From ef9a5a62c63456cbba1beef2fc1372fce105fbbc Mon Sep 17 00:00:00 2001 From: Roopa Prabhu Date: Sat, 26 Aug 2017 21:13:48 -0700 Subject: bridge: check for null fdb->dst before notifying switchdev drivers current switchdev drivers dont seem to support offloading fdb entries pointing to the bridge device which have fdb->dst not set to any port. This patch adds a NULL fdb->dst check in the switchdev notifier code. This patch fixes the below NULL ptr dereference: $bridge fdb add 00:02:00:00:00:33 dev br0 self [ 69.953374] BUG: unable to handle kernel NULL pointer dereference at 0000000000000008 [ 69.954044] IP: br_switchdev_fdb_notify+0x29/0x80 [ 69.954044] PGD 66527067 [ 69.954044] P4D 66527067 [ 69.954044] PUD 7899c067 [ 69.954044] PMD 0 [ 69.954044] [ 69.954044] Oops: 0000 [#1] SMP [ 69.954044] Modules linked in: [ 69.954044] CPU: 1 PID: 3074 Comm: bridge Not tainted 4.13.0-rc6+ #1 [ 69.954044] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.7.5.1-0-g8936dbb-20141113_115728-nilsson.home.kraxel.org 04/01/2014 [ 69.954044] task: ffff88007b827140 task.stack: ffffc90001564000 [ 69.954044] RIP: 0010:br_switchdev_fdb_notify+0x29/0x80 [ 69.954044] RSP: 0018:ffffc90001567918 EFLAGS: 00010246 [ 69.954044] RAX: 0000000000000000 RBX: ffff8800795e0880 RCX: 00000000000000c0 [ 69.954044] RDX: ffffc90001567920 RSI: 000000000000001c RDI: ffff8800795d0600 [ 69.954044] RBP: ffffc90001567938 R08: ffff8800795d0600 R09: 0000000000000000 [ 69.954044] R10: ffffc90001567a88 R11: ffff88007b849400 R12: ffff8800795e0880 [ 69.954044] R13: ffff8800795d0600 R14: ffffffff81ef8880 R15: 000000000000001c [ 69.954044] FS: 00007f93d3085700(0000) GS:ffff88007fd00000(0000) knlGS:0000000000000000 [ 69.954044] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 69.954044] CR2: 0000000000000008 CR3: 0000000066551000 CR4: 00000000000006e0 [ 69.954044] Call Trace: [ 69.954044] fdb_notify+0x3f/0xf0 [ 69.954044] __br_fdb_add.isra.12+0x1a7/0x370 [ 69.954044] br_fdb_add+0x178/0x280 [ 69.954044] rtnl_fdb_add+0x10a/0x200 [ 69.954044] rtnetlink_rcv_msg+0x1b4/0x240 [ 69.954044] ? skb_free_head+0x21/0x40 [ 69.954044] ? rtnl_calcit.isra.18+0xf0/0xf0 [ 69.954044] netlink_rcv_skb+0xed/0x120 [ 69.954044] rtnetlink_rcv+0x15/0x20 [ 69.954044] netlink_unicast+0x180/0x200 [ 69.954044] netlink_sendmsg+0x291/0x370 [ 69.954044] ___sys_sendmsg+0x180/0x2e0 [ 69.954044] ? filemap_map_pages+0x2db/0x370 [ 69.954044] ? do_wp_page+0x11d/0x420 [ 69.954044] ? __handle_mm_fault+0x794/0xd80 [ 69.954044] ? vma_link+0xcb/0xd0 [ 69.954044] __sys_sendmsg+0x4c/0x90 [ 69.954044] SyS_sendmsg+0x12/0x20 [ 69.954044] do_syscall_64+0x63/0xe0 [ 69.954044] entry_SYSCALL64_slow_path+0x25/0x25 [ 69.954044] RIP: 0033:0x7f93d2bad690 [ 69.954044] RSP: 002b:00007ffc7217a638 EFLAGS: 00000246 ORIG_RAX: 000000000000002e [ 69.954044] RAX: ffffffffffffffda RBX: 00007ffc72182eac RCX: 00007f93d2bad690 [ 69.954044] RDX: 0000000000000000 RSI: 00007ffc7217a670 RDI: 0000000000000003 [ 69.954044] RBP: 0000000059a1f7f8 R08: 0000000000000006 R09: 000000000000000a [ 69.954044] R10: 00007ffc7217a400 R11: 0000000000000246 R12: 00007ffc7217a670 [ 69.954044] R13: 00007ffc72182a98 R14: 00000000006114c0 R15: 00007ffc72182aa0 [ 69.954044] Code: 1f 00 66 66 66 66 90 55 48 89 e5 48 83 ec 20 f6 47 20 04 74 0a 83 fe 1c 74 09 83 fe 1d 74 2c c9 66 90 c3 48 8b 47 10 48 8d 55 e8 <48> 8b 70 08 0f b7 47 1e 48 83 c7 18 48 89 7d f0 bf 03 00 00 00 [ 69.954044] RIP: br_switchdev_fdb_notify+0x29/0x80 RSP: ffffc90001567918 [ 69.954044] CR2: 0000000000000008 [ 69.954044] ---[ end trace 03e9eec4a82c238b ]--- Fixes: 6b26b51b1d13 ("net: bridge: Add support for notifying devices about FDB add/del") Signed-off-by: Roopa Prabhu Signed-off-by: David S. Miller --- net/bridge/br_switchdev.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'net/bridge') diff --git a/net/bridge/br_switchdev.c b/net/bridge/br_switchdev.c index 181a44d0f1da..f6b1c7de059d 100644 --- a/net/bridge/br_switchdev.c +++ b/net/bridge/br_switchdev.c @@ -115,7 +115,7 @@ br_switchdev_fdb_call_notifiers(bool adding, const unsigned char *mac, void br_switchdev_fdb_notify(const struct net_bridge_fdb_entry *fdb, int type) { - if (!fdb->added_by_user) + if (!fdb->added_by_user || !fdb->dst) return; switch (type) { -- cgit v1.2.3 From 79e99bdd60b484af9afe0147e85a13e66d5c1cdb Mon Sep 17 00:00:00 2001 From: Ido Schimmel Date: Fri, 1 Sep 2017 12:22:25 +0300 Subject: bridge: switchdev: Clear forward mark when transmitting packet Commit 6bc506b4fb06 ("bridge: switchdev: Add forward mark support for stacked devices") added the 'offload_fwd_mark' bit to the skb in order to allow drivers to indicate to the bridge driver that they already forwarded the packet in L2. In case the bit is set, before transmitting the packet from each port, the port's mark is compared with the mark stored in the skb's control block. If both marks are equal, we know the packet arrived from a switch device that already forwarded the packet and it's not re-transmitted. However, if the packet is transmitted from the bridge device itself (e.g., br0), we should clear the 'offload_fwd_mark' bit as the mark stored in the skb's control block isn't valid. This scenario can happen in rare cases where a packet was trapped during L3 forwarding and forwarded by the kernel to a bridge device. Fixes: 6bc506b4fb06 ("bridge: switchdev: Add forward mark support for stacked devices") Signed-off-by: Ido Schimmel Reported-by: Yotam Gigi Tested-by: Yotam Gigi Reviewed-by: Jiri Pirko Acked-by: Nikolay Aleksandrov Signed-off-by: David S. Miller --- net/bridge/br_device.c | 3 +++ 1 file changed, 3 insertions(+) (limited to 'net/bridge') diff --git a/net/bridge/br_device.c b/net/bridge/br_device.c index 861ae2a165f4..5a7be3bddfa9 100644 --- a/net/bridge/br_device.c +++ b/net/bridge/br_device.c @@ -53,6 +53,9 @@ netdev_tx_t br_dev_xmit(struct sk_buff *skb, struct net_device *dev) brstats->tx_bytes += skb->len; u64_stats_update_end(&brstats->syncp); +#ifdef CONFIG_NET_SWITCHDEV + skb->offload_fwd_mark = 0; +#endif BR_INPUT_SKB_CB(skb)->brdev = dev; skb_reset_mac_header(skb); -- cgit v1.2.3