[PATCH 59/59] CRED: Wrap task credential accesses in the core kernel

David Howells
2008-08-27T14:03:39Z

Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-audit@redhat.com
Cc: containers@lists.linux-foundation.org
Cc: linux-mm@kvack.org
---

kernel/acct.c | 7 +++----
kernel/auditsc.c | 6 ++++--
kernel/cgroup.c | 9 +++++----
kernel/futex.c | 8 +++++---
kernel/futex_compat.c | 3 ++-
kernel/ptrace.c | 15 +++++++++------
kernel/sched.c | 11 +++++++----
kernel/signal.c | 15 +++++++++------
kernel/sys.c | 16 ++++++++--------
kernel/sysctl.c | 2 +-
kernel/timer.c | 8 ++++----
kernel/user_namespace.c | 2 +-
mm/mempolicy.c | 7 +++++--
mm/migrate.c | 7 +++++--
mm/shmem.c | 8 ++++----
15 files changed, 72 insertions(+), 52 deletions(-)

diff --git a/kernel/acct.c b/kernel/acct.c
index f6006a6..d57b7cb 100644
--- a/kernel/acct.c
+++ b/kernel/acct.c
@@ -530,15 +530,14 @@ static void do_acct_process(struct bsd_acct_struct *acct,
do_div(elapsed, AHZ);
ac.ac_btime = get_seconds() - elapsed;
/* we really need to bite the bullet and change layout */
- ac.ac_uid = current->uid;
- ac.ac_gid = current->gid;
+ current_uid_gid(&ac.ac_uid, &ac.ac_gid);
#if ACCT_VERSION==2
ac.ac_ahz = AHZ;
#endif
#if ACCT_VERSION==1 || ACCT_VERSION==2
/* backward-compatible 16 bit fields */
- ac.ac_uid16 = current->uid;
- ac.ac_gid16 = current->gid;
+ ac.ac_uid16 = ac.ac_uid;
+ ac.ac_gid16 = ac.ac_gid;
#endif
#if ACCT_VERSION==3
ac.ac_pid = task_tgid_nr_ns(current, ns);
diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index cf5bc2f..e7d7061 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -2440,7 +2440,8 @@ void audit_core_dumps(long signr)
{
struct audit_buffer *ab;
u32 sid;
- uid_t auid = audit_get_loginuid(current);
+ uid_t auid = audit_get_loginuid(current), uid;
+ gid_t gid;
unsigned int sessionid = audit_get_sessionid(current);

if (!audit_enabled)
@@ -2450,8 +2451,9 @@ void audit_core_dumps(long signr)
return;

ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_ANOM_ABEND);
+ current_uid_gid(&uid, &gid);
audit_log_format(ab, "auid=%u uid=%u gid=%u ses=%u",
- auid, current->uid, current->gid, sessionid);
+ auid, uid, gid, sessionid);
security_task_getsecid(current, &sid);
if (sid) {
char *ctx = NULL;
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 13932ab..9f5a62a 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -573,8 +573,8 @@ static struct inode *cgroup_new_inode(mode_t mode, struct super_block *sb)

if (inode) {
inode->i_mode = mode;
- inode->i_uid = current->fsuid;
- inode->i_gid = current->fsgid;
+ inode->i_uid = current_fsuid();
+ inode->i_gid = current_fsgid();
inode->i_blocks = 0;
inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
inode->i_mapping->backing_dev_info = &cgroup_backing_dev_info;
@@ -1276,6 +1276,7 @@ int cgroup_attach_task(struct cgroup *cgrp, struct task_struct *tsk)
static int attach_task_by_pid(struct cgroup *cgrp, u64 pid)
{
struct task_struct *tsk;
+ uid_t euid;
int ret;

if (pid) {
@@ -1288,8 +1289,8 @@ static int attach_task_by_pid(struct cgroup *cgrp, u64 pid)
get_task_struct(tsk);
rcu_read_unlock();

- if ((current->euid) && (current->euid != tsk->uid)
- && (current->euid != tsk->suid)) {
+ euid = current_euid();
+ if (euid && euid != tsk->uid && euid != tsk->suid) {
put_task_struct(tsk);
return -EACCES;
}
diff --git a/kernel/futex.c b/kernel/futex.c
index 7d1136e..a28b82b 100644
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -439,10 +439,11 @@ static void free_pi_state(struct futex_pi_state *pi_state)
static struct task_struct * futex_find_get_task(pid_t pid)
{
struct task_struct *p;
+ uid_t euid = current_euid();

rcu_read_lock();
p = find_task_by_vpid(pid);
- if (!p || ((current->euid != p->euid) && (current->euid != p->uid)))
+ if (!p || (euid != p->euid && euid != p->uid))
p = ERR_PTR(-ESRCH);
else
get_task_struct(p);
@@ -1826,6 +1827,7 @@ sys_get_robust_list(int pid, struct robust_list_head __user * __user *head_ptr,
{
struct robust_list_head __user *head;
unsigned long ret;
+ uid_t euid = current_euid();

if (!futex_cmpxchg_enabled)
return -ENOSYS;
@@ -1841,8 +1843,8 @@ sys_get_robust_list(int pid, struct robust_list_head __user * __user *head_ptr,
if (!p)
goto err_unlock;
ret = -EPERM;
- if ((current->euid != p->euid) && (current->euid != p->uid) &&
- !capable(CAP_SYS_PTRACE))
+ if (euid != p->euid && euid != p->uid &&
+ !capable(CAP_SYS_PTRACE))
goto err_unlock;
head = p->robust_list;
rcu_read_unlock();
diff --git a/kernel/futex_compat.c b/kernel/futex_compat.c
index 04ac3a9..3254d4e 100644
--- a/kernel/futex_compat.c
+++ b/kernel/futex_compat.c
@@ -135,6 +135,7 @@ compat_sys_get_robust_list(int pid, compat_uptr_t __user *head_ptr,
{
struct compat_robust_list_head __user *head;
unsigned long ret;
+ uid_t euid = current_euid();

if (!futex_cmpxchg_enabled)
return -ENOSYS;
@@ -150,7 +151,7 @@ compat_sys_get_robust_list(int pid, compat_uptr_t __user *head_ptr,
if (!p)
goto err_unlock;
ret = -EPERM;
- if ((current->euid != p->euid) && (current->euid != p->uid) &&
+ if (euid != p->euid && euid != p->uid &&
!capable(CAP_SYS_PTRACE))
goto err_unlock;
head = p->compat_robust_list;
diff --git a/kernel/ptrace.c b/kernel/ptrace.c
index 356699a..0dafab1 100644
--- a/kernel/ptrace.c
+++ b/kernel/ptrace.c
@@ -123,16 +123,19 @@ int __ptrace_may_access(struct task_struct *task, unsigned int mode)
* because setting up the necessary parent/child relationship
* or halting the specified task is impossible.
*/
+ uid_t uid;
+ gid_t gid;
int dumpable = 0;
/* Don't let security modules deny introspection */
if (task == current)
return 0;
- if (((current->uid != task->euid) ||
- (current->uid != task->suid) ||
- (current->uid != task->uid) ||
- (current->gid != task->egid) ||
- (current->gid != task->sgid) ||
- (current->gid != task->gid)) && !capable(CAP_SYS_PTRACE))
+ current_uid_gid(&uid, &gid);
+ if ((uid != task->euid ||
+ uid != task->suid ||
+ uid != task->uid ||
+ gid != task->egid ||
+ gid != task->sgid ||
+ gid != task->gid) && !capable(CAP_SYS_PTRACE))
return -EPERM;
smp_rmb();
if (task->mm)
diff --git a/kernel/sched.c b/kernel/sched.c
index 4a7da9e..58690f3 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -5008,6 +5008,7 @@ static int __sched_setscheduler(struct task_struct *p, int policy,
unsigned long flags;
const struct sched_class *prev_class = p->sched_class;
struct rq *rq;
+ uid_t euid;

/* may grab non-irq protected spin_locks */
BUG_ON(in_interrupt());
@@ -5060,8 +5061,9 @@ recheck:
return -EPERM;

/* can't change other user's priorities */
- if ((current->euid != p->euid) &&
- (current->euid != p->uid))
+ euid = current_euid();
+ if (euid != p->euid &&
+ euid != p->uid)
return -EPERM;
}

@@ -5272,6 +5274,7 @@ long sched_setaffinity(pid_t pid, const cpumask_t *in_mask)
cpumask_t cpus_allowed;
cpumask_t new_mask = *in_mask;
struct task_struct *p;
+ uid_t euid;
int retval;

get_online_cpus();
@@ -5292,9 +5295,9 @@ long sched_setaffinity(pid_t pid, const cpumask_t *in_mask)
get_task_struct(p);
read_unlock(&tasklist_lock);

+ euid = current_euid();
retval = -EPERM;
- if ((current->euid != p->euid) && (current->euid != p->uid) &&
- !capable(CAP_SYS_NICE))
+ if (euid != p->euid && euid != p->uid && !capable(CAP_SYS_NICE))
goto out_unlock;

retval = security_task_setscheduler(p, 0, NULL);
diff --git a/kernel/signal.c b/kernel/signal.c
index bf40ecc..141d2b9 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -567,6 +567,7 @@ static int check_kill_permission(int sig, struct siginfo *info,
struct task_struct *t)
{
struct pid *sid;
+ uid_t uid, euid;
int error;

if (!valid_signal(sig))
@@ -579,8 +580,10 @@ static int check_kill_permission(int sig, struct siginfo *info,
if (error)
return error;

- if ((current->euid ^ t->suid) && (current->euid ^ t->uid) &&
- (current->uid ^ t->suid) && (current->uid ^ t->uid) &&
+ uid = current_uid();
+ euid = current_euid();
+ if ((euid ^ t->suid) && (euid ^ t->uid) &&
+ (uid ^ t->suid) && (uid ^ t->uid) &&
!capable(CAP_KILL)) {
switch (sig) {
case SIGCONT:
@@ -844,7 +847,7 @@ static int send_signal(int sig, struct siginfo *info, struct task_struct *t,
q->info.si_errno = 0;
q->info.si_code = SI_USER;
q->info.si_pid = task_pid_vnr(current);
- q->info.si_uid = current->uid;
+ q->info.si_uid = current_uid();
break;
case (unsigned long) SEND_SIG_PRIV:
q->info.si_signo = sig;
@@ -1597,7 +1600,7 @@ void ptrace_notify(int exit_code)
info.si_signo = SIGTRAP;
info.si_code = exit_code;
info.si_pid = task_pid_vnr(current);
- info.si_uid = current->uid;
+ info.si_uid = current_uid();

/* Let the debugger run. */
spin_lock_irq(&current->sighand->siglock);
@@ -2210,7 +2213,7 @@ sys_kill(pid_t pid, int sig)
info.si_errno = 0;
info.si_code = SI_USER;
info.si_pid = task_tgid_vnr(current);
- info.si_uid = current->uid;
+ info.si_uid = current_uid();

return kill_something_info(sig, &info, pid);
}
@@ -2227,7 +2230,7 @@ static int do_tkill(pid_t tgid, pid_t pid, int sig)
info.si_errno = 0;
info.si_code = SI_TKILL;
info.si_pid = task_tgid_vnr(current);
- info.si_uid = current->uid;
+ info.si_uid = current_uid();

rcu_read_lock();
p = find_task_by_vpid(pid);
diff --git a/kernel/sys.c b/kernel/sys.c
index 234d945..f82827d 100644
--- a/kernel/sys.c
+++ b/kernel/sys.c
@@ -114,10 +114,10 @@ void (*pm_power_off_prepare)(void);

static int set_one_prio(struct task_struct *p, int niceval, int error)
{
+ uid_t euid = current_euid();
int no_nice;

- if (p->uid != current->euid &&
- p->euid != current->euid && !capable(CAP_SYS_NICE)) {
+ if (p->uid != euid && p->euid != euid && !capable(CAP_SYS_NICE)) {
error = -EPERM;
goto out;
}
@@ -176,16 +176,16 @@ asmlinkage long sys_setpriority(int which, int who, int niceval)
case PRIO_USER:
user = current->user;
if (!who)
- who = current->uid;
+ who = current_uid();
else
- if ((who != current->uid) && !(user = find_user(who)))
+ if (who != current_uid() && !(user = find_user(who)))
goto out_unlock; /* No processes for this user */

do_each_thread(g, p)
if (p->uid == who)
error = set_one_prio(p, niceval, error);
while_each_thread(g, p);
- if (who != current->uid)
+ if (who != current_uid())
free_uid(user); /* For find_user() */
break;
}
@@ -238,9 +238,9 @@ asmlinkage long sys_getpriority(int which, int who)
case PRIO_USER:
user = current->user;
if (!who)
- who = current->uid;
+ who = current_uid();
else
- if ((who != current->uid) && !(user = find_user(who)))
+ if (who != current_uid() && !(user = find_user(who)))
goto out_unlock; /* No processes for this user */

do_each_thread(g, p)
@@ -250,7 +250,7 @@ asmlinkage long sys_getpriority(int which, int who)
retval = niceval;
}
while_each_thread(g, p);
- if (who != current->uid)
+ if (who != current_uid())
free_uid(user); /* for find_user() */
break;
}
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index deceea0..9e4c8d3 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -1667,7 +1667,7 @@ out:

static int test_perm(int mode, int op)
{
- if (!current->euid)
+ if (!current_euid())
mode >>= 6;
else if (in_egroup_p(0))
mode >>= 3;
diff --git a/kernel/timer.c b/kernel/timer.c
index 56becf3..b54e464 100644
--- a/kernel/timer.c
+++ b/kernel/timer.c
@@ -1123,25 +1123,25 @@ asmlinkage long sys_getppid(void)
asmlinkage long sys_getuid(void)
{
/* Only we change this so SMP safe */
- return current->uid;
+ return current_uid();
}

asmlinkage long sys_geteuid(void)
{
/* Only we change this so SMP safe */
- return current->euid;
+ return current_euid();
}

asmlinkage long sys_getgid(void)
{
/* Only we change this so SMP safe */
- return current->gid;
+ return current_gid();
}

asmlinkage long sys_getegid(void)
{
/* Only we change this so SMP safe */
- return current->egid;
+ return current_egid();
}

#endif
diff --git a/kernel/user_namespace.c b/kernel/user_namespace.c
index 532858f..f82730a 100644
--- a/kernel/user_namespace.c
+++ b/kernel/user_namespace.c
@@ -38,7 +38,7 @@ static struct user_namespace *clone_user_ns(struct user_namespace *old_ns)
}

/* Reset current->user with a new one */
- new_user = alloc_uid(ns, current->uid);
+ new_user = alloc_uid(ns, current_uid());
if (!new_user) {
free_uid(ns->root_user);
kfree(ns);
diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 8336905..27bcf7e 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -1110,6 +1110,7 @@ asmlinkage long sys_migrate_pages(pid_t pid, unsigned long maxnode,
nodemask_t old;
nodemask_t new;
nodemask_t task_nodes;
+ uid_t uid, euid;
int err;

err = get_nodes(&old, old_nodes, maxnode);
@@ -1139,8 +1140,10 @@ asmlinkage long sys_migrate_pages(pid_t pid, unsigned long maxnode,
* capabilities, superuser privileges or the same
* userid as the target process.
*/
- if ((current->euid != task->suid) && (current->euid != task->uid) &&
- (current->uid != task->suid) && (current->uid != task->uid) &&
+ uid = current_uid();
+ euid = current_euid();
+ if (euid != task->suid && euid != task->uid &&
+ uid != task->suid && uid != task->uid &&
!capable(CAP_SYS_NICE)) {
err = -EPERM;
goto out;
diff --git a/mm/migrate.c b/mm/migrate.c
index f9897ba..e6223d1 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -990,6 +990,7 @@ asmlinkage long sys_move_pages(pid_t pid, unsigned long nr_pages,
nodemask_t task_nodes;
struct mm_struct *mm;
struct page_to_node *pm = NULL;
+ uid_t uid, euid;

/* Check flags */
if (flags & ~(MPOL_MF_MOVE|MPOL_MF_MOVE_ALL))
@@ -1017,8 +1018,10 @@ asmlinkage long sys_move_pages(pid_t pid, unsigned long nr_pages,
* capabilities, superuser privileges or the same
* userid as the target process.
*/
- if ((current->euid != task->suid) && (current->euid != task->uid) &&
- (current->uid != task->suid) && (current->uid != task->uid) &&
+ uid = current_uid();
+ euid = current_euid();
+ if (euid != task->suid && euid != task->uid &&
+ uid != task->suid && uid != task->uid &&
!capable(CAP_SYS_NICE)) {
err = -EPERM;
goto out2;
diff --git a/mm/shmem.c b/mm/shmem.c
index 04fb4f1..c935bb4 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -1510,8 +1510,8 @@ shmem_get_inode(struct super_block *sb, int mode, dev_t dev)
inode = new_inode(sb);
if (inode) {
inode->i_mode = mode;
- inode->i_uid = current->fsuid;
- inode->i_gid = current->fsgid;
+ inode->i_uid = current_fsuid();
+ inode->i_gid = current_fsgid();
inode->i_blocks = 0;
inode->i_mapping->backing_dev_info = &shmem_backing_dev_info;
inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
@@ -2275,8 +2275,8 @@ static int shmem_fill_super(struct super_block *sb,
sbinfo->max_blocks = 0;
sbinfo->max_inodes = 0;
sbinfo->mode = S_IRWXUGO | S_ISVTX;
- sbinfo->uid = current->fsuid;
- sbinfo->gid = current->fsgid;
+ sbinfo->uid = current_fsuid();
+ sbinfo->gid = current_fsgid();
sbinfo->mpol = NULL;
sb->s_fs_info = sbinfo;