diff options
author | Peter Wu <peter@lekensteyn.nl> | 2016-09-11 01:16:24 +0200 |
---|---|---|
committer | Roland Knall <rknall@gmail.com> | 2016-09-11 08:33:42 +0000 |
commit | 583150198b78c84d043455b0afcca58a9659eab3 (patch) | |
tree | e3ec231548eaf1b8a2de10ff75bf218d7f17169b /extcap.h | |
parent | b82695d9976ebed00f34bfc45f0358db095e0670 (diff) |
extcap: fix use-after-free for preferences
In commit v2.3.0rc0-117-g485bc45 (backported to v2.2.0rc0-44-g66721ca),
extcap_prefs_dynamic_vals and extcap_cleanup were added in an attempt to
address dangling pointers.
Unfortunately it is not sufficient:
- A pointer to the preference value is stored in extcap_arg and passed
to the prefs API, but this extcap_arg structure can become invalid
which result in use-after-free whenever the preference is accessed.
- On exit, a use-after-free occurs in prefs_cleanup when the preference
value is being checked.
As the preference subsystem actually manages the memory for the string
value and consumers should only provide a pointer where the value can be
stored, convert the char* field in extcap to char**. This has as
additional benefit that values are not limited to 256 bytes anymore.
extcap_cleanup is moved after epan_cleanup to ensure that prefs_cleanup
does not operate on dangling pointers.
Crash is reproducible under ASAN with: tshark -i randpkt
Ping-Bug: 12183
Change-Id: Ibf1ba1102a5633aa085dc278a12ffc05a4f4a34b
Reviewed-on: https://code.wireshark.org/review/17631
Petri-Dish: Peter Wu <peter@lekensteyn.nl>
Tested-by: Petri Dish Buildbot <buildbot-no-reply@wireshark.org>
Reviewed-by: Roland Knall <rknall@gmail.com>
Diffstat (limited to 'extcap.h')
-rw-r--r-- | extcap.h | 4 |
1 files changed, 4 insertions, 0 deletions
@@ -113,7 +113,11 @@ void extcap_pref_store(struct _extcap_arg * arg, const char * newval); /* Clean up global extcap stuff on program exit */ +#ifdef HAVE_EXTCAP void extcap_cleanup(void); +#else +static inline void extcap_cleanup(void) {} +#endif #ifdef __cplusplus } |