[PATCH AUTOSEL 4.9 35/41] Fix use after free in get_capset_info callback.

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



From: Doug Horn <doughorn@xxxxxxxxxx>

[ Upstream commit e219688fc5c3d0d9136f8d29d7e0498388f01440 ]

If a response to virtio_gpu_cmd_get_capset_info takes longer than
five seconds to return, the callback will access freed kernel memory
in vg->capsets.

Signed-off-by: Doug Horn <doughorn@xxxxxxxxxx>
Link: http://patchwork.freedesktop.org/patch/msgid/20200902210847.2689-2-gurchetansingh@xxxxxxxxxxxx
Signed-off-by: Gerd Hoffmann <kraxel@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 drivers/gpu/drm/virtio/virtgpu_kms.c |  2 ++
 drivers/gpu/drm/virtio/virtgpu_vq.c  | 10 +++++++---
 2 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/virtio/virtgpu_kms.c b/drivers/gpu/drm/virtio/virtgpu_kms.c
index 036b0fbae0fb7..ba7855da7c7f6 100644
--- a/drivers/gpu/drm/virtio/virtgpu_kms.c
+++ b/drivers/gpu/drm/virtio/virtgpu_kms.c
@@ -113,8 +113,10 @@ static void virtio_gpu_get_capsets(struct virtio_gpu_device *vgdev,
 					 vgdev->capsets[i].id > 0, 5 * HZ);
 		if (ret == 0) {
 			DRM_ERROR("timed out waiting for cap set %d\n", i);
+			spin_lock(&vgdev->display_info_lock);
 			kfree(vgdev->capsets);
 			vgdev->capsets = NULL;
+			spin_unlock(&vgdev->display_info_lock);
 			return;
 		}
 		DRM_INFO("cap set %d: id %d, max-version %d, max-size %d\n",
diff --git a/drivers/gpu/drm/virtio/virtgpu_vq.c b/drivers/gpu/drm/virtio/virtgpu_vq.c
index 772a5a3b0ce1a..18e8fcad6690b 100644
--- a/drivers/gpu/drm/virtio/virtgpu_vq.c
+++ b/drivers/gpu/drm/virtio/virtgpu_vq.c
@@ -596,9 +596,13 @@ static void virtio_gpu_cmd_get_capset_info_cb(struct virtio_gpu_device *vgdev,
 	int i = le32_to_cpu(cmd->capset_index);
 
 	spin_lock(&vgdev->display_info_lock);
-	vgdev->capsets[i].id = le32_to_cpu(resp->capset_id);
-	vgdev->capsets[i].max_version = le32_to_cpu(resp->capset_max_version);
-	vgdev->capsets[i].max_size = le32_to_cpu(resp->capset_max_size);
+	if (vgdev->capsets) {
+		vgdev->capsets[i].id = le32_to_cpu(resp->capset_id);
+		vgdev->capsets[i].max_version = le32_to_cpu(resp->capset_max_version);
+		vgdev->capsets[i].max_size = le32_to_cpu(resp->capset_max_size);
+	} else {
+		DRM_ERROR("invalid capset memory.");
+	}
 	spin_unlock(&vgdev->display_info_lock);
 	wake_up(&vgdev->resp_wq);
 }
-- 
2.25.1

_______________________________________________
Virtualization mailing list
Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx
https://lists.linuxfoundation.org/mailman/listinfo/virtualization



[Index of Archives]     [KVM Development]     [Libvirt Development]     [Libvirt Users]     [CentOS Virtualization]     [Netdev]     [Ethernet Bridging]     [Linux Wireless]     [Kernel Newbies]     [Security]     [Linux for Hams]     [Netfilter]     [Bugtraq]     [Yosemite Forum]     [MIPS Linux]     [ARM Linux]     [Linux RAID]     [Linux Admin]     [Samba]

  Powered by Linux