Patchwork [10/16] llc: Fix missing msg_namelen update in llc_ui_recvmsg()

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Submitter Mathias Krause
Date April 7, 2013, 11:51 a.m.
Message ID <1365335522-29931-11-git-send-email-minipli@googlemail.com>
Download mbox | patch
Permalink /patch/234493/
State Accepted
Delegated to: David Miller
Headers show

Comments

Mathias Krause - April 7, 2013, 11:51 a.m.
For stream sockets the code misses to update the msg_namelen member
to 0 and therefore makes net/socket.c leak the local, uninitialized
sockaddr_storage variable to userland -- 128 bytes of kernel stack
memory. The msg_namelen update is also missing for datagram sockets
in case the socket is shutting down during receive.

Fix both issues by setting msg_namelen to 0 early. It will be
updated later if we're going to fill the msg_name member.

Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Signed-off-by: Mathias Krause <minipli@googlemail.com>
---
 net/llc/af_llc.c |    2 ++
 1 file changed, 2 insertions(+)

Patch

diff --git a/net/llc/af_llc.c b/net/llc/af_llc.c
index 8870988..48aaa89 100644
--- a/net/llc/af_llc.c
+++ b/net/llc/af_llc.c
@@ -720,6 +720,8 @@  static int llc_ui_recvmsg(struct kiocb *iocb, struct socket *sock,
 	int target;	/* Read at least this many bytes */
 	long timeo;
 
+	msg->msg_namelen = 0;
+
 	lock_sock(sk);
 	copied = -ENOTCONN;
 	if (unlikely(sk->sk_type == SOCK_STREAM && sk->sk_state == TCP_LISTEN))