From: Zack Rusin Date: Tue, 5 May 2026 22:22:23 +0000 (-0400) Subject: drm/vmwgfx: reject DX_BIND_QUERY without a DX context X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=55ec09c9ce10b1272802c7ab6c1be2ea0dbc68db;p=thirdparty%2Flinux.git drm/vmwgfx: reject DX_BIND_QUERY without a DX context vmw_cmd_dx_bind_query() unconditionally dereferences sw_context->dx_ctx_node->ctx. Userspace can trigger a NULL pointer dereference from any render-node fd by submitting an execbuf with dx_context_handle == SVGA3D_INVALID_ID and a SVGA_3D_CMD_DX_BIND_QUERY opcode in the command stream: dx_ctx_node is left NULL and the kernel oopses on the assignment. The same NULL is then re-read in vmw_resources_reserve() via vmw_context_get_dx_query_mob(). All sibling DX handlers fail-close on a missing dx_ctx_node using VMW_GET_CTX_NODE(). Use the same pattern here, returning -EINVAL up front before any relocation state is published. Fixes: 9c079b8ce8bf ("drm/vmwgfx: Adapt execbuf to the new validation api") Cc: stable@vger.kernel.org Assisted-by: Claude:claude-opus-4.7 Signed-off-by: Zack Rusin Reviewed-by: Ian Forbes Link: https://patch.msgid.link/20260505222728.519626-3-zack.rusin@broadcom.com --- diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_execbuf.c b/drivers/gpu/drm/vmwgfx/vmwgfx_execbuf.c index e1f18020170a..b07f052474d0 100644 --- a/drivers/gpu/drm/vmwgfx/vmwgfx_execbuf.c +++ b/drivers/gpu/drm/vmwgfx/vmwgfx_execbuf.c @@ -1272,9 +1272,13 @@ static int vmw_cmd_dx_bind_query(struct vmw_private *dev_priv, SVGA3dCmdHeader *header) { VMW_DECLARE_CMD_VAR(*cmd, SVGA3dCmdDXBindQuery); + struct vmw_ctx_validation_info *ctx_node = VMW_GET_CTX_NODE(sw_context); struct vmw_bo *vmw_bo; int ret; + if (!ctx_node) + return -EINVAL; + cmd = container_of(header, typeof(*cmd), header); /* @@ -1288,7 +1292,7 @@ static int vmw_cmd_dx_bind_query(struct vmw_private *dev_priv, return ret; sw_context->dx_query_mob = vmw_bo; - sw_context->dx_query_ctx = sw_context->dx_ctx_node->ctx; + sw_context->dx_query_ctx = ctx_node->ctx; return 0; }