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Diffstat (limited to 'kernel/signal.c')
-rw-r--r--kernel/signal.c124
1 files changed, 67 insertions, 57 deletions
diff --git a/kernel/signal.c b/kernel/signal.c
index 4530fc65445..e73759783dc 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -41,6 +41,8 @@
static struct kmem_cache *sigqueue_cachep;
+DEFINE_TRACE(sched_signal_send);
+
static void __user *sig_handler(struct task_struct *t, int sig)
{
return t->sighand->action[sig - 1].sa.sa_handler;
@@ -177,6 +179,11 @@ int next_signal(struct sigpending *pending, sigset_t *mask)
return sig;
}
+/*
+ * allocate a new signal queue record
+ * - this may be called without locks if and only if t == current, otherwise an
+ * appopriate lock must be held to stop the target task from exiting
+ */
static struct sigqueue *__sigqueue_alloc(struct task_struct *t, gfp_t flags,
int override_rlimit)
{
@@ -184,11 +191,12 @@ static struct sigqueue *__sigqueue_alloc(struct task_struct *t, gfp_t flags,
struct user_struct *user;
/*
- * In order to avoid problems with "switch_user()", we want to make
- * sure that the compiler doesn't re-load "t->user"
+ * We won't get problems with the target's UID changing under us
+ * because changing it requires RCU be used, and if t != current, the
+ * caller must be holding the RCU readlock (by way of a spinlock) and
+ * we use RCU protection here
*/
- user = t->user;
- barrier();
+ user = get_uid(__task_cred(t)->user);
atomic_inc(&user->sigpending);
if (override_rlimit ||
atomic_read(&user->sigpending) <=
@@ -196,12 +204,14 @@ static struct sigqueue *__sigqueue_alloc(struct task_struct *t, gfp_t flags,
q = kmem_cache_alloc(sigqueue_cachep, flags);
if (unlikely(q == NULL)) {
atomic_dec(&user->sigpending);
+ free_uid(user);
} else {
INIT_LIST_HEAD(&q->list);
q->flags = 0;
- q->user = get_uid(user);
+ q->user = user;
}
- return(q);
+
+ return q;
}
static void __sigqueue_free(struct sigqueue *q)
@@ -562,10 +572,12 @@ static int rm_from_queue(unsigned long mask, struct sigpending *s)
/*
* Bad permissions for sending the signal
+ * - the caller must hold at least the RCU read lock
*/
static int check_kill_permission(int sig, struct siginfo *info,
struct task_struct *t)
{
+ const struct cred *cred = current_cred(), *tcred;
struct pid *sid;
int error;
@@ -579,8 +591,11 @@ 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) &&
+ tcred = __task_cred(t);
+ if ((cred->euid ^ tcred->suid) &&
+ (cred->euid ^ tcred->uid) &&
+ (cred->uid ^ tcred->suid) &&
+ (cred->uid ^ tcred->uid) &&
!capable(CAP_KILL)) {
switch (sig) {
case SIGCONT:
@@ -843,8 +858,9 @@ static int send_signal(int sig, struct siginfo *info, struct task_struct *t,
q->info.si_signo = sig;
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_pid = task_tgid_nr_ns(current,
+ task_active_pid_ns(t));
+ q->info.si_uid = current_uid();
break;
case (unsigned long) SEND_SIG_PRIV:
q->info.si_signo = sig;
@@ -1008,6 +1024,10 @@ struct sighand_struct *lock_task_sighand(struct task_struct *tsk, unsigned long
return sighand;
}
+/*
+ * send signal info to all the members of a group
+ * - the caller must hold the RCU read lock at least
+ */
int group_send_sig_info(int sig, struct siginfo *info, struct task_struct *p)
{
unsigned long flags;
@@ -1029,8 +1049,8 @@ int group_send_sig_info(int sig, struct siginfo *info, struct task_struct *p)
/*
* __kill_pgrp_info() sends a signal to a process group: this is what the tty
* control characters do (^C, ^Z etc)
+ * - the caller must hold at least a readlock on tasklist_lock
*/
-
int __kill_pgrp_info(int sig, struct siginfo *info, struct pid *pgrp)
{
struct task_struct *p = NULL;
@@ -1086,6 +1106,7 @@ int kill_pid_info_as_uid(int sig, struct siginfo *info, struct pid *pid,
{
int ret = -EINVAL;
struct task_struct *p;
+ const struct cred *pcred;
if (!valid_signal(sig))
return ret;
@@ -1096,9 +1117,11 @@ int kill_pid_info_as_uid(int sig, struct siginfo *info, struct pid *pid,
ret = -ESRCH;
goto out_unlock;
}
- if ((info == SEND_SIG_NOINFO || (!is_si_special(info) && SI_FROMUSER(info)))
- && (euid != p->suid) && (euid != p->uid)
- && (uid != p->suid) && (uid != p->uid)) {
+ pcred = __task_cred(p);
+ if ((info == SEND_SIG_NOINFO ||
+ (!is_si_special(info) && SI_FROMUSER(info))) &&
+ euid != pcred->suid && euid != pcred->uid &&
+ uid != pcred->suid && uid != pcred->uid) {
ret = -EPERM;
goto out_unlock;
}
@@ -1369,10 +1392,9 @@ int do_notify_parent(struct task_struct *tsk, int sig)
*/
rcu_read_lock();
info.si_pid = task_pid_nr_ns(tsk, tsk->parent->nsproxy->pid_ns);
+ info.si_uid = __task_cred(tsk)->uid;
rcu_read_unlock();
- info.si_uid = tsk->uid;
-
thread_group_cputime(tsk, &cputime);
info.si_utime = cputime_to_jiffies(cputime.utime);
info.si_stime = cputime_to_jiffies(cputime.stime);
@@ -1440,10 +1462,9 @@ static void do_notify_parent_cldstop(struct task_struct *tsk, int why)
*/
rcu_read_lock();
info.si_pid = task_pid_nr_ns(tsk, tsk->parent->nsproxy->pid_ns);
+ info.si_uid = __task_cred(tsk)->uid;
rcu_read_unlock();
- info.si_uid = tsk->uid;
-
info.si_utime = cputime_to_clock_t(tsk->utime);
info.si_stime = cputime_to_clock_t(tsk->stime);
@@ -1598,7 +1619,7 @@ 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);
@@ -1710,7 +1731,7 @@ static int ptrace_signal(int signr, siginfo_t *info,
info->si_errno = 0;
info->si_code = SI_USER;
info->si_pid = task_pid_vnr(current->parent);
- info->si_uid = current->parent->uid;
+ info->si_uid = task_uid(current->parent);
}
/* If the (new) signal is now blocked, requeue it. */
@@ -1940,7 +1961,7 @@ EXPORT_SYMBOL(unblock_all_signals);
* System call entry points.
*/
-asmlinkage long sys_restart_syscall(void)
+SYSCALL_DEFINE0(restart_syscall)
{
struct restart_block *restart = &current_thread_info()->restart_block;
return restart->fn(restart);
@@ -1993,8 +2014,8 @@ int sigprocmask(int how, sigset_t *set, sigset_t *oldset)
return error;
}
-asmlinkage long
-sys_rt_sigprocmask(int how, sigset_t __user *set, sigset_t __user *oset, size_t sigsetsize)
+SYSCALL_DEFINE4(rt_sigprocmask, int, how, sigset_t __user *, set,
+ sigset_t __user *, oset, size_t, sigsetsize)
{
int error = -EINVAL;
sigset_t old_set, new_set;
@@ -2053,8 +2074,7 @@ out:
return error;
}
-asmlinkage long
-sys_rt_sigpending(sigset_t __user *set, size_t sigsetsize)
+SYSCALL_DEFINE2(rt_sigpending, sigset_t __user *, set, size_t, sigsetsize)
{
return do_sigpending(set, sigsetsize);
}
@@ -2125,11 +2145,9 @@ int copy_siginfo_to_user(siginfo_t __user *to, siginfo_t *from)
#endif
-asmlinkage long
-sys_rt_sigtimedwait(const sigset_t __user *uthese,
- siginfo_t __user *uinfo,
- const struct timespec __user *uts,
- size_t sigsetsize)
+SYSCALL_DEFINE4(rt_sigtimedwait, const sigset_t __user *, uthese,
+ siginfo_t __user *, uinfo, const struct timespec __user *, uts,
+ size_t, sigsetsize)
{
int ret, sig;
sigset_t these;
@@ -2202,8 +2220,7 @@ sys_rt_sigtimedwait(const sigset_t __user *uthese,
return ret;
}
-asmlinkage long
-sys_kill(pid_t pid, int sig)
+SYSCALL_DEFINE2(kill, pid_t, pid, int, sig)
{
struct siginfo info;
@@ -2211,7 +2228,7 @@ 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);
}
@@ -2228,7 +2245,7 @@ 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);
@@ -2262,7 +2279,7 @@ static int do_tkill(pid_t tgid, pid_t pid, int sig)
* exists but it's not belonging to the target process anymore. This
* method solves the problem of threads exiting and PIDs getting reused.
*/
-asmlinkage long sys_tgkill(pid_t tgid, pid_t pid, int sig)
+SYSCALL_DEFINE3(tgkill, pid_t, tgid, pid_t, pid, int, sig)
{
/* This is only valid for single tasks */
if (pid <= 0 || tgid <= 0)
@@ -2274,8 +2291,7 @@ asmlinkage long sys_tgkill(pid_t tgid, pid_t pid, int sig)
/*
* Send a signal to only one task, even if it's a CLONE_THREAD task.
*/
-asmlinkage long
-sys_tkill(pid_t pid, int sig)
+SYSCALL_DEFINE2(tkill, pid_t, pid, int, sig)
{
/* This is only valid for single tasks */
if (pid <= 0)
@@ -2284,8 +2300,8 @@ sys_tkill(pid_t pid, int sig)
return do_tkill(0, pid, sig);
}
-asmlinkage long
-sys_rt_sigqueueinfo(pid_t pid, int sig, siginfo_t __user *uinfo)
+SYSCALL_DEFINE3(rt_sigqueueinfo, pid_t, pid, int, sig,
+ siginfo_t __user *, uinfo)
{
siginfo_t info;
@@ -2413,8 +2429,7 @@ out:
#ifdef __ARCH_WANT_SYS_SIGPENDING
-asmlinkage long
-sys_sigpending(old_sigset_t __user *set)
+SYSCALL_DEFINE1(sigpending, old_sigset_t __user *, set)
{
return do_sigpending(set, sizeof(*set));
}
@@ -2425,8 +2440,8 @@ sys_sigpending(old_sigset_t __user *set)
/* Some platforms have their own version with special arguments others
support only sys_rt_sigprocmask. */
-asmlinkage long
-sys_sigprocmask(int how, old_sigset_t __user *set, old_sigset_t __user *oset)
+SYSCALL_DEFINE3(sigprocmask, int, how, old_sigset_t __user *, set,
+ old_sigset_t __user *, oset)
{
int error;
old_sigset_t old_set, new_set;
@@ -2476,11 +2491,10 @@ out:
#endif /* __ARCH_WANT_SYS_SIGPROCMASK */
#ifdef __ARCH_WANT_SYS_RT_SIGACTION
-asmlinkage long
-sys_rt_sigaction(int sig,
- const struct sigaction __user *act,
- struct sigaction __user *oact,
- size_t sigsetsize)
+SYSCALL_DEFINE4(rt_sigaction, int, sig,
+ const struct sigaction __user *, act,
+ struct sigaction __user *, oact,
+ size_t, sigsetsize)
{
struct k_sigaction new_sa, old_sa;
int ret = -EINVAL;
@@ -2510,15 +2524,13 @@ out:
/*
* For backwards compatibility. Functionality superseded by sigprocmask.
*/
-asmlinkage long
-sys_sgetmask(void)
+SYSCALL_DEFINE0(sgetmask)
{
/* SMP safe */
return current->blocked.sig[0];
}
-asmlinkage long
-sys_ssetmask(int newmask)
+SYSCALL_DEFINE1(ssetmask, int, newmask)
{
int old;
@@ -2538,8 +2550,7 @@ sys_ssetmask(int newmask)
/*
* For backwards compatibility. Functionality superseded by sigaction.
*/
-asmlinkage unsigned long
-sys_signal(int sig, __sighandler_t handler)
+SYSCALL_DEFINE2(signal, int, sig, __sighandler_t, handler)
{
struct k_sigaction new_sa, old_sa;
int ret;
@@ -2556,8 +2567,7 @@ sys_signal(int sig, __sighandler_t handler)
#ifdef __ARCH_WANT_SYS_PAUSE
-asmlinkage long
-sys_pause(void)
+SYSCALL_DEFINE0(pause)
{
current->state = TASK_INTERRUPTIBLE;
schedule();
@@ -2567,7 +2577,7 @@ sys_pause(void)
#endif
#ifdef __ARCH_WANT_SYS_RT_SIGSUSPEND
-asmlinkage long sys_rt_sigsuspend(sigset_t __user *unewset, size_t sigsetsize)
+SYSCALL_DEFINE2(rt_sigsuspend, sigset_t __user *, unewset, size_t, sigsetsize)
{
sigset_t newset;
generated by cgit v1.2.3 (git 2.25.1) at 2024-05-03 18:21:37 +0000