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* [PATCH] mac80211: make ieee802_11_parse_elems return void
@ 2007-10-17  2:38 John W. Linville
  2007-10-17  3:17 ` Michael Wu
  2007-10-17  8:15 ` Johannes Berg
  0 siblings, 2 replies; 6+ messages in thread
From: John W. Linville @ 2007-10-17  2:38 UTC (permalink / raw)
  To: linux-wireless; +Cc: John W. Linville

Some APs send management frames with junk padding after the last IE.
We already account for a similar problem with some Apple Airport
devices, but at least one device is known to send more than a single
extra byte.  The device in question is the Draytek Vigor2900:

	http://www.draytek.com.au/products/Vigor2900.php

The junk in question looks like an IE that runs off the end of the
frame.  This cause us to return ParseFailed.  Since the frame in
question is an association response, this causes us to fail to associate
with this AP.

The return code from ieee802_11_parse_elems is superfluous.
All callers still check for the presence of the specific IEs that
interest them anyway.  So, remove the return code so the parse never
"fails".

Signed-off-by: John W. Linville <linville@tuxdriver.com>
---
 net/mac80211/ieee80211_sta.c |   53 ++++++++----------------------------------
 1 files changed, 10 insertions(+), 43 deletions(-)

diff --git a/net/mac80211/ieee80211_sta.c b/net/mac80211/ieee80211_sta.c
index db81aef..7f873b3 100644
--- a/net/mac80211/ieee80211_sta.c
+++ b/net/mac80211/ieee80211_sta.c
@@ -108,14 +108,11 @@ struct ieee802_11_elems {
 	u8 wmm_param_len;
 };
 
-enum ParseRes { ParseOK = 0, ParseUnknown = 1, ParseFailed = -1 };
-
-static enum ParseRes ieee802_11_parse_elems(u8 *start, size_t len,
-					    struct ieee802_11_elems *elems)
+static void ieee802_11_parse_elems(u8 *start, size_t len,
+				   struct ieee802_11_elems *elems)
 {
 	size_t left = len;
 	u8 *pos = start;
-	int unknown = 0;
 
 	memset(elems, 0, sizeof(*elems));
 
@@ -126,15 +123,8 @@ static enum ParseRes ieee802_11_parse_elems(u8 *start, size_t len,
 		elen = *pos++;
 		left -= 2;
 
-		if (elen > left) {
-#if 0
-			if (net_ratelimit())
-				printk(KERN_DEBUG "IEEE 802.11 element parse "
-				       "failed (id=%d elen=%d left=%d)\n",
-				       id, elen, left);
-#endif
-			return ParseFailed;
-		}
+		if (elen > left)
+			return;
 
 		switch (id) {
 		case WLAN_EID_SSID:
@@ -201,12 +191,6 @@ static enum ParseRes ieee802_11_parse_elems(u8 *start, size_t len,
 			elems->ext_supp_rates_len = elen;
 			break;
 		default:
-#if 0
-			printk(KERN_DEBUG "IEEE 802.11 element parse ignored "
-				      "unknown element (id=%d elen=%d)\n",
-				      id, elen);
-#endif
-			unknown++;
 			break;
 		}
 
@@ -214,10 +198,7 @@ static enum ParseRes ieee802_11_parse_elems(u8 *start, size_t len,
 		pos += elen;
 	}
 
-	/* Do not trigger error if left == 1 as Apple Airport base stations
-	 * send AssocResps that are one spurious byte too long. */
-
-	return unknown ? ParseUnknown : ParseOK;
+	return;
 }
 
 
@@ -931,12 +912,7 @@ static void ieee80211_auth_challenge(struct net_device *dev,
 
 	printk(KERN_DEBUG "%s: replying to auth challenge\n", dev->name);
 	pos = mgmt->u.auth.variable;
-	if (ieee802_11_parse_elems(pos, len - (pos - (u8 *) mgmt), &elems)
-	    == ParseFailed) {
-		printk(KERN_DEBUG "%s: failed to parse Auth(challenge)\n",
-		       dev->name);
-		return;
-	}
+	ieee802_11_parse_elems(pos, len - (pos - (u8 *) mgmt), &elems);
 	if (!elems.challenge) {
 		printk(KERN_DEBUG "%s: no challenge IE in shared key auth "
 		       "frame\n", dev->name);
@@ -1230,12 +1206,7 @@ static void ieee80211_rx_mgmt_assoc_resp(struct net_device *dev,
 	aid &= ~(BIT(15) | BIT(14));
 
 	pos = mgmt->u.assoc_resp.variable;
-	if (ieee802_11_parse_elems(pos, len - (pos - (u8 *) mgmt), &elems)
-	    == ParseFailed) {
-		printk(KERN_DEBUG "%s: failed to parse AssocResp\n",
-		       dev->name);
-		return;
-	}
+	ieee802_11_parse_elems(pos, len - (pos - (u8 *) mgmt), &elems);
 
 	if (!elems.supp_rates) {
 		printk(KERN_DEBUG "%s: no SuppRates element in AssocResp\n",
@@ -1459,7 +1430,7 @@ static void ieee80211_rx_bss_info(struct net_device *dev,
 	struct ieee80211_local *local = wdev_priv(dev->ieee80211_ptr);
 	struct ieee802_11_elems elems;
 	size_t baselen;
-	int channel, invalid = 0, clen;
+	int channel, clen;
 	struct ieee80211_sta_bss *bss;
 	struct sta_info *sta;
 	struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
@@ -1505,9 +1476,7 @@ static void ieee80211_rx_bss_info(struct net_device *dev,
 #endif /* CONFIG_MAC80211_IBSS_DEBUG */
 	}
 
-	if (ieee802_11_parse_elems(mgmt->u.beacon.variable, len - baselen,
-				   &elems) == ParseFailed)
-		invalid = 1;
+	ieee802_11_parse_elems(mgmt->u.beacon.variable, len - baselen, &elems);
 
 	if (sdata->type == IEEE80211_IF_TYPE_IBSS && elems.supp_rates &&
 	    memcmp(mgmt->bssid, sdata->u.sta.bssid, ETH_ALEN) == 0 &&
@@ -1724,9 +1693,7 @@ static void ieee80211_rx_mgmt_beacon(struct net_device *dev,
 	if (baselen > len)
 		return;
 
-	if (ieee802_11_parse_elems(mgmt->u.beacon.variable, len - baselen,
-				   &elems) == ParseFailed)
-		return;
+	ieee802_11_parse_elems(mgmt->u.beacon.variable, len - baselen, &elems);
 
 	if (elems.erp_info && elems.erp_info_len >= 1)
 		ieee80211_handle_erp_ie(dev, elems.erp_info[0]);
-- 
1.5.2.4


^ permalink raw reply related	[flat|nested] 6+ messages in thread
* [PATCH] Add get_unaligned to ieee80211_get_radiotap_len
@ 2007-10-26 21:04 John W. Linville
  2007-10-26 21:04 ` [PATCH] Improve sanity checks on injected packets John W. Linville
  0 siblings, 1 reply; 6+ messages in thread
From: John W. Linville @ 2007-10-26 21:04 UTC (permalink / raw)
  To: stable; +Cc: linux-wireless, warmcat, John W. Linville

From: warmcat <andy@warmcat.com>

ieee80211_get_radiotap_len() tries to dereference radiotap length without
taking care that it is completely unaligned and get_unaligned()
is required.

Signed-off-by: Andy Green <andy@warmcat.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
---
 net/mac80211/ieee80211.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/net/mac80211/ieee80211.c b/net/mac80211/ieee80211.c
index ff2172f..9b9d716 100644
--- a/net/mac80211/ieee80211.c
+++ b/net/mac80211/ieee80211.c
@@ -350,7 +350,7 @@ static int ieee80211_get_radiotap_len(struct sk_buff *skb)
 	struct ieee80211_radiotap_header *hdr =
 		(struct ieee80211_radiotap_header *) skb->data;
 
-	return le16_to_cpu(hdr->it_len);
+	return le16_to_cpu(get_unaligned(&hdr->it_len));
 }
 
 #ifdef CONFIG_MAC80211_LOWTX_FRAME_DUMP
-- 
1.5.2.4


^ permalink raw reply related	[flat|nested] 6+ messages in thread

end of thread, other threads:[~2007-10-26 21:07 UTC | newest]

Thread overview: 6+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2007-10-17  2:38 [PATCH] mac80211: make ieee802_11_parse_elems return void John W. Linville
2007-10-17  3:17 ` Michael Wu
2007-10-17  8:15 ` Johannes Berg
2007-10-17 14:04   ` John W. Linville
2007-10-18 11:56     ` Johannes Berg
  -- strict thread matches above, loose matches on Subject: below --
2007-10-26 21:04 [PATCH] Add get_unaligned to ieee80211_get_radiotap_len John W. Linville
2007-10-26 21:04 ` [PATCH] Improve sanity checks on injected packets John W. Linville
2007-10-26 21:04   ` [PATCH] mac80211: filter locally-originated multicast frames John W. Linville
2007-10-26 21:04     ` [PATCH] libertas: fix endianness breakage John W. Linville
2007-10-26 21:04       ` [PATCH] libertas: more " John W. Linville
2007-10-26 21:04         ` [PATCH] ieee80211: fix TKIP QoS bug John W. Linville
2007-10-26 21:04           ` [PATCH] mac80211: reorder association debug output John W. Linville
2007-10-26 21:04             ` [PATCH] mac80211: store channel info in sta_bss_list John W. Linville
2007-10-26 21:04               ` [PATCH] mac80211: store SSID " John W. Linville
2007-10-26 21:04                 ` [PATCH] mac80211: honor IW_SCAN_THIS_ESSID in siwscan ioctl John W. Linville
2007-10-26 21:04                   ` [PATCH] mac80211: only honor IW_SCAN_THIS_ESSID in STA, IBSS, and AP modes John W. Linville
2007-10-26 21:04                     ` [PATCH] mac80211: make ieee802_11_parse_elems return void John W. Linville

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