commit c2bb9e106a32619726cfc5052a1509e96b90de9f
parent c7e82d4863992c2f3bbb6f5a31fa8e5fd0e1643f
Author: Natanael Copa <ncopa@alpinelinux.org>
Date: Thu, 7 May 2015 14:50:03 +0200
fix realpath when stdlib.h is included before limits.h
If program includes stdlib.h before limits.h without _XOPEN_SOURCE,
_GNU_SOURCE or _BSD_SOURCE explicitly set, then will it always trigger
the trap with musl libc.
This is becase stdlib.h will pull in features.h which will set
_GNU_SOURCE. This means that the fortify stdlib.h will not include
limits.h but it will still trigger the fortified realpath(), but without
PATH_MAX set.
We fix this by including system stdlib.h before testing if limits.h
should be included.
Since PATH_MAX is known at compile time we can also error at compile
time, instead of compiling a broken realpath().
Diffstat:
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/include/stdlib.h b/include/stdlib.h
@@ -1,12 +1,12 @@
#ifndef _FORTIFY_STDLIB_H
#define _FORTIFY_STDLIB_H
+#include_next <stdlib.h>
+
#if defined(_XOPEN_SOURCE) || defined(_GNU_SOURCE) || defined(_BSD_SOURCE)
#include_next <limits.h>
#endif
-#include_next <stdlib.h>
-
#if defined(_FORTIFY_SOURCE) && _FORTIFY_SOURCE > 0 && defined(__OPTIMIZE__) && __OPTIMIZE__ > 0
#ifdef __cplusplus
@@ -23,7 +23,7 @@ char *realpath(const char *path, char *resolved)
if (resolved) {
#ifndef PATH_MAX
- __builtin_trap();
+# error PATH_MAX unset. A fortified realpath will not work.
#else
bos = __builtin_object_size(resolved, 0);
if (PATH_MAX > bos)