Maoyi Xie d5db3439ee memstick: ms_block: reject a card that reports too many blocks
commit 718178f524 upstream.

msb_ftl_initialize() computes the zone count from the card block count
with no bound:

	msb->zone_count = msb->block_count / MS_BLOCKS_IN_ZONE;
	...
	for (i = 0; i < msb->zone_count; i++)
		msb->free_block_count[i] = MS_BLOCKS_IN_ZONE;

msb->block_count is a card value. msb_read_boot_blocks() reads
number_of_blocks from the card boot page and byte swaps it.
free_block_count is a fixed int[MS_MAX_ZONES]. MS_MAX_ZONES is 16, so the
valid indices are 0 to 15. The init loop above indexes it by zone_count.
msb_mark_block_used() and msb_mark_block_unused() index it by
pba / MS_BLOCKS_IN_ZONE, for pba up to block_count - 1. A card may report
up to 65535 blocks. A block_count above 8192 (MS_MAX_ZONES *
MS_BLOCKS_IN_ZONE) lets the pba index reach 16. That writes past
free_block_count[] and corrupts struct msb_data. A larger count runs the
init loop past the end too.

A real Memory Stick has at most 16 zones. So it has at most 8192 blocks.
msb_ftl_initialize() now rejects a card that reports more than
MS_MAX_ZONES * MS_BLOCKS_IN_ZONE blocks.

Fixes: 0ab30494bc ("memstick: add support for legacy memorysticks")
Cc: stable@vger.kernel.org
Signed-off-by: Maoyi Xie <maoyixie.tju@gmail.com>
Signed-off-by: Ulf Hansson <ulfh@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2026-07-24 16:03:45 +02:00
2026-07-24 16:03:06 +02:00
2026-05-23 13:03:09 +02:00
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2026-05-23 13:03:09 +02:00
2026-07-04 13:42:28 +02:00
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Linux kernel
============

There are several guides for kernel developers and users. These guides can
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Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.
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