linux-kernel - [PATCH v2] vduse: prevent uninitialized memory accesses

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: <20220829073424.5677-1-maxime.coquelin@redhat.com>
Date:   Mon, 29 Aug 2022 09:34:24 +0200
From:   Maxime Coquelin <maxime.coquelin@...hat.com>
To:     linux-kernel@...r.kernel.org,
        virtualization@...ts.linux-foundation.org, elic@...dia.com,
        guanjun@...ux.alibaba.com, parav@...dia.com,
        gautam.dawar@...inx.com, dan.carpenter@...cle.com,
        xieyongji@...edance.com, jasowang@...hat.com, mst@...hat.com
Cc:     Maxime Coquelin <maxime.coquelin@...hat.com>,
        stable@...r.kernel.org
Subject: [PATCH v2] vduse: prevent uninitialized memory accesses

If the VDUSE application provides a smaller config space
than the driver expects, the driver may use uninitialized
memory from the stack.

This patch prevents it by initializing the buffer passed by
the driver to store the config value.

This fix addresses CVE-2022-2308.

Cc: xieyongji@...edance.com
Cc: stable@...r.kernel.org # v5.15+
Fixes: c8a6153b6c59 ("vduse: Introduce VDUSE - vDPA Device in Userspace")

Acked-by: Jason Wang <jasowang@...hat.com>
Signed-off-by: Maxime Coquelin <maxime.coquelin@...hat.com>
---
 drivers/vdpa/vdpa_user/vduse_dev.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/vdpa/vdpa_user/vduse_dev.c b/drivers/vdpa/vdpa_user/vduse_dev.c
index 41c0b29739f1..35dceee3ed56 100644
--- a/drivers/vdpa/vdpa_user/vduse_dev.c
+++ b/drivers/vdpa/vdpa_user/vduse_dev.c
@@ -673,10 +673,15 @@ static void vduse_vdpa_get_config(struct vdpa_device *vdpa, unsigned int offset,
 {
 	struct vduse_dev *dev = vdpa_to_vduse(vdpa);
 
-	if (offset > dev->config_size ||
-	    len > dev->config_size - offset)
+	/* Initialize the buffer in case of partial copy. */
+	memset(buf, 0, len);
+
+	if (offset > dev->config_size)
 		return;
 
+	if (len > dev->config_size - offset)
+		len = dev->config_size - offset;
+
 	memcpy(buf, dev->config + offset, len);
 }
 
-- 
2.37.2