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authorEric Biggers <ebiggers3@gmail.com>2015-01-07 12:10:52 +0530
committerSiddhesh Poyarekar <siddhesh@redhat.com>2015-01-07 12:10:52 +0530
commitd5b1c5ed8bd9515505d4177f105c19ea375106ae (patch)
tree5e7164983b8a3e4f3a16e8069495a46c8c33d7b3 /stdlib
parentfb87ee96d7dd0714d52004e4676629f8d9db732f (diff)
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setenv fix memory leak when setting large, duplicate string (BZ #17658)
glibc maintains a binary tree of environment strings it malloc()ed itself. However, it's possible for it to malloc() a string, then find that an identical string is already in the tree. In this case, the memory is leaked and is not freed if the application later calls __libc_freeres(). Fix this by freeing 'new_value' when it's unneeded. Test case: #include <stdlib.h> #include <string.h> int main() { char *p = calloc(100000, 1); memset(p, 'A', 99999); setenv("TESTVAR", p, 1); setenv("TESTVAR", p, 1); free(p); } Leak that was reported by valgrind: 100,008 bytes in 1 blocks are definitely lost in loss record 1 of 1 at 0x4C29F90: malloc (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so) by 0x4E6B3D4: __add_to_environ (setenv.c:176) by 0x4C31B8F: setenv (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so) by 0x400642: main (in /mnt/tmpfs/a.out)
Diffstat (limited to 'stdlib')
-rw-r--r--stdlib/setenv.c7
1 files changed, 7 insertions, 0 deletions
diff --git a/stdlib/setenv.c b/stdlib/setenv.c
index 710da13..b60c4f0 100644
--- a/stdlib/setenv.c
+++ b/stdlib/setenv.c
@@ -217,6 +217,13 @@ __add_to_environ (name, value, combined, replace)
/* And remember the value. */
STORE_VALUE (np);
}
+#ifdef USE_TSEARCH
+ else
+ {
+ if (__glibc_unlikely (! use_alloca))
+ free (new_value);
+ }
+#endif
}
*ep = np;