1 files changed, 19 insertions, 4 deletions

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);