vmw_shader_define() validates the user-supplied shader window against
its backing buffer with
(u64)buffer->tbo.base.size < (u64)size + (u64)offset
drm_vmw_shader_create_arg::offset is __u64 in the uapi; when it is
near U64_MAX the unsigned addition wraps and the resulting tiny value
passes the check. The unbounded offset is then stored in
res->guest_memory_offset and forwarded to host SVGA shader-create
commands.
Use check_add_overflow() to detect the wrap and compare the resulting
endpoint against the buffer size.
Fixes: 668b206601c5 ("drm/vmwgfx: Stop using raw ttm_buffer_object's")
Cc: [email protected]
Assisted-by: Claude:claude-opus-4.7
Signed-off-by: Zack Rusin <[email protected]>
---
drivers/gpu/drm/vmwgfx/vmwgfx_shader.c | 13 +++++++++----
1 file changed, 9 insertions(+), 4 deletions(-)
diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_shader.c
b/drivers/gpu/drm/vmwgfx/vmwgfx_shader.c
index eca4e3e97eb4..39811cf19db1 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_shader.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_shader.c
@@ -25,6 +25,8 @@
*
**************************************************************************/
+#include <linux/overflow.h>
+
#include <drm/ttm/ttm_placement.h>
#include "vmwgfx_binding.h"
@@ -685,7 +687,7 @@ int vmw_shader_destroy_ioctl(struct drm_device *dev, void
*data,
static int vmw_user_shader_alloc(struct vmw_private *dev_priv,
struct vmw_bo *buffer,
size_t shader_size,
- size_t offset,
+ u64 offset,
SVGA3dShaderType shader_type,
uint8_t num_input_sig,
uint8_t num_output_sig,
@@ -739,7 +741,7 @@ static int vmw_user_shader_alloc(struct vmw_private
*dev_priv,
static struct vmw_resource *vmw_shader_alloc(struct vmw_private *dev_priv,
struct vmw_bo *buffer,
size_t shader_size,
- size_t offset,
+ u64 offset,
SVGA3dShaderType shader_type)
{
struct vmw_shader *shader;
@@ -768,7 +770,7 @@ static struct vmw_resource *vmw_shader_alloc(struct
vmw_private *dev_priv,
static int vmw_shader_define(struct drm_device *dev, struct drm_file
*file_priv,
enum drm_vmw_shader_type shader_type_drm,
- u32 buffer_handle, size_t size, size_t offset,
+ u32 buffer_handle, size_t size, u64 offset,
uint8_t num_input_sig, uint8_t num_output_sig,
uint32_t *shader_handle)
{
@@ -779,13 +781,16 @@ static int vmw_shader_define(struct drm_device *dev,
struct drm_file *file_priv,
int ret;
if (buffer_handle != SVGA3D_INVALID_ID) {
+ u64 end;
+
ret = vmw_user_bo_lookup(file_priv, buffer_handle, &buffer);
if (unlikely(ret != 0)) {
VMW_DEBUG_USER("Couldn't find buffer for shader
creation.\n");
return ret;
}
- if ((u64)buffer->tbo.base.size < (u64)size + (u64)offset) {
+ if (check_add_overflow((u64)size, (u64)offset, &end) ||
+ end > buffer->tbo.base.size) {
VMW_DEBUG_USER("Illegal buffer- or shader size.\n");
ret = -EINVAL;
goto out_bad_arg;
--
2.51.0
