From d85839c78ae259bc6d5e3c2955ee1602c6cd6f00 Mon Sep 17 00:00:00 2001 From: Roger Pau Monne Date: Wed, 30 Mar 2022 09:03:48 +0200 Subject: [PATCH 1/4] xen/blkfront: fix leaking data in shared pages MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 Reviewed-by: Jan Beulich Reviewed-by: Juergen Gross --- drivers/block/xen-blkfront.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c index 91d74dacb1b1..0f2b4cb952a5 100644 --- a/drivers/block/xen-blkfront.c +++ b/drivers/block/xen-blkfront.c @@ -313,7 +313,7 @@ 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; @@ -1689,7 +1689,7 @@ 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; @@ -2208,7 +2208,8 @@ 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_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); -- 2.36.0