[3.5.y.z extended stable] Patch "aacraid: prevent invalid pointer dereference" has been added to staging queue

[Luis Henriques]

This is a note to let you know that I have just added a patch titled

    aacraid: prevent invalid pointer dereference

to the linux-3.5.y-queue branch of the 3.5.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.5.y-queue

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.5.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From 0a7a6b83f4c7a1ff39f9069f8d06c534e7d5d7b3 Mon Sep 17 00:00:00 2001
From: Mahesh Rajashekhara <Mahesh.Rajashekhara at pmcs.com>
Date: Thu, 31 Oct 2013 14:01:02 +0530
Subject: aacraid: prevent invalid pointer dereference

commit b4789b8e6be3151a955ade74872822f30e8cd914 upstream.

It appears that driver runs into a problem here if fibsize is too small
because we allocate user_srbcmd with fibsize size only but later we
access it until user_srbcmd->sg.count to copy it over to srbcmd.

It is not correct to test (fibsize < sizeof(*user_srbcmd)) because this
structure already includes one sg element and this is not needed for
commands without data.  So, we would recommend to add the following
(instead of test for fibsize == 0).

Signed-off-by: Mahesh Rajashekhara <Mahesh.Rajashekhara at pmcs.com>
Reported-by: Nico Golde <nico at ngolde.de>
Reported-by: Fabian Yamaguchi <fabs at goesec.de>
Signed-off-by: Linus Torvalds <torvalds at linux-foundation.org>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 drivers/scsi/aacraid/commctrl.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/scsi/aacraid/commctrl.c b/drivers/scsi/aacraid/commctrl.c
index 0bd38da..05fbc3d 100644
--- a/drivers/scsi/aacraid/commctrl.c
+++ b/drivers/scsi/aacraid/commctrl.c
@@ -508,7 +508,8 @@ static int aac_send_raw_srb(struct aac_dev* dev, void __user * arg)
 		goto cleanup;
 	}

-	if (fibsize > (dev->max_fib_size - sizeof(struct aac_fibhdr))) {
+	if ((fibsize < (sizeof(struct user_aac_srb) - sizeof(struct user_sgentry))) ||
+	    (fibsize > (dev->max_fib_size - sizeof(struct aac_fibhdr)))) {
 		rcode = -EINVAL;
 		goto cleanup;
 	}
--
1.8.3.2