* FAILED: patch "[PATCH] drm/virtio: Fix GEM handle creation UAF" failed to apply to 4.14-stable tree
@ 2023-01-14 9:58 gregkh
0 siblings, 0 replies; only message in thread
From: gregkh @ 2023-01-14 9:58 UTC (permalink / raw)
To: robdclark, dmitry.osipenko, olvaffe; +Cc: stable
The patch below does not apply to the 4.14-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.
Possible dependencies:
52531258318e ("drm/virtio: Fix GEM handle creation UAF")
897b4d1acaf5 ("drm/virtio: implement blob resources: resource create blob ioctl")
16845c5d5409 ("drm/virtio: implement blob resources: implement vram object")
6076a9711dc5 ("drm/virtio: implement blob resources: probe for host visible region")
6815cfe602d0 ("drm/virtio: implement blob resources: probe for the feature.")
30172efbfb84 ("drm/virtio: blob prep: refactor getting pages and attaching backing")
deb2464e4c6d ("drm/virtio: report uuid in debugfs")
c84adb304c10 ("drm/virtio: Support virtgpu exported resources")
0a19b068acc4 ("Merge tag 'drm-misc-next-2020-06-19' of git://anongit.freedesktop.org/drm/drm-misc into drm-next")
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 52531258318ed59a2dc5a43df2eaf0eb1d65438e Mon Sep 17 00:00:00 2001
From: Rob Clark <robdclark@chromium.org>
Date: Fri, 16 Dec 2022 15:33:55 -0800
Subject: [PATCH] drm/virtio: Fix GEM handle creation UAF
Userspace can guess the handle value and try to race GEM object creation
with handle close, resulting in a use-after-free if we dereference the
object after dropping the handle's reference. For that reason, dropping
the handle's reference must be done *after* we are done dereferencing
the object.
Signed-off-by: Rob Clark <robdclark@chromium.org>
Reviewed-by: Chia-I Wu <olvaffe@gmail.com>
Fixes: 62fb7a5e1096 ("virtio-gpu: add 3d/virgl support")
Cc: stable@vger.kernel.org
Signed-off-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20221216233355.542197-2-robdclark@gmail.com
diff --git a/drivers/gpu/drm/virtio/virtgpu_ioctl.c b/drivers/gpu/drm/virtio/virtgpu_ioctl.c
index 5d05093014ac..9f4a90493aea 100644
--- a/drivers/gpu/drm/virtio/virtgpu_ioctl.c
+++ b/drivers/gpu/drm/virtio/virtgpu_ioctl.c
@@ -358,10 +358,18 @@ static int virtio_gpu_resource_create_ioctl(struct drm_device *dev, void *data,
drm_gem_object_release(obj);
return ret;
}
- drm_gem_object_put(obj);
rc->res_handle = qobj->hw_res_handle; /* similiar to a VM address */
rc->bo_handle = handle;
+
+ /*
+ * The handle owns the reference now. But we must drop our
+ * remaining reference *after* we no longer need to dereference
+ * the obj. Otherwise userspace could guess the handle and
+ * race closing it from another thread.
+ */
+ drm_gem_object_put(obj);
+
return 0;
}
@@ -723,11 +731,18 @@ static int virtio_gpu_resource_create_blob_ioctl(struct drm_device *dev,
drm_gem_object_release(obj);
return ret;
}
- drm_gem_object_put(obj);
rc_blob->res_handle = bo->hw_res_handle;
rc_blob->bo_handle = handle;
+ /*
+ * The handle owns the reference now. But we must drop our
+ * remaining reference *after* we no longer need to dereference
+ * the obj. Otherwise userspace could guess the handle and
+ * race closing it from another thread.
+ */
+ drm_gem_object_put(obj);
+
return 0;
}
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2023-01-14 9:58 FAILED: patch "[PATCH] drm/virtio: Fix GEM handle creation UAF" failed to apply to 4.14-stable tree gregkh
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