diff options
Diffstat (limited to 'libdde_linux26/contrib')
| -rw-r--r-- | libdde_linux26/contrib/drivers/char/random.c | 1691 |
1 files changed, 0 insertions, 1691 deletions
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 <mpm@selenic.com>, 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 <linux/utsname.h> -#include <linux/module.h> -#include <linux/kernel.h> -#include <linux/major.h> -#include <linux/string.h> -#include <linux/fcntl.h> -#include <linux/slab.h> -#include <linux/random.h> -#include <linux/poll.h> -#include <linux/init.h> -#include <linux/fs.h> -#include <linux/genhd.h> -#include <linux/interrupt.h> -#include <linux/mm.h> -#include <linux/spinlock.h> -#include <linux/percpu.h> -#include <linux/cryptohash.h> - -#include <asm/processor.h> -#include <asm/uaccess.h> -#include <asm/irq.h> -#include <asm/io.h> - -/* - * 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 <linux/sysctl.h> - -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 <manfred@colorfullife.com> - * - */ -#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 <saw@msu.ru>. - */ -__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 - * - * [...... <range> .....] - * start end - * - * a <range> 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); -} |