3.18-stable review patch. If anyone has any objections, please let me know.
------------------
From: Davide Caratti <dcaratti@xxxxxxxxxx>
[ Upstream commit 804ec7ebe8ea003999ca8d1bfc499edc6a9e07df ]
sometimes ICMP replies to INIT chunks are ignored by the client, even if
the encapsulated SCTP headers match an open socket. This happens when the
ICMP packet is carried by a paged skb: use skb_header_pointer() to read
packet contents beyond the SCTP header, so that chunk header and initiate
tag are validated correctly.
v2:
- don't use skb_header_pointer() to read the transport header, since
icmp_socket_deliver() already puts these 8 bytes in the linear area.
- change commit message to make specific reference to INIT chunks.
Signed-off-by: Davide Caratti <dcaratti@xxxxxxxxxx>
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@xxxxxxxxx>
Acked-by: Vlad Yasevich <vyasevich@xxxxxxxxx>
Reviewed-by: Xin Long <lucien.xin@xxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/sctp/input.c | 16 +++++++++-------
1 file changed, 9 insertions(+), 7 deletions(-)
--- a/net/sctp/input.c
+++ b/net/sctp/input.c
@@ -472,15 +472,14 @@ struct sock *sctp_err_lookup(struct net
struct sctp_association **app,
struct sctp_transport **tpp)
{
+ struct sctp_init_chunk *chunkhdr, _chunkhdr;
union sctp_addr saddr;
union sctp_addr daddr;
struct sctp_af *af;
struct sock *sk = NULL;
struct sctp_association *asoc;
struct sctp_transport *transport = NULL;
- struct sctp_init_chunk *chunkhdr;
__u32 vtag = ntohl(sctphdr->vtag);
- int len = skb->len - ((void *)sctphdr - (void *)skb->data);
*app = NULL; *tpp = NULL;
@@ -515,13 +514,16 @@ struct sock *sctp_err_lookup(struct net
* discard the packet.
*/
if (vtag == 0) {
- chunkhdr = (void *)sctphdr + sizeof(struct sctphdr);
- if (len < sizeof(struct sctphdr) + sizeof(sctp_chunkhdr_t)
- + sizeof(__be32) ||
+ /* chunk header + first 4 octects of init header */
+ chunkhdr = skb_header_pointer(skb, skb_transport_offset(skb) +
+ sizeof(struct sctphdr),
+ sizeof(struct sctp_chunkhdr) +
+ sizeof(__be32), &_chunkhdr);
+ if (!chunkhdr ||
chunkhdr->chunk_hdr.type != SCTP_CID_INIT ||
- ntohl(chunkhdr->init_hdr.init_tag) != asoc->c.my_vtag) {
+ ntohl(chunkhdr->init_hdr.init_tag) != asoc->c.my_vtag)
goto out;
- }
+
} else if (vtag != asoc->c.peer_vtag) {
goto out;
}