[3.16.y-ckt stable] Patch "mac80211: move WEP tailroom size check" has been added to staging queue

[Luis Henriques]

This is a note to let you know that I have just added a patch titled

    mac80211: move WEP tailroom size check

to the linux-3.16.y-queue branch of the 3.16.y-ckt extended stable tree 
which can be found at:

    http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.16.y-queue

This patch is scheduled to be released in version 3.16.7-ckt13.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.16.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From aa56fe42fa021ffd999794e48b6e4ad3fa649365 Mon Sep 17 00:00:00 2001
From: Janusz Dziedzic <janusz.dziedzic at tieto.com>
Date: Mon, 11 May 2015 11:31:15 +0200
Subject: mac80211: move WEP tailroom size check

commit 47b4e1fc4972cc43a19121bc2608a60aef3bf216 upstream.

Remove checking tailroom when adding IV as it uses only
headroom, and move the check to the ICV generation that
actually needs the tailroom.

In other case I hit such warning and datapath don't work,
when testing:
- IBSS + WEP
- ath9k with hw crypt enabled
- IPv6 data (ping6)

WARNING: CPU: 3 PID: 13301 at net/mac80211/wep.c:102 ieee80211_wep_add_iv+0x129/0x190 [mac80211]()
[...]
Call Trace:
[<ffffffff817bf491>] dump_stack+0x45/0x57
[<ffffffff8107746a>] warn_slowpath_common+0x8a/0xc0
[<ffffffff8107755a>] warn_slowpath_null+0x1a/0x20
[<ffffffffc09ae109>] ieee80211_wep_add_iv+0x129/0x190 [mac80211]
[<ffffffffc09ae7ab>] ieee80211_crypto_wep_encrypt+0x6b/0xd0 [mac80211]
[<ffffffffc09d3fb1>] invoke_tx_handlers+0xc51/0xf30 [mac80211]
[...]

Signed-off-by: Janusz Dziedzic <janusz.dziedzic at tieto.com>
Signed-off-by: Johannes Berg <johannes.berg at intel.com>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 net/mac80211/wep.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/net/mac80211/wep.c b/net/mac80211/wep.c
index 6ee2b5863572..f21b142dee1f 100644
--- a/net/mac80211/wep.c
+++ b/net/mac80211/wep.c
@@ -98,8 +98,7 @@ static u8 *ieee80211_wep_add_iv(struct ieee80211_local *local,

 	hdr->frame_control |= cpu_to_le16(IEEE80211_FCTL_PROTECTED);

-	if (WARN_ON(skb_tailroom(skb) < IEEE80211_WEP_ICV_LEN ||
-		    skb_headroom(skb) < IEEE80211_WEP_IV_LEN))
+	if (WARN_ON(skb_headroom(skb) < IEEE80211_WEP_IV_LEN))
 		return NULL;

 	hdrlen = ieee80211_hdrlen(hdr->frame_control);
@@ -169,6 +168,9 @@ int ieee80211_wep_encrypt(struct ieee80211_local *local,
 	size_t len;
 	u8 rc4key[3 + WLAN_KEY_LEN_WEP104];

+	if (WARN_ON(skb_tailroom(skb) < IEEE80211_WEP_ICV_LEN))
+		return -1;
+
 	iv = ieee80211_wep_add_iv(local, skb, keylen, keyidx);
 	if (!iv)
 		return -1;