[PATCH 4.9 030/177] net: initialize msg.msg_flags in recvfrom

[Greg Kroah-Hartman]

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

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

From: Alexander Potapenko <glider@xxxxxxxxxx>


[ Upstream commit 9f138fa609c47403374a862a08a41394be53d461 ]

KMSAN reports a use of uninitialized memory in put_cmsg() because
msg.msg_flags in recvfrom haven't been initialized properly.
The flag values don't affect the result on this path, but it's still a
good idea to initialize them explicitly.

Signed-off-by: Alexander Potapenko <glider@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 net/socket.c |    1 +
 1 file changed, 1 insertion(+)

--- a/net/socket.c
+++ b/net/socket.c
@@ -1702,6 +1702,7 @@ SYSCALL_DEFINE6(recvfrom, int, fd, void
 	/* We assume all kernel code knows the size of sockaddr_storage */
 	msg.msg_namelen = 0;
 	msg.msg_iocb = NULL;
+	msg.msg_flags = 0;
 	if (sock->file->f_flags & O_NONBLOCK)
 		flags |= MSG_DONTWAIT;
 	err = sock_recvmsg(sock, &msg, flags);