path: root/net/ipv6/icmp.c
diff options
authorDavid Ahern <dsa@cumulusnetworks.com>2016-11-27 18:52:53 -0800
committerDavid S. Miller <davem@davemloft.net>2016-11-28 16:13:01 -0500
commit79dc7e3f1cd323be4c81aa1a94faa1b3ed987fb2 (patch)
treed1a9cdff4acc61f6400210db737623e3c3a8e8db /net/ipv6/icmp.c
parentMerge branch 'mlx4-fixes' (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>
Diffstat (limited to '')
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