drm/vmwgfx: use check_add_overflow for shader size+offset bound

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: stable@vger.kernel.org
Assisted-by: Claude:claude-opus-4.7
Signed-off-by: Zack Rusin <zack.rusin@broadcom.com>
Reviewed-by: Ian Forbes <ian.forbes@broadcom.com>
Link: https://patch.msgid.link/20260505222728.519626-12-zack.rusin@broadcom.com

0 files changed, 0 insertions, 0 deletions