diff options
author | Jann Horn <jannh@google.com> | 2023-08-25 15:32:41 +0200 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2023-09-23 10:48:11 +0200 |
commit | 177212bf6dc1ff2d13d0409cddc5c9e81feec63d (patch) | |
tree | e36cad99501bd250001bd04cb94778ebd874ddd8 | |
parent | 10214f9896312e5c6f2590943ac9fccc68468be9 (diff) | |
download | linux-stable-177212bf6dc1ff2d13d0409cddc5c9e81feec63d.tar.gz linux-stable-177212bf6dc1ff2d13d0409cddc5c9e81feec63d.tar.bz2 linux-stable-177212bf6dc1ff2d13d0409cddc5c9e81feec63d.zip |
dccp: Fix out of bounds access in DCCP error handler
commit 977ad86c2a1bcaf58f01ab98df5cc145083c489c upstream.
There was a previous attempt to fix an out-of-bounds access in the DCCP
error handlers, but that fix assumed that the error handlers only want
to access the first 8 bytes of the DCCP header. Actually, they also look
at the DCCP sequence number, which is stored beyond 8 bytes, so an
explicit pskb_may_pull() is required.
Fixes: 6706a97fec96 ("dccp: fix out of bound access in dccp_v4_err()")
Fixes: 1aa9d1a0e7ee ("ipv6: dccp: fix out of bound access in dccp_v6_err()")
Cc: stable@vger.kernel.org
Signed-off-by: Jann Horn <jannh@google.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r-- | net/dccp/ipv4.c | 13 | ||||
-rw-r--r-- | net/dccp/ipv6.c | 15 |
2 files changed, 19 insertions, 9 deletions
diff --git a/net/dccp/ipv4.c b/net/dccp/ipv4.c index c021d5dde8f7..b2fc9ef7708f 100644 --- a/net/dccp/ipv4.c +++ b/net/dccp/ipv4.c @@ -247,12 +247,17 @@ static void dccp_v4_err(struct sk_buff *skb, u32 info) int err; struct net *net = dev_net(skb->dev); - /* Only need dccph_dport & dccph_sport which are the first - * 4 bytes in dccp header. + /* For the first __dccp_basic_hdr_len() check, we only need dh->dccph_x, + * which is in byte 7 of the dccp header. * Our caller (icmp_socket_deliver()) already pulled 8 bytes for us. + * + * Later on, we want to access the sequence number fields, which are + * beyond 8 bytes, so we have to pskb_may_pull() ourselves. */ - 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); + if (!pskb_may_pull(skb, offset + __dccp_basic_hdr_len(dh))) + return; + iph = (struct iphdr *)skb->data; dh = (struct dccp_hdr *)(skb->data + offset); sk = __inet_lookup_established(net, &dccp_hashinfo, diff --git a/net/dccp/ipv6.c b/net/dccp/ipv6.c index 88732ab4887c..f8d8caa967b1 100644 --- a/net/dccp/ipv6.c +++ b/net/dccp/ipv6.c @@ -71,7 +71,7 @@ static inline __u64 dccp_v6_init_sequence(struct sk_buff *skb) 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 ipv6hdr *hdr; const struct dccp_hdr *dh; struct dccp_sock *dp; struct ipv6_pinfo *np; @@ -80,12 +80,17 @@ static void dccp_v6_err(struct sk_buff *skb, struct inet6_skb_parm *opt, __u64 seq; struct net *net = dev_net(skb->dev); - /* Only need dccph_dport & dccph_sport which are the first - * 4 bytes in dccp header. + /* For the first __dccp_basic_hdr_len() check, we only need dh->dccph_x, + * which is in byte 7 of the dccp header. * Our caller (icmpv6_notify()) already pulled 8 bytes for us. + * + * Later on, we want to access the sequence number fields, which are + * beyond 8 bytes, so we have to pskb_may_pull() ourselves. */ - 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); + if (!pskb_may_pull(skb, offset + __dccp_basic_hdr_len(dh))) + return; + hdr = (const struct ipv6hdr *)skb->data; dh = (struct dccp_hdr *)(skb->data + offset); sk = __inet6_lookup_established(net, &dccp_hashinfo, |