Looks good.
Can we assign a local variable for "EndPtr" and use that in the For loop,
instead of the expression and keep the implementation cleaner?
EndPtr = CurrPtr + ((EFI_ACPI_COMMON_HEADER *) CurrPtr)->Length;
for (DsdtPointer = CurrPtr; DsdtPointer < EndPtr; DsdtPointer++) {
-----Original Message-----
From: Desimone, Nathaniel L
Sent: Monday, July 15, 2019 1:40 PM
To: devel@edk2.groups.io
Cc: Chiu, Chasel <chasel.c...@intel.com>; Kubacki, Michael A
<michael.a.kuba...@intel.com>; Chaganty, Rangasai V
<rangasai.v.chaga...@intel.com>
Subject: [edk2-platforms] [PATCH] KabylakeSiliconPkg: Possible out-of-bounds
memory writes
- Add check for the DSDT not existing.
- Fixed logic errors in loop boundary check.
Cc: Chasel Chiu <chasel.c...@intel.com>
Cc: Michael A Kubacki <michael.a.kuba...@intel.com>
Cc: Sai Chaganty <rangasai.v.chaga...@intel.com>
Co-authored-by: John Mathews <john.math...@intel.com>
Signed-off-by: Nate DeSimone <nathaniel.l.desim...@intel.com>
---
.../Library/DxeAslUpdateLib/DxeAslUpdateLib.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git
a/Silicon/Intel/KabylakeSiliconPkg/Library/DxeAslUpdateLib/DxeAslUpdateLib.c
b/Silicon/Intel/KabylakeSiliconPkg/Library/DxeAslUpdateLib/DxeAslUpdateLib.c
index e6ab43db6d..a9611f750f 100644
--- a/Silicon/Intel/KabylakeSiliconPkg/Library/DxeAslUpdateLib/DxeAslUpdateLib.c
+++ b/Silicon/Intel/KabylakeSiliconPkg/Library/DxeAslUpdateLib/DxeAslUpdateLib.c
@@ -59,6 +59,7 @@ InitializeAslUpdateLib (
@param[in] Length - length of data to be overwritten
@retval EFI_SUCCESS - The function completed successfully.
+ @retval EFI_NOT_FOUND - Failed to locate AcpiTable.
**/
EFI_STATUS
UpdateNameAslCode (
@@ -99,11 +100,14 @@ UpdateNameAslCode (
/// Point to the beginning of the DSDT table
///
CurrPtr = (UINT8 *) Table;
+ if (CurrPtr == NULL) {
+ return EFI_NOT_FOUND;
+ }
///
/// Loop through the ASL looking for values that we must fix up.
///
- for (DsdtPointer = CurrPtr; DsdtPointer <= (CurrPtr +
((EFI_ACPI_COMMON_HEADER *) CurrPtr)->Length); DsdtPointer++) {
+ for (DsdtPointer = CurrPtr; DsdtPointer < (CurrPtr +
((EFI_ACPI_COMMON_HEADER *) CurrPtr)->Length); DsdtPointer++) {
///
/// Get a pointer to compare for signature
///
--
2.17.1.windows.2
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