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| author | Feng Sun <loyou85@gmail.com> | 2019-08-26 14:46:04 +0800 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2019-08-27 20:52:02 -0700 |
| commit | 2c1644cf6d46a8267d79ed95cb9b563839346562 (patch) | |
| tree | e44a95a6e23b9bb451a668b3b2743e2c6423b79f /net/core/netpoll.c | |
| parent | bcccb0a535bb99616e4b992568371efab1ab14e8 (diff) | |
| download | lwn-2c1644cf6d46a8267d79ed95cb9b563839346562.tar.gz lwn-2c1644cf6d46a8267d79ed95cb9b563839346562.zip | |
net: fix skb use after free in netpoll
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>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/core/netpoll.c')
| -rw-r--r-- | net/core/netpoll.c | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/net/core/netpoll.c b/net/core/netpoll.c index 2cf27da1baeb..849380a622ef 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); } |