1 files changed, 32 insertions, 8 deletions

diff --git a/net/x25/af_x25.c b/net/x25/af_x25.c
index d30615419b4d..5f03e4ea65bf 100644
--- a/net/x25/af_x25.c
+++ b/net/x25/af_x25.c
@@ -91,7 +91,7 @@ int x25_parse_address_block(struct sk_buff *skb,
         int needed;
         int rc;
 
-        if (skb->len < 1) {
+        if (!pskb_may_pull(skb, 1)) {
                 /* packet has no address block */
                 rc = 0;
                 goto empty;
@@ -100,7 +100,7 @@ int x25_parse_address_block(struct sk_buff *skb,
         len = *skb->data;
         needed = 1 + (len >> 4) + (len & 0x0f);
 
-        if (skb->len < needed) {
+        if (!pskb_may_pull(skb, needed)) {
                 /* packet is too short to hold the addresses it claims
                    to hold */
                 rc = -1;
@@ -295,7 +295,8 @@ static struct sock *x25_find_listener(struct x25_address *addr,
                          * Found a listening socket, now check the incoming
                          * call user data vs this sockets call user data
                          */
-                        if(skb->len > 0 && x25_sk(s)->cudmatchlength > 0) {
+                        if (x25_sk(s)->cudmatchlength > 0 &&
+                                skb->len >= x25_sk(s)->cudmatchlength) {
                                 if((memcmp(x25_sk(s)->calluserdata.cuddata,
                                         skb->data,
                                         x25_sk(s)->cudmatchlength)) == 0) {
@@ -951,14 +952,27 @@ int x25_rx_call_request(struct sk_buff *skb, struct x25_neigh *nb,
          *
          *      Facilities length is mandatory in call request packets
          */
-        if (skb->len < 1)
+        if (!pskb_may_pull(skb, 1))
                 goto out_clear_request;
         len = skb->data[0] + 1;
-        if (skb->len < len)
+        if (!pskb_may_pull(skb, len))
                 goto out_clear_request;
         skb_pull(skb,len);
 
         /*
+         *      Ensure that the amount of call user data is valid.
+         */
+        if (skb->len > X25_MAX_CUD_LEN)
+                goto out_clear_request;
+
+        /*
+         *      Get all the call user data so it can be used in
+         *      x25_find_listener and skb_copy_from_linear_data up ahead.
+         */
+        if (!pskb_may_pull(skb, skb->len))
+                goto out_clear_request;
+
+        /*
          *      Find a listener for the particular address/cud pair.
          */
         sk = x25_find_listener(&source_addr,skb);
@@ -1166,6 +1180,9 @@ static int x25_sendmsg(struct kiocb *iocb, struct socket *sock,
          *      byte of the user data is the logical value of the Q Bit.
          */
         if (test_bit(X25_Q_BIT_FLAG, &x25->flags)) {
+                if (!pskb_may_pull(skb, 1))
+                        goto out_kfree_skb;
+
                 qbit = skb->data[0];
                 skb_pull(skb, 1);
         }
@@ -1244,7 +1261,9 @@ static int x25_recvmsg(struct kiocb *iocb, struct socket *sock,
         struct x25_sock *x25 = x25_sk(sk);
         struct sockaddr_x25 *sx25 = (struct sockaddr_x25 *)msg->msg_name;
         size_t copied;
-        int qbit;
+        int qbit, header_len = x25->neighbour->extended ?
+                X25_EXT_MIN_LEN : X25_STD_MIN_LEN;
+
         struct sk_buff *skb;
         unsigned char *asmptr;
         int rc = -ENOTCONN;
@@ -1265,6 +1284,9 @@ static int x25_recvmsg(struct kiocb *iocb, struct socket *sock,
 
                 skb = skb_dequeue(&x25->interrupt_in_queue);
 
+                if (!pskb_may_pull(skb, X25_STD_MIN_LEN))
+                        goto out_free_dgram;
+
                 skb_pull(skb, X25_STD_MIN_LEN);
 
                 /*
@@ -1285,10 +1307,12 @@ static int x25_recvmsg(struct kiocb *iocb, struct socket *sock,
                 if (!skb)
                         goto out;
 
+                if (!pskb_may_pull(skb, header_len))
+                        goto out_free_dgram;
+
                 qbit = (skb->data[0] & X25_Q_BIT) == X25_Q_BIT;
 
-                skb_pull(skb, x25->neighbour->extended ?
-                                X25_EXT_MIN_LEN : X25_STD_MIN_LEN);
+                skb_pull(skb, header_len);
 
                 if (test_bit(X25_Q_BIT_FLAG, &x25->flags)) {
                         asmptr  = skb_push(skb, 1);