diff options
| author | David Ahern <dsa@cumulusnetworks.com> | 2016-11-27 18:52:53 -0800 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2016-11-28 16:13:01 -0500 |
| commit | 79dc7e3f1cd323be4c81aa1a94faa1b3ed987fb2 (patch) | |
| tree | d1a9cdff4acc61f6400210db737623e3c3a8e8db | |
| parent | 2fc8d112d73f604936712c02780b9a8fb402b67c (diff) | |
net: handle no dst on skb in icmp6_send
Andrey reported the following while fuzzing the kernel with syzkaller:
kasan: CONFIG_KASAN_INLINE enabled
kasan: GPF could be caused by NULL-ptr deref or user memory access
general protection fault: 0000 [#1] SMP KASAN
Modules linked in:
CPU: 0 PID: 3859 Comm: a.out Not tainted 4.9.0-rc6+ #429
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
task: ffff8800666d4200 task.stack: ffff880067348000
RIP: 0010:[<ffffffff833617ec>] [<ffffffff833617ec>]
icmp6_send+0x5fc/0x1e30 net/ipv6/icmp.c:451
RSP: 0018:ffff88006734f2c0 EFLAGS: 00010206
RAX: ffff8800666d4200 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 0000000000000000 RSI: dffffc0000000000 RDI: 0000000000000018
RBP: ffff88006734f630 R08: ffff880064138418 R09: 0000000000000003
R10: dffffc0000000000 R11: 0000000000000005 R12: 0000000000000000
R13: ffffffff84e7e200 R14: ffff880064138484 R15: ffff8800641383c0
FS: 00007fb3887a07c0(0000) GS:ffff88006cc00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020000000 CR3: 000000006b040000 CR4: 00000000000006f0
Stack:
ffff8800666d4200 ffff8800666d49f8 ffff8800666d4200 ffffffff84c02460
ffff8800666d4a1a 1ffff1000ccdaa2f ffff88006734f498 0000000000000046
ffff88006734f440 ffffffff832f4269 ffff880064ba7456 0000000000000000
Call Trace:
[<ffffffff83364ddc>] icmpv6_param_prob+0x2c/0x40 net/ipv6/icmp.c:557
[< inline >] ip6_tlvopt_unknown net/ipv6/exthdrs.c:88
[<ffffffff83394405>] ip6_parse_tlv+0x555/0x670 net/ipv6/exthdrs.c:157
[<ffffffff8339a759>] ipv6_parse_hopopts+0x199/0x460 net/ipv6/exthdrs.c:663
[<ffffffff832ee773>] ipv6_rcv+0xfa3/0x1dc0 net/ipv6/ip6_input.c:191
...
icmp6_send / icmpv6_send is invoked for both rx and tx paths. In both
cases the dst->dev should be preferred for determining the L3 domain
if the dst has been set on the skb. Fallback to the skb->dev if it has
not. This covers the case reported here where icmp6_send is invoked on
Rx before the route lookup.
Fixes: 5d41ce29e ("net: icmp6_send should use dst dev to determine L3 domain")
Reported-by: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: David Ahern <dsa@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | net/ipv6/icmp.c | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/net/ipv6/icmp.c b/net/ipv6/icmp.c index 7370ad2e693a..2772004ba5a1 100644 --- a/net/ipv6/icmp.c +++ b/net/ipv6/icmp.c @@ -447,8 +447,10 @@ static void icmp6_send(struct sk_buff *skb, u8 type, u8 code, __u32 info, if (__ipv6_addr_needs_scope_id(addr_type)) iif = skb->dev->ifindex; - else - iif = l3mdev_master_ifindex(skb_dst(skb)->dev); + else { + dst = skb_dst(skb); + iif = l3mdev_master_ifindex(dst ? dst->dev : skb->dev); + } /* * Must not send error if the source does not uniquely |