbytes; -} - -static void extract_buf(struct entropy_store *r, __u8 *out) -{ - int i; - __u32 hash[5], workspace[SHA_WORKSPACE_WORDS]; - __u8 extract[64]; - - /* Generate a hash across the pool, 16 words (512 bits) at a time */ - sha_init(hash); - for (i = 0; i < r->poolinfo->poolwords; i += 16) - sha_transform(hash, (__u8 *)(r->pool + i), workspace); - - /* - * We mix the hash back into the pool to prevent backtracking - * attacks (where the attacker knows the state of the pool - * plus the current outputs, and attempts to find previous - * ouputs), unless the hash function can be inverted. By - * mixing at least a SHA1 worth of hash data back, we make - * brute-forcing the feedback as hard as brute-forcing the - * hash. - */ - mix_pool_bytes_extract(r, hash, sizeof(hash), extract); - - /* - * To avoid duplicates, we atomically extract a portion of the - * pool while mixing, and hash one final time. - */ - sha_transform(hash, extract, workspace); - memset(extract, 0, sizeof(extract)); - memset(workspace, 0, sizeof(workspace)); - - /* - * In case the hash function has some recognizable output - * pattern, we fold it in half. Thus, we always feed back - * twice as much data as we output. - */ - hash[0] ^= hash[3]; - hash[1] ^= hash[4]; - hash[2] ^= rol32(hash[2], 16); - memcpy(out, hash, EXTRACT_SIZE); - memset(hash, 0, sizeof(hash)); -} - -static ssize_t extract_entropy(struct entropy_store *r, void *buf, - size_t nbytes, int min, int reserved) -{ - ssize_t ret = 0, i; - __u8 tmp[EXTRACT_SIZE]; - - xfer_secondary_pool(r, nbytes); - nbytes = account(r, nbytes, min, reserved); - - while (nbytes) { - extract_buf(r, tmp); - i = min_t(int, nbytes, EXTRACT_SIZE); - memcpy(buf, tmp, i); - nbytes -= i; - buf += i; - ret += i; - } - - /* Wipe data just returned from memory */ - memset(tmp, 0, sizeof(tmp)); - - return ret; -} - -static ssize_t extract_entropy_user(struct entropy_store *r, void __user *buf, - size_t nbytes) -{ - ssize_t ret = 0, i; - __u8 tmp[EXTRACT_SIZE]; - - xfer_secondary_pool(r, nbytes); - nbytes = account(r, nbytes, 0, 0); - - while (nbytes) { - if (need_resched()) { - if (signal_pending(current)) { - if (ret == 0) - ret = -ERESTARTSYS; - break; - } - schedule(); - } - - extract_buf(r, tmp); - i = min_t(int, nbytes, EXTRACT_SIZE); - if (copy_to_user(buf, tmp, i)) { - ret = -EFAULT; - break; - } - - nbytes -= i; - buf += i; - ret += i; - } - - /* Wipe data just returned from memory */ - memset(tmp, 0, sizeof(tmp)); - - return ret; -} - -/* - * This function is the exported kernel interface. It returns some - * number of good random numbers, suitable for seeding TCP sequence - * numbers, etc. - */ -void get_random_bytes(void *buf, int nbytes) -{ - extract_entropy(&nonblocking_pool, buf, nbytes, 0, 0); -} -EXPORT_SYMBOL(get_random_bytes); - -/* - * init_std_data - initialize pool with system data - * - * @r: pool to initialize - * - * This function clears the pool's entropy count and mixes some system - * data into the pool to prepare it for use. The pool is not cleared - * as that can only decrease the entropy in the pool. - */ -static void init_std_data(struct entropy_store *r) -{ - ktime_t now; - unsigned long flags; - - spin_lock_irqsave(&r->lock, flags); - r->entropy_count = 0; - spin_unlock_irqrestore(&r->lock, flags); - - now = ktime_get_real(); - mix_pool_bytes(r, &now, sizeof(now)); - mix_pool_bytes(r, utsname(), sizeof(*(utsname()))); -} - -static int rand_initialize(void) -{ - init_std_data(&input_pool); - init_std_data(&blocking_pool); - init_std_data(&nonblocking_pool); - return 0; -} -module_init(rand_initialize); - -void rand_initialize_irq(int irq) -{ - struct timer_rand_state *state; - - state = get_timer_rand_state(irq); - - if (state) - return; - - /* - * If kzalloc returns null, we just won't use that entropy - * source. - */ - state = kzalloc(sizeof(struct timer_rand_state), GFP_KERNEL); - if (state) - set_timer_rand_state(irq, state); -} - -#ifdef CONFIG_BLOCK -void rand_initialize_disk(struct gendisk *disk) -{ - struct timer_rand_state *state; - - /* - * If kzalloc returns null, we just won't use that entropy - * source. - */ - state = kzalloc(sizeof(struct timer_rand_state), GFP_KERNEL); - if (state) - disk->random = state; -} -#endif - -static ssize_t -random_read(struct file *file, char __user *buf, size_t nbytes, loff_t *ppos) -{ - ssize_t n, retval = 0, count = 0; - - if (nbytes == 0) - return 0; - - while (nbytes > 0) { - n = nbytes; - if (n > SEC_XFER_SIZE) - n = SEC_XFER_SIZE; - - DEBUG_ENT("reading %d bits\n", n*8); - - n = extract_entropy_user(&blocking_pool, buf, n); - - DEBUG_ENT("read got %d bits (%d still needed)\n", - n*8, (nbytes-n)*8); - - if (n == 0) { - if (file->f_flags & O_NONBLOCK) { - retval = -EAGAIN; - break; - } - - DEBUG_ENT("sleeping?\n"); - - wait_event_interruptible(random_read_wait, - input_pool.entropy_count >= - random_read_wakeup_thresh); - - DEBUG_ENT("awake\n"); - - if (signal_pending(current)) { - retval = -ERESTARTSYS; - break; - } - - continue; - } - - if (n < 0) { - retval = n; - break; - } - count += n; - buf += n; - nbytes -= n; - break; /* This break makes the device work */ - /* like a named pipe */ - } - - /* - * If we gave the user some bytes, update the access time. - */ - if (count) - file_accessed(file); - - return (count ? count : retval); -} - -static ssize_t -urandom_read(struct file *file, char __user *buf, size_t nbytes, loff_t *ppos) -{ - return extract_entropy_user(&nonblocking_pool, buf, nbytes); -} - -static unsigned int -random_poll(struct file *file, poll_table * wait) -{ - unsigned int mask; - - poll_wait(file, &random_read_wait, wait); - poll_wait(file, &random_write_wait, wait); - mask = 0; - if (input_pool.entropy_count >= random_read_wakeup_thresh) - mask |= POLLIN | POLLRDNORM; - if (input_pool.entropy_count < random_write_wakeup_thresh) - mask |= POLLOUT | POLLWRNORM; - return mask; -} - -static int -write_pool(struct entropy_store *r, const char __user *buffer, size_t count) -{ - size_t bytes; - __u32 buf[16]; - const char __user *p = buffer; - - while (count > 0) { - bytes = min(count, sizeof(buf)); - if (copy_from_user(&buf, p, bytes)) - return -EFAULT; - - count -= bytes; - p += bytes; - - mix_pool_bytes(r, buf, bytes); - cond_resched(); - } - - return 0; -} - -static ssize_t random_write(struct file *file, const char __user *buffer, - size_t count, loff_t *ppos) -{ - size_t ret; - struct inode *inode = file->f_path.dentry->d_inode; - - ret = write_pool(&blocking_pool, buffer, count); - if (ret) - return ret; - ret = write_pool(&nonblocking_pool, buffer, count); - if (ret) - return ret; - - inode->i_mtime = current_fs_time(inode->i_sb); - mark_inode_dirty(inode); - return (ssize_t)count; -} - -static long random_ioctl(struct file *f, unsigned int cmd, unsigned long arg) -{ - int size, ent_count; - int __user *p = (int __user *)arg; - int retval; - - switch (cmd) { - case RNDGETENTCNT: - /* inherently racy, no point locking */ - if (put_user(input_pool.entropy_count, p)) - return -EFAULT; - return 0; - case RNDADDTOENTCNT: - if (!capable(CAP_SYS_ADMIN)) - return -EPERM; - if (get_user(ent_count, p)) - return -EFAULT; - credit_entropy_bits(&input_pool, ent_count); - return 0; - case RNDADDENTROPY: - if (!capable(CAP_SYS_ADMIN)) - return -EPERM; - if (get_user(ent_count, p++)) - return -EFAULT; - if (ent_count < 0) - return -EINVAL; - if (get_user(size, p++)) - return -EFAULT; - retval = write_pool(&input_pool, (const char __user *)p, - size); - if (retval < 0) - return retval; - credit_entropy_bits(&input_pool, ent_count); - return 0; - case RNDZAPENTCNT: - case RNDCLEARPOOL: - /* Clear the entropy pool counters. */ - if (!capable(CAP_SYS_ADMIN)) - return -EPERM; - rand_initialize(); - return 0; - default: - return -EINVAL; - } -} - -static int random_fasync(int fd, struct file *filp, int on) -{ - return fasync_helper(fd, filp, on, &fasync); -} - -const struct file_operations random_fops = { - .read = random_read, - .write = random_write, - .poll = random_poll, - .unlocked_ioctl = random_ioctl, - .fasync = random_fasync, -}; - -const struct file_operations urandom_fops = { - .read = urandom_read, - .write = random_write, - .unlocked_ioctl = random_ioctl, - .fasync = random_fasync, -}; - -/*************************************************************** - * Random UUID interface - * - * Used here for a Boot ID, but can be useful for other kernel - * drivers. - ***************************************************************/ - -/* - * Generate random UUID - */ -void generate_random_uuid(unsigned char uuid_out[16]) -{ - get_random_bytes(uuid_out, 16); - /* Set UUID version to 4 --- truely random generation */ - uuid_out[6] = (uuid_out[6] & 0x0F) | 0x40; - /* Set the UUID variant to DCE */ - uuid_out[8] = (uuid_out[8] & 0x3F) | 0x80; -} -EXPORT_SYMBOL(generate_random_uuid); - -/******************************************************************** - * - * Sysctl interface - * - ********************************************************************/ - -#ifdef CONFIG_SYSCTL - -#include - -static int min_read_thresh = 8, min_write_thresh; -static int max_read_thresh = INPUT_POOL_WORDS * 32; -static int max_write_thresh = INPUT_POOL_WORDS * 32; -static char sysctl_bootid[16]; - -/* - * These functions is used to return both the bootid UUID, and random - * UUID. The difference is in whether table->data is NULL; if it is, - * then a new UUID is generated and returned to the user. - * - * If the user accesses this via the proc interface, it will be returned - * as an ASCII string in the standard UUID format. If accesses via the - * sysctl system call, it is returned as 16 bytes of binary data. - */ -static int proc_do_uuid(ctl_table *table, int write, struct file *filp, - void __user *buffer, size_t *lenp, loff_t *ppos) -{ - ctl_table fake_table; - unsigned char buf[64], tmp_uuid[16], *uuid; - - uuid = table->data; - if (!uuid) { - uuid = tmp_uuid; - uuid[8] = 0; - } - if (uuid[8] == 0) - generate_random_uuid(uuid); - - sprintf(buf, "%02x%02x%02x%02x-%02x%02x-%02x%02x-%02x%02x-" - "%02x%02x%02x%02x%02x%02x", - uuid[0], uuid[1], uuid[2], uuid[3], - uuid[4], uuid[5], uuid[6], uuid[7], - uuid[8], uuid[9], uuid[10], uuid[11], - uuid[12], uuid[13], uuid[14], uuid[15]); - fake_table.data = buf; - fake_table.maxlen = sizeof(buf); - - return proc_dostring(&fake_table, write, filp, buffer, lenp, ppos); -} - -static int uuid_strategy(ctl_table *table, - void __user *oldval, size_t __user *oldlenp, - void __user *newval, size_t newlen) -{ - unsigned char tmp_uuid[16], *uuid; - unsigned int len; - - if (!oldval || !oldlenp) - return 1; - - uuid = table->data; - if (!uuid) { - uuid = tmp_uuid; - uuid[8] = 0; - } - if (uuid[8] == 0) - generate_random_uuid(uuid); - - if (get_user(len, oldlenp)) - return -EFAULT; - if (len) { - if (len > 16) - len = 16; - if (copy_to_user(oldval, uuid, len) || - put_user(len, oldlenp)) - return -EFAULT; - } - return 1; -} - -static int sysctl_poolsize = INPUT_POOL_WORDS * 32; -ctl_table random_table[] = { - { - .ctl_name = RANDOM_POOLSIZE, - .procname = "poolsize", - .data = &sysctl_poolsize, - .maxlen = sizeof(int), - .mode = 0444, - .proc_handler = &proc_dointvec, - }, - { - .ctl_name = RANDOM_ENTROPY_COUNT, - .procname = "entropy_avail", - .maxlen = sizeof(int), - .mode = 0444, - .proc_handler = &proc_dointvec, - .data = &input_pool.entropy_count, - }, - { - .ctl_name = RANDOM_READ_THRESH, - .procname = "read_wakeup_threshold", - .data = &random_read_wakeup_thresh, - .maxlen = sizeof(int), - .mode = 0644, - .proc_handler = &proc_dointvec_minmax, - .strategy = &sysctl_intvec, - .extra1 = &min_read_thresh, - .extra2 = &max_read_thresh, - }, - { - .ctl_name = RANDOM_WRITE_THRESH, - .procname = "write_wakeup_threshold", - .data = &random_write_wakeup_thresh, - .maxlen = sizeof(int), - .mode = 0644, - .proc_handler = &proc_dointvec_minmax, - .strategy = &sysctl_intvec, - .extra1 = &min_write_thresh, - .extra2 = &max_write_thresh, - }, - { - .ctl_name = RANDOM_BOOT_ID, - .procname = "boot_id", - .data = &sysctl_bootid, - .maxlen = 16, - .mode = 0444, - .proc_handler = &proc_do_uuid, - .strategy = &uuid_strategy, - }, - { - .ctl_name = RANDOM_UUID, - .procname = "uuid", - .maxlen = 16, - .mode = 0444, - .proc_handler = &proc_do_uuid, - .strategy = &uuid_strategy, - }, - { .ctl_name = 0 } -}; -#endif /* CONFIG_SYSCTL */ - -/******************************************************************** - * - * Random funtions for networking - * - ********************************************************************/ - -/* - * TCP initial sequence number picking. This uses the random number - * generator to pick an initial secret value. This value is hashed - * along with the TCP endpoint information to provide a unique - * starting point for each pair of TCP endpoints. This defeats - * attacks which rely on guessing the initial TCP sequence number. - * This algorithm was suggested by Steve Bellovin. - * - * Using a very strong hash was taking an appreciable amount of the total - * TCP connection establishment time, so this is a weaker hash, - * compensated for by changing the secret periodically. - */ - -/* F, G and H are basic MD4 functions: selection, majority, parity */ -#define F(x, y, z) ((z) ^ ((x) & ((y) ^ (z)))) -#define G(x, y, z) (((x) & (y)) + (((x) ^ (y)) & (z))) -#define H(x, y, z) ((x) ^ (y) ^ (z)) - -/* - * The generic round function. The application is so specific that - * we don't bother protecting all the arguments with parens, as is generally - * good macro practice, in favor of extra legibility. - * Rotation is separate from addition to prevent recomputation - */ -#define ROUND(f, a, b, c, d, x, s) \ - (a += f(b, c, d) + x, a = (a << s) | (a >> (32 - s))) -#define K1 0 -#define K2 013240474631UL -#define K3 015666365641UL - -#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE) - -static __u32 twothirdsMD4Transform(__u32 const buf[4], __u32 const in[12]) -{ - __u32 a = buf[0], b = buf[1], c = buf[2], d = buf[3]; - - /* Round 1 */ - ROUND(F, a, b, c, d, in[ 0] + K1, 3); - ROUND(F, d, a, b, c, in[ 1] + K1, 7); - ROUND(F, c, d, a, b, in[ 2] + K1, 11); - ROUND(F, b, c, d, a, in[ 3] + K1, 19); - ROUND(F, a, b, c, d, in[ 4] + K1, 3); - ROUND(F, d, a, b, c, in[ 5] + K1, 7); - ROUND(F, c, d, a, b, in[ 6] + K1, 11); - ROUND(F, b, c, d, a, in[ 7] + K1, 19); - ROUND(F, a, b, c, d, in[ 8] + K1, 3); - ROUND(F, d, a, b, c, in[ 9] + K1, 7); - ROUND(F, c, d, a, b, in[10] + K1, 11); - ROUND(F, b, c, d, a, in[11] + K1, 19); - - /* Round 2 */ - ROUND(G, a, b, c, d, in[ 1] + K2, 3); - ROUND(G, d, a, b, c, in[ 3] + K2, 5); - ROUND(G, c, d, a, b, in[ 5] + K2, 9); - ROUND(G, b, c, d, a, in[ 7] + K2, 13); - ROUND(G, a, b, c, d, in[ 9] + K2, 3); - ROUND(G, d, a, b, c, in[11] + K2, 5); - ROUND(G, c, d, a, b, in[ 0] + K2, 9); - ROUND(G, b, c, d, a, in[ 2] + K2, 13); - ROUND(G, a, b, c, d, in[ 4] + K2, 3); - ROUND(G, d, a, b, c, in[ 6] + K2, 5); - ROUND(G, c, d, a, b, in[ 8] + K2, 9); - ROUND(G, b, c, d, a, in[10] + K2, 13); - - /* Round 3 */ - ROUND(H, a, b, c, d, in[ 3] + K3, 3); - ROUND(H, d, a, b, c, in[ 7] + K3, 9); - ROUND(H, c, d, a, b, in[11] + K3, 11); - ROUND(H, b, c, d, a, in[ 2] + K3, 15); - ROUND(H, a, b, c, d, in[ 6] + K3, 3); - ROUND(H, d, a, b, c, in[10] + K3, 9); - ROUND(H, c, d, a, b, in[ 1] + K3, 11); - ROUND(H, b, c, d, a, in[ 5] + K3, 15); - ROUND(H, a, b, c, d, in[ 9] + K3, 3); - ROUND(H, d, a, b, c, in[ 0] + K3, 9); - ROUND(H, c, d, a, b, in[ 4] + K3, 11); - ROUND(H, b, c, d, a, in[ 8] + K3, 15); - - return buf[1] + b; /* "most hashed" word */ - /* Alternative: return sum of all words? */ -} -#endif - -#undef ROUND -#undef F -#undef G -#undef H -#undef K1 -#undef K2 -#undef K3 - -/* This should not be decreased so low that ISNs wrap too fast. */ -#define REKEY_INTERVAL (300 * HZ) -/* - * Bit layout of the tcp sequence numbers (before adding current time): - * bit 24-31: increased after every key exchange - * bit 0-23: hash(source,dest) - * - * The implementation is similar to the algorithm described - * in the Appendix of RFC 1185, except that - * - it uses a 1 MHz clock instead of a 250 kHz clock - * - it performs a rekey every 5 minutes, which is equivalent - * to a (source,dest) tulple dependent forward jump of the - * clock by 0..2^(HASH_BITS+1) - * - * Thus the average ISN wraparound time is 68 minutes instead of - * 4.55 hours. - * - * SMP cleanup and lock avoidance with poor man's RCU. - * Manfred Spraul - * - */ -#define COUNT_BITS 8 -#define COUNT_MASK ((1 << COUNT_BITS) - 1) -#define HASH_BITS 24 -#define HASH_MASK ((1 << HASH_BITS) - 1) - -static struct keydata { - __u32 count; /* already shifted to the final position */ - __u32 secret[12]; -} ____cacheline_aligned ip_keydata[2]; - -static unsigned int ip_cnt; - -static void rekey_seq_generator(struct work_struct *work); - -static DECLARE_DELAYED_WORK(rekey_work, rekey_seq_generator); - -/* - * Lock avoidance: - * The ISN generation runs lockless - it's just a hash over random data. - * State changes happen every 5 minutes when the random key is replaced. - * Synchronization is performed by having two copies of the hash function - * state and rekey_seq_generator always updates the inactive copy. - * The copy is then activated by updating ip_cnt. - * The implementation breaks down if someone blocks the thread - * that processes SYN requests for more than 5 minutes. Should never - * happen, and even if that happens only a not perfectly compliant - * ISN is generated, nothing fatal. - */ -static void rekey_seq_generator(struct work_struct *work) -{ - struct keydata *keyptr = &ip_keydata[1 ^ (ip_cnt & 1)]; - - get_random_bytes(keyptr->secret, sizeof(keyptr->secret)); - keyptr->count = (ip_cnt & COUNT_MASK) << HASH_BITS; - smp_wmb(); - ip_cnt++; - schedule_delayed_work(&rekey_work, REKEY_INTERVAL); -} - -static inline struct keydata *get_keyptr(void) -{ - struct keydata *keyptr = &ip_keydata[ip_cnt & 1]; - - smp_rmb(); - - return keyptr; -} - -static __init int seqgen_init(void) -{ - rekey_seq_generator(NULL); - return 0; -} -late_initcall(seqgen_init); - -#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE) -__u32 secure_tcpv6_sequence_number(__be32 *saddr, __be32 *daddr, - __be16 sport, __be16 dport) -{ - __u32 seq; - __u32 hash[12]; - struct keydata *keyptr = get_keyptr(); - - /* The procedure is the same as for IPv4, but addresses are longer. - * Thus we must use twothirdsMD4Transform. - */ - - memcpy(hash, saddr, 16); - hash[4] = ((__force u16)sport << 16) + (__force u16)dport; - memcpy(&hash[5], keyptr->secret, sizeof(__u32) * 7); - - seq = twothirdsMD4Transform((const __u32 *)daddr, hash) & HASH_MASK; - seq += keyptr->count; - - seq += ktime_to_ns(ktime_get_real()); - - return seq; -} -EXPORT_SYMBOL(secure_tcpv6_sequence_number); -#endif - -/* The code below is shamelessly stolen from secure_tcp_sequence_number(). - * All blames to Andrey V. Savochkin . - */ -__u32 secure_ip_id(__be32 daddr) -{ - struct keydata *keyptr; - __u32 hash[4]; - - keyptr = get_keyptr(); - - /* - * Pick a unique starting offset for each IP destination. - * The dest ip address is placed in the starting vector, - * which is then hashed with random data. - */ - hash[0] = (__force __u32)daddr; - hash[1] = keyptr->secret[9]; - hash[2] = keyptr->secret[10]; - hash[3] = keyptr->secret[11]; - - return half_md4_transform(hash, keyptr->secret); -} - -#ifdef CONFIG_INET - -__u32 secure_tcp_sequence_number(__be32 saddr, __be32 daddr, - __be16 sport, __be16 dport) -{ - __u32 seq; - __u32 hash[4]; - struct keydata *keyptr = get_keyptr(); - - /* - * Pick a unique starting offset for each TCP connection endpoints - * (saddr, daddr, sport, dport). - * Note that the words are placed into the starting vector, which is - * then mixed with a partial MD4 over random data. - */ - hash[0] = (__force u32)saddr; - hash[1] = (__force u32)daddr; - hash[2] = ((__force u16)sport << 16) + (__force u16)dport; - hash[3] = keyptr->secret[11]; - - seq = half_md4_transform(hash, keyptr->secret) & HASH_MASK; - seq += keyptr->count; - /* - * As close as possible to RFC 793, which - * suggests using a 250 kHz clock. - * Further reading shows this assumes 2 Mb/s networks. - * For 10 Mb/s Ethernet, a 1 MHz clock is appropriate. - * For 10 Gb/s Ethernet, a 1 GHz clock should be ok, but - * we also need to limit the resolution so that the u32 seq - * overlaps less than one time per MSL (2 minutes). - * Choosing a clock of 64 ns period is OK. (period of 274 s) - */ - seq += ktime_to_ns(ktime_get_real()) >> 6; - - return seq; -} - -/* Generate secure starting point for ephemeral IPV4 transport port search */ -u32 secure_ipv4_port_ephemeral(__be32 saddr, __be32 daddr, __be16 dport) -{ - struct keydata *keyptr = get_keyptr(); - u32 hash[4]; - - /* - * Pick a unique starting offset for each ephemeral port search - * (saddr, daddr, dport) and 48bits of random data. - */ - hash[0] = (__force u32)saddr; - hash[1] = (__force u32)daddr; - hash[2] = (__force u32)dport ^ keyptr->secret[10]; - hash[3] = keyptr->secret[11]; - - return half_md4_transform(hash, keyptr->secret); -} -EXPORT_SYMBOL_GPL(secure_ipv4_port_ephemeral); - -#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE) -u32 secure_ipv6_port_ephemeral(const __be32 *saddr, const __be32 *daddr, - __be16 dport) -{ - struct keydata *keyptr = get_keyptr(); - u32 hash[12]; - - memcpy(hash, saddr, 16); - hash[4] = (__force u32)dport; - memcpy(&hash[5], keyptr->secret, sizeof(__u32) * 7); - - return twothirdsMD4Transform((const __u32 *)daddr, hash); -} -#endif - -#if defined(CONFIG_IP_DCCP) || defined(CONFIG_IP_DCCP_MODULE) -/* Similar to secure_tcp_sequence_number but generate a 48 bit value - * bit's 32-47 increase every key exchange - * 0-31 hash(source, dest) - */ -u64 secure_dccp_sequence_number(__be32 saddr, __be32 daddr, - __be16 sport, __be16 dport) -{ - u64 seq; - __u32 hash[4]; - struct keydata *keyptr = get_keyptr(); - - hash[0] = (__force u32)saddr; - hash[1] = (__force u32)daddr; - hash[2] = ((__force u16)sport << 16) + (__force u16)dport; - hash[3] = keyptr->secret[11]; - - seq = half_md4_transform(hash, keyptr->secret); - seq |= ((u64)keyptr->count) << (32 - HASH_BITS); - - seq += ktime_to_ns(ktime_get_real()); - seq &= (1ull << 48) - 1; - - return seq; -} -EXPORT_SYMBOL(secure_dccp_sequence_number); -#endif - -#endif /* CONFIG_INET */ - - -/* - * Get a random word for internal kernel use only. Similar to urandom but - * with the goal of minimal entropy pool depletion. As a result, the random - * value is not cryptographically secure but for several uses the cost of - * depleting entropy is too high - */ -unsigned int get_random_int(void) -{ - /* - * Use IP's RNG. It suits our purpose perfectly: it re-keys itself - * every second, from the entropy pool (and thus creates a limited - * drain on it), and uses halfMD4Transform within the second. We - * also mix it with jiffies and the PID: - */ - return secure_ip_id((__force __be32)(current->pid + jiffies)); -} - -/* - * randomize_range() returns a start address such that - * - * [...... .....] - * start end - * - * a with size "len" starting at the return value is inside in the - * area defined by [start, end], but is otherwise randomized. - */ -unsigned long -randomize_range(unsigned long start, unsigned long end, unsigned long len) -{ - unsigned long range = end - len - start; - - if (end <= start + len) - return 0; - return PAGE_ALIGN(get_random_int() % range + start); -} diff --git a/libdde_linux26/lib/src/Makefile b/libdde_linux26/lib/src/Makefile index 36af1365..ed53fdeb 100644 --- a/libdde_linux26/lib/src/Makefile +++ b/libdde_linux26/lib/src/Makefile @@ -144,7 +144,8 @@ SRC_C_libdde_linux26.o.a += \ drivers/pci/probe.c \ drivers/pci/search.c \ drivers/pci/setup-bus.c \ - drivers/pci/setup-res.c + drivers/pci/setup-res.c \ + drivers/char/random.c ################################################################## # Sources for libdde_linux_net.a # diff --git a/libdde_linux26/lib/src/drivers/char/random.c b/libdde_linux26/lib/src/drivers/char/random.c new file mode 100644 index 00000000..0430c9d0 --- /dev/null +++ b/libdde_linux26/lib/src/drivers/char/random.c @@ -0,0 +1,1709 @@ +/* + * random.c -- A strong random number generator + * + * Copyright Matt Mackall , 2003, 2004, 2005 + * + * Copyright Theodore Ts'o, 1994, 1995, 1996, 1997, 1998, 1999. All + * rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, and the entire permission notice in its entirety, + * including the disclaimer of warranties. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * 3. The name of the author may not be used to endorse or promote + * products derived from this software without specific prior + * written permission. + * + * ALTERNATIVELY, this product may be distributed under the terms of + * the GNU General Public License, in which case the provisions of the GPL are + * required INSTEAD OF the above restrictions. (This clause is + * necessary due to a potential bad interaction between the GPL and + * the restrictions contained in a BSD-style copyright.) + * + * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED + * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES + * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, ALL OF + * WHICH ARE HEREBY DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE + * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR + * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT + * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR + * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF + * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE + * USE OF THIS SOFTWARE, EVEN IF NOT ADVISED OF THE POSSIBILITY OF SUCH + * DAMAGE. + */ + +/* + * (now, with legal B.S. out of the way.....) + * + * This routine gathers environmental noise from device drivers, etc., + * and returns good random numbers, suitable for cryptographic use. + * Besides the obvious cryptographic uses, these numbers are also good + * for seeding TCP sequence numbers, and other places where it is + * desirable to have numbers which are not only random, but hard to + * predict by an attacker. + * + * Theory of operation + * =================== + * + * Computers are very predictable devices. Hence it is extremely hard + * to produce truly random numbers on a computer --- as opposed to + * pseudo-random numbers, which can easily generated by using a + * algorithm. Unfortunately, it is very easy for attackers to guess + * the sequence of pseudo-random number generators, and for some + * applications this is not acceptable. So instead, we must try to + * gather "environmental noise" from the computer's environment, which + * must be hard for outside attackers to observe, and use that to + * generate random numbers. In a Unix environment, this is best done + * from inside the kernel. + * + * Sources of randomness from the environment include inter-keyboard + * timings, inter-interrupt timings from some interrupts, and other + * events which are both (a) non-deterministic and (b) hard for an + * outside observer to measure. Randomness from these sources are + * added to an "entropy pool", which is mixed using a CRC-like function. + * This is not cryptographically strong, but it is adequate assuming + * the randomness is not chosen maliciously, and it is fast enough that + * the overhead of doing it on every interrupt is very reasonable. + * As random bytes are mixed into the entropy pool, the routines keep + * an *estimate* of how many bits of randomness have been stored into + * the random number generator's internal state. + * + * When random bytes are desired, they are obtained by taking the SHA + * hash of the contents of the "entropy pool". The SHA hash avoids + * exposing the internal state of the entropy pool. It is believed to + * be computationally infeasible to derive any useful information + * about the input of SHA from its output. Even if it is possible to + * analyze SHA in some clever way, as long as the amount of data + * returned from the generator is less than the inherent entropy in + * the pool, the output data is totally unpredictable. For this + * reason, the routine decreases its internal estimate of how many + * bits of "true randomness" are contained in the entropy pool as it + * outputs random numbers. + * + * If this estimate goes to zero, the routine can still generate + * random numbers; however, an attacker may (at least in theory) be + * able to infer the future output of the generator from prior + * outputs. This requires successful cryptanalysis of SHA, which is + * not believed to be feasible, but there is a remote possibility. + * Nonetheless, these numbers should be useful for the vast majority + * of purposes. + * + * Exported interfaces ---- output + * =============================== + * + * There are three exported interfaces; the first is one designed to + * be used from within the kernel: + * + * void get_random_bytes(void *buf, int nbytes); + * + * This interface will return the requested number of random bytes, + * and place it in the requested buffer. + * + * The two other interfaces are two character devices /dev/random and + * /dev/urandom. /dev/random is suitable for use when very high + * quality randomness is desired (for example, for key generation or + * one-time pads), as it will only return a maximum of the number of + * bits of randomness (as estimated by the random number generator) + * contained in the entropy pool. + * + * The /dev/urandom device does not have this limit, and will return + * as many bytes as are requested. As more and more random bytes are + * requested without giving time for the entropy pool to recharge, + * this will result in random numbers that are merely cryptographically + * strong. For many applications, however, this is acceptable. + * + * Exported interfaces ---- input + * ============================== + * + * The current exported interfaces for gathering environmental noise + * from the devices are: + * + * void add_input_randomness(unsigned int type, unsigned int code, + * unsigned int value); + * void add_interrupt_randomness(int irq); + * + * add_input_randomness() uses the input layer interrupt timing, as well as + * the event type information from the hardware. + * + * add_interrupt_randomness() uses the inter-interrupt timing as random + * inputs to the entropy pool. Note that not all interrupts are good + * sources of randomness! For example, the timer interrupts is not a + * good choice, because the periodicity of the interrupts is too + * regular, and hence predictable to an attacker. Disk interrupts are + * a better measure, since the timing of the disk interrupts are more + * unpredictable. + * + * All of these routines try to estimate how many bits of randomness a + * particular randomness source. They do this by keeping track of the + * first and second order deltas of the event timings. + * + * Ensuring unpredictability at system startup + * ============================================ + * + * When any operating system starts up, it will go through a sequence + * of actions that are fairly predictable by an adversary, especially + * if the start-up does not involve interaction with a human operator. + * This reduces the actual number of bits of unpredictability in the + * entropy pool below the value in entropy_count. In order to + * counteract this effect, it helps to carry information in the + * entropy pool across shut-downs and start-ups. To do this, put the + * following lines an appropriate script which is run during the boot + * sequence: + * + * echo "Initializing random number generator..." + * random_seed=/var/run/random-seed + * # Carry a random seed from start-up to start-up + * # Load and then save the whole entropy pool + * if [ -f $random_seed ]; then + * cat $random_seed >/dev/urandom + * else + * touch $random_seed + * fi + * chmod 600 $random_seed + * dd if=/dev/urandom of=$random_seed count=1 bs=512 + * + * and the following lines in an appropriate script which is run as + * the system is shutdown: + * + * # Carry a random seed from shut-down to start-up + * # Save the whole entropy pool + * echo "Saving random seed..." + * random_seed=/var/run/random-seed + * touch $random_seed + * chmod 600 $random_seed + * dd if=/dev/urandom of=$random_seed count=1 bs=512 + * + * For example, on most modern systems using the System V init + * scripts, such code fragments would be found in + * /etc/rc.d/init.d/random. On older Linux systems, the correct script + * location might be in /etc/rcb.d/rc.local or /etc/rc.d/rc.0. + * + * Effectively, these commands cause the contents of the entropy pool + * to be saved at shut-down time and reloaded into the entropy pool at + * start-up. (The 'dd' in the addition to the bootup script is to + * make sure that /etc/random-seed is different for every start-up, + * even if the system crashes without executing rc.0.) Even with + * complete knowledge of the start-up activities, predicting the state + * of the entropy pool requires knowledge of the previous history of + * the system. + * + * Configuring the /dev/random driver under Linux + * ============================================== + * + * The /dev/random driver under Linux uses minor numbers 8 and 9 of + * the /dev/mem major number (#1). So if your system does not have + * /dev/random and /dev/urandom created already, they can be created + * by using the commands: + * + * mknod /dev/random c 1 8 + * mknod /dev/urandom c 1 9 + * + * Acknowledgements: + * ================= + * + * Ideas for constructing this random number generator were derived + * from Pretty Good Privacy's random number generator, and from private + * discussions with Phil Karn. Colin Plumb provided a faster random + * number generator, which speed up the mixing function of the entropy + * pool, taken from PGPfone. Dale Worley has also contributed many + * useful ideas and suggestions to improve this driver. + * + * Any flaws in the design are solely my responsibility, and should + * not be attributed to the Phil, Colin, or any of authors of PGP. + * + * Further background information on this topic may be obtained from + * RFC 1750, "Randomness Recommendations for Security", by Donald + * Eastlake, Steve Crocker, and Jeff Schiller. + */ + +#ifdef DDE_LINUX +#include +#else + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include +#include +#include +#include + +/* + * Configuration information + */ +#define INPUT_POOL_WORDS 128 +#define OUTPUT_POOL_WORDS 32 +#define SEC_XFER_SIZE 512 + +/* + * The minimum number of bits of entropy before we wake up a read on + * /dev/random. Should be enough to do a significant reseed. + */ +static int random_read_wakeup_thresh = 64; + +/* + * If the entropy count falls under this number of bits, then we + * should wake up processes which are selecting or polling on write + * access to /dev/random. + */ +static int random_write_wakeup_thresh = 128; + +/* + * When the input pool goes over trickle_thresh, start dropping most + * samples to avoid wasting CPU time and reduce lock contention. + */ + +static int trickle_thresh __read_mostly = INPUT_POOL_WORDS * 28; + +static DEFINE_PER_CPU(int, trickle_count); + +/* + * A pool of size .poolwords is stirred with a primitive polynomial + * of degree .poolwords over GF(2). The taps for various sizes are + * defined below. They are chosen to be evenly spaced (minimum RMS + * distance from evenly spaced; the numbers in the comments are a + * scaled squared error sum) except for the last tap, which is 1 to + * get the twisting happening as fast as possible. + */ +static struct poolinfo { + int poolwords; + int tap1, tap2, tap3, tap4, tap5; +} poolinfo_table[] = { + /* x^128 + x^103 + x^76 + x^51 +x^25 + x + 1 -- 105 */ + { 128, 103, 76, 51, 25, 1 }, + /* x^32 + x^26 + x^20 + x^14 + x^7 + x + 1 -- 15 */ + { 32, 26, 20, 14, 7, 1 }, +#if 0 + /* x^2048 + x^1638 + x^1231 + x^819 + x^411 + x + 1 -- 115 */ + { 2048, 1638, 1231, 819, 411, 1 }, + + /* x^1024 + x^817 + x^615 + x^412 + x^204 + x + 1 -- 290 */ + { 1024, 817, 615, 412, 204, 1 }, + + /* x^1024 + x^819 + x^616 + x^410 + x^207 + x^2 + 1 -- 115 */ + { 1024, 819, 616, 410, 207, 2 }, + + /* x^512 + x^411 + x^308 + x^208 + x^104 + x + 1 -- 225 */ + { 512, 411, 308, 208, 104, 1 }, + + /* x^512 + x^409 + x^307 + x^206 + x^102 + x^2 + 1 -- 95 */ + { 512, 409, 307, 206, 102, 2 }, + /* x^512 + x^409 + x^309 + x^205 + x^103 + x^2 + 1 -- 95 */ + { 512, 409, 309, 205, 103, 2 }, + + /* x^256 + x^205 + x^155 + x^101 + x^52 + x + 1 -- 125 */ + { 256, 205, 155, 101, 52, 1 }, + + /* x^128 + x^103 + x^78 + x^51 + x^27 + x^2 + 1 -- 70 */ + { 128, 103, 78, 51, 27, 2 }, + + /* x^64 + x^52 + x^39 + x^26 + x^14 + x + 1 -- 15 */ + { 64, 52, 39, 26, 14, 1 }, +#endif +}; + +#define POOLBITS poolwords*32 +#define POOLBYTES poolwords*4 + +/* + * For the purposes of better mixing, we use the CRC-32 polynomial as + * well to make a twisted Generalized Feedback Shift Reigster + * + * (See M. Matsumoto & Y. Kurita, 1992. Twisted GFSR generators. ACM + * Transactions on Modeling and Computer Simulation 2(3):179-194. + * Also see M. Matsumoto & Y. Kurita, 1994. Twisted GFSR generators + * II. ACM Transactions on Mdeling and Computer Simulation 4:254-266) + * + * Thanks to Colin Plumb for suggesting this. + * + * We have not analyzed the resultant polynomial to prove it primitive; + * in fact it almost certainly isn't. Nonetheless, the irreducible factors + * of a random large-degree polynomial over GF(2) are more than large enough + * that periodicity is not a concern. + * + * The input hash is much less sensitive than the output hash. All + * that we want of it is that it be a good non-cryptographic hash; + * i.e. it not produce collisions when fed "random" data of the sort + * we expect to see. As long as the pool state differs for different + * inputs, we have preserved the input entropy and done a good job. + * The fact that an intelligent attacker can construct inputs that + * will produce controlled alterations to the pool's state is not + * important because we don't consider such inputs to contribute any + * randomness. The only property we need with respect to them is that + * the attacker can't increase his/her knowledge of the pool's state. + * Since all additions are reversible (knowing the final state and the + * input, you can reconstruct the initial state), if an attacker has + * any uncertainty about the initial state, he/she can only shuffle + * that uncertainty about, but never cause any collisions (which would + * decrease the uncertainty). + * + * The chosen system lets the state of the pool be (essentially) the input + * modulo the generator polymnomial. Now, for random primitive polynomials, + * this is a universal class of hash functions, meaning that the chance + * of a collision is limited by the attacker's knowledge of the generator + * polynomail, so if it is chosen at random, an attacker can never force + * a collision. Here, we use a fixed polynomial, but we *can* assume that + * ###--> it is unknown to the processes generating the input entropy. <-### + * Because of this important property, this is a good, collision-resistant + * hash; hash collisions will occur no more often than chance. + */ + +/* + * Static global variables + */ +static DECLARE_WAIT_QUEUE_HEAD(random_read_wait); +static DECLARE_WAIT_QUEUE_HEAD(random_write_wait); +static struct fasync_struct *fasync; + +#if 0 +static int debug; +module_param(debug, bool, 0644); +#define DEBUG_ENT(fmt, arg...) do { \ + if (debug) \ + printk(KERN_DEBUG "random %04d %04d %04d: " \ + fmt,\ + input_pool.entropy_count,\ + blocking_pool.entropy_count,\ + nonblocking_pool.entropy_count,\ + ## arg); } while (0) +#else +#define DEBUG_ENT(fmt, arg...) do {} while (0) +#endif + +/********************************************************************** + * + * OS independent entropy store. Here are the functions which handle + * storing entropy in an entropy pool. + * + **********************************************************************/ + +struct entropy_store; +struct entropy_store { + /* read-only data: */ + struct poolinfo *poolinfo; + __u32 *pool; + const char *name; + int limit; + struct entropy_store *pull; + + /* read-write data: */ + spinlock_t lock; + unsigned add_ptr; + int entropy_count; + int input_rotate; +}; + +static __u32 input_pool_data[INPUT_POOL_WORDS]; +static __u32 blocking_pool_data[OUTPUT_POOL_WORDS]; +static __u32 nonblocking_pool_data[OUTPUT_POOL_WORDS]; + +static struct entropy_store input_pool = { + .poolinfo = &poolinfo_table[0], + .name = "input", + .limit = 1, + .lock = __SPIN_LOCK_UNLOCKED(&input_pool.lock), + .pool = input_pool_data +}; + +static struct entropy_store blocking_pool = { + .poolinfo = &poolinfo_table[1], + .name = "blocking", + .limit = 1, + .pull = &input_pool, + .lock = __SPIN_LOCK_UNLOCKED(&blocking_pool.lock), + .pool = blocking_pool_data +}; + +static struct entropy_store nonblocking_pool = { + .poolinfo = &poolinfo_table[1], + .name = "nonblocking", + .pull = &input_pool, + .lock = __SPIN_LOCK_UNLOCKED(&nonblocking_pool.lock), + .pool = nonblocking_pool_data +}; + +/* + * This function adds bytes into the entropy "pool". It does not + * update the entropy estimate. The caller should call + * credit_entropy_bits if this is appropriate. + * + * The pool is stirred with a primitive polynomial of the appropriate + * degree, and then twisted. We twist by three bits at a time because + * it's cheap to do so and helps slightly in the expected case where + * the entropy is concentrated in the low-order bits. + */ +static void mix_pool_bytes_extract(struct entropy_store *r, const void *in, + int nbytes, __u8 out[64]) +{ + static __u32 const twist_table[8] = { + 0x00000000, 0x3b6e20c8, 0x76dc4190, 0x4db26158, + 0xedb88320, 0xd6d6a3e8, 0x9b64c2b0, 0xa00ae278 }; + unsigned long i, j, tap1, tap2, tap3, tap4, tap5; + int input_rotate; + int wordmask = r->poolinfo->poolwords - 1; + const char *bytes = in; + __u32 w; + unsigned long flags; + + /* Taps are constant, so we can load them without holding r->lock. */ + tap1 = r->poolinfo->tap1; + tap2 = r->poolinfo->tap2; + tap3 = r->poolinfo->tap3; + tap4 = r->poolinfo->tap4; + tap5 = r->poolinfo->tap5; + + spin_lock_irqsave(&r->lock, flags); + input_rotate = r->input_rotate; + i = r->add_ptr; + + /* mix one byte at a time to simplify size handling and churn faster */ + while (nbytes--) { + w = rol32(*bytes++, input_rotate & 31); + i = (i - 1) & wordmask; + + /* XOR in the various taps */ + w ^= r->pool[i]; + w ^= r->pool[(i + tap1) & wordmask]; + w ^= r->pool[(i + tap2) & wordmask]; + w ^= r->pool[(i + tap3) & wordmask]; + w ^= r->pool[(i + tap4) & wordmask]; + w ^= r->pool[(i + tap5) & wordmask]; + + /* Mix the result back in with a twist */ + r->pool[i] = (w >> 3) ^ twist_table[w & 7]; + + /* + * Normally, we add 7 bits of rotation to the pool. + * At the beginning of the pool, add an extra 7 bits + * rotation, so that successive passes spread the + * input bits across the pool evenly. + */ + input_rotate += i ? 7 : 14; + } + + r->input_rotate = input_rotate; + r->add_ptr = i; + + if (out) + for (j = 0; j < 16; j++) + ((__u32 *)out)[j] = r->pool[(i - j) & wordmask]; + + spin_unlock_irqrestore(&r->lock, flags); +} + +static void mix_pool_bytes(struct entropy_store *r, const void *in, int bytes) +{ + mix_pool_bytes_extract(r, in, bytes, NULL); +} + +/* + * Credit (or debit) the entropy store with n bits of entropy + */ +static void credit_entropy_bits(struct entropy_store *r, int nbits) +{ + unsigned long flags; + int entropy_count; + + if (!nbits) + return; + + spin_lock_irqsave(&r->lock, flags); + + DEBUG_ENT("added %d entropy credits to %s\n", nbits, r->name); + entropy_count = r->entropy_count; + entropy_count += nbits; + if (entropy_count < 0) { + DEBUG_ENT("negative entropy/overflow\n"); + entropy_count = 0; + } else if (entropy_count > r->poolinfo->POOLBITS) + entropy_count = r->poolinfo->POOLBITS; + r->entropy_count = entropy_count; + + /* should we wake readers? */ + if (r == &input_pool && entropy_count >= random_read_wakeup_thresh) { + wake_up_interruptible(&random_read_wait); + kill_fasync(&fasync, SIGIO, POLL_IN); + } + spin_unlock_irqrestore(&r->lock, flags); +} + +/********************************************************************* + * + * Entropy input management + * + *********************************************************************/ + +/* There is one of these per entropy source */ +struct timer_rand_state { + cycles_t last_time; + long last_delta, last_delta2; + unsigned dont_count_entropy:1; +}; + +#ifndef CONFIG_SPARSE_IRQ + +static struct timer_rand_state *irq_timer_state[NR_IRQS]; + +static struct timer_rand_state *get_timer_rand_state(unsigned int irq) +{ + return irq_timer_state[irq]; +} + +static void set_timer_rand_state(unsigned int irq, + struct timer_rand_state *state) +{ + irq_timer_state[irq] = state; +} + +#else + +static struct timer_rand_state *get_timer_rand_state(unsigned int irq) +{ + struct irq_desc *desc; + + desc = irq_to_desc(irq); + + return desc->timer_rand_state; +} + +static void set_timer_rand_state(unsigned int irq, + struct timer_rand_state *state) +{ + struct irq_desc *desc; + + desc = irq_to_desc(irq); + + desc->timer_rand_state = state; +} +#endif + +static struct timer_rand_state input_timer_state; + +/* + * This function adds entropy to the entropy "pool" by using timing + * delays. It uses the timer_rand_state structure to make an estimate + * of how many bits of entropy this call has added to the pool. + * + * The number "num" is also added to the pool - it should somehow describe + * the type of event which just happened. This is currently 0-255 for + * keyboard scan codes, and 256 upwards for interrupts. + * + */ +static void add_timer_randomness(struct timer_rand_state *state, unsigned num) +{ + struct { + cycles_t cycles; + long jiffies; + unsigned num; + } sample; + long delta, delta2, delta3; + + preempt_disable(); + /* if over the trickle threshold, use only 1 in 4096 samples */ + if (input_pool.entropy_count > trickle_thresh && + (__get_cpu_var(trickle_count)++ & 0xfff)) + goto out; + + sample.jiffies = jiffies; + sample.cycles = get_cycles(); + sample.num = num; + mix_pool_bytes(&input_pool, &sample, sizeof(sample)); + + /* + * Calculate number of bits of randomness we probably added. + * We take into account the first, second and third-order deltas + * in order to make our estimate. + */ + + if (!state->dont_count_entropy) { + delta = sample.jiffies - state->last_time; + state->last_time = sample.jiffies; + + delta2 = delta - state->last_delta; + state->last_delta = delta; + + delta3 = delta2 - state->last_delta2; + state->last_delta2 = delta2; + + if (delta < 0) + delta = -delta; + if (delta2 < 0) + delta2 = -delta2; + if (delta3 < 0) + delta3 = -delta3; + if (delta > delta2) + delta = delta2; + if (delta > delta3) + delta = delta3; + + /* + * delta is now minimum absolute delta. + * Round down by 1 bit on general principles, + * and limit entropy entimate to 12 bits. + */ + credit_entropy_bits(&input_pool, + min_t(int, fls(delta>>1), 11)); + } +out: + preempt_enable(); +} + +void add_input_randomness(unsigned int type, unsigned int code, + unsigned int value) +{ + static unsigned char last_value; + + /* ignore autorepeat and the like */ + if (value == last_value) + return; + + DEBUG_ENT("input event\n"); + last_value = value; + add_timer_randomness(&input_timer_state, + (type << 4) ^ code ^ (code >> 4) ^ value); +} +EXPORT_SYMBOL_GPL(add_input_randomness); + +void add_interrupt_randomness(int irq) +{ + struct timer_rand_state *state; + + state = get_timer_rand_state(irq); + + if (state == NULL) + return; + + DEBUG_ENT("irq event %d\n", irq); + add_timer_randomness(state, 0x100 + irq); +} + +#ifdef CONFIG_BLOCK +void add_disk_randomness(struct gendisk *disk) +{ + if (!disk || !disk->random) + return; + /* first major is 1, so we get >= 0x200 here */ + DEBUG_ENT("disk event %d:%d\n", + MAJOR(disk_devt(disk)), MINOR(disk_devt(disk))); + + add_timer_randomness(disk->random, 0x100 + disk_devt(disk)); +} +#endif + +#define EXTRACT_SIZE 10 + +/********************************************************************* + * + * Entropy extraction routines + * + *********************************************************************/ + +static ssize_t extract_entropy(struct entropy_store *r, void *buf, + size_t nbytes, int min, int rsvd); + +/* + * This utility inline function is responsible for transfering entropy + * from the primary pool to the secondary extraction pool. We make + * sure we pull enough for a 'catastrophic reseed'. + */ +static void xfer_secondary_pool(struct entropy_store *r, size_t nbytes) +{ + __u32 tmp[OUTPUT_POOL_WORDS]; + + if (r->pull && r->entropy_count < nbytes * 8 && + r->entropy_count < r->poolinfo->POOLBITS) { + /* If we're limited, always leave two wakeup worth's BITS */ + int rsvd = r->limit ? 0 : random_read_wakeup_thresh/4; + int bytes = nbytes; + + /* pull at least as many as BYTES as wakeup BITS */ + bytes = max_t(int, bytes, random_read_wakeup_thresh / 8); + /* but never more than the buffer size */ + bytes = min_t(int, bytes, sizeof(tmp)); + + DEBUG_ENT("going to reseed %s with %d bits " + "(%d of %d requested)\n", + r->name, bytes * 8, nbytes * 8, r->entropy_count); + + bytes = extract_entropy(r->pull, tmp, bytes, + random_read_wakeup_thresh / 8, rsvd); + mix_pool_bytes(r, tmp, bytes); + credit_entropy_bits(r, bytes*8); + } +} + +/* + * These functions extracts randomness from the "entropy pool", and + * returns it in a buffer. + * + * The min parameter specifies the minimum amount we can pull before + * failing to avoid races that defeat catastrophic reseeding while the + * reserved parameter indicates how much entropy we must leave in the + * pool after each pull to avoid starving other readers. + * + * Note: extract_entropy() assumes that .poolwords is a multiple of 16 words. + */ + +static size_t account(struct entropy_store *r, size_t nbytes, int min, + int reserved) +{ + unsigned long flags; + + /* Hold lock while accounting */ + spin_lock_irqsave(&r->lock, flags); + + BUG_ON(r->entropy_count > r->poolinfo->POOLBITS); + DEBUG_ENT("trying to extract %d bits from %s\n", + nbytes * 8, r->name); + + /* Can we pull enough? */ + if (r->entropy_count / 8 < min + reserved) { + nbytes = 0; + } else { + /* If limited, never pull more than available */ + if (r->limit && nbytes + reserved >= r->entropy_count / 8) + nbytes = r->entropy_count/8 - reserved; + + if (r->entropy_count / 8 >= nbytes + reserved) + r->entropy_count -= nbytes*8; + else + r->entropy_count = reserved; + + if (r->entropy_count < random_write_wakeup_thresh) { + wake_up_interruptible(&random_write_wait); + kill_fasync(&fasync, SIGIO, POLL_OUT); + } + } + + DEBUG_ENT("debiting %d entropy credits from %s%s\n", + nbytes * 8, r->name, r->limit ? "" : " (unlimited)"); + + spin_unlock_irqrestore(&r->lock, flags); + + return nbytes; +} + +static void extract_buf(struct entropy_store *r, __u8 *out) +{ + int i; + __u32 hash[5], workspace[SHA_WORKSPACE_WORDS]; + __u8 extract[64]; + + /* Generate a hash across the pool, 16 words (512 bits) at a time */ + sha_init(hash); + for (i = 0; i < r->poolinfo->poolwords; i += 16) + sha_transform(hash, (__u8 *)(r->pool + i), workspace); + + /* + * We mix the hash back into the pool to prevent backtracking + * attacks (where the attacker knows the state of the pool + * plus the current outputs, and attempts to find previous + * ouputs), unless the hash function can be inverted. By + * mixing at least a SHA1 worth of hash data back, we make + * brute-forcing the feedback as hard as brute-forcing the + * hash. + */ + mix_pool_bytes_extract(r, hash, sizeof(hash), extract); + + /* + * To avoid duplicates, we atomically extract a portion of the + * pool while mixing, and hash one final time. + */ + sha_transform(hash, extract, workspace); + memset(extract, 0, sizeof(extract)); + memset(workspace, 0, sizeof(workspace)); + + /* + * In case the hash function has some recognizable output + * pattern, we fold it in half. Thus, we always feed back + * twice as much data as we output. + */ + hash[0] ^= hash[3]; + hash[1] ^= hash[4]; + hash[2] ^= rol32(hash[2], 16); + memcpy(out, hash, EXTRACT_SIZE); + memset(hash, 0, sizeof(hash)); +} + +static ssize_t extract_entropy(struct entropy_store *r, void *buf, + size_t nbytes, int min, int reserved) +{ + ssize_t ret = 0, i; + __u8 tmp[EXTRACT_SIZE]; + + xfer_secondary_pool(r, nbytes); + nbytes = account(r, nbytes, min, reserved); + + while (nbytes) { + extract_buf(r, tmp); + i = min_t(int, nbytes, EXTRACT_SIZE); + memcpy(buf, tmp, i); + nbytes -= i; + buf += i; + ret += i; + } + + /* Wipe data just returned from memory */ + memset(tmp, 0, sizeof(tmp)); + + return ret; +} + +static ssize_t extract_entropy_user(struct entropy_store *r, void __user *buf, + size_t nbytes) +{ + ssize_t ret = 0, i; + __u8 tmp[EXTRACT_SIZE]; + + xfer_secondary_pool(r, nbytes); + nbytes = account(r, nbytes, 0, 0); + + while (nbytes) { + if (need_resched()) { + if (signal_pending(current)) { + if (ret == 0) + ret = -ERESTARTSYS; + break; + } + schedule(); + } + + extract_buf(r, tmp); + i = min_t(int, nbytes, EXTRACT_SIZE); + if (copy_to_user(buf, tmp, i)) { + ret = -EFAULT; + break; + } + + nbytes -= i; + buf += i; + ret += i; + } + + /* Wipe data just returned from memory */ + memset(tmp, 0, sizeof(tmp)); + + return ret; +} + +#endif + +/* + * This function is the exported kernel interface. It returns some + * number of good random numbers, suitable for seeding TCP sequence + * numbers, etc. + */ +void get_random_bytes(void *buf, int nbytes) +{ +#ifndef DDE_LINUX + extract_entropy(&nonblocking_pool, buf, nbytes, 0, 0); +#else + int i; + int nlwords = nbytes / sizeof (long); + for (i = 0; i < nlwords; i++) + ((long *) buf)[i] = ddekit_random (); + for (i = nlwords * sizeof (long); i < nbytes; i++) + ((char *) buf)[i] = (char) ddekit_random (); +#endif +} +EXPORT_SYMBOL(get_random_bytes); + +#ifndef DDE_LINUX +/* + * init_std_data - initialize pool with system data + * + * @r: pool to initialize + * + * This function clears the pool's entropy count and mixes some system + * data into the pool to prepare it for use. The pool is not cleared + * as that can only decrease the entropy in the pool. + */ +static void init_std_data(struct entropy_store *r) +{ + ktime_t now; + unsigned long flags; + + spin_lock_irqsave(&r->lock, flags); + r->entropy_count = 0; + spin_unlock_irqrestore(&r->lock, flags); + + now = ktime_get_real(); + mix_pool_bytes(r, &now, sizeof(now)); + mix_pool_bytes(r, utsname(), sizeof(*(utsname()))); +} + +static int rand_initialize(void) +{ + init_std_data(&input_pool); + init_std_data(&blocking_pool); + init_std_data(&nonblocking_pool); + return 0; +} +module_init(rand_initialize); + +void rand_initialize_irq(int irq) +{ + struct timer_rand_state *state; + + state = get_timer_rand_state(irq); + + if (state) + return; + + /* + * If kzalloc returns null, we just won't use that entropy + * source. + */ + state = kzalloc(sizeof(struct timer_rand_state), GFP_KERNEL); + if (state) + set_timer_rand_state(irq, state); +} + +#ifdef CONFIG_BLOCK +void rand_initialize_disk(struct gendisk *disk) +{ + struct timer_rand_state *state; + + /* + * If kzalloc returns null, we just won't use that entropy + * source. + */ + state = kzalloc(sizeof(struct timer_rand_state), GFP_KERNEL); + if (state) + disk->random = state; +} +#endif + +static ssize_t +random_read(struct file *file, char __user *buf, size_t nbytes, loff_t *ppos) +{ + ssize_t n, retval = 0, count = 0; + + if (nbytes == 0) + return 0; + + while (nbytes > 0) { + n = nbytes; + if (n > SEC_XFER_SIZE) + n = SEC_XFER_SIZE; + + DEBUG_ENT("reading %d bits\n", n*8); + + n = extract_entropy_user(&blocking_pool, buf, n); + + DEBUG_ENT("read got %d bits (%d still needed)\n", + n*8, (nbytes-n)*8); + + if (n == 0) { + if (file->f_flags & O_NONBLOCK) { + retval = -EAGAIN; + break; + } + + DEBUG_ENT("sleeping?\n"); + + wait_event_interruptible(random_read_wait, + input_pool.entropy_count >= + random_read_wakeup_thresh); + + DEBUG_ENT("awake\n"); + + if (signal_pending(current)) { + retval = -ERESTARTSYS; + break; + } + + continue; + } + + if (n < 0) { + retval = n; + break; + } + count += n; + buf += n; + nbytes -= n; + break; /* This break makes the device work */ + /* like a named pipe */ + } + + /* + * If we gave the user some bytes, update the access time. + */ + if (count) + file_accessed(file); + + return (count ? count : retval); +} + +static ssize_t +urandom_read(struct file *file, char __user *buf, size_t nbytes, loff_t *ppos) +{ + return extract_entropy_user(&nonblocking_pool, buf, nbytes); +} + +static unsigned int +random_poll(struct file *file, poll_table * wait) +{ + unsigned int mask; + + poll_wait(file, &random_read_wait, wait); + poll_wait(file, &random_write_wait, wait); + mask = 0; + if (input_pool.entropy_count >= random_read_wakeup_thresh) + mask |= POLLIN | POLLRDNORM; + if (input_pool.entropy_count < random_write_wakeup_thresh) + mask |= POLLOUT | POLLWRNORM; + return mask; +} + +static int +write_pool(struct entropy_store *r, const char __user *buffer, size_t count) +{ + size_t bytes; + __u32 buf[16]; + const char __user *p = buffer; + + while (count > 0) { + bytes = min(count, sizeof(buf)); + if (copy_from_user(&buf, p, bytes)) + return -EFAULT; + + count -= bytes; + p += bytes; + + mix_pool_bytes(r, buf, bytes); + cond_resched(); + } + + return 0; +} + +static ssize_t random_write(struct file *file, const char __user *buffer, + size_t count, loff_t *ppos) +{ + size_t ret; + struct inode *inode = file->f_path.dentry->d_inode; + + ret = write_pool(&blocking_pool, buffer, count); + if (ret) + return ret; + ret = write_pool(&nonblocking_pool, buffer, count); + if (ret) + return ret; + + inode->i_mtime = current_fs_time(inode->i_sb); + mark_inode_dirty(inode); + return (ssize_t)count; +} + +static long random_ioctl(struct file *f, unsigned int cmd, unsigned long arg) +{ + int size, ent_count; + int __user *p = (int __user *)arg; + int retval; + + switch (cmd) { + case RNDGETENTCNT: + /* inherently racy, no point locking */ + if (put_user(input_pool.entropy_count, p)) + return -EFAULT; + return 0; + case RNDADDTOENTCNT: + if (!capable(CAP_SYS_ADMIN)) + return -EPERM; + if (get_user(ent_count, p)) + return -EFAULT; + credit_entropy_bits(&input_pool, ent_count); + return 0; + case RNDADDENTROPY: + if (!capable(CAP_SYS_ADMIN)) + return -EPERM; + if (get_user(ent_count, p++)) + return -EFAULT; + if (ent_count < 0) + return -EINVAL; + if (get_user(size, p++)) + return -EFAULT; + retval = write_pool(&input_pool, (const char __user *)p, + size); + if (retval < 0) + return retval; + credit_entropy_bits(&input_pool, ent_count); + return 0; + case RNDZAPENTCNT: + case RNDCLEARPOOL: + /* Clear the entropy pool counters. */ + if (!capable(CAP_SYS_ADMIN)) + return -EPERM; + rand_initialize(); + return 0; + default: + return -EINVAL; + } +} + +static int random_fasync(int fd, struct file *filp, int on) +{ + return fasync_helper(fd, filp, on, &fasync); +} + +const struct file_operations random_fops = { + .read = random_read, + .write = random_write, + .poll = random_poll, + .unlocked_ioctl = random_ioctl, + .fasync = random_fasync, +}; + +const struct file_operations urandom_fops = { + .read = urandom_read, + .write = random_write, + .unlocked_ioctl = random_ioctl, + .fasync = random_fasync, +}; + +/*************************************************************** + * Random UUID interface + * + * Used here for a Boot ID, but can be useful for other kernel + * drivers. + ***************************************************************/ + +/* + * Generate random UUID + */ +void generate_random_uuid(unsigned char uuid_out[16]) +{ + get_random_bytes(uuid_out, 16); + /* Set UUID version to 4 --- truely random generation */ + uuid_out[6] = (uuid_out[6] & 0x0F) | 0x40; + /* Set the UUID variant to DCE */ + uuid_out[8] = (uuid_out[8] & 0x3F) | 0x80; +} +EXPORT_SYMBOL(generate_random_uuid); + +/******************************************************************** + * + * Sysctl interface + * + ********************************************************************/ + +#ifdef CONFIG_SYSCTL + +#include + +static int min_read_thresh = 8, min_write_thresh; +static int max_read_thresh = INPUT_POOL_WORDS * 32; +static int max_write_thresh = INPUT_POOL_WORDS * 32; +static char sysctl_bootid[16]; + +/* + * These functions is used to return both the bootid UUID, and random + * UUID. The difference is in whether table->data is NULL; if it is, + * then a new UUID is generated and returned to the user. + * + * If the user accesses this via the proc interface, it will be returned + * as an ASCII string in the standard UUID format. If accesses via the + * sysctl system call, it is returned as 16 bytes of binary data. + */ +static int proc_do_uuid(ctl_table *table, int write, struct file *filp, + void __user *buffer, size_t *lenp, loff_t *ppos) +{ + ctl_table fake_table; + unsigned char buf[64], tmp_uuid[16], *uuid; + + uuid = table->data; + if (!uuid) { + uuid = tmp_uuid; + uuid[8] = 0; + } + if (uuid[8] == 0) + generate_random_uuid(uuid); + + sprintf(buf, "%02x%02x%02x%02x-%02x%02x-%02x%02x-%02x%02x-" + "%02x%02x%02x%02x%02x%02x", + uuid[0], uuid[1], uuid[2], uuid[3], + uuid[4], uuid[5], uuid[6], uuid[7], + uuid[8], uuid[9], uuid[10], uuid[11], + uuid[12], uuid[13], uuid[14], uuid[15]); + fake_table.data = buf; + fake_table.maxlen = sizeof(buf); + + return proc_dostring(&fake_table, write, filp, buffer, lenp, ppos); +} + +static int uuid_strategy(ctl_table *table, + void __user *oldval, size_t __user *oldlenp, + void __user *newval, size_t newlen) +{ + unsigned char tmp_uuid[16], *uuid; + unsigned int len; + + if (!oldval || !oldlenp) + return 1; + + uuid = table->data; + if (!uuid) { + uuid = tmp_uuid; + uuid[8] = 0; + } + if (uuid[8] == 0) + generate_random_uuid(uuid); + + if (get_user(len, oldlenp)) + return -EFAULT; + if (len) { + if (len > 16) + len = 16; + if (copy_to_user(oldval, uuid, len) || + put_user(len, oldlenp)) + return -EFAULT; + } + return 1; +} + +static int sysctl_poolsize = INPUT_POOL_WORDS * 32; +ctl_table random_table[] = { + { + .ctl_name = RANDOM_POOLSIZE, + .procname = "poolsize", + .data = &sysctl_poolsize, + .maxlen = sizeof(int), + .mode = 0444, + .proc_handler = &proc_dointvec, + }, + { + .ctl_name = RANDOM_ENTROPY_COUNT, + .procname = "entropy_avail", + .maxlen = sizeof(int), + .mode = 0444, + .proc_handler = &proc_dointvec, + .data = &input_pool.entropy_count, + }, + { + .ctl_name = RANDOM_READ_THRESH, + .procname = "read_wakeup_threshold", + .data = &random_read_wakeup_thresh, + .maxlen = sizeof(int), + .mode = 0644, + .proc_handler = &proc_dointvec_minmax, + .strategy = &sysctl_intvec, + .extra1 = &min_read_thresh, + .extra2 = &max_read_thresh, + }, + { + .ctl_name = RANDOM_WRITE_THRESH, + .procname = "write_wakeup_threshold", + .data = &random_write_wakeup_thresh, + .maxlen = sizeof(int), + .mode = 0644, + .proc_handler = &proc_dointvec_minmax, + .strategy = &sysctl_intvec, + .extra1 = &min_write_thresh, + .extra2 = &max_write_thresh, + }, + { + .ctl_name = RANDOM_BOOT_ID, + .procname = "boot_id", + .data = &sysctl_bootid, + .maxlen = 16, + .mode = 0444, + .proc_handler = &proc_do_uuid, + .strategy = &uuid_strategy, + }, + { + .ctl_name = RANDOM_UUID, + .procname = "uuid", + .maxlen = 16, + .mode = 0444, + .proc_handler = &proc_do_uuid, + .strategy = &uuid_strategy, + }, + { .ctl_name = 0 } +}; +#endif /* CONFIG_SYSCTL */ + +/******************************************************************** + * + * Random funtions for networking + * + ********************************************************************/ + +/* + * TCP initial sequence number picking. This uses the random number + * generator to pick an initial secret value. This value is hashed + * along with the TCP endpoint information to provide a unique + * starting point for each pair of TCP endpoints. This defeats + * attacks which rely on guessing the initial TCP sequence number. + * This algorithm was suggested by Steve Bellovin. + * + * Using a very strong hash was taking an appreciable amount of the total + * TCP connection establishment time, so this is a weaker hash, + * compensated for by changing the secret periodically. + */ + +/* F, G and H are basic MD4 functions: selection, majority, parity */ +#define F(x, y, z) ((z) ^ ((x) & ((y) ^ (z)))) +#define G(x, y, z) (((x) & (y)) + (((x) ^ (y)) & (z))) +#define H(x, y, z) ((x) ^ (y) ^ (z)) + +/* + * The generic round function. The application is so specific that + * we don't bother protecting all the arguments with parens, as is generally + * good macro practice, in favor of extra legibility. + * Rotation is separate from addition to prevent recomputation + */ +#define ROUND(f, a, b, c, d, x, s) \ + (a += f(b, c, d) + x, a = (a << s) | (a >> (32 - s))) +#define K1 0 +#define K2 013240474631UL +#define K3 015666365641UL + +#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE) + +static __u32 twothirdsMD4Transform(__u32 const buf[4], __u32 const in[12]) +{ + __u32 a = buf[0], b = buf[1], c = buf[2], d = buf[3]; + + /* Round 1 */ + ROUND(F, a, b, c, d, in[ 0] + K1, 3); + ROUND(F, d, a, b, c, in[ 1] + K1, 7); + ROUND(F, c, d, a, b, in[ 2] + K1, 11); + ROUND(F, b, c, d, a, in[ 3] + K1, 19); + ROUND(F, a, b, c, d, in[ 4] + K1, 3); + ROUND(F, d, a, b, c, in[ 5] + K1, 7); + ROUND(F, c, d, a, b, in[ 6] + K1, 11); + ROUND(F, b, c, d, a, in[ 7] + K1, 19); + ROUND(F, a, b, c, d, in[ 8] + K1, 3); + ROUND(F, d, a, b, c, in[ 9] + K1, 7); + ROUND(F, c, d, a, b, in[10] + K1, 11); + ROUND(F, b, c, d, a, in[11] + K1, 19); + + /* Round 2 */ + ROUND(G, a, b, c, d, in[ 1] + K2, 3); + ROUND(G, d, a, b, c, in[ 3] + K2, 5); + ROUND(G, c, d, a, b, in[ 5] + K2, 9); + ROUND(G, b, c, d, a, in[ 7] + K2, 13); + ROUND(G, a, b, c, d, in[ 9] + K2, 3); + ROUND(G, d, a, b, c, in[11] + K2, 5); + ROUND(G, c, d, a, b, in[ 0] + K2, 9); + ROUND(G, b, c, d, a, in[ 2] + K2, 13); + ROUND(G, a, b, c, d, in[ 4] + K2, 3); + ROUND(G, d, a, b, c, in[ 6] + K2, 5); + ROUND(G, c, d, a, b, in[ 8] + K2, 9); + ROUND(G, b, c, d, a, in[10] + K2, 13); + + /* Round 3 */ + ROUND(H, a, b, c, d, in[ 3] + K3, 3); + ROUND(H, d, a, b, c, in[ 7] + K3, 9); + ROUND(H, c, d, a, b, in[11] + K3, 11); + ROUND(H, b, c, d, a, in[ 2] + K3, 15); + ROUND(H, a, b, c, d, in[ 6] + K3, 3); + ROUND(H, d, a, b, c, in[10] + K3, 9); + ROUND(H, c, d, a, b, in[ 1] + K3, 11); + ROUND(H, b, c, d, a, in[ 5] + K3, 15); + ROUND(H, a, b, c, d, in[ 9] + K3, 3); + ROUND(H, d, a, b, c, in[ 0] + K3, 9); + ROUND(H, c, d, a, b, in[ 4] + K3, 11); + ROUND(H, b, c, d, a, in[ 8] + K3, 15); + + return buf[1] + b; /* "most hashed" word */ + /* Alternative: return sum of all words? */ +} +#endif + +#undef ROUND +#undef F +#undef G +#undef H +#undef K1 +#undef K2 +#undef K3 + +/* This should not be decreased so low that ISNs wrap too fast. */ +#define REKEY_INTERVAL (300 * HZ) +/* + * Bit layout of the tcp sequence numbers (before adding current time): + * bit 24-31: increased after every key exchange + * bit 0-23: hash(source,dest) + * + * The implementation is similar to the algorithm described + * in the Appendix of RFC 1185, except that + * - it uses a 1 MHz clock instead of a 250 kHz clock + * - it performs a rekey every 5 minutes, which is equivalent + * to a (source,dest) tulple dependent forward jump of the + * clock by 0..2^(HASH_BITS+1) + * + * Thus the average ISN wraparound time is 68 minutes instead of + * 4.55 hours. + * + * SMP cleanup and lock avoidance with poor man's RCU. + * Manfred Spraul + * + */ +#define COUNT_BITS 8 +#define COUNT_MASK ((1 << COUNT_BITS) - 1) +#define HASH_BITS 24 +#define HASH_MASK ((1 << HASH_BITS) - 1) + +static struct keydata { + __u32 count; /* already shifted to the final position */ + __u32 secret[12]; +} ____cacheline_aligned ip_keydata[2]; + +static unsigned int ip_cnt; + +static void rekey_seq_generator(struct work_struct *work); + +static DECLARE_DELAYED_WORK(rekey_work, rekey_seq_generator); + +/* + * Lock avoidance: + * The ISN generation runs lockless - it's just a hash over random data. + * State changes happen every 5 minutes when the random key is replaced. + * Synchronization is performed by having two copies of the hash function + * state and rekey_seq_generator always updates the inactive copy. + * The copy is then activated by updating ip_cnt. + * The implementation breaks down if someone blocks the thread + * that processes SYN requests for more than 5 minutes. Should never + * happen, and even if that happens only a not perfectly compliant + * ISN is generated, nothing fatal. + */ +static void rekey_seq_generator(struct work_struct *work) +{ + struct keydata *keyptr = &ip_keydata[1 ^ (ip_cnt & 1)]; + + get_random_bytes(keyptr->secret, sizeof(keyptr->secret)); + keyptr->count = (ip_cnt & COUNT_MASK) << HASH_BITS; + smp_wmb(); + ip_cnt++; + schedule_delayed_work(&rekey_work, REKEY_INTERVAL); +} + +static inline struct keydata *get_keyptr(void) +{ + struct keydata *keyptr = &ip_keydata[ip_cnt & 1]; + + smp_rmb(); + + return keyptr; +} + +static __init int seqgen_init(void) +{ + rekey_seq_generator(NULL); + return 0; +} +late_initcall(seqgen_init); + +#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE) +__u32 secure_tcpv6_sequence_number(__be32 *saddr, __be32 *daddr, + __be16 sport, __be16 dport) +{ + __u32 seq; + __u32 hash[12]; + struct keydata *keyptr = get_keyptr(); + + /* The procedure is the same as for IPv4, but addresses are longer. + * Thus we must use twothirdsMD4Transform. + */ + + memcpy(hash, saddr, 16); + hash[4] = ((__force u16)sport << 16) + (__force u16)dport; + memcpy(&hash[5], keyptr->secret, sizeof(__u32) * 7); + + seq = twothirdsMD4Transform((const __u32 *)daddr, hash) & HASH_MASK; + seq += keyptr->count; + + seq += ktime_to_ns(ktime_get_real()); + + return seq; +} +EXPORT_SYMBOL(secure_tcpv6_sequence_number); +#endif + +/* The code below is shamelessly stolen from secure_tcp_sequence_number(). + * All blames to Andrey V. Savochkin . + */ +__u32 secure_ip_id(__be32 daddr) +{ + struct keydata *keyptr; + __u32 hash[4]; + + keyptr = get_keyptr(); + + /* + * Pick a unique starting offset for each IP destination. + * The dest ip address is placed in the starting vector, + * which is then hashed with random data. + */ + hash[0] = (__force __u32)daddr; + hash[1] = keyptr->secret[9]; + hash[2] = keyptr->secret[10]; + hash[3] = keyptr->secret[11]; + + return half_md4_transform(hash, keyptr->secret); +} + +#ifdef CONFIG_INET + +__u32 secure_tcp_sequence_number(__be32 saddr, __be32 daddr, + __be16 sport, __be16 dport) +{ + __u32 seq; + __u32 hash[4]; + struct keydata *keyptr = get_keyptr(); + + /* + * Pick a unique starting offset for each TCP connection endpoints + * (saddr, daddr, sport, dport). + * Note that the words are placed into the starting vector, which is + * then mixed with a partial MD4 over random data. + */ + hash[0] = (__force u32)saddr; + hash[1] = (__force u32)daddr; + hash[2] = ((__force u16)sport << 16) + (__force u16)dport; + hash[3] = keyptr->secret[11]; + + seq = half_md4_transform(hash, keyptr->secret) & HASH_MASK; + seq += keyptr->count; + /* + * As close as possible to RFC 793, which + * suggests using a 250 kHz clock. + * Further reading shows this assumes 2 Mb/s networks. + * For 10 Mb/s Ethernet, a 1 MHz clock is appropriate. + * For 10 Gb/s Ethernet, a 1 GHz clock should be ok, but + * we also need to limit the resolution so that the u32 seq + * overlaps less than one time per MSL (2 minutes). + * Choosing a clock of 64 ns period is OK. (period of 274 s) + */ + seq += ktime_to_ns(ktime_get_real()) >> 6; + + return seq; +} + +/* Generate secure starting point for ephemeral IPV4 transport port search */ +u32 secure_ipv4_port_ephemeral(__be32 saddr, __be32 daddr, __be16 dport) +{ + struct keydata *keyptr = get_keyptr(); + u32 hash[4]; + + /* + * Pick a unique starting offset for each ephemeral port search + * (saddr, daddr, dport) and 48bits of random data. + */ + hash[0] = (__force u32)saddr; + hash[1] = (__force u32)daddr; + hash[2] = (__force u32)dport ^ keyptr->secret[10]; + hash[3] = keyptr->secret[11]; + + return half_md4_transform(hash, keyptr->secret); +} +EXPORT_SYMBOL_GPL(secure_ipv4_port_ephemeral); + +#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE) +u32 secure_ipv6_port_ephemeral(const __be32 *saddr, const __be32 *daddr, + __be16 dport) +{ + struct keydata *keyptr = get_keyptr(); + u32 hash[12]; + + memcpy(hash, saddr, 16); + hash[4] = (__force u32)dport; + memcpy(&hash[5], keyptr->secret, sizeof(__u32) * 7); + + return twothirdsMD4Transform((const __u32 *)daddr, hash); +} +#endif + +#if defined(CONFIG_IP_DCCP) || defined(CONFIG_IP_DCCP_MODULE) +/* Similar to secure_tcp_sequence_number but generate a 48 bit value + * bit's 32-47 increase every key exchange + * 0-31 hash(source, dest) + */ +u64 secure_dccp_sequence_number(__be32 saddr, __be32 daddr, + __be16 sport, __be16 dport) +{ + u64 seq; + __u32 hash[4]; + struct keydata *keyptr = get_keyptr(); + + hash[0] = (__force u32)saddr; + hash[1] = (__force u32)daddr; + hash[2] = ((__force u16)sport << 16) + (__force u16)dport; + hash[3] = keyptr->secret[11]; + + seq = half_md4_transform(hash, keyptr->secret); + seq |= ((u64)keyptr->count) << (32 - HASH_BITS); + + seq += ktime_to_ns(ktime_get_real()); + seq &= (1ull << 48) - 1; + + return seq; +} +EXPORT_SYMBOL(secure_dccp_sequence_number); +#endif + +#endif /* CONFIG_INET */ + + +/* + * Get a random word for internal kernel use only. Similar to urandom but + * with the goal of minimal entropy pool depletion. As a result, the random + * value is not cryptographically secure but for several uses the cost of + * depleting entropy is too high + */ +unsigned int get_random_int(void) +{ + /* + * Use IP's RNG. It suits our purpose perfectly: it re-keys itself + * every second, from the entropy pool (and thus creates a limited + * drain on it), and uses halfMD4Transform within the second. We + * also mix it with jiffies and the PID: + */ + return secure_ip_id((__force __be32)(current->pid + jiffies)); +} + +/* + * randomize_range() returns a start address such that + * + * [...... .....] + * start end + * + * a with size "len" starting at the return value is inside in the + * area defined by [start, end], but is otherwise randomized. + */ +unsigned long +randomize_range(unsigned long start, unsigned long end, unsigned long len) +{ + unsigned long range = end - len - start; + + if (end <= start + len) + return 0; + return PAGE_ALIGN(get_random_int() % range + start); +} + +#endif diff --git a/libddekit/include/ddekit/resources.h b/libddekit/include/ddekit/resources.h index dfbb1322..657295a0 100644 --- a/libddekit/include/ddekit/resources.h +++ b/libddekit/include/ddekit/resources.h @@ -9,5 +9,6 @@ int ddekit_request_io (ddekit_addr_t start, ddekit_addr_t count); int ddekit_release_io (ddekit_addr_t start, ddekit_addr_t count); int ddekit_request_mem(ddekit_addr_t start, ddekit_addr_t count, ddekit_addr_t *vaddr); int ddekit_release_mem(ddekit_addr_t start, ddekit_addr_t count); +long ddekit_random (void); #endif diff --git a/libddekit/resources.c b/libddekit/resources.c index 212dcae7..45704378 100644 --- a/libddekit/resources.c +++ b/libddekit/resources.c @@ -1,3 +1,4 @@ +#include #include #include #include @@ -117,3 +118,8 @@ int ddekit_release_mem(ddekit_addr_t start, ddekit_addr_t count) { } return 0; } + +long ddekit_random () +{ + return random (); +} -- cgit v1.2.3