Patch "net: sctp: prevent writes to cookie_hmac_alg from accessing invalid memory" has been added to the 4.3-stable tree

Patch "net: sctp: prevent writes to cookie_hmac_alg from accessing invalid memory" has been added to the 4.3-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    net: sctp: prevent writes to cookie_hmac_alg from accessing invalid memory

to the 4.3-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     net-sctp-prevent-writes-to-cookie_hmac_alg-from-accessing-invalid-memory.patch
and it can be found in the queue-4.3 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From foo@baz Tue Jan 26 21:35:03 PST 2016
From: Sasha Levin <sasha.levin@oracle.com>
Date: Thu, 7 Jan 2016 14:52:43 -0500
Subject: net: sctp: prevent writes to cookie_hmac_alg from accessing invalid memory

From: Sasha Levin <sasha.levin@oracle.com>

[ Upstream commit 320f1a4a175e7cd5d3f006f92b4d4d3e2cbb7bb5 ]

proc_dostring() needs an initialized destination string, while the one
provided in proc_sctp_do_hmac_alg() contains stack garbage.

Thus, writing to cookie_hmac_alg would strlen() that garbage and end up
accessing invalid memory.

Fixes: 3c68198e7 ("sctp: Make hmac algorithm selection for cookie generation dynamic")
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 net/sctp/sysctl.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/net/sctp/sysctl.c
+++ b/net/sctp/sysctl.c
@@ -320,7 +320,7 @@ static int proc_sctp_do_hmac_alg(struct
 	struct ctl_table tbl;
 	bool changed = false;
 	char *none = "none";
-	char tmp[8];
+	char tmp[8] = {0};
 	int ret;
 
 	memset(&tbl, 0, sizeof(struct ctl_table));


Patches currently in stable-queue which might be from sasha.levin@oracle.com are

queue-4.3/net-sctp-prevent-writes-to-cookie_hmac_alg-from-accessing-invalid-memory.patch
queue-4.3/addrconf-always-initialize-sysctl-table-data.patch