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authorEric Dumazet <edumazet@google.com>2016-11-02 20:30:48 -0700
committerDavid S. Miller <davem@davemloft.net>2016-11-03 16:16:51 -0400
commit1aa9d1a0e7eefcc61696e147d123453fc0016005 (patch)
tree552c032ae3d6773f8130e154fa5223f6676537e5 /net/dccp
parentnetlink: netlink_diag_dump() runs without locks (diff)
downloadlinux-dev-1aa9d1a0e7eefcc61696e147d123453fc0016005.tar.xz
linux-dev-1aa9d1a0e7eefcc61696e147d123453fc0016005.zip
ipv6: dccp: fix out of bound access in dccp_v6_err()
dccp_v6_err() does not use pskb_may_pull() and might access garbage. We only need 4 bytes at the beginning of the DCCP header, like TCP, so the 8 bytes pulled in icmpv6_notify() are more than enough. Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/dccp')
-rw-r--r--net/dccp/ipv6.c15
1 files changed, 8 insertions, 7 deletions
diff --git a/net/dccp/ipv6.c b/net/dccp/ipv6.c
index 09c4e19aa285..b2a43af967e5 100644
--- a/net/dccp/ipv6.c
+++ b/net/dccp/ipv6.c
@@ -70,7 +70,7 @@ static void dccp_v6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
u8 type, u8 code, int offset, __be32 info)
{
const struct ipv6hdr *hdr = (const struct ipv6hdr *)skb->data;
- const struct dccp_hdr *dh = (struct dccp_hdr *)(skb->data + offset);
+ const struct dccp_hdr *dh;
struct dccp_sock *dp;
struct ipv6_pinfo *np;
struct sock *sk;
@@ -78,12 +78,13 @@ static void dccp_v6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
__u64 seq;
struct net *net = dev_net(skb->dev);
- if (skb->len < offset + sizeof(*dh) ||
- skb->len < offset + __dccp_basic_hdr_len(dh)) {
- __ICMP6_INC_STATS(net, __in6_dev_get(skb->dev),
- ICMP6_MIB_INERRORS);
- return;
- }
+ /* Only need dccph_dport & dccph_sport which are the first
+ * 4 bytes in dccp header.
+ * Our caller (icmpv6_notify()) already pulled 8 bytes for us.
+ */
+ BUILD_BUG_ON(offsetofend(struct dccp_hdr, dccph_sport) > 8);
+ BUILD_BUG_ON(offsetofend(struct dccp_hdr, dccph_dport) > 8);
+ dh = (struct dccp_hdr *)(skb->data + offset);
sk = __inet6_lookup_established(net, &dccp_hashinfo,
&hdr->daddr, dh->dccph_dport,