radiotap: fix bitmap-end-finding buffer overrun

commit bd02cd2549 upstream.

Evan Huus found (by fuzzing in wireshark) that the radiotap
iterator code can access beyond the length of the buffer if
the first bitmap claims an extension but then there's no
data at all. Fix this.

Reported-by: Evan Huus <eapache@gmail.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Johannes Berg
2013-12-16 12:04:36 +01:00
committed by Greg Kroah-Hartman
parent 4e7255f33a
commit 6646ce885f

View File

@@ -124,6 +124,10 @@ int ieee80211_radiotap_iterator_init(
/* find payload start allowing for extended bitmap(s) */
if (iterator->_bitmap_shifter & (1<<IEEE80211_RADIOTAP_EXT)) {
if ((unsigned long)iterator->_arg -
(unsigned long)iterator->_rtheader + sizeof(uint32_t) >
(unsigned long)iterator->_max_length)
return -EINVAL;
while (get_unaligned_le32(iterator->_arg) &
(1 << IEEE80211_RADIOTAP_EXT)) {
iterator->_arg += sizeof(uint32_t);