From: Feng Sun <loyou85@gmail.com>
To: davem@davemloft.net
Cc: edumazet@google.com, dsterba@suse.com, dbanerje@akamai.com,
fw@strlen.de, davej@codemonkey.org.uk, tglx@linutronix.de,
matwey@sai.msu.ru, sakari.ailus@linux.intel.com,
netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
Feng Sun <loyou85@gmail.com>,
Xiaojun Zhao <xiaojunzhao141@gmail.com>
Subject: [PATCH v3] net: fix skb use after free in netpoll
Date: Mon, 26 Aug 2019 14:46:04 +0800 [thread overview]
Message-ID: <1566801964-14691-1-git-send-email-loyou85@gmail.com> (raw)
In-Reply-To: <20190825.232003.1145950065287854577.davem@davemloft.net>
After commit baeababb5b85d5c4e6c917efe2a1504179438d3b
("tun: return NET_XMIT_DROP for dropped packets"),
when tun_net_xmit drop packets, it will free skb and return NET_XMIT_DROP,
netpoll_send_skb_on_dev will run into following use after free cases:
1. retry netpoll_start_xmit with freed skb;
2. queue freed skb in npinfo->txq.
queue_process will also run into use after free case.
hit netpoll_send_skb_on_dev first case with following kernel log:
[ 117.864773] kernel BUG at mm/slub.c:306!
[ 117.864773] invalid opcode: 0000 [#1] SMP PTI
[ 117.864774] CPU: 3 PID: 2627 Comm: loop_printmsg Kdump: loaded Tainted: P OE 5.3.0-050300rc5-generic #201908182231
[ 117.864775] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Ubuntu-1.8.2-1ubuntu1 04/01/2014
[ 117.864775] RIP: 0010:kmem_cache_free+0x28d/0x2b0
[ 117.864781] Call Trace:
[ 117.864781] ? tun_net_xmit+0x21c/0x460
[ 117.864781] kfree_skbmem+0x4e/0x60
[ 117.864782] kfree_skb+0x3a/0xa0
[ 117.864782] tun_net_xmit+0x21c/0x460
[ 117.864782] netpoll_start_xmit+0x11d/0x1b0
[ 117.864788] netpoll_send_skb_on_dev+0x1b8/0x200
[ 117.864789] __br_forward+0x1b9/0x1e0 [bridge]
[ 117.864789] ? skb_clone+0x53/0xd0
[ 117.864790] ? __skb_clone+0x2e/0x120
[ 117.864790] deliver_clone+0x37/0x50 [bridge]
[ 117.864790] maybe_deliver+0x89/0xc0 [bridge]
[ 117.864791] br_flood+0x6c/0x130 [bridge]
[ 117.864791] br_dev_xmit+0x315/0x3c0 [bridge]
[ 117.864792] netpoll_start_xmit+0x11d/0x1b0
[ 117.864792] netpoll_send_skb_on_dev+0x1b8/0x200
[ 117.864792] netpoll_send_udp+0x2c6/0x3e8
[ 117.864793] write_msg+0xd9/0xf0 [netconsole]
[ 117.864793] console_unlock+0x386/0x4e0
[ 117.864793] vprintk_emit+0x17e/0x280
[ 117.864794] vprintk_default+0x29/0x50
[ 117.864794] vprintk_func+0x4c/0xbc
[ 117.864794] printk+0x58/0x6f
[ 117.864795] loop_fun+0x24/0x41 [printmsg_loop]
[ 117.864795] kthread+0x104/0x140
[ 117.864795] ? 0xffffffffc05b1000
[ 117.864796] ? kthread_park+0x80/0x80
[ 117.864796] ret_from_fork+0x35/0x40
Signed-off-by: Feng Sun <loyou85@gmail.com>
Signed-off-by: Xiaojun Zhao <xiaojunzhao141@gmail.com>
---
Changes in v3:
- use dev_xmit_complete directly
Changes in v2:
- change commit and title
- add netpoll_xmit_complete helper
- add one more return value check of netpoll_start_xmit
---
net/core/netpoll.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/net/core/netpoll.c b/net/core/netpoll.c
index 2cf27da..849380a6 100644
--- a/net/core/netpoll.c
+++ b/net/core/netpoll.c
@@ -122,7 +122,7 @@ static void queue_process(struct work_struct *work)
txq = netdev_get_tx_queue(dev, q_index);
HARD_TX_LOCK(dev, txq, smp_processor_id());
if (netif_xmit_frozen_or_stopped(txq) ||
- netpoll_start_xmit(skb, dev, txq) != NETDEV_TX_OK) {
+ !dev_xmit_complete(netpoll_start_xmit(skb, dev, txq))) {
skb_queue_head(&npinfo->txq, skb);
HARD_TX_UNLOCK(dev, txq);
local_irq_restore(flags);
@@ -335,7 +335,7 @@ void netpoll_send_skb_on_dev(struct netpoll *np, struct sk_buff *skb,
HARD_TX_UNLOCK(dev, txq);
- if (status == NETDEV_TX_OK)
+ if (dev_xmit_complete(status))
break;
}
@@ -352,7 +352,7 @@ void netpoll_send_skb_on_dev(struct netpoll *np, struct sk_buff *skb,
}
- if (status != NETDEV_TX_OK) {
+ if (!dev_xmit_complete(status)) {
skb_queue_tail(&npinfo->txq, skb);
schedule_delayed_work(&npinfo->tx_work,0);
}
--
2.7.4
next prev parent reply other threads:[~2019-08-26 6:46 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-23 16:32 [PATCH] net: fix skb use after free in netpoll_send_skb_on_dev Feng Sun
2019-08-26 2:48 ` David Miller
2019-08-26 6:13 ` [PATCH v2] net: fix skb use after free in netpoll Feng Sun
2019-08-26 6:20 ` David Miller
2019-08-26 6:46 ` Feng Sun [this message]
2019-08-28 3:52 ` [PATCH v3] " David Miller
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