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-rw-r--r--net/sctp/input.c124
1 files changed, 103 insertions, 21 deletions
diff --git a/net/sctp/input.c b/net/sctp/input.c
index b08c7cb5c9d6..d695f710fc77 100644
--- a/net/sctp/input.c
+++ b/net/sctp/input.c
@@ -891,14 +891,6 @@ static struct sctp_association *__sctp_rcv_init_lookup(struct sk_buff *skb,
ch = (sctp_chunkhdr_t *) skb->data;
- /* The code below will attempt to walk the chunk and extract
- * parameter information. Before we do that, we need to verify
- * that the chunk length doesn't cause overflow. Otherwise, we'll
- * walk off the end.
- */
- if (WORD_ROUND(ntohs(ch->length)) > skb->len)
- return NULL;
-
/*
* This code will NOT touch anything inside the chunk--it is
* strictly READ-ONLY.
@@ -935,6 +927,44 @@ static struct sctp_association *__sctp_rcv_init_lookup(struct sk_buff *skb,
return NULL;
}
+/* ADD-IP, Section 5.2
+ * When an endpoint receives an ASCONF Chunk from the remote peer
+ * special procedures may be needed to identify the association the
+ * ASCONF Chunk is associated with. To properly find the association
+ * the following procedures SHOULD be followed:
+ *
+ * D2) If the association is not found, use the address found in the
+ * Address Parameter TLV combined with the port number found in the
+ * SCTP common header. If found proceed to rule D4.
+ *
+ * D2-ext) If more than one ASCONF Chunks are packed together, use the
+ * address found in the ASCONF Address Parameter TLV of each of the
+ * subsequent ASCONF Chunks. If found, proceed to rule D4.
+ */
+static struct sctp_association *__sctp_rcv_asconf_lookup(
+ sctp_chunkhdr_t *ch,
+ const union sctp_addr *laddr,
+ __be32 peer_port,
+ struct sctp_transport **transportp)
+{
+ sctp_addip_chunk_t *asconf = (struct sctp_addip_chunk *)ch;
+ struct sctp_af *af;
+ union sctp_addr_param *param;
+ union sctp_addr paddr;
+
+ /* Skip over the ADDIP header and find the Address parameter */
+ param = (union sctp_addr_param *)(asconf + 1);
+
+ af = sctp_get_af_specific(param_type2af(param->v4.param_hdr.type));
+ if (unlikely(!af))
+ return NULL;
+
+ af->from_addr_param(&paddr, param, peer_port, 0);
+
+ return __sctp_lookup_association(laddr, &paddr, transportp);
+}
+
+
/* SCTP-AUTH, Section 6.3:
* If the receiver does not find a STCB for a packet containing an AUTH
* chunk as the first chunk and not a COOKIE-ECHO chunk as the second
@@ -943,20 +973,64 @@ static struct sctp_association *__sctp_rcv_init_lookup(struct sk_buff *skb,
*
* This means that any chunks that can help us identify the association need
* to be looked at to find this assocation.
-*
-* TODO: The only chunk currently defined that can do that is ASCONF, but we
-* don't support that functionality yet.
*/
-static struct sctp_association *__sctp_rcv_auth_lookup(struct sk_buff *skb,
- const union sctp_addr *paddr,
+static struct sctp_association *__sctp_rcv_walk_lookup(struct sk_buff *skb,
const union sctp_addr *laddr,
struct sctp_transport **transportp)
{
- /* XXX - walk through the chunks looking for something that can
- * help us find the association. INIT, and INIT-ACK are not permitted.
- * That leaves ASCONF, but we don't support that yet.
+ struct sctp_association *asoc = NULL;
+ sctp_chunkhdr_t *ch;
+ int have_auth = 0;
+ unsigned int chunk_num = 1;
+ __u8 *ch_end;
+
+ /* Walk through the chunks looking for AUTH or ASCONF chunks
+ * to help us find the association.
*/
- return NULL;
+ ch = (sctp_chunkhdr_t *) skb->data;
+ do {
+ /* Break out if chunk length is less then minimal. */
+ if (ntohs(ch->length) < sizeof(sctp_chunkhdr_t))
+ break;
+
+ ch_end = ((__u8 *)ch) + WORD_ROUND(ntohs(ch->length));
+ if (ch_end > skb_tail_pointer(skb))
+ break;
+
+ switch(ch->type) {
+ case SCTP_CID_AUTH:
+ have_auth = chunk_num;
+ break;
+
+ case SCTP_CID_COOKIE_ECHO:
+ /* If a packet arrives containing an AUTH chunk as
+ * a first chunk, a COOKIE-ECHO chunk as the second
+ * chunk, and possibly more chunks after them, and
+ * the receiver does not have an STCB for that
+ * packet, then authentication is based on
+ * the contents of the COOKIE- ECHO chunk.
+ */
+ if (have_auth == 1 && chunk_num == 2)
+ return NULL;
+ break;
+
+ case SCTP_CID_ASCONF:
+ if (have_auth || sctp_addip_noauth)
+ asoc = __sctp_rcv_asconf_lookup(ch, laddr,
+ sctp_hdr(skb)->source,
+ transportp);
+ default:
+ break;
+ }
+
+ if (asoc)
+ break;
+
+ ch = (sctp_chunkhdr_t *) ch_end;
+ chunk_num++;
+ } while (ch_end < skb_tail_pointer(skb));
+
+ return asoc;
}
/*
@@ -966,7 +1040,6 @@ static struct sctp_association *__sctp_rcv_auth_lookup(struct sk_buff *skb,
* chunks.
*/
static struct sctp_association *__sctp_rcv_lookup_harder(struct sk_buff *skb,
- const union sctp_addr *paddr,
const union sctp_addr *laddr,
struct sctp_transport **transportp)
{
@@ -974,6 +1047,14 @@ static struct sctp_association *__sctp_rcv_lookup_harder(struct sk_buff *skb,
ch = (sctp_chunkhdr_t *) skb->data;
+ /* The code below will attempt to walk the chunk and extract
+ * parameter information. Before we do that, we need to verify
+ * that the chunk length doesn't cause overflow. Otherwise, we'll
+ * walk off the end.
+ */
+ if (WORD_ROUND(ntohs(ch->length)) > skb->len)
+ return NULL;
+
/* If this is INIT/INIT-ACK look inside the chunk too. */
switch (ch->type) {
case SCTP_CID_INIT:
@@ -981,11 +1062,12 @@ static struct sctp_association *__sctp_rcv_lookup_harder(struct sk_buff *skb,
return __sctp_rcv_init_lookup(skb, laddr, transportp);
break;
- case SCTP_CID_AUTH:
- return __sctp_rcv_auth_lookup(skb, paddr, laddr, transportp);
+ default:
+ return __sctp_rcv_walk_lookup(skb, laddr, transportp);
break;
}
+
return NULL;
}
@@ -1004,7 +1086,7 @@ static struct sctp_association *__sctp_rcv_lookup(struct sk_buff *skb,
* parameters within the INIT or INIT-ACK.
*/
if (!asoc)
- asoc = __sctp_rcv_lookup_harder(skb, paddr, laddr, transportp);
+ asoc = __sctp_rcv_lookup_harder(skb, laddr, transportp);
return asoc;
}