1 files changed, 44 insertions, 3 deletions
diff --git a/sysdeps/posix/raise.c b/sysdeps/posix/raise.c
index 1f02b201e1..f171dc2407 100644
--- a/sysdeps/posix/raise.c
+++ b/sysdeps/posix/raise.c
@@ -15,14 +15,55 @@
    License along with the GNU C Library; if not, see
    <http://www.gnu.org/licenses/>.  */
 
+#include <errno.h>
 #include <signal.h>
 #include <unistd.h>
+#include <internal-signals.h>
 
-/* Raise the signal SIG.  */
+/* Raise the signal SIG.  POSIX requires raise to be async-signal-safe,
+   but calling getpid and then raise is *not* async-signal-safe; if an
+   async signal handler calls fork (which is also async-signal-safe)
+   in between the two operations, and returns normally on both sides
+   of the fork, kill will be called twice.  So we must block signals
+   around the operation.  See bug 15368 for more detail.
+ */
 int
-raise (int sig)
+__libc_raise (int sig)
 {
-  return __kill (__getpid (), sig);
+  /* Disallow sending the signals we use for cancellation, timers,
+     setxid, etc.  This check is also performed in __kill, but
+     if we do it now we can avoid blocking and then unblocking signals
+     unnecessarily.  */
+  if (__glibc_unlikely (__is_internal_signal (sig)))
+    {
+      __set_errno (EINVAL);
+      return -1;
+    }
+
+  /* We can safely assume that __libc_signal_block_app and
+     __libc_signal_restore_set will not fail, because
+     sigprocmask can only fail under three circumstances:
+
+     1. sigsetsize != sizeof (sigset_t) (EINVAL)
+     2. a failure in copy from/to user space (EFAULT)
+     3. an invalid 'how' operation (EINVAL)
+
+     Getting any of these would indicate a bug in either the
+     definition of sigset_t or the implementations of the
+     wrappers.  */
+  sigset_t omask;
+  __libc_signal_block_app (&omask);
+
+  int ret = __kill (__getpid (), sig);
+
+  /* ... But just because sigprocmask will not fail here, that doesn't
+     mean it won't clobber errno.  */
+  int save_errno = errno;
+  __libc_signal_restore_set (&omask);
+  __set_errno (errno);
+
+  return ret;
 }
+strong_alias (__libc_raise, raise)
 libc_hidden_def (raise)
 weak_alias (raise, gsignal)