From: Florian Westphal <fw@xxxxxxxxx>
This patch has been added to the 4.1 stable tree. If you have any
objections, please let us know.
===============
[ Upstream commit 5d150a985520bbe3cb2aa1ceef24a7e32f20c15f ]
When ipv6_find_hdr is used to find a fragment header
(caller specifies target NEXTHDR_FRAGMENT) we erronously return
-ENOENT for all fragments with nonzero offset.
Before commit 9195bb8e381d, when target was specified, we did not
enter the exthdr walk loop as nexthdr == target so this used to work.
Now we do (so we can skip empty route headers). When we then stumble upon
a frag with nonzero frag_off we must return -ENOENT ("header not found")
only if the caller did not specifically request NEXTHDR_FRAGMENT.
This allows nfables exthdr expression to match ipv6 fragments, e.g. via
nft add rule ip6 filter input frag frag-off gt 0
Fixes: 9195bb8e381d ("ipv6: improve ipv6_find_hdr() to skip empty routing headers")
Signed-off-by: Florian Westphal <fw@xxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sasha.levin@xxxxxxxxxx>
---
net/ipv6/exthdrs_core.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/net/ipv6/exthdrs_core.c b/net/ipv6/exthdrs_core.c
index 5c5d23e..9508a20 100644
--- a/net/ipv6/exthdrs_core.c
+++ b/net/ipv6/exthdrs_core.c
@@ -257,7 +257,11 @@ int ipv6_find_hdr(const struct sk_buff *skb, unsigned int *offset,
*fragoff = _frag_off;
return hp->nexthdr;
}
- return -ENOENT;
+ if (!found)
+ return -ENOENT;
+ if (fragoff)
+ *fragoff = _frag_off;
+ break;
}
hdrlen = 8;
} else if (nexthdr == NEXTHDR_AUTH) {
--
2.5.0
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