ipv6: Fix OOPS, ip -f inet6 route get fec0::1, linux-2.6.26, ip6_route_output, rt6_fill_node+0x175
Alexey Dobriyan wrote:
> On Thu, Aug 07, 2008 at 07:00:56PM +0200, John Gumb wrote:
>> Scenario: no ipv6 default route set.
>
>> # ip -f inet6 route get fec0::1
>>
>> BUG: unable to handle kernel NULL pointer dereference at 00000000
>> IP: [<c0369b85>] rt6_fill_node+0x175/0x3b0
>> EIP is at rt6_fill_node+0x175/0x3b0
>
> 0xffffffff80424dd3 is in rt6_fill_node (net/ipv6/route.c:2191).
> 2186 } else
> 2187 #endif
> 2188 NLA_PUT_U32(skb, RTA_IIF, iif);
> 2189 } else if (dst) {
> 2190 struct in6_addr saddr_buf;
> 2191 ====> if (ipv6_dev_get_saddr(ip6_dst_idev(&rt->u.dst)->dev,
> ^^^^^^^^^^^^^^^^^^^^^^^^
> NULL
>
> 2192 dst, 0, &saddr_buf) == 0)
> 2193 NLA_PUT(skb, RTA_PREFSRC, 16, &saddr_buf);
> 2194 }
The commit that changed this can't be reverted easily, but the patch
below works for me.
Fix NULL de-reference in rt6_fill_node() when there's no IPv6 input
device present in the dst entry.
Signed-off-by: Brian Haley <brian.haley@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index 5a3e87e..41b165f 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -2187,8 +2187,9 @@
#endif
NLA_PUT_U32(skb, RTA_IIF, iif);
} else if (dst) {
+ struct inet6_dev *idev = ip6_dst_idev(&rt->u.dst);
struct in6_addr saddr_buf;
- if (ipv6_dev_get_saddr(ip6_dst_idev(&rt->u.dst)->dev,
+ if (ipv6_dev_get_saddr(idev ? idev->dev : NULL,
dst, 0, &saddr_buf) == 0)
NLA_PUT(skb, RTA_PREFSRC, 16, &saddr_buf);
}