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authorFeng Sun <loyou85@gmail.com>2019-08-26 14:46:04 +0800
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2019-09-10 10:29:50 +0100
commite6198d2b4ff0195ebc228a231f96918855ce722f (patch)
tree145dd1a53c1febd379360042e00cec282bbfc165
parent94eb5357f6d688b364eaf52d4f7fa187102396a7 (diff)
net: fix skb use after free in netpoll
[ Upstream commit 2c1644cf6d46a8267d79ed95cb9b563839346562 ] 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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--net/core/netpoll.c6
1 files changed, 3 insertions, 3 deletions
diff --git a/net/core/netpoll.c b/net/core/netpoll.c
index 440aa9f6e0a8..0d7c2cc1ff09 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);
@@ -357,7 +357,7 @@ 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;
}
@@ -374,7 +374,7 @@ 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);
}