diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h index d5e7f690bad9..533cb6410678 100644 --- a/include/net/cfg80211.h +++ b/include/net/cfg80211.h @@ -3946,6 +3946,34 @@ void ieee80211_amsdu_to_8023s(struct sk_buff *skb, struct sk_buff_head *list, unsigned int cfg80211_classify8021d(struct sk_buff *skb, struct cfg80211_qos_map *qos_map); +/** + * cfg80211_find_ie_match - match information element and byte array in data + * + * @eid: element ID + * @ies: data consisting of IEs + * @len: length of data + * @match: byte array to match + * @match_len: number of bytes in the match array + * @match_offset: offset in the IE where the byte array should match. + * If match_len is zero, this must also be set to zero. + * Otherwise this must be set to 2 or more, because the first + * byte is the element id, which is already compared to eid, and + * the second byte is the IE length. + * + * Return: %NULL if the element ID could not be found or if + * the element is invalid (claims to be longer than the given + * data) or if the byte array doesn't match, or a pointer to the first + * byte of the requested element, that is the byte containing the + * element ID. + * + * Note: There are no checks on the element length other than + * having to fit into the given data and being large enough for the + * byte array to match. + */ +const u8 *cfg80211_find_ie_match(u8 eid, const u8 *ies, int len, + const u8 *match, int match_len, + int match_offset); + /** * cfg80211_find_ie - find information element in data * @@ -3961,7 +3989,10 @@ unsigned int cfg80211_classify8021d(struct sk_buff *skb, * Note: There are no checks on the element length other than * having to fit into the given data. */ -const u8 *cfg80211_find_ie(u8 eid, const u8 *ies, int len); +static inline const u8 *cfg80211_find_ie(u8 eid, const u8 *ies, int len) +{ + return cfg80211_find_ie_match(eid, ies, len, NULL, 0, 0); +} /** * cfg80211_find_vendor_ie - find vendor specific information element in data diff --git a/net/wireless/scan.c b/net/wireless/scan.c index 0358e12be54b..b5bd58d0f731 100644 --- a/net/wireless/scan.c +++ b/net/wireless/scan.c @@ -352,52 +352,48 @@ void cfg80211_bss_expire(struct cfg80211_registered_device *rdev) __cfg80211_bss_expire(rdev, jiffies - IEEE80211_SCAN_RESULT_EXPIRE); } -const u8 *cfg80211_find_ie(u8 eid, const u8 *ies, int len) +const u8 *cfg80211_find_ie_match(u8 eid, const u8 *ies, int len, + const u8 *match, int match_len, + int match_offset) { - while (len > 2 && ies[0] != eid) { + /* match_offset can't be smaller than 2, unless match_len is + * zero, in which case match_offset must be zero as well. + */ + if (WARN_ON((match_len && match_offset < 2) || + (!match_len && match_offset))) + return NULL; + + while (len >= 2 && len >= ies[1] + 2) { + if ((ies[0] == eid) && + (ies[1] + 2 >= match_offset + match_len) && + !memcmp(ies + match_offset, match, match_len)) + return ies; + len -= ies[1] + 2; ies += ies[1] + 2; } - if (len < 2) - return NULL; - if (len < 2 + ies[1]) - return NULL; - return ies; + + return NULL; } -EXPORT_SYMBOL(cfg80211_find_ie); +EXPORT_SYMBOL(cfg80211_find_ie_match); const u8 *cfg80211_find_vendor_ie(unsigned int oui, int oui_type, const u8 *ies, int len) { - struct ieee80211_vendor_ie *ie; - const u8 *pos = ies, *end = ies + len; - int ie_oui; + const u8 *ie; + u8 match[] = { oui >> 16, oui >> 8, oui, oui_type }; + int match_len = (oui_type < 0) ? 3 : sizeof(match); if (WARN_ON(oui_type > 0xff)) return NULL; - while (pos < end) { - pos = cfg80211_find_ie(WLAN_EID_VENDOR_SPECIFIC, pos, - end - pos); - if (!pos) - return NULL; + ie = cfg80211_find_ie_match(WLAN_EID_VENDOR_SPECIFIC, ies, len, + match, match_len, 2); - ie = (struct ieee80211_vendor_ie *)pos; + if (ie && (ie[1] < 4)) + return NULL; - /* make sure we can access ie->len */ - BUILD_BUG_ON(offsetof(struct ieee80211_vendor_ie, len) != 1); - - if (ie->len < sizeof(*ie)) - goto cont; - - ie_oui = ie->oui[0] << 16 | ie->oui[1] << 8 | ie->oui[2]; - if (ie_oui == oui && - (oui_type < 0 || ie->oui_type == oui_type)) - return pos; -cont: - pos += 2 + ie->len; - } - return NULL; + return ie; } EXPORT_SYMBOL(cfg80211_find_vendor_ie);