linux-kernel - [ 011/143] drivers/cdrom/cdrom.c: use kzalloc() for failing hardware

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20140512003201.094335349@1wt.eu>
Date:	Mon, 12 May 2014 02:32:11 +0200
From:	Willy Tarreau <w@....eu>
To:	linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:	Dan Carpenter <dan.carpenter@...cle.com>,
	Jens Axboe <axboe@...nel.dk>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Willy Tarreau <w@....eu>
Subject: [ 011/143] drivers/cdrom/cdrom.c: use kzalloc() for failing hardware

2.6.32-longterm review patch.  If anyone has any objections, please let me know.

------------------

From: Jonathan Salwan <jonathan.salwan@...il.com>

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@...cle.com>
Cc: Jens Axboe <axboe@...nel.dk>
Signed-off-by: Andrew Morton <akpm@...ux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@...ux-foundation.org>
Signed-off-by: Willy Tarreau <w@....eu>
---
 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 a4592ec..71a78dc 100644
--- a/drivers/cdrom/cdrom.c
+++ b/drivers/cdrom/cdrom.c
@@ -2822,7 +2822,7 @@ 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;
 
-- 
1.7.12.2.21.g234cd45.dirty



--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/