netdev - [PATCH] net: lan78xx: Fix race in tx pending skb size calculation

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-next>] [day] [month] [year] [list]

Date:   Sun, 15 Jul 2018 21:53:20 +0200
From:   Stefan Wahren <stefan.wahren@...e.com>
To:     Woojung Huh <woojung.huh@...rochip.com>,
        UNGLinuxDriver@...rochip.com,
        "David S. Miller" <davem@...emloft.net>
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Dave Stevenson <dave.stevenson@...pberrypi.org>,
        netdev@...r.kernel.org, linux-usb@...r.kernel.org,
        Stefan Wahren <stefan.wahren@...e.com>,
        stable <stable@...r.kernel.org>,
        Floris Bos <bos@...eigen-domein.nl>
Subject: [PATCH] net: lan78xx: Fix race in tx pending skb size calculation

The skb size calculation in lan78xx_tx_bh is in race with the start_xmit,
which could lead to rare kernel oopses. So protect the whole skb walk with
a spin lock. As a benefit we can unlink the skb directly.

This patch was tested on Raspberry Pi 3B+

Link: https://github.com/raspberrypi/linux/issues/2608
Fixes: 55d7de9de6c3 ("Microchip's LAN7800 family USB 2/3 to 10/100/1000 Ethernet")
Cc: stable <stable@...r.kernel.org>
Signed-off-by: Floris Bos <bos@...eigen-domein.nl>
Signed-off-by: Stefan Wahren <stefan.wahren@...e.com>
---
 drivers/net/usb/lan78xx.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/net/usb/lan78xx.c b/drivers/net/usb/lan78xx.c
index 2e41307..ed10d49 100644
--- a/drivers/net/usb/lan78xx.c
+++ b/drivers/net/usb/lan78xx.c
@@ -3344,6 +3344,7 @@ static void lan78xx_tx_bh(struct lan78xx_net *dev)
 	pkt_cnt = 0;
 	count = 0;
 	length = 0;
+	spin_lock_irqsave(&tqp->lock, flags);
 	for (skb = tqp->next; pkt_cnt < tqp->qlen; skb = skb->next) {
 		if (skb_is_gso(skb)) {
 			if (pkt_cnt) {
@@ -3352,7 +3353,8 @@ static void lan78xx_tx_bh(struct lan78xx_net *dev)
 			}
 			count = 1;
 			length = skb->len - TX_OVERHEAD;
-			skb2 = skb_dequeue(tqp);
+			__skb_unlink(skb, tqp);
+			spin_unlock_irqrestore(&tqp->lock, flags);
 			goto gso_skb;
 		}
 
@@ -3361,6 +3363,7 @@ static void lan78xx_tx_bh(struct lan78xx_net *dev)
 		skb_totallen = skb->len + roundup(skb_totallen, sizeof(u32));
 		pkt_cnt++;
 	}
+	spin_unlock_irqrestore(&tqp->lock, flags);
 
 	/* copy to a single skb */
 	skb = alloc_skb(skb_totallen, GFP_ATOMIC);
-- 
2.7.4