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From: Ard Biesheuvel <ard.biesheuvel@linaro.org>
To: edk2-devel@lists.01.org
Subject: [PATCH 1/5] ArmPkg/ArmMmuLib AARCH64: fix out of bounds access
Date: Mon,  7 Jan 2019 08:15:00 +0100	[thread overview]
Message-ID: <20190107071504.2431-2-ard.biesheuvel@linaro.org> (raw)
In-Reply-To: <20190107071504.2431-1-ard.biesheuvel@linaro.org>

Take care not to dereference BlockEntry if it may be pointing past
the end of the page table we are manipulating. It is only a read,
and thus harmless, but HeapGuard triggers on it so let's fix it.

Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
---
 ArmPkg/Library/ArmMmuLib/AArch64/ArmMmuLibCore.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/ArmPkg/Library/ArmMmuLib/AArch64/ArmMmuLibCore.c b/ArmPkg/Library/ArmMmuLib/AArch64/ArmMmuLibCore.c
index e41044142ef4..d66df3e17a02 100644
--- a/ArmPkg/Library/ArmMmuLib/AArch64/ArmMmuLibCore.c
+++ b/ArmPkg/Library/ArmMmuLib/AArch64/ArmMmuLibCore.c
@@ -382,7 +382,7 @@ UpdateRegionMapping (
 
       // Break the inner loop when next block is a table
       // Rerun GetBlockEntryListFromAddress to avoid page table memory leak
-      if (TableLevel != 3 &&
+      if (TableLevel != 3 && BlockEntry <= LastBlockEntry &&
           (*BlockEntry & TT_TYPE_MASK) == TT_TYPE_TABLE_ENTRY) {
             break;
       }
-- 
2.20.1



  reply	other threads:[~2019-01-07  7:15 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-01-07  7:14 [PATCH 0/5] memory/MMU hardening for AArch64 Ard Biesheuvel
2019-01-07  7:15 ` Ard Biesheuvel [this message]
2019-01-14 12:00   ` [PATCH 1/5] ArmPkg/ArmMmuLib AARCH64: fix out of bounds access Leif Lindholm
2019-01-14 18:48     ` Ard Biesheuvel
2019-01-07  7:15 ` [PATCH 2/5] ArmPkg/ArmMmuLib AARCH64: get rid of needless TLB invalidation Ard Biesheuvel
2019-01-23 15:46   ` Leif Lindholm
2019-01-23 15:55     ` Ard Biesheuvel
2019-01-23 16:12       ` Leif Lindholm
2019-01-23 16:16         ` Ard Biesheuvel
2019-01-23 16:20           ` Leif Lindholm
2019-01-28 12:29             ` Ard Biesheuvel
2019-01-28 18:01               ` Leif Lindholm
2019-01-29 10:32                 ` Ard Biesheuvel
2019-01-07  7:15 ` [PATCH 3/5] ArmPkg/ArmMmuLib AARCH64: implement support for EFI_MEMORY_RP permissions Ard Biesheuvel
2019-01-14 14:29   ` Leif Lindholm
2019-01-14 14:59     ` Ard Biesheuvel
2019-01-14 15:06       ` Leif Lindholm
2019-01-07  7:15 ` [PATCH 4/5] ArmPkg/ArmMmuLib AARCH64: add support for read-only page tables Ard Biesheuvel
2019-01-07  7:15 ` [PATCH 5/5] ArmPkg/CpuDxe: switch to read-only page tables at EndOfDxe Ard Biesheuvel

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