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| author | Eric Dumazet <edumazet@google.com> | 2016-11-02 20:30:48 -0700 |
|---|---|---|
| committer | Jiri Slaby <jslaby@suse.cz> | 2016-11-28 22:22:37 +0100 |
| commit | bfe7d1dee859cad6802f8e21a0a863f408114612 (patch) | |
| tree | 00096ca403682830a2e85dcb370accccb39219fc | |
| parent | dbf1719c65fb0368a94d15767c669e47e295a073 (diff) | |
| download | lwn-bfe7d1dee859cad6802f8e21a0a863f408114612.tar.gz lwn-bfe7d1dee859cad6802f8e21a0a863f408114612.zip | |
ipv6: dccp: fix out of bound access in dccp_v6_err()
[ Upstream commit 1aa9d1a0e7eefcc61696e147d123453fc0016005 ]
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>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
| -rw-r--r-- | net/dccp/ipv6.c | 15 |
1 files changed, 8 insertions, 7 deletions
diff --git a/net/dccp/ipv6.c b/net/dccp/ipv6.c index 86eedbaf037f..e9ce581b9502 100644 --- a/net/dccp/ipv6.c +++ b/net/dccp/ipv6.c @@ -83,7 +83,7 @@ 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; @@ -91,12 +91,13 @@ 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_BH(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(net, &dccp_hashinfo, &hdr->daddr, dh->dccph_dport, |