Revert "can: gw: ensure DLC boundaries after CAN frame modification"

euler inclusion
category: feature
Bugzilla: N/A
CVE: N/A

Using lts patch instead of this patch.

----------------------------------------

This reverts commit 1378af97f8d132a0913c382a14ba4aa8dd37a06a.
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>

net/can/gw.c

@@ -416,29 +416,13 @@ static void can_can_gw_rcv(struct sk_buff *skb, void *data)
 	while (modidx < MAX_MODFUNCTIONS && gwj->mod.modfunc[modidx])
 		(*gwj->mod.modfunc[modidx++])(cf, &gwj->mod);
 
-	/* Has the CAN frame been modified? */
+	/* check for checksum updates when the CAN frame has been modified */
 	if (modidx) {
-		/* get available space for the processed CAN frame type */
-		int max_len = nskb->len - offsetof(struct can_frame, data);
-
-		/* dlc may have changed, make sure it fits to the CAN frame */
-		if (cf->can_dlc > max_len)
-			goto out_delete;
-
-		/* check for checksum updates in classic CAN length only */
-		if (gwj->mod.csumfunc.crc8) {
-			if (cf->can_dlc > 8)
-				goto out_delete;
-
+		if (gwj->mod.csumfunc.crc8)
 			(*gwj->mod.csumfunc.crc8)(cf, &gwj->mod.csum.crc8);
-		}
-
-		if (gwj->mod.csumfunc.xor) {
-			if (cf->can_dlc > 8)
-				goto out_delete;
 
+		if (gwj->mod.csumfunc.xor)
 			(*gwj->mod.csumfunc.xor)(cf, &gwj->mod.csum.xor);
-		}
 	}
 
 	/* clear the skb timestamp if not configured the other way */
@@ -450,14 +434,6 @@ static void can_can_gw_rcv(struct sk_buff *skb, void *data)
 		gwj->dropped_frames++;
 	else
 		gwj->handled_frames++;
-
-	return;
-
- out_delete:
-	/* delete frame due to misconfiguration */
-	gwj->deleted_frames++;
-	kfree_skb(nskb);
-	return;
 }
 
 static inline int cgw_register_filter(struct net *net, struct cgw_job *gwj)