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authorSamuel Thibault <samuel.thibault@ens-lyon.org>2013-07-27 22:07:53 +0000
committerSamuel Thibault <samuel.thibault@ens-lyon.org>2013-07-27 22:07:53 +0000
commit4fbe7358c7747a9165f776eb19addbb9baf7def2 (patch)
treebc7076b4f6d10c2cc2942539bb666e50f0b66954 /libdde_linux26/contrib/security/commoncap.c
parent21adb5284111190057db245cfc2b54091920c373 (diff)
rename libdde_linux26 into libdde-linux26 to make dpkg-source happy
Diffstat (limited to 'libdde_linux26/contrib/security/commoncap.c')
-rw-r--r--libdde_linux26/contrib/security/commoncap.c955
1 files changed, 0 insertions, 955 deletions
diff --git a/libdde_linux26/contrib/security/commoncap.c b/libdde_linux26/contrib/security/commoncap.c
deleted file mode 100644
index 7cd61a5f..00000000
--- a/libdde_linux26/contrib/security/commoncap.c
+++ /dev/null
@@ -1,955 +0,0 @@
-/* Common capabilities, needed by capability.o and root_plug.o
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- */
-
-#include <linux/capability.h>
-#include <linux/audit.h>
-#include <linux/module.h>
-#include <linux/init.h>
-#include <linux/kernel.h>
-#include <linux/security.h>
-#include <linux/file.h>
-#include <linux/mm.h>
-#include <linux/mman.h>
-#include <linux/pagemap.h>
-#include <linux/swap.h>
-#include <linux/skbuff.h>
-#include <linux/netlink.h>
-#include <linux/ptrace.h>
-#include <linux/xattr.h>
-#include <linux/hugetlb.h>
-#include <linux/mount.h>
-#include <linux/sched.h>
-#include <linux/prctl.h>
-#include <linux/securebits.h>
-
-int cap_netlink_send(struct sock *sk, struct sk_buff *skb)
-{
- NETLINK_CB(skb).eff_cap = current_cap();
- return 0;
-}
-
-int cap_netlink_recv(struct sk_buff *skb, int cap)
-{
- if (!cap_raised(NETLINK_CB(skb).eff_cap, cap))
- return -EPERM;
- return 0;
-}
-EXPORT_SYMBOL(cap_netlink_recv);
-
-/**
- * cap_capable - Determine whether a task has a particular effective capability
- * @tsk: The task to query
- * @cred: The credentials to use
- * @cap: The capability to check for
- * @audit: Whether to write an audit message or not
- *
- * Determine whether the nominated task has the specified capability amongst
- * its effective set, returning 0 if it does, -ve if it does not.
- *
- * NOTE WELL: cap_has_capability() cannot be used like the kernel's capable()
- * and has_capability() functions. That is, it has the reverse semantics:
- * cap_has_capability() returns 0 when a task has a capability, but the
- * kernel's capable() and has_capability() returns 1 for this case.
- */
-int cap_capable(struct task_struct *tsk, const struct cred *cred, int cap,
- int audit)
-{
- return cap_raised(cred->cap_effective, cap) ? 0 : -EPERM;
-}
-
-/**
- * cap_settime - Determine whether the current process may set the system clock
- * @ts: The time to set
- * @tz: The timezone to set
- *
- * Determine whether the current process may set the system clock and timezone
- * information, returning 0 if permission granted, -ve if denied.
- */
-int cap_settime(struct timespec *ts, struct timezone *tz)
-{
- if (!capable(CAP_SYS_TIME))
- return -EPERM;
- return 0;
-}
-
-/**
- * cap_ptrace_may_access - Determine whether the current process may access
- * another
- * @child: The process to be accessed
- * @mode: The mode of attachment.
- *
- * Determine whether a process may access another, returning 0 if permission
- * granted, -ve if denied.
- */
-int cap_ptrace_may_access(struct task_struct *child, unsigned int mode)
-{
- int ret = 0;
-
- rcu_read_lock();
- if (!cap_issubset(__task_cred(child)->cap_permitted,
- current_cred()->cap_permitted) &&
- !capable(CAP_SYS_PTRACE))
- ret = -EPERM;
- rcu_read_unlock();
- return ret;
-}
-
-/**
- * cap_ptrace_traceme - Determine whether another process may trace the current
- * @parent: The task proposed to be the tracer
- *
- * Determine whether the nominated task is permitted to trace the current
- * process, returning 0 if permission is granted, -ve if denied.
- */
-int cap_ptrace_traceme(struct task_struct *parent)
-{
- int ret = 0;
-
- rcu_read_lock();
- if (!cap_issubset(current_cred()->cap_permitted,
- __task_cred(parent)->cap_permitted) &&
- !has_capability(parent, CAP_SYS_PTRACE))
- ret = -EPERM;
- rcu_read_unlock();
- return ret;
-}
-
-/**
- * cap_capget - Retrieve a task's capability sets
- * @target: The task from which to retrieve the capability sets
- * @effective: The place to record the effective set
- * @inheritable: The place to record the inheritable set
- * @permitted: The place to record the permitted set
- *
- * This function retrieves the capabilities of the nominated task and returns
- * them to the caller.
- */
-int cap_capget(struct task_struct *target, kernel_cap_t *effective,
- kernel_cap_t *inheritable, kernel_cap_t *permitted)
-{
- const struct cred *cred;
-
- /* Derived from kernel/capability.c:sys_capget. */
- rcu_read_lock();
- cred = __task_cred(target);
- *effective = cred->cap_effective;
- *inheritable = cred->cap_inheritable;
- *permitted = cred->cap_permitted;
- rcu_read_unlock();
- return 0;
-}
-
-/*
- * Determine whether the inheritable capabilities are limited to the old
- * permitted set. Returns 1 if they are limited, 0 if they are not.
- */
-static inline int cap_inh_is_capped(void)
-{
-#ifdef CONFIG_SECURITY_FILE_CAPABILITIES
-
- /* they are so limited unless the current task has the CAP_SETPCAP
- * capability
- */
- if (cap_capable(current, current_cred(), CAP_SETPCAP,
- SECURITY_CAP_AUDIT) == 0)
- return 0;
-#endif
- return 1;
-}
-
-/**
- * cap_capset - Validate and apply proposed changes to current's capabilities
- * @new: The proposed new credentials; alterations should be made here
- * @old: The current task's current credentials
- * @effective: A pointer to the proposed new effective capabilities set
- * @inheritable: A pointer to the proposed new inheritable capabilities set
- * @permitted: A pointer to the proposed new permitted capabilities set
- *
- * This function validates and applies a proposed mass change to the current
- * process's capability sets. The changes are made to the proposed new
- * credentials, and assuming no error, will be committed by the caller of LSM.
- */
-int cap_capset(struct cred *new,
- const struct cred *old,
- const kernel_cap_t *effective,
- const kernel_cap_t *inheritable,
- const kernel_cap_t *permitted)
-{
- if (cap_inh_is_capped() &&
- !cap_issubset(*inheritable,
- cap_combine(old->cap_inheritable,
- old->cap_permitted)))
- /* incapable of using this inheritable set */
- return -EPERM;
-
- if (!cap_issubset(*inheritable,
- cap_combine(old->cap_inheritable,
- old->cap_bset)))
- /* no new pI capabilities outside bounding set */
- return -EPERM;
-
- /* verify restrictions on target's new Permitted set */
- if (!cap_issubset(*permitted, old->cap_permitted))
- return -EPERM;
-
- /* verify the _new_Effective_ is a subset of the _new_Permitted_ */
- if (!cap_issubset(*effective, *permitted))
- return -EPERM;
-
- new->cap_effective = *effective;
- new->cap_inheritable = *inheritable;
- new->cap_permitted = *permitted;
- return 0;
-}
-
-/*
- * Clear proposed capability sets for execve().
- */
-static inline void bprm_clear_caps(struct linux_binprm *bprm)
-{
- cap_clear(bprm->cred->cap_permitted);
- bprm->cap_effective = false;
-}
-
-#ifdef CONFIG_SECURITY_FILE_CAPABILITIES
-
-/**
- * cap_inode_need_killpriv - Determine if inode change affects privileges
- * @dentry: The inode/dentry in being changed with change marked ATTR_KILL_PRIV
- *
- * Determine if an inode having a change applied that's marked ATTR_KILL_PRIV
- * affects the security markings on that inode, and if it is, should
- * inode_killpriv() be invoked or the change rejected?
- *
- * Returns 0 if granted; +ve if granted, but inode_killpriv() is required; and
- * -ve to deny the change.
- */
-int cap_inode_need_killpriv(struct dentry *dentry)
-{
- struct inode *inode = dentry->d_inode;
- int error;
-
- if (!inode->i_op->getxattr)
- return 0;
-
- error = inode->i_op->getxattr(dentry, XATTR_NAME_CAPS, NULL, 0);
- if (error <= 0)
- return 0;
- return 1;
-}
-
-/**
- * cap_inode_killpriv - Erase the security markings on an inode
- * @dentry: The inode/dentry to alter
- *
- * Erase the privilege-enhancing security markings on an inode.
- *
- * Returns 0 if successful, -ve on error.
- */
-int cap_inode_killpriv(struct dentry *dentry)
-{
- struct inode *inode = dentry->d_inode;
-
- if (!inode->i_op->removexattr)
- return 0;
-
- return inode->i_op->removexattr(dentry, XATTR_NAME_CAPS);
-}
-
-/*
- * Calculate the new process capability sets from the capability sets attached
- * to a file.
- */
-static inline int bprm_caps_from_vfs_caps(struct cpu_vfs_cap_data *caps,
- struct linux_binprm *bprm,
- bool *effective)
-{
- struct cred *new = bprm->cred;
- unsigned i;
- int ret = 0;
-
- if (caps->magic_etc & VFS_CAP_FLAGS_EFFECTIVE)
- *effective = true;
-
- CAP_FOR_EACH_U32(i) {
- __u32 permitted = caps->permitted.cap[i];
- __u32 inheritable = caps->inheritable.cap[i];
-
- /*
- * pP' = (X & fP) | (pI & fI)
- */
- new->cap_permitted.cap[i] =
- (new->cap_bset.cap[i] & permitted) |
- (new->cap_inheritable.cap[i] & inheritable);
-
- if (permitted & ~new->cap_permitted.cap[i])
- /* insufficient to execute correctly */
- ret = -EPERM;
- }
-
- /*
- * For legacy apps, with no internal support for recognizing they
- * do not have enough capabilities, we return an error if they are
- * missing some "forced" (aka file-permitted) capabilities.
- */
- return *effective ? ret : 0;
-}
-
-/*
- * Extract the on-exec-apply capability sets for an executable file.
- */
-int get_vfs_caps_from_disk(const struct dentry *dentry, struct cpu_vfs_cap_data *cpu_caps)
-{
- struct inode *inode = dentry->d_inode;
- __u32 magic_etc;
- unsigned tocopy, i;
- int size;
- struct vfs_cap_data caps;
-
- memset(cpu_caps, 0, sizeof(struct cpu_vfs_cap_data));
-
- if (!inode || !inode->i_op->getxattr)
- return -ENODATA;
-
- size = inode->i_op->getxattr((struct dentry *)dentry, XATTR_NAME_CAPS, &caps,
- XATTR_CAPS_SZ);
- if (size == -ENODATA || size == -EOPNOTSUPP)
- /* no data, that's ok */
- return -ENODATA;
- if (size < 0)
- return size;
-
- if (size < sizeof(magic_etc))
- return -EINVAL;
-
- cpu_caps->magic_etc = magic_etc = le32_to_cpu(caps.magic_etc);
-
- switch (magic_etc & VFS_CAP_REVISION_MASK) {
- case VFS_CAP_REVISION_1:
- if (size != XATTR_CAPS_SZ_1)
- return -EINVAL;
- tocopy = VFS_CAP_U32_1;
- break;
- case VFS_CAP_REVISION_2:
- if (size != XATTR_CAPS_SZ_2)
- return -EINVAL;
- tocopy = VFS_CAP_U32_2;
- break;
- default:
- return -EINVAL;
- }
-
- CAP_FOR_EACH_U32(i) {
- if (i >= tocopy)
- break;
- cpu_caps->permitted.cap[i] = le32_to_cpu(caps.data[i].permitted);
- cpu_caps->inheritable.cap[i] = le32_to_cpu(caps.data[i].inheritable);
- }
-
- return 0;
-}
-
-/*
- * Attempt to get the on-exec apply capability sets for an executable file from
- * its xattrs and, if present, apply them to the proposed credentials being
- * constructed by execve().
- */
-static int get_file_caps(struct linux_binprm *bprm, bool *effective)
-{
- struct dentry *dentry;
- int rc = 0;
- struct cpu_vfs_cap_data vcaps;
-
- bprm_clear_caps(bprm);
-
- if (!file_caps_enabled)
- return 0;
-
- if (bprm->file->f_vfsmnt->mnt_flags & MNT_NOSUID)
- return 0;
-
- dentry = dget(bprm->file->f_dentry);
-
- rc = get_vfs_caps_from_disk(dentry, &vcaps);
- if (rc < 0) {
- if (rc == -EINVAL)
- printk(KERN_NOTICE "%s: get_vfs_caps_from_disk returned %d for %s\n",
- __func__, rc, bprm->filename);
- else if (rc == -ENODATA)
- rc = 0;
- goto out;
- }
-
- rc = bprm_caps_from_vfs_caps(&vcaps, bprm, effective);
- if (rc == -EINVAL)
- printk(KERN_NOTICE "%s: cap_from_disk returned %d for %s\n",
- __func__, rc, bprm->filename);
-
-out:
- dput(dentry);
- if (rc)
- bprm_clear_caps(bprm);
-
- return rc;
-}
-
-#else
-int cap_inode_need_killpriv(struct dentry *dentry)
-{
- return 0;
-}
-
-int cap_inode_killpriv(struct dentry *dentry)
-{
- return 0;
-}
-
-int get_vfs_caps_from_disk(const struct dentry *dentry, struct cpu_vfs_cap_data *cpu_caps)
-{
- memset(cpu_caps, 0, sizeof(struct cpu_vfs_cap_data));
- return -ENODATA;
-}
-
-static inline int get_file_caps(struct linux_binprm *bprm, bool *effective)
-{
- bprm_clear_caps(bprm);
- return 0;
-}
-#endif
-
-/*
- * Determine whether a exec'ing process's new permitted capabilities should be
- * limited to just what it already has.
- *
- * This prevents processes that are being ptraced from gaining access to
- * CAP_SETPCAP, unless the process they're tracing already has it, and the
- * binary they're executing has filecaps that elevate it.
- *
- * Returns 1 if they should be limited, 0 if they are not.
- */
-static inline int cap_limit_ptraced_target(void)
-{
-#ifndef CONFIG_SECURITY_FILE_CAPABILITIES
- if (capable(CAP_SETPCAP))
- return 0;
-#endif
- return 1;
-}
-
-/**
- * cap_bprm_set_creds - Set up the proposed credentials for execve().
- * @bprm: The execution parameters, including the proposed creds
- *
- * Set up the proposed credentials for a new execution context being
- * constructed by execve(). The proposed creds in @bprm->cred is altered,
- * which won't take effect immediately. Returns 0 if successful, -ve on error.
- */
-int cap_bprm_set_creds(struct linux_binprm *bprm)
-{
- const struct cred *old = current_cred();
- struct cred *new = bprm->cred;
- bool effective;
- int ret;
-
- effective = false;
- ret = get_file_caps(bprm, &effective);
- if (ret < 0)
- return ret;
-
- if (!issecure(SECURE_NOROOT)) {
- /*
- * To support inheritance of root-permissions and suid-root
- * executables under compatibility mode, we override the
- * capability sets for the file.
- *
- * If only the real uid is 0, we do not set the effective bit.
- */
- if (new->euid == 0 || new->uid == 0) {
- /* pP' = (cap_bset & ~0) | (pI & ~0) */
- new->cap_permitted = cap_combine(old->cap_bset,
- old->cap_inheritable);
- }
- if (new->euid == 0)
- effective = true;
- }
-
- /* Don't let someone trace a set[ug]id/setpcap binary with the revised
- * credentials unless they have the appropriate permit
- */
- if ((new->euid != old->uid ||
- new->egid != old->gid ||
- !cap_issubset(new->cap_permitted, old->cap_permitted)) &&
- bprm->unsafe & ~LSM_UNSAFE_PTRACE_CAP) {
- /* downgrade; they get no more than they had, and maybe less */
- if (!capable(CAP_SETUID)) {
- new->euid = new->uid;
- new->egid = new->gid;
- }
- if (cap_limit_ptraced_target())
- new->cap_permitted = cap_intersect(new->cap_permitted,
- old->cap_permitted);
- }
-
- new->suid = new->fsuid = new->euid;
- new->sgid = new->fsgid = new->egid;
-
- /* For init, we want to retain the capabilities set in the initial
- * task. Thus we skip the usual capability rules
- */
- if (!is_global_init(current)) {
- if (effective)
- new->cap_effective = new->cap_permitted;
- else
- cap_clear(new->cap_effective);
- }
- bprm->cap_effective = effective;
-
- /*
- * Audit candidate if current->cap_effective is set
- *
- * We do not bother to audit if 3 things are true:
- * 1) cap_effective has all caps
- * 2) we are root
- * 3) root is supposed to have all caps (SECURE_NOROOT)
- * Since this is just a normal root execing a process.
- *
- * Number 1 above might fail if you don't have a full bset, but I think
- * that is interesting information to audit.
- */
- if (!cap_isclear(new->cap_effective)) {
- if (!cap_issubset(CAP_FULL_SET, new->cap_effective) ||
- new->euid != 0 || new->uid != 0 ||
- issecure(SECURE_NOROOT)) {
- ret = audit_log_bprm_fcaps(bprm, new, old);
- if (ret < 0)
- return ret;
- }
- }
-
- new->securebits &= ~issecure_mask(SECURE_KEEP_CAPS);
- return 0;
-}
-
-/**
- * cap_bprm_secureexec - Determine whether a secure execution is required
- * @bprm: The execution parameters
- *
- * Determine whether a secure execution is required, return 1 if it is, and 0
- * if it is not.
- *
- * The credentials have been committed by this point, and so are no longer
- * available through @bprm->cred.
- */
-int cap_bprm_secureexec(struct linux_binprm *bprm)
-{
- const struct cred *cred = current_cred();
-
- if (cred->uid != 0) {
- if (bprm->cap_effective)
- return 1;
- if (!cap_isclear(cred->cap_permitted))
- return 1;
- }
-
- return (cred->euid != cred->uid ||
- cred->egid != cred->gid);
-}
-
-/**
- * cap_inode_setxattr - Determine whether an xattr may be altered
- * @dentry: The inode/dentry being altered
- * @name: The name of the xattr to be changed
- * @value: The value that the xattr will be changed to
- * @size: The size of value
- * @flags: The replacement flag
- *
- * Determine whether an xattr may be altered or set on an inode, returning 0 if
- * permission is granted, -ve if denied.
- *
- * This is used to make sure security xattrs don't get updated or set by those
- * who aren't privileged to do so.
- */
-int cap_inode_setxattr(struct dentry *dentry, const char *name,
- const void *value, size_t size, int flags)
-{
- if (!strcmp(name, XATTR_NAME_CAPS)) {
- if (!capable(CAP_SETFCAP))
- return -EPERM;
- return 0;
- }
-
- if (!strncmp(name, XATTR_SECURITY_PREFIX,
- sizeof(XATTR_SECURITY_PREFIX) - 1) &&
- !capable(CAP_SYS_ADMIN))
- return -EPERM;
- return 0;
-}
-
-/**
- * cap_inode_removexattr - Determine whether an xattr may be removed
- * @dentry: The inode/dentry being altered
- * @name: The name of the xattr to be changed
- *
- * Determine whether an xattr may be removed from an inode, returning 0 if
- * permission is granted, -ve if denied.
- *
- * This is used to make sure security xattrs don't get removed by those who
- * aren't privileged to remove them.
- */
-int cap_inode_removexattr(struct dentry *dentry, const char *name)
-{
- if (!strcmp(name, XATTR_NAME_CAPS)) {
- if (!capable(CAP_SETFCAP))
- return -EPERM;
- return 0;
- }
-
- if (!strncmp(name, XATTR_SECURITY_PREFIX,
- sizeof(XATTR_SECURITY_PREFIX) - 1) &&
- !capable(CAP_SYS_ADMIN))
- return -EPERM;
- return 0;
-}
-
-/*
- * cap_emulate_setxuid() fixes the effective / permitted capabilities of
- * a process after a call to setuid, setreuid, or setresuid.
- *
- * 1) When set*uiding _from_ one of {r,e,s}uid == 0 _to_ all of
- * {r,e,s}uid != 0, the permitted and effective capabilities are
- * cleared.
- *
- * 2) When set*uiding _from_ euid == 0 _to_ euid != 0, the effective
- * capabilities of the process are cleared.
- *
- * 3) When set*uiding _from_ euid != 0 _to_ euid == 0, the effective
- * capabilities are set to the permitted capabilities.
- *
- * fsuid is handled elsewhere. fsuid == 0 and {r,e,s}uid!= 0 should
- * never happen.
- *
- * -astor
- *
- * cevans - New behaviour, Oct '99
- * A process may, via prctl(), elect to keep its capabilities when it
- * calls setuid() and switches away from uid==0. Both permitted and
- * effective sets will be retained.
- * Without this change, it was impossible for a daemon to drop only some
- * of its privilege. The call to setuid(!=0) would drop all privileges!
- * Keeping uid 0 is not an option because uid 0 owns too many vital
- * files..
- * Thanks to Olaf Kirch and Peter Benie for spotting this.
- */
-static inline void cap_emulate_setxuid(struct cred *new, const struct cred *old)
-{
- if ((old->uid == 0 || old->euid == 0 || old->suid == 0) &&
- (new->uid != 0 && new->euid != 0 && new->suid != 0) &&
- !issecure(SECURE_KEEP_CAPS)) {
- cap_clear(new->cap_permitted);
- cap_clear(new->cap_effective);
- }
- if (old->euid == 0 && new->euid != 0)
- cap_clear(new->cap_effective);
- if (old->euid != 0 && new->euid == 0)
- new->cap_effective = new->cap_permitted;
-}
-
-/**
- * cap_task_fix_setuid - Fix up the results of setuid() call
- * @new: The proposed credentials
- * @old: The current task's current credentials
- * @flags: Indications of what has changed
- *
- * Fix up the results of setuid() call before the credential changes are
- * actually applied, returning 0 to grant the changes, -ve to deny them.
- */
-int cap_task_fix_setuid(struct cred *new, const struct cred *old, int flags)
-{
- switch (flags) {
- case LSM_SETID_RE:
- case LSM_SETID_ID:
- case LSM_SETID_RES:
- /* juggle the capabilities to follow [RES]UID changes unless
- * otherwise suppressed */
- if (!issecure(SECURE_NO_SETUID_FIXUP))
- cap_emulate_setxuid(new, old);
- break;
-
- case LSM_SETID_FS:
- /* juggle the capabilties to follow FSUID changes, unless
- * otherwise suppressed
- *
- * FIXME - is fsuser used for all CAP_FS_MASK capabilities?
- * if not, we might be a bit too harsh here.
- */
- if (!issecure(SECURE_NO_SETUID_FIXUP)) {
- if (old->fsuid == 0 && new->fsuid != 0)
- new->cap_effective =
- cap_drop_fs_set(new->cap_effective);
-
- if (old->fsuid != 0 && new->fsuid == 0)
- new->cap_effective =
- cap_raise_fs_set(new->cap_effective,
- new->cap_permitted);
- }
- break;
-
- default:
- return -EINVAL;
- }
-
- return 0;
-}
-
-#ifdef CONFIG_SECURITY_FILE_CAPABILITIES
-/*
- * Rationale: code calling task_setscheduler, task_setioprio, and
- * task_setnice, assumes that
- * . if capable(cap_sys_nice), then those actions should be allowed
- * . if not capable(cap_sys_nice), but acting on your own processes,
- * then those actions should be allowed
- * This is insufficient now since you can call code without suid, but
- * yet with increased caps.
- * So we check for increased caps on the target process.
- */
-static int cap_safe_nice(struct task_struct *p)
-{
- int is_subset;
-
- rcu_read_lock();
- is_subset = cap_issubset(__task_cred(p)->cap_permitted,
- current_cred()->cap_permitted);
- rcu_read_unlock();
-
- if (!is_subset && !capable(CAP_SYS_NICE))
- return -EPERM;
- return 0;
-}
-
-/**
- * cap_task_setscheduler - Detemine if scheduler policy change is permitted
- * @p: The task to affect
- * @policy: The policy to effect
- * @lp: The parameters to the scheduling policy
- *
- * Detemine if the requested scheduler policy change is permitted for the
- * specified task, returning 0 if permission is granted, -ve if denied.
- */
-int cap_task_setscheduler(struct task_struct *p, int policy,
- struct sched_param *lp)
-{
- return cap_safe_nice(p);
-}
-
-/**
- * cap_task_ioprio - Detemine if I/O priority change is permitted
- * @p: The task to affect
- * @ioprio: The I/O priority to set
- *
- * Detemine if the requested I/O priority change is permitted for the specified
- * task, returning 0 if permission is granted, -ve if denied.
- */
-int cap_task_setioprio(struct task_struct *p, int ioprio)
-{
- return cap_safe_nice(p);
-}
-
-/**
- * cap_task_ioprio - Detemine if task priority change is permitted
- * @p: The task to affect
- * @nice: The nice value to set
- *
- * Detemine if the requested task priority change is permitted for the
- * specified task, returning 0 if permission is granted, -ve if denied.
- */
-int cap_task_setnice(struct task_struct *p, int nice)
-{
- return cap_safe_nice(p);
-}
-
-/*
- * Implement PR_CAPBSET_DROP. Attempt to remove the specified capability from
- * the current task's bounding set. Returns 0 on success, -ve on error.
- */
-static long cap_prctl_drop(struct cred *new, unsigned long cap)
-{
- if (!capable(CAP_SETPCAP))
- return -EPERM;
- if (!cap_valid(cap))
- return -EINVAL;
-
- cap_lower(new->cap_bset, cap);
- return 0;
-}
-
-#else
-int cap_task_setscheduler (struct task_struct *p, int policy,
- struct sched_param *lp)
-{
- return 0;
-}
-int cap_task_setioprio (struct task_struct *p, int ioprio)
-{
- return 0;
-}
-int cap_task_setnice (struct task_struct *p, int nice)
-{
- return 0;
-}
-#endif
-
-/**
- * cap_task_prctl - Implement process control functions for this security module
- * @option: The process control function requested
- * @arg2, @arg3, @arg4, @arg5: The argument data for this function
- *
- * Allow process control functions (sys_prctl()) to alter capabilities; may
- * also deny access to other functions not otherwise implemented here.
- *
- * Returns 0 or +ve on success, -ENOSYS if this function is not implemented
- * here, other -ve on error. If -ENOSYS is returned, sys_prctl() and other LSM
- * modules will consider performing the function.
- */
-int cap_task_prctl(int option, unsigned long arg2, unsigned long arg3,
- unsigned long arg4, unsigned long arg5)
-{
- struct cred *new;
- long error = 0;
-
- new = prepare_creds();
- if (!new)
- return -ENOMEM;
-
- switch (option) {
- case PR_CAPBSET_READ:
- error = -EINVAL;
- if (!cap_valid(arg2))
- goto error;
- error = !!cap_raised(new->cap_bset, arg2);
- goto no_change;
-
-#ifdef CONFIG_SECURITY_FILE_CAPABILITIES
- case PR_CAPBSET_DROP:
- error = cap_prctl_drop(new, arg2);
- if (error < 0)
- goto error;
- goto changed;
-
- /*
- * The next four prctl's remain to assist with transitioning a
- * system from legacy UID=0 based privilege (when filesystem
- * capabilities are not in use) to a system using filesystem
- * capabilities only - as the POSIX.1e draft intended.
- *
- * Note:
- *
- * PR_SET_SECUREBITS =
- * issecure_mask(SECURE_KEEP_CAPS_LOCKED)
- * | issecure_mask(SECURE_NOROOT)
- * | issecure_mask(SECURE_NOROOT_LOCKED)
- * | issecure_mask(SECURE_NO_SETUID_FIXUP)
- * | issecure_mask(SECURE_NO_SETUID_FIXUP_LOCKED)
- *
- * will ensure that the current process and all of its
- * children will be locked into a pure
- * capability-based-privilege environment.
- */
- case PR_SET_SECUREBITS:
- error = -EPERM;
- if ((((new->securebits & SECURE_ALL_LOCKS) >> 1)
- & (new->securebits ^ arg2)) /*[1]*/
- || ((new->securebits & SECURE_ALL_LOCKS & ~arg2)) /*[2]*/
- || (arg2 & ~(SECURE_ALL_LOCKS | SECURE_ALL_BITS)) /*[3]*/
- || (cap_capable(current, current_cred(), CAP_SETPCAP,
- SECURITY_CAP_AUDIT) != 0) /*[4]*/
- /*
- * [1] no changing of bits that are locked
- * [2] no unlocking of locks
- * [3] no setting of unsupported bits
- * [4] doing anything requires privilege (go read about
- * the "sendmail capabilities bug")
- */
- )
- /* cannot change a locked bit */
- goto error;
- new->securebits = arg2;
- goto changed;
-
- case PR_GET_SECUREBITS:
- error = new->securebits;
- goto no_change;
-
-#endif /* def CONFIG_SECURITY_FILE_CAPABILITIES */
-
- case PR_GET_KEEPCAPS:
- if (issecure(SECURE_KEEP_CAPS))
- error = 1;
- goto no_change;
-
- case PR_SET_KEEPCAPS:
- error = -EINVAL;
- if (arg2 > 1) /* Note, we rely on arg2 being unsigned here */
- goto error;
- error = -EPERM;
- if (issecure(SECURE_KEEP_CAPS_LOCKED))
- goto error;
- if (arg2)
- new->securebits |= issecure_mask(SECURE_KEEP_CAPS);
- else
- new->securebits &= ~issecure_mask(SECURE_KEEP_CAPS);
- goto changed;
-
- default:
- /* No functionality available - continue with default */
- error = -ENOSYS;
- goto error;
- }
-
- /* Functionality provided */
-changed:
- return commit_creds(new);
-
-no_change:
- error = 0;
-error:
- abort_creds(new);
- return error;
-}
-
-/**
- * cap_syslog - Determine whether syslog function is permitted
- * @type: Function requested
- *
- * Determine whether the current process is permitted to use a particular
- * syslog function, returning 0 if permission is granted, -ve if not.
- */
-int cap_syslog(int type)
-{
- if ((type != 3 && type != 10) && !capable(CAP_SYS_ADMIN))
- return -EPERM;
- return 0;
-}
-
-/**
- * cap_vm_enough_memory - Determine whether a new virtual mapping is permitted
- * @mm: The VM space in which the new mapping is to be made
- * @pages: The size of the mapping
- *
- * Determine whether the allocation of a new virtual mapping by the current
- * task is permitted, returning 0 if permission is granted, -ve if not.
- */
-int cap_vm_enough_memory(struct mm_struct *mm, long pages)
-{
- int cap_sys_admin = 0;
-
- if (cap_capable(current, current_cred(), CAP_SYS_ADMIN,
- SECURITY_CAP_NOAUDIT) == 0)
- cap_sys_admin = 1;
- return __vm_enough_memory(mm, pages, cap_sys_admin);
-}