linux-kernel - [PATCH] VDUSE: avoid leaking information to userspace

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-ID: <20260130050750.4050-1-jasowang@redhat.com>
Date: Fri, 30 Jan 2026 13:07:50 +0800
From: Jason Wang <jasowang@...hat.com>
To: mst@...hat.com,
	jasowang@...hat.com,
	virtualization@...ts.linux.dev,
	linux-kernel@...r.kernel.org
Cc: xuanzhuo@...ux.alibaba.com,
	eperezma@...hat.com,
	xieyongji@...edance.com,
	stable@...r.kernel.org
Subject: [PATCH] VDUSE: avoid leaking information to userspace

The bounceing is not necessarily page aligned, so current VDUSE can
leak kernel information through mapping bounce pages to
userspace. Allocate bounce pages with __GFP_ZERO to avoid leaking
information to userspace.

Fixes: 8c773d53fb7b ("vduse: Implement an MMU-based software IOTLB")
Cc: stable@...r.kernel.org
Signed-off-by: Jason Wang <jasowang@...hat.com>
---
 drivers/vdpa/vdpa_user/iova_domain.c | 2 +-
 drivers/vdpa/vdpa_user/vduse_dev.c   | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/vdpa/vdpa_user/iova_domain.c b/drivers/vdpa/vdpa_user/iova_domain.c
index 0a9f668467a8..ec743bed361c 100644
--- a/drivers/vdpa/vdpa_user/iova_domain.c
+++ b/drivers/vdpa/vdpa_user/iova_domain.c
@@ -124,7 +124,7 @@ static int vduse_domain_map_bounce_page(struct vduse_iova_domain *domain,
 		if (!map->bounce_page) {
 			head_map = &domain->bounce_maps[(iova & PAGE_MASK) >> BOUNCE_MAP_SHIFT];
 			if (!head_map->bounce_page) {
-				tmp_page = alloc_page(GFP_ATOMIC);
+				tmp_page = alloc_page(GFP_ATOMIC | __GFP_ZERO);
 				if (!tmp_page)
 					return -ENOMEM;
 				if (cmpxchg(&head_map->bounce_page, NULL, tmp_page))
diff --git a/drivers/vdpa/vdpa_user/vduse_dev.c b/drivers/vdpa/vdpa_user/vduse_dev.c
index 73d1d517dc6c..57a40a821c65 100644
--- a/drivers/vdpa/vdpa_user/vduse_dev.c
+++ b/drivers/vdpa/vdpa_user/vduse_dev.c
@@ -976,7 +976,7 @@ static void *vduse_dev_alloc_coherent(union virtio_map token, size_t size,
 	if (!token.group)
 		return NULL;
 
-	addr = alloc_pages_exact(size, flag);
+	addr = alloc_pages_exact(size, flag | __GFP_ZERO);
 	if (!addr)
 		return NULL;
 
-- 
2.34.1