| From | Greg Kroah-Hartman <> | Subject | [PATCH 5.4 51/58] xen/blkfront: fix leaking data in shared pages | Date | Tue, 5 Jul 2022 13:58:27 +0200 |
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From: Roger Pau Monne <roger.pau@citrix.com>
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: Roger Pau Monné <roger.pau@citrix.com> Reviewed-by: Jan Beulich <jbeulich@suse.com> Reviewed-by: Juergen Gross <jgross@suse.com> Signed-off-by: Juergen Gross <jgross@suse.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- drivers/block/xen-blkfront.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-)
--- a/drivers/block/xen-blkfront.c +++ b/drivers/block/xen-blkfront.c @@ -301,7 +301,7 @@ static int fill_grant_buffer(struct blkf 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; @@ -1744,7 +1744,7 @@ static int setup_blkring(struct xenbus_d 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; @@ -2283,7 +2283,8 @@ static int blkfront_setup_indirect(struc BUG_ON(!list_empty(&rinfo->indirect_pages)); for (i = 0; i < num; i++) { - struct page *indirect_page = alloc_page(GFP_KERNEL); + struct page *indirect_page = alloc_page(GFP_KERNEL | + __GFP_ZERO); if (!indirect_page) goto out_of_memory; list_add(&indirect_page->lru, &rinfo->indirect_pages);
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