diff options
| author | David Ahern <dsa@cumulusnetworks.com> | 2016-11-02 12:08:25 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2016-11-03 16:05:44 -0400 |
| commit | da96786e26c3ae47316db2b92046b11268c4379c (patch) | |
| tree | 927e46eccc644ed5b0395194175da0eb226cce68 /include/linux/ipv6.h | |
| parent | ac9e70b17ecd7c6e933ff2eaf7ab37429e71bf4d (diff) | |
| download | lwn-da96786e26c3ae47316db2b92046b11268c4379c.tar.gz lwn-da96786e26c3ae47316db2b92046b11268c4379c.zip | |
net: tcp: check skb is non-NULL for exact match on lookups
Andrey reported the following error report while running the syzkaller
fuzzer:
general protection fault: 0000 [#1] SMP KASAN
Dumping ftrace buffer:
(ftrace buffer empty)
Modules linked in:
CPU: 0 PID: 648 Comm: syz-executor Not tainted 4.9.0-rc3+ #333
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
task: ffff8800398c4480 task.stack: ffff88003b468000
RIP: 0010:[<ffffffff83091106>] [< inline >]
inet_exact_dif_match include/net/tcp.h:808
RIP: 0010:[<ffffffff83091106>] [<ffffffff83091106>]
__inet_lookup_listener+0xb6/0x500 net/ipv4/inet_hashtables.c:219
RSP: 0018:ffff88003b46f270 EFLAGS: 00010202
RAX: 0000000000000004 RBX: 0000000000004242 RCX: 0000000000000001
RDX: 0000000000000000 RSI: ffffc90000e3c000 RDI: 0000000000000054
RBP: ffff88003b46f2d8 R08: 0000000000004000 R09: ffffffff830910e7
R10: 0000000000000000 R11: 000000000000000a R12: ffffffff867fa0c0
R13: 0000000000004242 R14: 0000000000000003 R15: dffffc0000000000
FS: 00007fb135881700(0000) GS:ffff88003ec00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020cc3000 CR3: 000000006d56a000 CR4: 00000000000006f0
Stack:
0000000000000000 000000000601a8c0 0000000000000000 ffffffff00004242
424200003b9083c2 ffff88003def4041 ffffffff84e7e040 0000000000000246
ffff88003a0911c0 0000000000000000 ffff88003a091298 ffff88003b9083ae
Call Trace:
[<ffffffff831100f4>] tcp_v4_send_reset+0x584/0x1700 net/ipv4/tcp_ipv4.c:643
[<ffffffff83115b1b>] tcp_v4_rcv+0x198b/0x2e50 net/ipv4/tcp_ipv4.c:1718
[<ffffffff83069d22>] ip_local_deliver_finish+0x332/0xad0
net/ipv4/ip_input.c:216
...
MD5 has a code path that calls __inet_lookup_listener with a null skb,
so inet{6}_exact_dif_match needs to check skb against null before pulling
the flag.
Fixes: a04a480d4392 ("net: Require exact match for TCP socket lookups if
dif is l3mdev")
Reported-by: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: David Ahern <dsa@cumulusnetworks.com>
Tested-by: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include/linux/ipv6.h')
| -rw-r--r-- | include/linux/ipv6.h | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/include/linux/ipv6.h b/include/linux/ipv6.h index ca1ad9ebbc92..a0649973ee5b 100644 --- a/include/linux/ipv6.h +++ b/include/linux/ipv6.h @@ -149,7 +149,7 @@ static inline bool inet6_exact_dif_match(struct net *net, struct sk_buff *skb) { #if defined(CONFIG_NET_L3_MASTER_DEV) if (!net->ipv4.sysctl_tcp_l3mdev_accept && - ipv6_l3mdev_skb(IP6CB(skb)->flags)) + skb && ipv6_l3mdev_skb(IP6CB(skb)->flags)) return true; #endif return false; |