3 files changed, 32 insertions, 4 deletions

diff --git a/net/can/af_can.c b/net/can/af_can.c
index 7e8ca2836452..484bbf6dd032 100644
--- a/net/can/af_can.c
+++ b/net/can/af_can.c
@@ -205,12 +205,19 @@ static int can_create(struct net *net, struct socket *sock, int protocol)
  *  -ENOBUFS on full driver queue (see net_xmit_errno())
  *  -ENOMEM when local loopback failed at calling skb_clone()
  *  -EPERM when trying to send on a non-CAN interface
+ *  -EINVAL when the skb->data does not contain a valid CAN frame
  */
 int can_send(struct sk_buff *skb, int loop)
 {
         struct sk_buff *newskb = NULL;
+        struct can_frame *cf = (struct can_frame *)skb->data;
         int err;
 
+        if (skb->len != sizeof(struct can_frame) || cf->can_dlc > 8) {
+                kfree_skb(skb);
+                return -EINVAL;
+        }
+
         if (skb->dev->type != ARPHRD_CAN) {
                 kfree_skb(skb);
                 return -EPERM;
@@ -605,6 +612,7 @@ static int can_rcv(struct sk_buff *skb, struct net_device *dev,
                    struct packet_type *pt, struct net_device *orig_dev)
 {
         struct dev_rcv_lists *d;
+        struct can_frame *cf = (struct can_frame *)skb->data;
         int matches;
 
         if (dev->type != ARPHRD_CAN || dev_net(dev) != &init_net) {
@@ -612,6 +620,8 @@ static int can_rcv(struct sk_buff *skb, struct net_device *dev,
                 return 0;
         }
 
+        BUG_ON(skb->len != sizeof(struct can_frame) || cf->can_dlc > 8);
+
         /* update statistics */
         can_stats.rx_frames++;
         can_stats.rx_frames_delta++;
diff --git a/net/can/bcm.c b/net/can/bcm.c
index d9a3a9d13bed..72c2ce904f83 100644
--- a/net/can/bcm.c
+++ b/net/can/bcm.c
@@ -298,7 +298,7 @@ static void bcm_send_to_user(struct bcm_op *op, struct bcm_msg_head *head,
 
         if (head->nframes) {
                 /* can_frames starting here */
-                firstframe = (struct can_frame *) skb_tail_pointer(skb);
+                firstframe = (struct can_frame *)skb_tail_pointer(skb);
 
                 memcpy(skb_put(skb, datalen), frames, datalen);
 
@@ -826,6 +826,10 @@ static int bcm_tx_setup(struct bcm_msg_head *msg_head, struct msghdr *msg,
                 for (i = 0; i < msg_head->nframes; i++) {
                         err = memcpy_fromiovec((u8 *)&op->frames[i],
                                                msg->msg_iov, CFSIZ);
+
+                        if (op->frames[i].can_dlc > 8)
+                                err = -EINVAL;
+
                         if (err < 0)
                                 return err;
 
@@ -858,6 +862,10 @@ static int bcm_tx_setup(struct bcm_msg_head *msg_head, struct msghdr *msg,
                 for (i = 0; i < msg_head->nframes; i++) {
                         err = memcpy_fromiovec((u8 *)&op->frames[i],
                                                msg->msg_iov, CFSIZ);
+
+                        if (op->frames[i].can_dlc > 8)
+                                err = -EINVAL;
+
                         if (err < 0) {
                                 if (op->frames != &op->sframe)
                                         kfree(op->frames);
@@ -1164,9 +1172,12 @@ static int bcm_tx_send(struct msghdr *msg, int ifindex, struct sock *sk)
 
         skb->dev = dev;
         skb->sk  = sk;
-        can_send(skb, 1); /* send with loopback */
+        err = can_send(skb, 1); /* send with loopback */
         dev_put(dev);
 
+        if (err)
+                return err;
+
         return CFSIZ + MHSIZ;
 }
 
@@ -1185,6 +1196,10 @@ static int bcm_sendmsg(struct kiocb *iocb, struct socket *sock,
         if (!bo->bound)
                 return -ENOTCONN;
 
+        /* check for valid message length from userspace */
+        if (size < MHSIZ || (size - MHSIZ) % CFSIZ)
+                return -EINVAL;
+
         /* check for alternative ifindex for this bcm_op */
 
         if (!ifindex && msg->msg_name) {
@@ -1259,8 +1274,8 @@ static int bcm_sendmsg(struct kiocb *iocb, struct socket *sock,
                 break;
 
         case TX_SEND:
-                /* we need at least one can_frame */
-                if (msg_head.nframes < 1)
+                /* we need exactly one can_frame behind the msg head */
+                if ((msg_head.nframes != 1) || (size != CFSIZ + MHSIZ))
                         ret = -EINVAL;
                 else
                         ret = bcm_tx_send(msg, ifindex, sk);
diff --git a/net/can/raw.c b/net/can/raw.c
index 69877b8e7e9c..3e46ee36a1aa 100644
--- a/net/can/raw.c
+++ b/net/can/raw.c
@@ -632,6 +632,9 @@ static int raw_sendmsg(struct kiocb *iocb, struct socket *sock,
         } else
                 ifindex = ro->ifindex;
 
+        if (size != sizeof(struct can_frame))
+                return -EINVAL;
+
         dev = dev_get_by_index(&init_net, ifindex);
         if (!dev)
                 return -ENXIO;