[PATCH AUTOSEL for 4.9 007/156] net: initialize msg.msg_flags in recvfrom

From: alexander . levin
Date: Thu Dec 07 2017 - 12:41:55 EST


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>
---
net/socket.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/net/socket.c b/net/socket.c
index 6bbccf05854f..05f13b24572c 100644
--- a/net/socket.c
+++ b/net/socket.c
@@ -1702,6 +1702,7 @@ SYSCALL_DEFINE6(recvfrom, int, fd, void __user *, ubuf, size_t, size,
/* 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);
--
2.11.0