diff options
| author | Johannes Berg <johannes@sipsolutions.net> | 2009-04-18 17:33:24 +0200 |
|---|---|---|
| committer | John W. Linville <linville@tuxdriver.com> | 2009-04-22 16:57:18 -0400 |
| commit | e7ec86f54e519e8e86f1cf328db13263f3ef8bd4 (patch) | |
| tree | 2b0a66930abf4ac710cc15120195c9259a0fcaba /include | |
| parent | ba44cb7226afd4e19308c1d8a90e8b7c566c0d8b (diff) | |
mac80211: validate TIM IE length (redux)
The TIM IE must not be shorter than 4 bytes, so verify that
when parsing it and use the proper type. To ease that adjust
struct ieee80211_tim_ie to have a virtual bitmap of size
at least 1.
Also check that the TIM IE is actually present before trying
to parse it!
Because other people may need the function, make it a static
inline in ieee80211.h.
(The original "mac80211: validate TIM IE length" was a minimal fix for
2.6.30. This purports to be the full, correct fix. -- JWL)
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/ieee80211.h | 32 |
1 files changed, 31 insertions, 1 deletions
diff --git a/include/linux/ieee80211.h b/include/linux/ieee80211.h index 53563d53b5a..c52e7fba4e4 100644 --- a/include/linux/ieee80211.h +++ b/include/linux/ieee80211.h @@ -540,7 +540,7 @@ struct ieee80211_tim_ie { u8 dtim_period; u8 bitmap_ctrl; /* variable size: 1 - 251 bytes */ - u8 virtual_map[0]; + u8 virtual_map[1]; } __attribute__ ((packed)); #define WLAN_SA_QUERY_TR_ID_LEN 16 @@ -1392,4 +1392,34 @@ static inline unsigned long ieee80211_tu_to_usec(unsigned long tu) return 1024 * tu; } +/** + * ieee80211_check_tim - check if AID bit is set in TIM + * @tim: the TIM IE + * @tim_len: length of the TIM IE + * @aid: the AID to look for + */ +static inline bool ieee80211_check_tim(struct ieee80211_tim_ie *tim, + u8 tim_len, u16 aid) +{ + u8 mask; + u8 index, indexn1, indexn2; + + if (unlikely(!tim || tim_len < sizeof(*tim))) + return false; + + aid &= 0x3fff; + index = aid / 8; + mask = 1 << (aid & 7); + + indexn1 = tim->bitmap_ctrl & 0xfe; + indexn2 = tim_len + indexn1 - 4; + + if (index < indexn1 || index > indexn2) + return false; + + index -= indexn1; + + return !!(tim->virtual_map[index] & mask); +} + #endif /* LINUX_IEEE80211_H */ |