Commits
Alexander Duyck committed ed7cbbce544
udp: Resolve NULL pointer dereference over flow-based vxlan device
While testing an OpenStack configuration using VXLANs I saw the following
call trace:
RIP: 0010:[<ffffffff815fad49>] udp4_lib_lookup_skb+0x49/0x80
RSP: 0018:ffff88103867bc50 EFLAGS: 00010286
RAX: ffff88103269bf00 RBX: ffff88103269bf00 RCX: 00000000ffffffff
RDX: 0000000000004300 RSI: 0000000000000000 RDI: ffff880f2932e780
RBP: ffff88103867bc60 R08: 0000000000000000 R09: 000000009001a8c0
R10: 0000000000004400 R11: ffffffff81333a58 R12: ffff880f2932e794
R13: 0000000000000014 R14: 0000000000000014 R15: ffffe8efbfd89ca0
FS: 0000000000000000(0000) GS:ffff88103fd80000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000488 CR3: 0000000001c06000 CR4: 00000000001426e0
Stack:
ffffffff81576515 ffffffff815733c0 ffff88103867bc98 ffffffff815fcc17
ffff88103269bf00 ffffe8efbfd89ca0 0000000000000014 0000000000000080
ffffe8efbfd89ca0 ffff88103867bcc8 ffffffff815fcf8b ffff880f2932e794
Call Trace:
[<ffffffff81576515>] ? skb_checksum+0x35/0x50
[<ffffffff815733c0>] ? skb_push+0x40/0x40
[<ffffffff815fcc17>] udp_gro_receive+0x57/0x130
[<ffffffff815fcf8b>] udp4_gro_receive+0x10b/0x2c0
[<ffffffff81605863>] inet_gro_receive+0x1d3/0x270
[<ffffffff81589e59>] dev_gro_receive+0x269/0x3b0
[<ffffffff8158a1b8>] napi_gro_receive+0x38/0x120
[<ffffffffa0871297>] gro_cell_poll+0x57/0x80 [vxlan]
[<ffffffff815899d0>] net_rx_action+0x160/0x380
[<ffffffff816965c7>] __do_softirq+0xd7/0x2c5
[<ffffffff8107d969>] run_ksoftirqd+0x29/0x50
[<ffffffff8109a50f>] smpboot_thread_fn+0x10f/0x160
[<ffffffff8109a400>] ? sort_range+0x30/0x30
[<ffffffff81096da8>] kthread+0xd8/0xf0
[<ffffffff81693c82>] ret_from_fork+0x22/0x40
[<ffffffff81096cd0>] ? kthread_park+0x60/0x60
The following trace is seen when receiving a DHCP request over a flow-based
VXLAN tunnel. I believe this is caused by the metadata dst having a NULL
dev value and as a result dev_net(dev) is causing a NULL pointer dereference.
To resolve this I am replacing the check for skb_dst(skb)->dev with just
skb->dev. This makes sense as the callers of this function are usually in
the receive path and as such skb->dev should always be populated. In
addition other functions in the area where these are called are already
using dev_net(skb->dev) to determine the namespace the UDP packet belongs
in.
Fixes: 63058308cd55 ("udp: Add udp6_lib_lookup_skb and udp4_lib_lookup_skb")
Signed-off-by: Alexander Duyck <aduyck@mirantis.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>