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 @@ -311,7 +311,7 @@ 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; @@ -1753,7 +1753,7 @@ 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; @@ -2293,7 +2293,8 @@ 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);