From fe806e4992c9047affd263bcc13b2c047029a726 Mon Sep 17 00:00:00 2001 From: Sara Sharon Date: Fri, 15 Mar 2019 17:39:05 +0200 Subject: cfg80211: support profile split between elements Since an element is limited to 255 octets, a profile may be split split to several elements. Support the split as defined in the 11ax draft 3. Detect legacy split and print a net-rate limited warning, since there is no ROI in supporting this probably non-existent split. Signed-off-by: Sara Sharon Signed-off-by: Luca Coelho Signed-off-by: Johannes Berg --- net/wireless/scan.c | 109 +++++++++++++++++++++++++++++++++++++++++++++++++--- 1 file changed, 103 insertions(+), 6 deletions(-) (limited to 'net/wireless') diff --git a/net/wireless/scan.c b/net/wireless/scan.c index bda9114ded77..878c867f3f7d 100644 --- a/net/wireless/scan.c +++ b/net/wireless/scan.c @@ -1456,6 +1456,78 @@ cfg80211_inform_single_bss_data(struct wiphy *wiphy, return &res->pub; } +static const struct element +*cfg80211_get_profile_continuation(const u8 *ie, size_t ielen, + const struct element *mbssid_elem, + const struct element *sub_elem) +{ + const u8 *mbssid_end = mbssid_elem->data + mbssid_elem->datalen; + const struct element *next_mbssid; + const struct element *next_sub; + + next_mbssid = cfg80211_find_elem(WLAN_EID_MULTIPLE_BSSID, + mbssid_end, + ielen - (mbssid_end - ie)); + + /* + * If is is not the last subelement in current MBSSID IE or there isn't + * a next MBSSID IE - profile is complete. + */ + if ((sub_elem->data + sub_elem->datalen < mbssid_end - 1) || + !next_mbssid) + return NULL; + + /* For any length error, just return NULL */ + + if (next_mbssid->datalen < 4) + return NULL; + + next_sub = (void *)&next_mbssid->data[1]; + + if (next_mbssid->data + next_mbssid->datalen < + next_sub->data + next_sub->datalen) + return NULL; + + if (next_sub->id != 0 || next_sub->datalen < 2) + return NULL; + + /* + * Check if the first element in the next sub element is a start + * of a new profile + */ + return next_sub->data[0] == WLAN_EID_NON_TX_BSSID_CAP ? + NULL : next_mbssid; +} + +size_t cfg80211_merge_profile(const u8 *ie, size_t ielen, + const struct element *mbssid_elem, + const struct element *sub_elem, + u8 **merged_ie, size_t max_copy_len) +{ + size_t copied_len = sub_elem->datalen; + const struct element *next_mbssid; + + if (sub_elem->datalen > max_copy_len) + return 0; + + memcpy(*merged_ie, sub_elem->data, sub_elem->datalen); + + while ((next_mbssid = cfg80211_get_profile_continuation(ie, ielen, + mbssid_elem, + sub_elem))) { + const struct element *next_sub = (void *)&next_mbssid->data[1]; + + if (copied_len + next_sub->datalen > max_copy_len) + break; + memcpy(*merged_ie + copied_len, next_sub->data, + next_sub->datalen); + copied_len += next_sub->datalen; + } + + return copied_len; +} +EXPORT_SYMBOL(cfg80211_merge_profile); + static void cfg80211_parse_mbssid_data(struct wiphy *wiphy, struct cfg80211_inform_bss *data, enum cfg80211_bss_frame_type ftype, @@ -1469,7 +1541,8 @@ static void cfg80211_parse_mbssid_data(struct wiphy *wiphy, const struct element *elem, *sub; size_t new_ie_len; u8 new_bssid[ETH_ALEN]; - u8 *new_ie; + u8 *new_ie, *profile; + u64 seen_indices = 0; u16 capability; struct cfg80211_bss *bss; @@ -1487,10 +1560,16 @@ static void cfg80211_parse_mbssid_data(struct wiphy *wiphy, if (!new_ie) return; + profile = kmalloc(ielen, gfp); + if (!profile) + goto out; + for_each_element_id(elem, WLAN_EID_MULTIPLE_BSSID, ie, ielen) { if (elem->datalen < 4) continue; for_each_element(sub, elem->data + 1, elem->datalen - 1) { + u8 profile_len; + if (sub->id != 0 || sub->datalen < 4) { /* not a valid BSS profile */ continue; @@ -1505,16 +1584,31 @@ static void cfg80211_parse_mbssid_data(struct wiphy *wiphy, continue; } + memset(profile, 0, ielen); + profile_len = cfg80211_merge_profile(ie, ielen, + elem, + sub, + &profile, + ielen); + /* found a Nontransmitted BSSID Profile */ mbssid_index_ie = cfg80211_find_ie (WLAN_EID_MULTI_BSSID_IDX, - sub->data, sub->datalen); + profile, profile_len); if (!mbssid_index_ie || mbssid_index_ie[1] < 1 || - mbssid_index_ie[2] == 0) { + mbssid_index_ie[2] == 0 || + mbssid_index_ie[2] > 46) { /* No valid Multiple BSSID-Index element */ continue; } + if (seen_indices & BIT(mbssid_index_ie[2])) + /* We don't support legacy split of a profile */ + net_dbg_ratelimited("Partial info for BSSID index %d\n", + mbssid_index_ie[2]); + + seen_indices |= BIT(mbssid_index_ie[2]); + non_tx_data->bssid_index = mbssid_index_ie[2]; non_tx_data->max_bssid_indicator = elem->data[0]; @@ -1523,13 +1617,14 @@ static void cfg80211_parse_mbssid_data(struct wiphy *wiphy, non_tx_data->bssid_index, new_bssid); memset(new_ie, 0, IEEE80211_MAX_DATA_LEN); - new_ie_len = cfg80211_gen_new_ie(ie, ielen, sub->data, - sub->datalen, new_ie, + new_ie_len = cfg80211_gen_new_ie(ie, ielen, + profile, + profile_len, new_ie, gfp); if (!new_ie_len) continue; - capability = get_unaligned_le16(sub->data + 2); + capability = get_unaligned_le16(profile + 2); bss = cfg80211_inform_single_bss_data(wiphy, data, ftype, new_bssid, tsf, @@ -1545,7 +1640,9 @@ static void cfg80211_parse_mbssid_data(struct wiphy *wiphy, } } +out: kfree(new_ie); + kfree(profile); } struct cfg80211_bss * -- cgit