[PATCH 3.2 45/70] Revert "net: add length argument to skb_copy_and_csum_datagram_iovec"

[Ben Hutchings <ben@xxxxxxxxxxxxxxx>]

3.2.76-rc1 review patch.  If anyone has any objections, please let me know.

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

From: Ben Hutchings <ben@xxxxxxxxxxxxxxx>

This reverts commit 127500d724f8c43f452610c9080444eedb5eaa6c.  That fixed
the problem of buffer over-reads introduced by backporting commit
89c22d8c3b27 ("net: Fix skb csum races when peeking"), but resulted in
incorrect checksumming for short reads.  It will be replaced with a
complete fix.

Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -2134,8 +2134,7 @@ extern int	       skb_copy_datagram_iove
 					       int size);
 extern int	       skb_copy_and_csum_datagram_iovec(struct sk_buff *skb,
 							int hlen,
-							struct iovec *iov,
-							int len);
+							struct iovec *iov);
 extern int	       skb_copy_datagram_from_iovec(struct sk_buff *skb,
 						    int offset,
 						    const struct iovec *from,
--- a/net/core/datagram.c
+++ b/net/core/datagram.c
@@ -709,7 +709,6 @@ EXPORT_SYMBOL(__skb_checksum_complete);
  *	@skb: skbuff
  *	@hlen: hardware length
  *	@iov: io vector
- *	@len: amount of data to copy from skb to iov
  *
  *	Caller _must_ check that skb will fit to this iovec.
  *
@@ -719,14 +718,11 @@ EXPORT_SYMBOL(__skb_checksum_complete);
  *			   can be modified!
  */
 int skb_copy_and_csum_datagram_iovec(struct sk_buff *skb,
-				     int hlen, struct iovec *iov, int len)
+				     int hlen, struct iovec *iov)
 {
 	__wsum csum;
 	int chunk = skb->len - hlen;
 
-	if (chunk > len)
-		chunk = len;
-
 	if (!chunk)
 		return 0;
 
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -5198,7 +5198,7 @@ static int tcp_copy_to_iovec(struct sock
 		err = skb_copy_datagram_iovec(skb, hlen, tp->ucopy.iov, chunk);
 	else
 		err = skb_copy_and_csum_datagram_iovec(skb, hlen,
-						       tp->ucopy.iov, chunk);
+						       tp->ucopy.iov);
 
 	if (!err) {
 		tp->ucopy.len -= chunk;
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -1207,7 +1207,7 @@ try_again:
 	else {
 		err = skb_copy_and_csum_datagram_iovec(skb,
 						       sizeof(struct udphdr),
-						       msg->msg_iov, copied);
+						       msg->msg_iov);
 
 		if (err == -EINVAL)
 			goto csum_copy_err;
--- a/net/ipv6/raw.c
+++ b/net/ipv6/raw.c
@@ -479,7 +479,7 @@ static int rawv6_recvmsg(struct kiocb *i
 			goto csum_copy_err;
 		err = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, copied);
 	} else {
-		err = skb_copy_and_csum_datagram_iovec(skb, 0, msg->msg_iov, copied);
+		err = skb_copy_and_csum_datagram_iovec(skb, 0, msg->msg_iov);
 		if (err == -EINVAL)
 			goto csum_copy_err;
 	}
--- a/net/ipv6/udp.c
+++ b/net/ipv6/udp.c
@@ -383,8 +383,7 @@ try_again:
 		err = skb_copy_datagram_iovec(skb, sizeof(struct udphdr),
 					      msg->msg_iov, copied       );
 	else {
-		err = skb_copy_and_csum_datagram_iovec(skb, sizeof(struct udphdr),
-						       msg->msg_iov, copied);
+		err = skb_copy_and_csum_datagram_iovec(skb, sizeof(struct udphdr), msg->msg_iov);
 		if (err == -EINVAL)
 			goto csum_copy_err;
 	}
--- a/net/rxrpc/ar-recvmsg.c
+++ b/net/rxrpc/ar-recvmsg.c
@@ -185,8 +185,7 @@ int rxrpc_recvmsg(struct kiocb *iocb, st
 						      msg->msg_iov, copy);
 		} else {
 			ret = skb_copy_and_csum_datagram_iovec(skb, offset,
-							       msg->msg_iov,
-							       copy);
+							       msg->msg_iov);
 			if (ret == -EINVAL)
 				goto csum_copy_error;
 		}

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