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* [glibc] stdlib: Avoid -Wuse-after-free in __add_to_environ [BZ #26779]
@ 2022-01-26 2:58 Martin Sebor
0 siblings, 0 replies; only message in thread
From: Martin Sebor @ 2022-01-26 2:58 UTC (permalink / raw)
To: glibc-cvs
https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=4f20a1dc5242fb4bb8763e0451df898fa48e740c
commit 4f20a1dc5242fb4bb8763e0451df898fa48e740c
Author: Martin Sebor <msebor@redhat.com>
Date: Tue Jan 25 17:39:36 2022 -0700
stdlib: Avoid -Wuse-after-free in __add_to_environ [BZ #26779]
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Diff:
---
stdlib/setenv.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/stdlib/setenv.c b/stdlib/setenv.c
index c3d2cee7b6..2176cbac31 100644
--- a/stdlib/setenv.c
+++ b/stdlib/setenv.c
@@ -150,7 +150,9 @@ __add_to_environ (const char *name, const char *value, const char *combined,
{
char **new_environ;
- /* We allocated this space; we can extend it. */
+ /* We allocated this space; we can extend it. Avoid using the raw
+ reallocated pointer to avoid GCC -Wuse-after-free. */
+ uintptr_t ip_last_environ = (uintptr_t)last_environ;
new_environ = (char **) realloc (last_environ,
(size + 2) * sizeof (char *));
if (new_environ == NULL)
@@ -159,7 +161,7 @@ __add_to_environ (const char *name, const char *value, const char *combined,
return -1;
}
- if (__environ != last_environ)
+ if ((uintptr_t)__environ != ip_last_environ)
memcpy ((char *) new_environ, (char *) __environ,
size * sizeof (char *));
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2022-01-26 2:58 [glibc] stdlib: Avoid -Wuse-after-free in __add_to_environ [BZ #26779] Martin Sebor
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