Return-Path: Message-Id: <20130813155832.166886525@goodmis.org> Date: Tue, 13 Aug 2013 11:57:48 -0400 From: Steven Rostedt To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Dan Carpenter , Jens Axboe , Andrew Morton Subject: [54/88] drivers/cdrom/cdrom.c: use kzalloc() for failing hardware References: <20130813155654.069291373@goodmis.org> Content-Disposition: inline; filename=0054-drivers-cdrom-cdrom.c-use-kzalloc-for-failing-hardwa.patch Sender: linux-kernel-owner@vger.kernel.org List-ID: 3.6.11.7-rc1 stable review patch. If anyone has any objections, please let me know. ------------------ From: Jonathan Salwan [ Upstream commit 542db01579fbb7ea7d1f7bb9ddcef1559df660b2 ] 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 Cc: Jens Axboe Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Steven Rostedt --- 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; -- 1.7.10.4