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| author | Mathias Krause <mathias.krause@secunet.com> | 2015-09-11 09:57:20 +0200 |
|---|---|---|
| committer | Steffen Klassert <steffen.klassert@secunet.com> | 2015-09-14 10:53:05 +0200 |
| commit | 04a6b8bfee06e309be7e9ae4527cdab19c081761 (patch) | |
| tree | 82e72d3ed231222243487b575887c2b974025a6d /net/ipv6/xfrm6_policy.c | |
| parent | 93efac3f2e03321129de67a3c0ba53048bb53e31 (diff) | |
| download | linux-04a6b8bfee06e309be7e9ae4527cdab19c081761.tar.bz2 | |
xfrm6: Fix ICMPv6 and MH header checks in _decode_session6
Ensure there's enough data left prior calling pskb_may_pull(). If
skb->data was already advanced, we'll call pskb_may_pull() with a
negative value converted to unsigned int -- leading to a huge
positive value. That won't matter in practice as pskb_may_pull()
will likely fail in this case, but it leads to underflow reports on
kernels handling such kind of over-/underflows, e.g. a PaX enabled
kernel instrumented with the size_overflow plugin.
Reported-by: satmd <satmd@lain.at>
Reported-and-tested-by: Marcin Jurkowski <marcin1j@gmail.com>
Signed-off-by: Mathias Krause <mathias.krause@secunet.com>
Cc: PaX Team <pageexec@freemail.hu>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Diffstat (limited to 'net/ipv6/xfrm6_policy.c')
| -rw-r--r-- | net/ipv6/xfrm6_policy.c | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/net/ipv6/xfrm6_policy.c b/net/ipv6/xfrm6_policy.c index 30caa289c5db..f10b9400b6d7 100644 --- a/net/ipv6/xfrm6_policy.c +++ b/net/ipv6/xfrm6_policy.c @@ -178,7 +178,8 @@ _decode_session6(struct sk_buff *skb, struct flowi *fl, int reverse) return; case IPPROTO_ICMPV6: - if (!onlyproto && pskb_may_pull(skb, nh + offset + 2 - skb->data)) { + if (!onlyproto && (nh + offset + 2 < skb->data || + pskb_may_pull(skb, nh + offset + 2 - skb->data))) { u8 *icmp; nh = skb_network_header(skb); @@ -192,7 +193,8 @@ _decode_session6(struct sk_buff *skb, struct flowi *fl, int reverse) #if IS_ENABLED(CONFIG_IPV6_MIP6) case IPPROTO_MH: offset += ipv6_optlen(exthdr); - if (!onlyproto && pskb_may_pull(skb, nh + offset + 3 - skb->data)) { + if (!onlyproto && (nh + offset + 3 < skb->data || + pskb_may_pull(skb, nh + offset + 3 - skb->data))) { struct ip6_mh *mh; nh = skb_network_header(skb); |