[PATCH 3.12 007/155] rxrpc: bogus MSG_PEEK test in rxrpc_recvmsg()

From: Jiri Slaby
Date: Tue Apr 07 2015 - 08:52:31 EST

From: Al Viro <viro@xxxxxxxxxxxxxxxxxx>

3.12-stable review patch. If anyone has any objections, please let me know.


[ Upstream commit 7d985ed1dca5c90535d67ce92ef6ca520302340a ]

[I would really like an ACK on that one from dhowells; it appears to be
quite straightforward, but...]

MSG_PEEK isn't passed to ->recvmsg() via msg->msg_flags; as the matter of
fact, neither the kernel users of rxrpc, nor the syscalls ever set that bit
in there. It gets passed via flags; in fact, another such check in the same
function is done correctly - as flags & MSG_PEEK.

It had been that way (effectively disabled) for 8 years, though, so the patch
needs beating up - that case had never been tested. If it is correct, it's
-stable fodder.

Signed-off-by: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Jiri Slaby <jslaby@xxxxxxx>
net/rxrpc/ar-recvmsg.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/rxrpc/ar-recvmsg.c b/net/rxrpc/ar-recvmsg.c
index 898492a8d61b..5cc2da5d295d 100644
--- a/net/rxrpc/ar-recvmsg.c
+++ b/net/rxrpc/ar-recvmsg.c
@@ -87,7 +87,7 @@ int rxrpc_recvmsg(struct kiocb *iocb, struct socket *sock,
if (!skb) {
/* nothing remains on the queue */
if (copied &&
- (msg->msg_flags & MSG_PEEK || timeo == 0))
+ (flags & MSG_PEEK || timeo == 0))
goto out;

/* wait for a message to turn up */

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