linux-kernel - [PATCH 3.19.y-ckt 194/210] phonet: properly unshare skbs in phonet

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <1454030348-17736-195-git-send-email-kamal@canonical.com>
Date:	Thu, 28 Jan 2016 17:18:52 -0800
From:	Kamal Mostafa <kamal@...onical.com>
To:	linux-kernel@...r.kernel.org, stable@...r.kernel.org,
	kernel-team@...ts.ubuntu.com
Cc:	Eric Dumazet <edumazet@...gle.com>,
	Remi Denis-Courmont <courmisch@...il.com>,
	"David S. Miller" <davem@...emloft.net>,
	Kamal Mostafa <kamal@...onical.com>
Subject: [PATCH 3.19.y-ckt 194/210] phonet: properly unshare skbs in phonet_rcv()

3.19.8-ckt14 -stable review patch.  If anyone has any objections, please let me know.

---8<------------------------------------------------------------

From: Eric Dumazet <edumazet@...gle.com>

[ Upstream commit 7aaed57c5c2890634cfadf725173c7c68ea4cb4f ]

Ivaylo Dimitrov reported a regression caused by commit 7866a621043f
("dev: add per net_device packet type chains").

skb->dev becomes NULL and we crash in __netif_receive_skb_core().

Before above commit, different kind of bugs or corruptions could happen
without major crash.

But the root cause is that phonet_rcv() can queue skb without checking
if skb is shared or not.

Many thanks to Ivaylo Dimitrov for his help, diagnosis and tests.

Reported-by: Ivaylo Dimitrov <ivo.g.dimitrov.75@...il.com>
Tested-by: Ivaylo Dimitrov <ivo.g.dimitrov.75@...il.com>
Signed-off-by: Eric Dumazet <edumazet@...gle.com>
Cc: Remi Denis-Courmont <courmisch@...il.com>
Signed-off-by: David S. Miller <davem@...emloft.net>
Signed-off-by: Kamal Mostafa <kamal@...onical.com>
---
 net/phonet/af_phonet.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/net/phonet/af_phonet.c b/net/phonet/af_phonet.c
index 32ab87d..11d0b29 100644
--- a/net/phonet/af_phonet.c
+++ b/net/phonet/af_phonet.c
@@ -377,6 +377,10 @@ static int phonet_rcv(struct sk_buff *skb, struct net_device *dev,
 	struct sockaddr_pn sa;
 	u16 len;
 
+	skb = skb_share_check(skb, GFP_ATOMIC);
+	if (!skb)
+		return NET_RX_DROP;
+
 	/* check we have at least a full Phonet header */
 	if (!pskb_pull(skb, sizeof(struct phonethdr)))
 		goto out;
-- 
1.9.1