1 files changed, 23 insertions, 45 deletions

diff --git a/net/ipv4/igmp.c b/net/ipv4/igmp.c
index 765b2b32c4a4..a40e48ded10d 100644
--- a/net/ipv4/igmp.c
+++ b/net/ipv4/igmp.c
@@ -1493,22 +1493,22 @@ static int ip_mc_check_igmp_reportv3(struct sk_buff *skb)
 
 	len += sizeof(struct igmpv3_report);
 
-	return pskb_may_pull(skb, len) ? 0 : -EINVAL;
+	return ip_mc_may_pull(skb, len) ? 0 : -EINVAL;
 }
 
 static int ip_mc_check_igmp_query(struct sk_buff *skb)
 {
-	unsigned int len = skb_transport_offset(skb);
-
-	len += sizeof(struct igmphdr);
-	if (skb->len < len)
-		return -EINVAL;
+	unsigned int transport_len = ip_transport_len(skb);
+	unsigned int len;
 
 	/* IGMPv{1,2}? */
-	if (skb->len != len) {
+	if (transport_len != sizeof(struct igmphdr)) {
 		/* or IGMPv3? */
-		len += sizeof(struct igmpv3_query) - sizeof(struct igmphdr);
-		if (skb->len < len || !pskb_may_pull(skb, len))
+		if (transport_len < sizeof(struct igmpv3_query))
+			return -EINVAL;
+
+		len = skb_transport_offset(skb) + sizeof(struct igmpv3_query);
+		if (!ip_mc_may_pull(skb, len))
 			return -EINVAL;
 	}
 
@@ -1544,47 +1544,29 @@ static inline __sum16 ip_mc_validate_checksum(struct sk_buff *skb)
 	return skb_checksum_simple_validate(skb);
 }
 
-static int __ip_mc_check_igmp(struct sk_buff *skb, struct sk_buff **skb_trimmed)
-
+static int ip_mc_check_igmp_csum(struct sk_buff *skb)
 {
-	struct sk_buff *skb_chk;
-	unsigned int transport_len;
 	unsigned int len = skb_transport_offset(skb) + sizeof(struct igmphdr);
-	int ret = -EINVAL;
+	unsigned int transport_len = ip_transport_len(skb);
+	struct sk_buff *skb_chk;
 
-	transport_len = ntohs(ip_hdr(skb)->tot_len) - ip_hdrlen(skb);
+	if (!ip_mc_may_pull(skb, len))
+		return -EINVAL;
 
 	skb_chk = skb_checksum_trimmed(skb, transport_len,
 				       ip_mc_validate_checksum);
 	if (!skb_chk)
-		goto err;
-
-	if (!pskb_may_pull(skb_chk, len))
-		goto err;
-
-	ret = ip_mc_check_igmp_msg(skb_chk);
-	if (ret)
-		goto err;
-
-	if (skb_trimmed)
-		*skb_trimmed = skb_chk;
-	/* free now unneeded clone */
-	else if (skb_chk != skb)
-		kfree_skb(skb_chk);
-
-	ret = 0;
+		return -EINVAL;
 
-err:
-	if (ret && skb_chk && skb_chk != skb)
+	if (skb_chk != skb)
 		kfree_skb(skb_chk);
 
-	return ret;
+	return 0;
 }
 
 /**
  * ip_mc_check_igmp - checks whether this is a sane IGMP packet
  * @skb: the skb to validate
- * @skb_trimmed: to store an skb pointer trimmed to IPv4 packet tail (optional)
  *
  * Checks whether an IPv4 packet is a valid IGMP packet. If so sets
  * skb transport header accordingly and returns zero.
@@ -1594,18 +1576,10 @@ err:
  * -ENOMSG: IP header validation succeeded but it is not an IGMP packet.
  * -ENOMEM: A memory allocation failure happened.
  *
- * Optionally, an skb pointer might be provided via skb_trimmed (or set it
- * to NULL): After parsing an IGMP packet successfully it will point to
- * an skb which has its tail aligned to the IP packet end. This might
- * either be the originally provided skb or a trimmed, cloned version if
- * the skb frame had data beyond the IP packet. A cloned skb allows us
- * to leave the original skb and its full frame unchanged (which might be
- * desirable for layer 2 frame jugglers).
- *
  * Caller needs to set the skb network header and free any returned skb if it
  * differs from the provided skb.
  */
-int ip_mc_check_igmp(struct sk_buff *skb, struct sk_buff **skb_trimmed)
+int ip_mc_check_igmp(struct sk_buff *skb)
 {
 	int ret = ip_mc_check_iphdr(skb);
 
@@ -1615,7 +1589,11 @@ int ip_mc_check_igmp(struct sk_buff *skb, struct sk_buff **skb_trimmed)
 	if (ip_hdr(skb)->protocol != IPPROTO_IGMP)
 		return -ENOMSG;
 
-	return __ip_mc_check_igmp(skb, skb_trimmed);
+	ret = ip_mc_check_igmp_csum(skb);
+	if (ret < 0)
+		return ret;
+
+	return ip_mc_check_igmp_msg(skb);
 }
 EXPORT_SYMBOL(ip_mc_check_igmp);