[NETFILTER]: Fix undersized skb allocation in ipt_ULOG/ebt_ulog/nfnetlink_log

The skb allocated is always of size nlbufsize, even if that is smaller than
the size needed for the current packet.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/bridge/netfilter/ebt_ulog.c

@@ -98,12 +98,14 @@ static void ulog_timer(unsigned long data)
 static struct sk_buff *ulog_alloc_skb(unsigned int size)
 {
 	struct sk_buff *skb;
+	unsigned int n;
 
-	skb = alloc_skb(nlbufsiz, GFP_ATOMIC);
+	n = max(size, nlbufsiz);
+	skb = alloc_skb(n, GFP_ATOMIC);
 	if (!skb) {
 		PRINTR(KERN_ERR "ebt_ulog: can't alloc whole buffer "
-		       "of size %ub!\n", nlbufsiz);
-		if (size < nlbufsiz) {
+		       "of size %ub!\n", n);
+		if (n > size) {
 			/* try to allocate only as much as we need for
 			 * current packet */
 			skb = alloc_skb(size, GFP_ATOMIC);

net/ipv4/netfilter/ipt_ULOG.c

@@ -147,22 +147,26 @@ static void ulog_timer(unsigned long data)
 static struct sk_buff *ulog_alloc_skb(unsigned int size)
 {
 	struct sk_buff *skb;
+	unsigned int n;
 
 	/* alloc skb which should be big enough for a whole
 	 * multipart message. WARNING: has to be <= 131000
 	 * due to slab allocator restrictions */
 
-	skb = alloc_skb(nlbufsiz, GFP_ATOMIC);
+	n = max(size, nlbufsiz);
+	skb = alloc_skb(n, GFP_ATOMIC);
 	if (!skb) {
-		PRINTR("ipt_ULOG: can't alloc whole buffer %ub!\n",
-			nlbufsiz);
+		PRINTR("ipt_ULOG: can't alloc whole buffer %ub!\n", n);
 
-		/* try to allocate only as much as we need for 
-		 * current packet */
+		if (n > size) {
+			/* try to allocate only as much as we need for 
+			 * current packet */
 
-		skb = alloc_skb(size, GFP_ATOMIC);
-		if (!skb)
-			PRINTR("ipt_ULOG: can't even allocate %ub\n", size);
+			skb = alloc_skb(size, GFP_ATOMIC);
+			if (!skb)
+				PRINTR("ipt_ULOG: can't even allocate %ub\n",
+				       size);
+		}
 	}
 
 	return skb;

net/netfilter/nfnetlink_log.c

@@ -314,24 +314,28 @@ static struct sk_buff *nfulnl_alloc_skb(unsigned int inst_size,
 					unsigned int pkt_size)
 {
 	struct sk_buff *skb;
+	unsigned int n;
 
 	UDEBUG("entered (%u, %u)\n", inst_size, pkt_size);
 
 	/* alloc skb which should be big enough for a whole multipart
 	 * message.  WARNING: has to be <= 128k due to slab restrictions */
 
-	skb = alloc_skb(inst_size, GFP_ATOMIC);
+	n = max(inst_size, pkt_size);
+	skb = alloc_skb(n, GFP_ATOMIC);
 	if (!skb) {
 		PRINTR("nfnetlink_log: can't alloc whole buffer (%u bytes)\n",
 			inst_size);
 
-		/* try to allocate only as much as we need for current
-		 * packet */
+		if (n > pkt_size) {
+			/* try to allocate only as much as we need for current
+			 * packet */
 
-		skb = alloc_skb(pkt_size, GFP_ATOMIC);
-		if (!skb)
-			PRINTR("nfnetlink_log: can't even alloc %u bytes\n",
-				pkt_size);
+			skb = alloc_skb(pkt_size, GFP_ATOMIC);
+			if (!skb)
+				PRINTR("nfnetlink_log: can't even alloc %u "
+				       "bytes\n", pkt_size);
+		}
 	}
 
 	return skb;