Merge pull request #14654 from FRRouting/mergify/bp/stable/9.0/pr-14645

bgpd: A couple more bgpd crashes on malformed attributes (backport #14645)
FRRouting · Oct 25, 2023 · d5d6be1 · d5d6be1
2 parents 8d04bac + 77e4046
commit d5d6be1
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Showing 3 changed files with 8 additions and 15 deletions.
diff --git a/bgpd/bgp_attr.c b/bgpd/bgp_attr.c
@@ -2388,7 +2388,7 @@ int bgp_mp_reach_parse(struct bgp_attr_parser_args *args,
 
 		mp_update->afi = afi;
 		mp_update->safi = safi;
-		return BGP_ATTR_PARSE_EOR;
+		return bgp_attr_malformed(args, BGP_NOTIFY_UPDATE_MAL_ATTR, 0);
 	}
 
 	mp_update->afi = afi;
@@ -3349,13 +3349,15 @@ bgp_attr_unknown(struct bgp_attr_parser_args *args)
 }
 
 /* Well-known attribute check. */
-static int bgp_attr_check(struct peer *peer, struct attr *attr)
+static int bgp_attr_check(struct peer *peer, struct attr *attr,
+			  bgp_size_t length)
 {
 	uint8_t type = 0;
 
 	/* BGP Graceful-Restart End-of-RIB for IPv4 unicast is signaled as an
 	 * empty UPDATE.  */
-	if (CHECK_FLAG(peer->cap, PEER_CAP_RESTART_RCV) && !attr->flag)
+	if (CHECK_FLAG(peer->cap, PEER_CAP_RESTART_RCV) && !attr->flag &&
+	    !length)
 		return BGP_ATTR_PARSE_PROCEED;
 
 	/* "An UPDATE message that contains the MP_UNREACH_NLRI is not required
@@ -3407,7 +3409,7 @@ enum bgp_attr_parse_ret bgp_attr_parse(struct peer *peer, struct attr *attr,
 	enum bgp_attr_parse_ret ret;
 	uint8_t flag = 0;
 	uint8_t type = 0;
-	bgp_size_t length;
+	bgp_size_t length = 0;
 	uint8_t *startp, *endp;
 	uint8_t *attr_endp;
 	uint8_t seen[BGP_ATTR_BITMAP_SIZE];
@@ -3658,10 +3660,6 @@ enum bgp_attr_parse_ret bgp_attr_parse(struct peer *peer, struct attr *attr,
 			goto done;
 		}
 
-		if (ret == BGP_ATTR_PARSE_EOR) {
-			goto done;
-		}
-
 		if (ret == BGP_ATTR_PARSE_ERROR) {
 			flog_warn(EC_BGP_ATTRIBUTE_PARSE_ERROR,
 				  "%s: Attribute %s, parse error", peer->host,
@@ -3734,7 +3732,7 @@ enum bgp_attr_parse_ret bgp_attr_parse(struct peer *peer, struct attr *attr,
 	}
 
 	/* Check all mandatory well-known attributes are present */
-	ret = bgp_attr_check(peer, attr);
+	ret = bgp_attr_check(peer, attr, length);
 	if (ret < 0)
 		goto done;
 

diff --git a/bgpd/bgp_attr.h b/bgpd/bgp_attr.h
@@ -364,7 +364,6 @@ enum bgp_attr_parse_ret {
 	/* only used internally, send notify + convert to BGP_ATTR_PARSE_ERROR
 	 */
 	BGP_ATTR_PARSE_ERROR_NOTIFYPLS = -3,
-	BGP_ATTR_PARSE_EOR = -4,
 };
 
 struct bpacket_attr_vec_arr;

diff --git a/bgpd/bgp_packet.c b/bgpd/bgp_packet.c
@@ -2053,8 +2053,7 @@ static int bgp_update_receive(struct peer *peer, bgp_size_t size)
 	 * Non-MP IPv4/Unicast EoR is a completely empty UPDATE
 	 * and MP EoR should have only an empty MP_UNREACH
 	 */
-	if ((!update_len && !withdraw_len && nlris[NLRI_MP_UPDATE].length == 0)
-	    || (attr_parse_ret == BGP_ATTR_PARSE_EOR)) {
+	if (!update_len && !withdraw_len && nlris[NLRI_MP_UPDATE].length == 0) {
 		afi_t afi = 0;
 		safi_t safi;
 		struct graceful_restart_info *gr_info;
@@ -2075,9 +2074,6 @@ static int bgp_update_receive(struct peer *peer, bgp_size_t size)
 			   && nlris[NLRI_MP_WITHDRAW].length == 0) {
 			afi = nlris[NLRI_MP_WITHDRAW].afi;
 			safi = nlris[NLRI_MP_WITHDRAW].safi;
-		} else if (attr_parse_ret == BGP_ATTR_PARSE_EOR) {
-			afi = nlris[NLRI_MP_UPDATE].afi;
-			safi = nlris[NLRI_MP_UPDATE].safi;
 		}
 
 		if (afi && peer->afc[afi][safi]) {