From 46f8a29272e51b6df7393d58fc5cb8967397ef2b 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 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 --- 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 41c0b29739f16..35dceee3ed560 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); } -- 2.30.2