From dc248ddf41eab4566e95b1ee2433c8a5134ad94a Mon Sep 17 00:00:00 2001 From: Maxime Coquelin Date: Wed, 31 Aug 2022 17:49:23 +0200 Subject: [PATCH] vduse: prevent uninitialized memory accesses commit 46f8a29272e51b6df7393d58fc5cb8967397ef2b upstream. 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: stable@vger.kernel.org # v5.15+ Fixes: c8a6153b6c59 ("vduse: Introduce VDUSE - vDPA Device in Userspace") Reviewed-by: Xie Yongji Acked-by: Jason Wang Signed-off-by: Maxime Coquelin Message-Id: <20220831154923.97809-1-maxime.coquelin@redhat.com> Signed-off-by: Michael S. Tsirkin Reviewed-by: Chaitanya Kulkarni Signed-off-by: Greg Kroah-Hartman --- 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 73e67fa..e7d2d5b7 100644 --- a/drivers/vdpa/vdpa_user/vduse_dev.c +++ b/drivers/vdpa/vdpa_user/vduse_dev.c @@ -655,10 +655,15 @@ 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); } -- 2.7.4