1 files changed, 104 insertions, 21 deletions

diff --git a/net/sctp/input.c b/net/sctp/input.c
index 91ae463..d695f71 100644
--- a/net/sctp/input.c
+++ b/net/sctp/input.c
@@ -60,6 +60,7 @@
 #include <net/xfrm.h>
 #include <net/sctp/sctp.h>
 #include <net/sctp/sm.h>
+#include <net/sctp/checksum.h>
 
 /* Forward declarations for internal helpers. */
 static int sctp_rcv_ootb(struct sk_buff *);
@@ -890,14 +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.
@@ -934,6 +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
@@ -942,20 +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;
 }
 
 /*
@@ -965,7 +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)
 {
@@ -973,6 +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:
@@ -980,11 +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;
 }
 
@@ -1003,7 +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;
 }