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authorJohannes Berg <johannes@sipsolutions.net>2009-04-18 17:33:24 +0200
committerJohn W. Linville <linville@tuxdriver.com>2009-04-22 16:57:18 -0400
commite7ec86f54e519e8e86f1cf328db13263f3ef8bd4 (patch)
tree2b0a66930abf4ac710cc15120195c9259a0fcaba /include
parentba44cb7226afd4e19308c1d8a90e8b7c566c0d8b (diff)
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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.h32
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 */