[ 3.5.y.z extended stable ] Patch "drivers/cdrom/cdrom.c: use kzalloc() for failing hardware" has been added to staging queue
Luis Henriques
luis.henriques at canonical.com
Wed Jul 10 15:34:01 UTC 2013
This is a note to let you know that I have just added a patch titled
drivers/cdrom/cdrom.c: use kzalloc() for failing hardware
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 6b9adf2d0284dc40073dc48a5d8d9876296545ec Mon Sep 17 00:00:00 2001
From: Jonathan Salwan <jonathan.salwan at gmail.com>
Date: Wed, 3 Jul 2013 15:01:13 -0700
Subject: [PATCH] drivers/cdrom/cdrom.c: use kzalloc() for failing hardware
commit 542db01579fbb7ea7d1f7bb9ddcef1559df660b2 upstream.
In drivers/cdrom/cdrom.c mmc_ioctl_cdrom_read_data() allocates a memory
area with kmalloc in line 2885.
2885 cgc->buffer = kmalloc(blocksize, GFP_KERNEL);
2886 if (cgc->buffer == NULL)
2887 return -ENOMEM;
In line 2908 we can find the copy_to_user function:
2908 if (!ret && copy_to_user(arg, cgc->buffer, blocksize))
The cgc->buffer is never cleaned and initialized before this function.
If ret = 0 with the previous basic block, it's possible to display some
memory bytes in kernel space from userspace.
When we read a block from the disk it normally fills the ->buffer but if
the drive is malfunctioning there is a chance that it would only be
partially filled. The result is an leak information to userspace.
Signed-off-by: Dan Carpenter <dan.carpenter at oracle.com>
Cc: Jens Axboe <axboe at kernel.dk>
Signed-off-by: Andrew Morton <akpm at linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds at linux-foundation.org>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
drivers/cdrom/cdrom.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/cdrom/cdrom.c b/drivers/cdrom/cdrom.c
index d620b44..8a3aff7 100644
--- a/drivers/cdrom/cdrom.c
+++ b/drivers/cdrom/cdrom.c
@@ -2882,7 +2882,7 @@ static noinline int mmc_ioctl_cdrom_read_data(struct cdrom_device_info *cdi,
if (lba < 0)
return -EINVAL;
- cgc->buffer = kmalloc(blocksize, GFP_KERNEL);
+ cgc->buffer = kzalloc(blocksize, GFP_KERNEL);
if (cgc->buffer == NULL)
return -ENOMEM;
--
1.8.1.2
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