From: Zack Rusin Date: Wed, 17 Sep 2025 15:36:55 +0000 (-0400) Subject: drm/vmwgfx: Fix a null-ptr access in the cursor snooper X-Git-Tag: v6.18-rc1~15^2^2~3 X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=5ac2c0279053a2c5265d46903432fb26ae2d0da2;p=thirdparty%2Flinux.git drm/vmwgfx: Fix a null-ptr access in the cursor snooper Check that the resource which is converted to a surface exists before trying to use the cursor snooper on it. vmw_cmd_res_check allows explicit invalid (SVGA3D_INVALID_ID) identifiers because some svga commands accept SVGA3D_INVALID_ID to mean "no surface", unfortunately functions that accept the actual surfaces as objects might (and in case of the cursor snooper, do not) be able to handle null objects. Make sure that we validate not only the identifier (via the vmw_cmd_res_check) but also check that the actual resource exists before trying to do something with it. Fixes unchecked null-ptr reference in the snooping code. Signed-off-by: Zack Rusin Fixes: c0951b797e7d ("drm/vmwgfx: Refactor resource management") Reported-by: Kuzey Arda Bulut Cc: Broadcom internal kernel review list Cc: dri-devel@lists.freedesktop.org Reviewed-by: Ian Forbes Link: https://lore.kernel.org/r/20250917153655.1968583-1-zack.rusin@broadcom.com --- diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_execbuf.c b/drivers/gpu/drm/vmwgfx/vmwgfx_execbuf.c index 819704ac675d0..d539f25b5fbe0 100644 --- a/drivers/gpu/drm/vmwgfx/vmwgfx_execbuf.c +++ b/drivers/gpu/drm/vmwgfx/vmwgfx_execbuf.c @@ -1497,6 +1497,7 @@ static int vmw_cmd_dma(struct vmw_private *dev_priv, SVGA3dCmdHeader *header) { struct vmw_bo *vmw_bo = NULL; + struct vmw_resource *res; struct vmw_surface *srf = NULL; VMW_DECLARE_CMD_VAR(*cmd, SVGA3dCmdSurfaceDMA); int ret; @@ -1532,18 +1533,24 @@ static int vmw_cmd_dma(struct vmw_private *dev_priv, dirty = (cmd->body.transfer == SVGA3D_WRITE_HOST_VRAM) ? VMW_RES_DIRTY_SET : 0; - ret = vmw_cmd_res_check(dev_priv, sw_context, vmw_res_surface, - dirty, user_surface_converter, - &cmd->body.host.sid, NULL); + ret = vmw_cmd_res_check(dev_priv, sw_context, vmw_res_surface, dirty, + user_surface_converter, &cmd->body.host.sid, + NULL); if (unlikely(ret != 0)) { if (unlikely(ret != -ERESTARTSYS)) VMW_DEBUG_USER("could not find surface for DMA.\n"); return ret; } - srf = vmw_res_to_srf(sw_context->res_cache[vmw_res_surface].res); + res = sw_context->res_cache[vmw_res_surface].res; + if (!res) { + VMW_DEBUG_USER("Invalid DMA surface.\n"); + return -EINVAL; + } - vmw_kms_cursor_snoop(srf, sw_context->fp->tfile, &vmw_bo->tbo, header); + srf = vmw_res_to_srf(res); + vmw_kms_cursor_snoop(srf, sw_context->fp->tfile, &vmw_bo->tbo, + header); return 0; }