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From 050e4b8fb7cdd7096c987a9cd556029c622c7fe2 Mon Sep 17 00:00:00 2001
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From: Jonathan Salwan <jonathan.salwan@gmail.com>
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Date: Thu, 06 Jun 2013 00:39:39 +0000
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Subject: drivers/cdrom/cdrom.c: use kzalloc() for failing hardware
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In drivers/cdrom/cdrom.c mmc_ioctl_cdrom_read_data() allocates a memory
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area with kmalloc in line 2885.
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2885 cgc->buffer = kmalloc(blocksize, GFP_KERNEL);
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2886 if (cgc->buffer == NULL)
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2887 return -ENOMEM;
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In line 2908 we can find the copy_to_user function:
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2908 if (!ret && copy_to_user(arg, cgc->buffer, blocksize))
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The cgc->buffer is never cleaned and initialized before this function. If
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ret = 0 with the previous basic block, it's possible to display some
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memory bytes in kernel space from userspace.
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When we read a block from the disk it normally fills the ->buffer but if
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the drive is malfunctioning there is a chance that it would only be
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partially filled. The result is an leak information to userspace.
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Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
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Cc: Jens Axboe <axboe@kernel.dk>
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Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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---
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(limited to 'drivers/cdrom/cdrom.c')
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diff --git a/drivers/cdrom/cdrom.c b/drivers/cdrom/cdrom.c
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index d620b44..8a3aff7 100644
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--- a/drivers/cdrom/cdrom.c
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+++ b/drivers/cdrom/cdrom.c
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@@ -2882,7 +2882,7 @@ static noinline int mmc_ioctl_cdrom_read_data(struct cdrom_device_info *cdi,
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if (lba < 0)
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return -EINVAL;
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- cgc->buffer = kmalloc(blocksize, GFP_KERNEL);
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+ cgc->buffer = kzalloc(blocksize, GFP_KERNEL);
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if (cgc->buffer == NULL)
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return -ENOMEM;
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--
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