From add8ec07b2a000af11be64a89b99afc8c90797e5 Mon Sep 17 00:00:00 2001 From: Johannes Berg Date: Fri, 11 Oct 2013 14:47:05 +0200 Subject: [PATCH] wireless: radiotap: fix parsing buffer overrun commit f5563318ff1bde15b10e736e97ffce13be08bc1a upstream. When parsing an invalid radiotap header, the parser can overrun the buffer that is passed in because it doesn't correctly check 1) the minimum radiotap header size 2) the space for extended bitmaps The first issue doesn't affect any in-kernel user as they all check the minimum size before calling the radiotap function. The second issue could potentially affect the kernel if an skb is passed in that consists only of the radiotap header with a lot of extended bitmaps that extend past the SKB. In that case a read-only buffer overrun by at most 4 bytes is possible. Fix this by adding the appropriate checks to the parser. Reported-by: Evan Huus Signed-off-by: Johannes Berg Signed-off-by: Greg Kroah-Hartman --- net/wireless/radiotap.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/net/wireless/radiotap.c b/net/wireless/radiotap.c index 7d604c06c3d..a271c27fac7 100644 --- a/net/wireless/radiotap.c +++ b/net/wireless/radiotap.c @@ -97,6 +97,10 @@ int ieee80211_radiotap_iterator_init( struct ieee80211_radiotap_header *radiotap_header, int max_length, const struct ieee80211_radiotap_vendor_namespaces *vns) { + /* check the radiotap header can actually be present */ + if (max_length < sizeof(struct ieee80211_radiotap_header)) + return -EINVAL; + /* Linux only supports version 0 radiotap format */ if (radiotap_header->it_version) return -EINVAL; @@ -131,7 +135,8 @@ int ieee80211_radiotap_iterator_init( */ if ((unsigned long)iterator->_arg - - (unsigned long)iterator->_rtheader > + (unsigned long)iterator->_rtheader + + sizeof(uint32_t) > (unsigned long)iterator->_max_length) return -EINVAL; } -- 2.11.0