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From: "Krzysztof Koch" <krzysztof.koch@arm.com>
To: <devel@edk2.groups.io>
Cc: <jaben.carsey@intel.com>, <ray.ni@intel.com>,
	<zhichao.gao@intel.com>, <Sami.Mujawar@arm.com>,
	<Matteo.Carlini@arm.com>, <nd@arm.com>
Subject: [PATCH v1 01/11] ShellPkg: acpiview: Set ItemPtr to NULL for unprocessed table fields
Date: Thu, 15 Aug 2019 14:11:11 +0100	[thread overview]
Message-ID: <20190815131121.52644-2-krzysztof.koch@arm.com> (raw)
In-Reply-To: <20190815131121.52644-1-krzysztof.koch@arm.com>

For fields outside the buffer length provided, reset any pointers,
which were supposed to be updated by a ParseAcpi() function call to
NULL. This way one can easily validate if a pointer was successfully
updated.

The ParseAcpi() function parses the given ACPI table buffer by a
number of bytes which is a minimum of the buffer length and the length
described by ACPI_PARSER array. If the buffer length is shorter than
the array describing how to process the ACPI structure, then it is
possible that the ItemPtr inside ACPI_PARSER may not get updated or
initialized. This can lead to an error if the value pointed to by
ItemPtr is later used to control the parsing logic.

A typical example would be a 'number of elements' field in an ACPI
structure header which defines how many substructures of a given type
are present in the structure body. If the 'number of elements' field
is not parsed, this could result in a dangling pointer which could
cause a problem later.

Signed-off-by: Krzysztof Koch <krzysztof.koch@arm.com>
---

Notes:
    v1:
    - Set ItemPtr to NULL for unprocessed table fields [Krzysztof]

 ShellPkg/Library/UefiShellAcpiViewCommandLib/AcpiParser.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/ShellPkg/Library/UefiShellAcpiViewCommandLib/AcpiParser.c b/ShellPkg/Library/UefiShellAcpiViewCommandLib/AcpiParser.c
index 2d6ff80e299eebe7853061d3db89332197c0dc0e..1ede12859721db75d17fd0bfc14dc9e9c0d573aa 100644
--- a/ShellPkg/Library/UefiShellAcpiViewCommandLib/AcpiParser.c
+++ b/ShellPkg/Library/UefiShellAcpiViewCommandLib/AcpiParser.c
@@ -502,8 +502,15 @@ ParseAcpi (
 
   for (Index = 0; Index < ParserItems; Index++) {
     if ((Offset + Parser[Index].Length) > Length) {
+
+      // For fields outside the buffer length provided, reset any pointers
+      // which were supposed to be updated by this function call
+      if (Parser[Index].ItemPtr != NULL) {
+        *Parser[Index].ItemPtr = NULL;
+      }
+
       // We don't parse past the end of the max length specified
-      break;
+      continue;
     }
 
     if (GetConsistencyChecking () &&
--
'Guid(CE165669-3EF3-493F-B85D-6190EE5B9759)'



  reply	other threads:[~2019-08-15 13:11 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-08-15 13:11 [PATCH v1 00/11] Test against invalid pointers in acpiview Krzysztof Koch
2019-08-15 13:11 ` Krzysztof Koch [this message]
2019-08-15 13:11 ` [PATCH v1 02/11] ShellPkg: acpiview: RSDP: Validate global pointer before use Krzysztof Koch
2019-08-15 13:11 ` [PATCH v1 03/11] ShellPkg: acpiview: FADT: " Krzysztof Koch
2019-08-16  7:34   ` Gao, Zhichao
2019-08-16 10:25     ` Krzysztof Koch
2019-08-15 13:11 ` [PATCH v1 04/11] ShellPkg: acpiview: SLIT: " Krzysztof Koch
2019-08-15 13:11 ` [PATCH v1 05/11] ShellPkg: acpiview: SLIT: Validate System Locality count Krzysztof Koch
2019-08-19  1:18   ` [edk2-devel] " Gao, Zhichao
2019-08-19  6:28     ` Krzysztof Koch
2019-08-19  7:16       ` Gao, Zhichao
2019-08-19  9:30   ` Sami Mujawar
2019-08-15 13:11 ` [PATCH v1 06/11] ShellPkg: acpiview: SRAT: Validate global pointers before use Krzysztof Koch
2019-08-15 13:11 ` [PATCH v1 07/11] ShellPkg: acpiview: MADT: " Krzysztof Koch
2019-08-15 13:11 ` [PATCH v1 08/11] ShellPkg: acpiview: PPTT: " Krzysztof Koch
2019-08-15 13:11 ` [PATCH v1 09/11] ShellPkg: acpiview: IORT: " Krzysztof Koch
2019-08-15 13:11 ` [PATCH v1 10/11] ShellPkg: acpiview: GTDT: " Krzysztof Koch
2019-08-15 13:11 ` [PATCH v1 11/11] ShellPkg: acpiview: DBG2: " Krzysztof Koch
2019-08-16  4:02 ` [edk2-devel] [PATCH v1 00/11] Test against invalid pointers in acpiview Liming Gao
2019-08-16  7:21   ` Krzysztof Koch
2019-08-19  9:29 ` Sami Mujawar
2019-08-21  1:46 ` [edk2-devel] " Gao, Zhichao

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