From 3f2ae009ec66430f13bd24f2de475965eb3bc6df Mon Sep 17 00:00:00 2001 From: Ard Biesheuvel Date: Thu, 16 Mar 2017 11:35:28 +0000 Subject: [PATCH] MdeModulePkg/DxeCore: deal with allocations spanning several memmap entries When attempting to perform page allocations using AllocateAddress, we fail to check whether the entire region is free before splitting the region. This may lead to memory being leaked further into the routine, when it turns out that one of the memory map entries intersected by the region is already occupied. In this case, prior conversions are not rolled back. For instance, starting from this situation 0x000040000000-0x00004007ffff [ConventionalMemory ] 0x000040080000-0x00004009ffff [Boot Data ] 0x0000400a0000-0x000047ffffff [ConventionalMemory ] a failed EfiLoaderData allocation @ 0x40000000 that covers the BootData region will fail, but leave the first part of the allocation converted, so we end up with 0x000040000000-0x00004007ffff [Loader Data ] 0x000040080000-0x00004009ffff [Boot Data ] 0x0000400a0000-0x000047ffffff [ConventionalMemory ] even though the AllocatePages() call returned an error. So let's check beforehand that AllocateAddress allocations are covered by a single memory map entry, so that it either succeeds or fails completely, rather than leaking allocations. Contributed-under: TianoCore Contribution Agreement 1.0 Signed-off-by: Ard Biesheuvel Reviewed-by: Star Zeng --- MdeModulePkg/Core/Dxe/Mem/Page.c | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/MdeModulePkg/Core/Dxe/Mem/Page.c b/MdeModulePkg/Core/Dxe/Mem/Page.c index 260a30a214..3b3b9a8131 100644 --- a/MdeModulePkg/Core/Dxe/Mem/Page.c +++ b/MdeModulePkg/Core/Dxe/Mem/Page.c @@ -754,6 +754,17 @@ CoreConvertPagesEx ( return EFI_NOT_FOUND; } + // + // If we are converting the type of the range from EfiConventionalMemory to + // another type, we have to ensure that the entire range is covered by a + // single entry. + // + if (ChangingType && (NewType != EfiConventionalMemory)) { + if (Entry->End < End) { + DEBUG ((DEBUG_ERROR | DEBUG_PAGE, "ConvertPages: range %lx - %lx covers multiple entries\n", Start, End)); + return EFI_NOT_FOUND; + } + } // // Convert range to the end, or to the end of the descriptor // if that's all we've got -- 2.39.2