Patchwork [11/16] netrom: fix info leak via msg_name in nr_recvmsg()

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Submitter Mathias Krause
Date April 7, 2013, 11:51 a.m.
Message ID <1365335522-29931-12-git-send-email-minipli@googlemail.com>
Download mbox | patch
Permalink /patch/234485/
State Accepted
Delegated to: David Miller
Headers show

Comments

Mathias Krause - April 7, 2013, 11:51 a.m.
In case msg_name is set the sockaddr info gets filled out, as
requested, but the code fails to initialize the padding bytes of
struct sockaddr_ax25 inserted by the compiler for alignment. Also
the sax25_ndigis member does not get assigned, leaking four more
bytes.

Both issues lead to the fact that the code will leak uninitialized
kernel stack bytes in net/socket.c.

Fix both issues by initializing the memory with memset(0).

Cc: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Mathias Krause <minipli@googlemail.com>
---
 net/netrom/af_netrom.c |    1 +
 1 file changed, 1 insertion(+)

Patch

diff --git a/net/netrom/af_netrom.c b/net/netrom/af_netrom.c
index d1fa1d9..7fcb307 100644
--- a/net/netrom/af_netrom.c
+++ b/net/netrom/af_netrom.c
@@ -1173,6 +1173,7 @@  static int nr_recvmsg(struct kiocb *iocb, struct socket *sock,
 	}
 
 	if (sax != NULL) {
+		memset(sax, 0, sizeof(sax));
 		sax->sax25_family = AF_NETROM;
 		skb_copy_from_linear_data_offset(skb, 7, sax->sax25_call.ax25_call,
 			      AX25_ADDR_LEN);