X-Git-Url: http://nsz.repo.hu/git/?a=blobdiff_plain;f=src%2Fenv%2F__stack_chk_fail.c;h=e53526020f751d34542f07c6b30d94c5dc08bf72;hb=c499c1084eaccd83e4b6e60883a5d92df0202c5e;hp=3e2e4b6dfabac5d60194c33eee3c1e4b58371dec;hpb=0a96a37f06fda78ce3674b425888b1fc090578aa;p=musl

diff --git a/src/env/__stack_chk_fail.c b/src/env/__stack_chk_fail.c
index 3e2e4b6d..e5352602 100644
--- a/src/env/__stack_chk_fail.c
+++ b/src/env/__stack_chk_fail.c
@@ -1,23 +1,31 @@
 #include <string.h>
-#include <inttypes.h>
-#include <elf.h>
+#include <stdint.h>
 #include "pthread_impl.h"
-#include "atomic.h"
 
 uintptr_t __stack_chk_guard;
 
 void __init_ssp(void *entropy)
 {
-	size_t i;
-	pthread_t self = __pthread_self_init();
-	uintptr_t canary;
-	if (entropy) memcpy(&canary, entropy, sizeof canary);
-	else canary = (uintptr_t)&canary * 1103515245;
-	a_cas_l(&__stack_chk_guard, 0, canary);
-	self->canary = __stack_chk_guard;
+	if (entropy) memcpy(&__stack_chk_guard, entropy, sizeof(uintptr_t));
+	else __stack_chk_guard = (uintptr_t)&__stack_chk_guard * 1103515245;
+
+#if UINTPTR_MAX >= 0xffffffffffffffff
+	/* Sacrifice 8 bits of entropy on 64bit to prevent leaking/
+	 * overwriting the canary via string-manipulation functions.
+	 * The NULL byte is on the second byte so that off-by-ones can
+	 * still be detected. Endianness is taken care of
+	 * automatically. */
+	((char *)&__stack_chk_guard)[1] = 0;
+#endif
+
+	__pthread_self()->canary = __stack_chk_guard;
 }
 
 void __stack_chk_fail(void)
 {
 	a_crash();
 }
+
+hidden void __stack_chk_fail_local(void);
+
+weak_alias(__stack_chk_fail, __stack_chk_fail_local);