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-rw-r--r--kernel/signal.c111
1 files changed, 88 insertions, 23 deletions
diff --git a/kernel/signal.c b/kernel/signal.c
index 0af8868525d..7aaa51d8e5b 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -31,6 +31,7 @@
#include <linux/nsproxy.h>
#include <linux/user_namespace.h>
#include <linux/uprobes.h>
+#include <linux/compat.h>
#define CREATE_TRACE_POINTS
#include <trace/events/signal.h>
@@ -1159,8 +1160,9 @@ static int send_signal(int sig, struct siginfo *info, struct task_struct *t,
return __send_signal(sig, info, t, group, from_ancestor_ns);
}
-static void print_fatal_signal(struct pt_regs *regs, int signr)
+static void print_fatal_signal(int signr)
{
+ struct pt_regs *regs = signal_pt_regs();
printk("%s/%d: potentially unexpected fatal signal %d.\n",
current->comm, task_pid_nr(current), signr);
@@ -1752,7 +1754,7 @@ static void do_notify_parent_cldstop(struct task_struct *tsk,
* see comment in do_notify_parent() about the following 4 lines
*/
rcu_read_lock();
- info.si_pid = task_pid_nr_ns(tsk, parent->nsproxy->pid_ns);
+ info.si_pid = task_pid_nr_ns(tsk, task_active_pid_ns(parent));
info.si_uid = from_kuid_munged(task_cred_xxx(parent, user_ns), task_uid(tsk));
rcu_read_unlock();
@@ -1908,7 +1910,7 @@ static void ptrace_stop(int exit_code, int why, int clear_code, siginfo_t *info)
preempt_disable();
read_unlock(&tasklist_lock);
preempt_enable_no_resched();
- schedule();
+ freezable_schedule();
} else {
/*
* By the time we got the lock, our tracer went away.
@@ -1930,13 +1932,6 @@ static void ptrace_stop(int exit_code, int why, int clear_code, siginfo_t *info)
}
/*
- * While in TASK_TRACED, we were considered "frozen enough".
- * Now that we woke up, it's crucial if we're supposed to be
- * frozen that we freeze now before running anything substantial.
- */
- try_to_freeze();
-
- /*
* We are back. Now reacquire the siglock before touching
* last_siginfo, so that we are sure to have synchronized with
* any signal-sending on another CPU that wants to examine it.
@@ -2092,7 +2087,7 @@ static bool do_signal_stop(int signr)
}
/* Now we don't run again until woken by SIGCONT or SIGKILL */
- schedule();
+ freezable_schedule();
return true;
} else {
/*
@@ -2138,10 +2133,9 @@ static void do_jobctl_trap(void)
}
}
-static int ptrace_signal(int signr, siginfo_t *info,
- struct pt_regs *regs, void *cookie)
+static int ptrace_signal(int signr, siginfo_t *info)
{
- ptrace_signal_deliver(regs, cookie);
+ ptrace_signal_deliver();
/*
* We do not check sig_kernel_stop(signr) but set this marker
* unconditionally because we do not know whether debugger will
@@ -2200,15 +2194,14 @@ int get_signal_to_deliver(siginfo_t *info, struct k_sigaction *return_ka,
if (unlikely(uprobe_deny_signal()))
return 0;
-relock:
/*
- * We'll jump back here after any time we were stopped in TASK_STOPPED.
- * While in TASK_STOPPED, we were considered "frozen enough".
- * Now that we woke up, it's crucial if we're supposed to be
- * frozen that we freeze now before running anything substantial.
+ * Do this once, we can't return to user-mode if freezing() == T.
+ * do_signal_stop() and ptrace_stop() do freezable_schedule() and
+ * thus do not need another check after return.
*/
try_to_freeze();
+relock:
spin_lock_irq(&sighand->siglock);
/*
* Every stopped thread goes here after wakeup. Check to see if
@@ -2265,8 +2258,7 @@ relock:
break; /* will return 0 */
if (unlikely(current->ptrace) && signr != SIGKILL) {
- signr = ptrace_signal(signr, info,
- regs, cookie);
+ signr = ptrace_signal(signr, info);
if (!signr)
continue;
}
@@ -2351,7 +2343,7 @@ relock:
if (sig_kernel_coredump(signr)) {
if (print_fatal_signals)
- print_fatal_signal(regs, info->si_signo);
+ print_fatal_signal(info->si_signo);
/*
* If it was able to dump core, this kills all
* other threads in the group and synchronizes with
@@ -2360,7 +2352,7 @@ relock:
* first and our do_group_exit call below will use
* that value and ignore the one we pass it.
*/
- do_coredump(info, regs);
+ do_coredump(info);
}
/*
@@ -3103,6 +3095,79 @@ do_sigaltstack (const stack_t __user *uss, stack_t __user *uoss, unsigned long s
out:
return error;
}
+#ifdef CONFIG_GENERIC_SIGALTSTACK
+SYSCALL_DEFINE2(sigaltstack,const stack_t __user *,uss, stack_t __user *,uoss)
+{
+ return do_sigaltstack(uss, uoss, current_user_stack_pointer());
+}
+#endif
+
+int restore_altstack(const stack_t __user *uss)
+{
+ int err = do_sigaltstack(uss, NULL, current_user_stack_pointer());
+ /* squash all but EFAULT for now */
+ return err == -EFAULT ? err : 0;
+}
+
+int __save_altstack(stack_t __user *uss, unsigned long sp)
+{
+ struct task_struct *t = current;
+ return __put_user((void __user *)t->sas_ss_sp, &uss->ss_sp) |
+ __put_user(sas_ss_flags(sp), &uss->ss_flags) |
+ __put_user(t->sas_ss_size, &uss->ss_size);
+}
+
+#ifdef CONFIG_COMPAT
+#ifdef CONFIG_GENERIC_SIGALTSTACK
+asmlinkage long compat_sys_sigaltstack(const compat_stack_t __user *uss_ptr,
+ compat_stack_t __user *uoss_ptr)
+{
+ stack_t uss, uoss;
+ int ret;
+ mm_segment_t seg;
+
+ if (uss_ptr) {
+ compat_stack_t uss32;
+
+ memset(&uss, 0, sizeof(stack_t));
+ if (copy_from_user(&uss32, uss_ptr, sizeof(compat_stack_t)))
+ return -EFAULT;
+ uss.ss_sp = compat_ptr(uss32.ss_sp);
+ uss.ss_flags = uss32.ss_flags;
+ uss.ss_size = uss32.ss_size;
+ }
+ seg = get_fs();
+ set_fs(KERNEL_DS);
+ ret = do_sigaltstack((stack_t __force __user *) (uss_ptr ? &uss : NULL),
+ (stack_t __force __user *) &uoss,
+ compat_user_stack_pointer());
+ set_fs(seg);
+ if (ret >= 0 && uoss_ptr) {
+ if (!access_ok(VERIFY_WRITE, uoss_ptr, sizeof(compat_stack_t)) ||
+ __put_user(ptr_to_compat(uoss.ss_sp), &uoss_ptr->ss_sp) ||
+ __put_user(uoss.ss_flags, &uoss_ptr->ss_flags) ||
+ __put_user(uoss.ss_size, &uoss_ptr->ss_size))
+ ret = -EFAULT;
+ }
+ return ret;
+}
+
+int compat_restore_altstack(const compat_stack_t __user *uss)
+{
+ int err = compat_sys_sigaltstack(uss, NULL);
+ /* squash all but -EFAULT for now */
+ return err == -EFAULT ? err : 0;
+}
+
+int __compat_save_altstack(compat_stack_t __user *uss, unsigned long sp)
+{
+ struct task_struct *t = current;
+ return __put_user(ptr_to_compat((void __user *)t->sas_ss_sp), &uss->ss_sp) |
+ __put_user(sas_ss_flags(sp), &uss->ss_flags) |
+ __put_user(t->sas_ss_size, &uss->ss_size);
+}
+#endif
+#endif
#ifdef __ARCH_WANT_SYS_SIGPENDING
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