Maxime Coquelin
2022-Aug-26 16:16 UTC
[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.
Signed-off-by: Maxime Coquelin <maxime.coquelin at redhat.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);
}
--
2.37.1
On Fri, Aug 26, 2022 at 06:16:05PM +0200, Maxime Coquelin wrote:> 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. > > Signed-off-by: Maxime Coquelin <maxime.coquelin at redhat.com>This sounds like it needs a Fixes tag? regards, dan carpenter
On Sat, Aug 27, 2022 at 12:16 AM Maxime Coquelin <maxime.coquelin at redhat.com> wrote:> > 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. > > Signed-off-by: Maxime Coquelin <maxime.coquelin at redhat.com>Acked-by: Jason Wang <jasowang at redhat.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); > } > > -- > 2.37.1 >