From f5563318ff1bde15b10e736e97ffce13be08bc1a Mon Sep 17 00:00:00 2001 From: Johannes Berg Date: Fri, 11 Oct 2013 14:47:05 +0200 Subject: wireless: radiotap: fix parsing buffer overrun 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. Cc: stable@vger.kernel.org Reported-by: Evan Huus Signed-off-by: Johannes Berg --- net/wireless/radiotap.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) (limited to 'net') diff --git a/net/wireless/radiotap.c b/net/wireless/radiotap.c index 7d604c06c3dc..a271c27fac77 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; } -- cgit v1.2.3