From: Rich Felker <dalias@aerifal.cx>
Date: Sun, 3 Jun 2012 00:04:27 +0000 (-0400)
Subject: remove implementation-reserved bits when saving signal mask
X-Git-Url: http://nsz.repo.hu/git/?a=commitdiff_plain;h=40bd1726b6aa93a8311a77a1fec6da0fe0489fd0;p=musl

remove implementation-reserved bits when saving signal mask

this fix is necessary because a program could be started with some of
the implementation-reserved signals masked (e.g. due to exec having
been called from a signal handler, or from a non-musl program) and
then could obtain an invalid-to-use-later sigset_t as the old/saved
signal mask.
---

diff --git a/src/thread/pthread_sigmask.c b/src/thread/pthread_sigmask.c
index 60a440b4..decc38f8 100644
--- a/src/thread/pthread_sigmask.c
+++ b/src/thread/pthread_sigmask.c
@@ -5,6 +5,16 @@
 
 int pthread_sigmask(int how, const sigset_t *set, sigset_t *old)
 {
+	int ret;
 	if (how > 2U) return EINVAL;
-	return -__syscall(SYS_rt_sigprocmask, how, set, old, 8);
+	ret = -__syscall(SYS_rt_sigprocmask, how, set, old, 8);
+	if (!ret && old) {
+		if (sizeof old->__bits[0] == 8) {
+			old->__bits[0] &= ~0x380000000ULL;
+		} else {
+			old->__bits[0] &= ~0x80000000UL;
+			old->__bits[1] &= ~0x3UL;
+		}
+	}
+	return ret;
 }