linux-kernel - [PATCH AUTOSEL for 4.4 005/101] net: initialize msg.msg

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Message-ID: <20171207155005.5852-5-alexander.levin@verizon.com>
Date:   Thu, 7 Dec 2017 15:50:12 +0000
From:   alexander.levin@...izon.com
To:     "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "stable@...r.kernel.org" <stable@...r.kernel.org>
Cc:     Alexander Potapenko <glider@...gle.com>,
        "David S . Miller" <davem@...emloft.net>,
        alexander.levin@...izon.com
Subject: [PATCH AUTOSEL for 4.4 005/101] net: initialize msg.msg_flags in
 recvfrom

From: Alexander Potapenko <glider@...gle.com>

[ 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@...gle.com>
Signed-off-by: David S. Miller <davem@...emloft.net>
Signed-off-by: Sasha Levin <alexander.levin@...izon.com>
---
 net/socket.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/net/socket.c b/net/socket.c
index fbfa9d2492cf..2cf4f25f5c2b 100644
--- a/net/socket.c
+++ b/net/socket.c
@@ -1697,6 +1697,7 @@ 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, iov_iter_count(&msg.msg_iter), flags);
-- 
2.11.0