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Commit 9f4af4cf authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Greg Kroah-Hartman
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block: initialize integrity buffer to zero before writing it to media 



commit 899ee2c3829c5ac14bfc7d3c4a5846c0b709b78f upstream.

Metadata added by bio_integrity_prep is using plain kmalloc, which leads
to random kernel memory being written media.  For PI metadata this is
limited to the app tag that isn't used by kernel generated metadata,
but for non-PI metadata the entire buffer leaks kernel memory.

Fix this by adding the __GFP_ZERO flag to allocations for writes.

Fixes: 7ba1ba12 ("block: Block layer data integrity support")
Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarMartin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: default avatarKanchan Joshi <joshi.k@samsung.com>
Reviewed-by: default avatarChaitanya Kulkarni <kch@nvidia.com>
Link: https://lore.kernel.org/r/20240613084839.1044015-2-hch@lst.de


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
Signed-off-by: default avatarShivani Agarwal <shivani.agarwal@broadcom.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent d1a4c613

block/bio-integrity.c

+10 −1
Original line number Diff line number Diff line
@@ -227,6 +227,7 @@ bool bio_integrity_prep(struct bio *bio) 
	unsigned int bytes, offset, i;

	unsigned int intervals;

	blk_status_t status;

	gfp_t gfp = GFP_NOIO;



	if (!bi)

		return true;
@@ -249,12 +250,20 @@ bool bio_integrity_prep(struct bio *bio) 
		if (!bi->profile->generate_fn ||

		    !(bi->flags & BLK_INTEGRITY_GENERATE))

			return true;



		/*

		 * Zero the memory allocated to not leak uninitialized kernel

		 * memory to disk.  For PI this only affects the app tag, but

		 * for non-integrity metadata it affects the entire metadata

		 * buffer.

		 */

		gfp |= __GFP_ZERO;

	}

	intervals = bio_integrity_intervals(bi, bio_sectors(bio));



	/* Allocate kernel buffer for protection data */

	len = intervals * bi->tuple_size;

	buf = kmalloc(len, GFP_NOIO | q->bounce_gfp);

	buf = kmalloc(len, gfp | q->bounce_gfp);

	status = BLK_STS_RESOURCE;

	if (unlikely(buf == NULL)) {

		printk(KERN_ERR "could not allocate integrity buffer\n");