[PATCH 17/25] vmwgfx: Disallow user space to send present and readback commands

[Thomas Hellstrom]

From: Jakob Bornecrantz <ja...@vmware.com>

Signed-off-by: Jakob Bornecrantz <jakob at vmware.com>
Reviewed-by: Thomas Hellstrom <thellstrom at vmware.com>
---
 drivers/gpu/drm/vmwgfx/vmwgfx_execbuf.c |   16 +++++++++++++---
 1 files changed, 13 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_execbuf.c 
b/drivers/gpu/drm/vmwgfx/vmwgfx_execbuf.c
index 66dd70c..6f28182 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_execbuf.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_execbuf.c
@@ -197,6 +197,12 @@ static int vmw_cmd_blt_surf_screen_check(struct 
vmw_private *dev_priv,
        } *cmd;

        cmd = container_of(header, struct vmw_sid_cmd, header);
+
+       if (unlikely(!sw_context->kernel)) {
+               DRM_ERROR("Kernel only SVGA3d command: %u.\n", cmd->header.id);
+               return -EPERM;
+       }
+
        return vmw_cmd_sid_check(dev_priv, sw_context, &cmd->body.srcImage.sid);
 }

@@ -210,6 +216,12 @@ static int vmw_cmd_present_check(struct vmw_private 
*dev_priv,
        } *cmd;

        cmd = container_of(header, struct vmw_sid_cmd, header);
+
+       if (unlikely(!sw_context->kernel)) {
+               DRM_ERROR("Kernel only SVGA3d command: %u.\n", cmd->header.id);
+               return -EPERM;
+       }
+
        return vmw_cmd_sid_check(dev_priv, sw_context, &cmd->body.sid);
 }

@@ -477,14 +489,12 @@ static int vmw_cmd_check_not_3d(struct vmw_private 
*dev_priv,
                                void *buf, uint32_t *size)
 {
        uint32_t size_remaining = *size;
-       bool need_kernel = true;
        uint32_t cmd_id;

        cmd_id = le32_to_cpu(((uint32_t *)buf)[0]);
        switch (cmd_id) {
        case SVGA_CMD_UPDATE:
                *size = sizeof(uint32_t) + sizeof(SVGAFifoCmdUpdate);
-               need_kernel = false;
                break;
        case SVGA_CMD_DEFINE_GMRFB:
                *size = sizeof(uint32_t) + sizeof(SVGAFifoCmdDefineGMRFB);
@@ -506,7 +516,7 @@ static int vmw_cmd_check_not_3d(struct vmw_private 
*dev_priv,
                return -EINVAL;
        }

-       if (unlikely(need_kernel && !sw_context->kernel)) {
+       if (unlikely(!sw_context->kernel)) {
                DRM_ERROR("Kernel only SVGA command: %u.\n", cmd_id);
                return -EPERM;
        }
-- 
1.7.4.4