[PATCH] Fix use after free() in builtin-fetch
As reported by Dave Jones:
Since master.kernel.org updated to latest, I noticed that I could crash git-fetch by doing this..
export KERNEL=/pub/scm/linux/kernel/git/ git fetch $KERNEL/torvalds/linux-2.6 master:linus
(gdb) bt
0 0x000000349fd6d44b in free () from /lib64/libc.so.6
1 0x000000000048f4eb in transport_unlock_pack (transport=0x7ce530) at transport.c:811
2 0x000000349fd31b25 in exit () from /lib64/libc.so.6
3 0x00000000004043d8 in handle_internal_command (argc=3, argv=0x7fffea4449f0) at git.c:379
4 0x0000000000404547 in main (argc=3, argv=0x7fffea4449f0) at git.c:443
5 0x000000349fd1c784 in __libc_start_main () from /lib64/libc.so.6
6 0x0000000000403ef9 in ?? ()
7 0x00007fffea4449d8 in ?? ()
8 0x0000000000000000 in ?? ()
I then remembered, my .bashrc has this..
export MALLOC_PERTURB_=$(($RANDOM % 255 + 1))
which is handy for showing up such bugs.
More info on this glibc feature is at http://udrepper.livejournal.com/11429.html
Signed-off-by: Alex Riesen <raa.lkml@gmail.com>
---
Dave Jones, Mon, Apr 28, 2008 20:41:38 +0200:
> (gdb) bt
> #0 0x000000349fd6d44b in free () from /lib64/libc.so.6
> #1 0x000000000048f4eb in transport_unlock_pack (transport=0x7ce530) at transport.c:811
> #2 0x000000349fd31b25 in exit () from /lib64/libc.so.6
atexit strikes again. Besides, I believe, do_fetch has no bussiness in deallocation of resources it did not allocate.
builtin-fetch.c | 8 +++++---
1 files changed, 5 insertions(+), 3 deletions(-)
diff --git a/builtin-fetch.c b/builtin-fetch.c
index 139a6b1..167f948 100644
--- a/builtin-fetch.c
+++ b/builtin-fetch.c
@@ -577,8 +577,6 @@ static int do_fetch(struct transport *transport,
free_refs(ref_map);
}
- transport_disconnect(transport);
-
return 0;
}
@@ -599,6 +597,7 @@ int cmd_fetch(int argc, const char **argv, const char *prefix)
int i;
static const char **refs = NULL;
int ref_nr = 0;
+ int exit_code;
/* Record the command line for the reflog */
strbuf_addstr(&default_rla, "fetch");
@@ -652,6 +651,9 @@ int cmd_fetch(int argc, const char **argv, const char *prefix)
signal(SIGINT, unlock_pack_on_signal);
atexit(unlock_pack);
- return do_fetch(transport,
+ exit_code = do_fetch(transport,
parse_fetch_refspec(ref_nr, refs), ref_nr);
+ transport_disconnect(transport);
+ transport = NULL;
+ return exit_code;
}
--
1.5.5.1.118.g6dd1b6.dirty
