X-Git-Url: http://git.rot13.org/?a=blobdiff_plain;f=kernel%2Fsignal.c;h=bfdb5686fa3e4e3d23075afd2bf21bf680ba0aae;hb=6e936d3e9a45a4307e7f4a29ee9829e7a0464af1;hp=1b3c921737e219a6f56281db270f8ccfbef0e6ab;hpb=28e4b224955cbe30275b2a7842e729023a4f4b03;p=powerpc.git

diff --git a/kernel/signal.c b/kernel/signal.c
index 1b3c921737..bfdb5686fa 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -10,7 +10,6 @@
  *		to allow signals to be sent reliably.
  */
 
-#include <linux/config.h>
 #include <linux/slab.h>
 #include <linux/module.h>
 #include <linux/smp_lock.h>
@@ -584,7 +583,7 @@ static int check_kill_permission(int sig, struct siginfo *info,
 	    && !capable(CAP_KILL))
 		return error;
 
-	error = security_task_kill(t, info, sig);
+	error = security_task_kill(t, info, sig, 0);
 	if (!error)
 		audit_signal_info(sig, t); /* Let audit system see the signal */
 	return error;
@@ -792,22 +791,31 @@ out:
 /*
  * Force a signal that the process can't ignore: if necessary
  * we unblock the signal and change any SIG_IGN to SIG_DFL.
+ *
+ * Note: If we unblock the signal, we always reset it to SIG_DFL,
+ * since we do not want to have a signal handler that was blocked
+ * be invoked when user space had explicitly blocked it.
+ *
+ * We don't want to have recursive SIGSEGV's etc, for example.
  */
-
 int
 force_sig_info(int sig, struct siginfo *info, struct task_struct *t)
 {
 	unsigned long int flags;
-	int ret;
+	int ret, blocked, ignored;
+	struct k_sigaction *action;
 
 	spin_lock_irqsave(&t->sighand->siglock, flags);
-	if (t->sighand->action[sig-1].sa.sa_handler == SIG_IGN) {
-		t->sighand->action[sig-1].sa.sa_handler = SIG_DFL;
-	}
-	if (sigismember(&t->blocked, sig)) {
-		sigdelset(&t->blocked, sig);
+	action = &t->sighand->action[sig-1];
+	ignored = action->sa.sa_handler == SIG_IGN;
+	blocked = sigismember(&t->blocked, sig);
+	if (blocked || ignored) {
+		action->sa.sa_handler = SIG_DFL;
+		if (blocked) {
+			sigdelset(&t->blocked, sig);
+			recalc_sigpending_tsk(t);
+		}
 	}
-	recalc_sigpending_tsk(t);
 	ret = specific_send_sig_info(sig, info, t);
 	spin_unlock_irqrestore(&t->sighand->siglock, flags);
 
@@ -1107,7 +1115,7 @@ kill_proc_info(int sig, struct siginfo *info, pid_t pid)
 
 /* like kill_proc_info(), but doesn't use uid/euid of "current" */
 int kill_proc_info_as_uid(int sig, struct siginfo *info, pid_t pid,
-		      uid_t uid, uid_t euid)
+		      uid_t uid, uid_t euid, u32 secid)
 {
 	int ret = -EINVAL;
 	struct task_struct *p;
@@ -1127,6 +1135,9 @@ int kill_proc_info_as_uid(int sig, struct siginfo *info, pid_t pid,
 		ret = -EPERM;
 		goto out_unlock;
 	}
+	ret = security_task_kill(p, info, sig, secid);
+	if (ret)
+		goto out_unlock;
 	if (sig && p->sighand) {
 		unsigned long flags;
 		spin_lock_irqsave(&p->sighand->siglock, flags);
@@ -1531,6 +1542,35 @@ static void do_notify_parent_cldstop(struct task_struct *tsk, int why)
 	spin_unlock_irqrestore(&sighand->siglock, flags);
 }
 
+static inline int may_ptrace_stop(void)
+{
+	if (!likely(current->ptrace & PT_PTRACED))
+		return 0;
+
+	if (unlikely(current->parent == current->real_parent &&
+		    (current->ptrace & PT_ATTACHED)))
+		return 0;
+
+	if (unlikely(current->signal == current->parent->signal) &&
+	    unlikely(current->signal->flags & SIGNAL_GROUP_EXIT))
+		return 0;
+
+	/*
+	 * Are we in the middle of do_coredump?
+	 * If so and our tracer is also part of the coredump stopping
+	 * is a deadlock situation, and pointless because our tracer
+	 * is dead so don't allow us to stop.
+	 * If SIGKILL was already sent before the caller unlocked
+	 * ->siglock we must see ->core_waiters != 0. Otherwise it
+	 * is safe to enter schedule().
+	 */
+	if (unlikely(current->mm->core_waiters) &&
+	    unlikely(current->mm == current->parent->mm))
+		return 0;
+
+	return 1;
+}
+
 /*
  * This must be called with current->sighand->siglock held.
  *
@@ -1559,11 +1599,7 @@ static void ptrace_stop(int exit_code, int nostop_code, siginfo_t *info)
 	spin_unlock_irq(&current->sighand->siglock);
 	try_to_freeze();
 	read_lock(&tasklist_lock);
-	if (likely(current->ptrace & PT_PTRACED) &&
-	    likely(current->parent != current->real_parent ||
-		   !(current->ptrace & PT_ATTACHED)) &&
-	    (likely(current->parent->signal != current->signal) ||
-	     !unlikely(current->signal->flags & SIGNAL_GROUP_EXIT))) {
+	if (may_ptrace_stop()) {
 		do_notify_parent_cldstop(current, CLD_TRAPPED);
 		read_unlock(&tasklist_lock);
 		schedule();