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Commit 4fbda9d1 authored by Roger Pau Monne's avatar Roger Pau Monne Committed by Greg Kroah-Hartman
Browse files

xen/blkfront: fix leaking data in shared pages 



commit 2f446ffe9d737e9a844b97887919c4fda18246e7 upstream.

When allocating pages to be used for shared communication with the
backend always zero them, this avoids leaking unintended data present
on the pages.

This is CVE-2022-26365, part of XSA-403.

Signed-off-by: default avatarRoger Pau Monné <roger.pau@citrix.com>
Reviewed-by: default avatarJan Beulich <jbeulich@suse.com>
Reviewed-by: default avatarJuergen Gross <jgross@suse.com>
Signed-off-by: default avatarJuergen Gross <jgross@suse.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent b0740b25

drivers/block/xen-blkfront.c

+4 −3
Original line number Diff line number Diff line
@@ -297,7 +297,7 @@ static int fill_grant_buffer(struct blkfront_ring_info *rinfo, int num) 
			goto out_of_memory;



		if (info->feature_persistent) {

			granted_page = alloc_page(GFP_NOIO);

			granted_page = alloc_page(GFP_NOIO | __GFP_ZERO);

			if (!granted_page) {

				kfree(gnt_list_entry);

				goto out_of_memory;
@@ -1729,7 +1729,7 @@ static int setup_blkring(struct xenbus_device *dev, 
	for (i = 0; i < info->nr_ring_pages; i++)

		rinfo->ring_ref[i] = GRANT_INVALID_REF;



	sring = alloc_pages_exact(ring_size, GFP_NOIO);

	sring = alloc_pages_exact(ring_size, GFP_NOIO | __GFP_ZERO);

	if (!sring) {

		xenbus_dev_fatal(dev, -ENOMEM, "allocating shared ring");

		return -ENOMEM;
@@ -2311,7 +2311,8 @@ static int blkfront_setup_indirect(struct blkfront_ring_info *rinfo) 


		BUG_ON(!list_empty(&rinfo->indirect_pages));

		for (i = 0; i < num; i++) {

			struct page *indirect_page = alloc_page(GFP_NOIO);

			struct page *indirect_page = alloc_page(GFP_NOIO |

			                                        __GFP_ZERO);

			if (!indirect_page)

				goto out_of_memory;

			list_add(&indirect_page->lru, &rinfo->indirect_pages);