From 1fab0b299bc4c5b3f5106f718692f8f9bad5e635 Mon Sep 17 00:00:00 2001 From: Laszlo Ersek Date: Fri, 1 Mar 2019 13:45:08 +0100 Subject: [PATCH 2/2] MdeModulePkg/RamDiskDxe: Restrict on RAM disk size (CVE-2018-12180) Message-id: <20190301124508.18497-3-lersek@redhat.com> Patchwork-id: 84760 O-Subject: [RHEL-8.0 edk2 PATCH 2/2] MdeModulePkg/RamDiskDxe: Restrict on RAM disk size (CVE-2018-12180) Bugzilla: 1690501 Acked-by: Thomas Huth Acked-by: Vitaly Kuznetsov From: Hao Wu REF:https://bugzilla.tianocore.org/show_bug.cgi?id=1134 Originally, the block size of created Ram disks is hard-coded to 512 bytes. However, if the total size of the Ram disk is not a multiple of 512 bytes, there will be potential memory access issues when dealing with the last block of the Ram disk. This commit will adjust the block size of the Ram disks to ensure that the total size is a multiple of the block size. Cc: Jian J Wang Cc: Star Zeng Cc: Laszlo Ersek Contributed-under: TianoCore Contribution Agreement 1.1 Signed-off-by: Hao Wu Reviewed-by: Ray Ni (cherry picked from commit 38c9fbdcaa0219eb86fe82d90e3f8cfb5a54be9f) Signed-off-by: Laszlo Ersek Signed-off-by: Danilo C. L. de Paula --- .../Universal/Disk/RamDiskDxe/RamDiskBlockIo.c | 20 ++++++++++++++------ MdeModulePkg/Universal/Disk/RamDiskDxe/RamDiskImpl.h | 6 +++--- .../Universal/Disk/RamDiskDxe/RamDiskProtocol.c | 5 +++-- 3 files changed, 20 insertions(+), 11 deletions(-) diff --git a/MdeModulePkg/Universal/Disk/RamDiskDxe/RamDiskBlockIo.c b/MdeModulePkg/Universal/Disk/RamDiskDxe/RamDiskBlockIo.c index 4f74b5e..8926ad7 100644 --- a/MdeModulePkg/Universal/Disk/RamDiskDxe/RamDiskBlockIo.c +++ b/MdeModulePkg/Universal/Disk/RamDiskDxe/RamDiskBlockIo.c @@ -1,7 +1,7 @@ /** @file Produce EFI_BLOCK_IO_PROTOCOL on a RAM disk device. - Copyright (c) 2016 - 2018, Intel Corporation. All rights reserved.
+ Copyright (c) 2016 - 2019, Intel Corporation. All rights reserved.
This program and the accompanying materials are licensed and made available under the terms and conditions of the BSD License which accompanies this distribution. The full text of the license may be found at @@ -54,6 +54,7 @@ RamDiskInitBlockIo ( EFI_BLOCK_IO_PROTOCOL *BlockIo; EFI_BLOCK_IO2_PROTOCOL *BlockIo2; EFI_BLOCK_IO_MEDIA *Media; + UINT32 Remainder; BlockIo = &PrivateData->BlockIo; BlockIo2 = &PrivateData->BlockIo2; @@ -69,11 +70,18 @@ RamDiskInitBlockIo ( Media->LogicalPartition = FALSE; Media->ReadOnly = FALSE; Media->WriteCaching = FALSE; - Media->BlockSize = RAM_DISK_BLOCK_SIZE; - Media->LastBlock = DivU64x32 ( - PrivateData->Size + RAM_DISK_BLOCK_SIZE - 1, - RAM_DISK_BLOCK_SIZE - ) - 1; + + for (Media->BlockSize = RAM_DISK_DEFAULT_BLOCK_SIZE; + Media->BlockSize >= 1; + Media->BlockSize = Media->BlockSize >> 1) { + Media->LastBlock = DivU64x32Remainder (PrivateData->Size, Media->BlockSize, &Remainder) - 1; + if (Remainder == 0) { + break; + } + } + ASSERT (Media->BlockSize != 0); + + return; } diff --git a/MdeModulePkg/Universal/Disk/RamDiskDxe/RamDiskImpl.h b/MdeModulePkg/Universal/Disk/RamDiskDxe/RamDiskImpl.h index 077bb77..18c7bb2 100644 --- a/MdeModulePkg/Universal/Disk/RamDiskDxe/RamDiskImpl.h +++ b/MdeModulePkg/Universal/Disk/RamDiskDxe/RamDiskImpl.h @@ -1,7 +1,7 @@ /** @file The header file of RamDiskDxe driver. - Copyright (c) 2016, Intel Corporation. All rights reserved.
+ Copyright (c) 2016 - 2019, Intel Corporation. All rights reserved.
This program and the accompanying materials are licensed and made available under the terms and conditions of the BSD License which accompanies this distribution. The full text of the license may be found at @@ -49,9 +49,9 @@ /// // -// Block size for RAM disk +// Default block size for RAM disk // -#define RAM_DISK_BLOCK_SIZE 512 +#define RAM_DISK_DEFAULT_BLOCK_SIZE 512 // // Iterate through the double linked list. NOT delete safe diff --git a/MdeModulePkg/Universal/Disk/RamDiskDxe/RamDiskProtocol.c b/MdeModulePkg/Universal/Disk/RamDiskDxe/RamDiskProtocol.c index 6784e2b..e8250d5 100644 --- a/MdeModulePkg/Universal/Disk/RamDiskDxe/RamDiskProtocol.c +++ b/MdeModulePkg/Universal/Disk/RamDiskDxe/RamDiskProtocol.c @@ -1,7 +1,7 @@ /** @file The realization of EFI_RAM_DISK_PROTOCOL. - Copyright (c) 2016, Intel Corporation. All rights reserved.
+ Copyright (c) 2016 - 2019, Intel Corporation. All rights reserved.
(C) Copyright 2016 Hewlett Packard Enterprise Development LP
This program and the accompanying materials are licensed and made available under the terms and conditions of the BSD License @@ -613,7 +613,8 @@ RamDiskRegister ( // // Add check to prevent data read across the memory boundary // - if (RamDiskBase + RamDiskSize > ((UINTN) -1) - RAM_DISK_BLOCK_SIZE + 1) { + if ((RamDiskSize > MAX_UINTN) || + (RamDiskBase > MAX_UINTN - RamDiskSize + 1)) { return EFI_INVALID_PARAMETER; } -- 1.8.3.1