From 750d8cad72a532d977df10ffbbdd1902bd06f50b Mon Sep 17 00:00:00 2001 From: Eduardo Lima Mitev Date: Tue, 25 Oct 2016 10:20:12 +0200 Subject: [PATCH] vulkan/wsi/x11: Fix behavior of vkGetPhysicalDeviceSurfaceFormatsKHR x11_surface_get_formats() is currently asserting that the number of elements in pSurfaceFormats must be greater than or equal to the number of formats available. This is buggy because pSurfaceFormatsCount elements are later copied from the internal formats' array, so if pSurfaceFormatCount is greater, it will overflow it. On top of that, this assertion violates the spec. From the Vulkan 1.0 (revision 32, with KHR extensions), page 579 of the PDF: "If pSurfaceFormats is NULL, then the number of format pairs supported for the given surface is returned in pSurfaceFormatCount. Otherwise, pSurfaceFormatCount must point to a variable set by the user to the number of elements in the pSurfaceFormats array, and on return the variable is overwritten with the number of structures actually written to pSurfaceFormats. If the value of pSurfaceFormatCount is less than the number of format pairs supported, at most pSurfaceFormatCount structures will be written. If pSurfaceFormatCount is smaller than the number of format pairs supported for the given surface, VK_INCOMPLETE will be returned instead of VK_SUCCESS to indicate that not all the available values were returned." So, the correct behavior is: if pSurfaceFormatCount is greater than the internal number of formats, it is clamped to that many formats. But if it is lesser than that, then pSurfaceFormatCount elements are copied, and the call returns VK_INCOMPLETE. Reviewed-by: Dave Airlie --- src/vulkan/wsi/wsi_common_x11.c | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-) diff --git a/src/vulkan/wsi/wsi_common_x11.c b/src/vulkan/wsi/wsi_common_x11.c index b5832c685e6..548352eec24 100644 --- a/src/vulkan/wsi/wsi_common_x11.c +++ b/src/vulkan/wsi/wsi_common_x11.c @@ -394,11 +394,16 @@ x11_surface_get_formats(VkIcdSurfaceBase *surface, return VK_SUCCESS; } - assert(*pSurfaceFormatCount >= ARRAY_SIZE(formats)); - typed_memcpy(pSurfaceFormats, formats, *pSurfaceFormatCount); - *pSurfaceFormatCount = ARRAY_SIZE(formats); + VkResult result = VK_SUCCESS; - return VK_SUCCESS; + if (*pSurfaceFormatCount > ARRAY_SIZE(formats)) + *pSurfaceFormatCount = ARRAY_SIZE(formats); + else if (*pSurfaceFormatCount < ARRAY_SIZE(formats)) + result = VK_INCOMPLETE; + + typed_memcpy(pSurfaceFormats, formats, *pSurfaceFormatCount); + + return result; } static VkResult