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MdeModulePkg: introduce UEFI freed-memory guard bit in HeapGuard PCD

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UAF (Use-After-Free) memory issue is kind of illegal access to memory
which has been freed. It can be detected by a new freed-memory guard
enforced onto freed memory.

BIT4 of following PCD is used to enable the freed-memory guard feature.

  gEfiMdeModulePkgTokenSpaceGuid.PcdHeapGuardPropertyMask

Please note this feature is for debug purpose and should not be enabled
in product BIOS, and cannot be enabled with pool/page heap guard at the
same time. It's disabled by default.

Cc: Star Zeng <star.zeng@intel.com>
Cc: Michael D Kinney <michael.d.kinney@intel.com>
Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Ruiyu Ni <ruiyu.ni@intel.com>
Cc: Laszlo Ersek <lersek@redhat.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Jian J Wang <jian.j.wang@intel.com>
Reviewed-by: Star Zeng <star.zeng@intel.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
This commit is contained in:
Jian J Wang
2018-10-24 10:26:07 +08:00
parent a6bde8a644
commit 5323e918c3
2 changed files with 22 additions and 8 deletions
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16
MdeModulePkg/MdeModulePkg.dec
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@@ -1011,14 +1011,22 @@
gEfiMdeModulePkgTokenSpaceGuid.PcdHeapGuardPoolType|0x0|UINT64|0x30001053
## This mask is to control Heap Guard behavior.
# Note that due to the limit of pool memory implementation and the alignment
# requirement of UEFI spec, BIT7 is a try-best setting which cannot guarantee
# that the returned pool is exactly adjacent to head guard page or tail guard
# page.
#
# Note:
# a) Heap Guard is for debug purpose and should not be enabled in product
# BIOS.
# b) Due to the limit of pool memory implementation and the alignment
# requirement of UEFI spec, BIT7 is a try-best setting which cannot
# guarantee that the returned pool is exactly adjacent to head guard
# page or tail guard page.
# c) UEFI freed-memory guard and UEFI pool/page guard cannot be enabled
# at the same time.
#
# BIT0 - Enable UEFI page guard.<BR>
# BIT1 - Enable UEFI pool guard.<BR>
# BIT2 - Enable SMM page guard.<BR>
# BIT3 - Enable SMM pool guard.<BR>
# BIT4 - Enable UEFI freed-memory guard (Use-After-Free memory detection).<BR>
# BIT6 - Enable non-stop mode.<BR>
# BIT7 - The direction of Guard Page for Pool Guard.
# 0 - The returned pool is near the tail guard page.<BR>