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From: Hao Wu <hao.a.wu@intel.com>
To: edk2-devel@lists.01.org
Cc: Hao Wu <hao.a.wu@intel.com>, Paulo Alcantara <paulo@paulo.ac>,
	Ruiyu Ni <ruiyu.ni@intel.com>, Star Zeng <star.zeng@intel.com>
Subject: [PATCH v1 09/10] MdeModulePkg/UdfDxe: Add more check when getting PD from LongAd
Date: Tue, 16 Oct 2018 15:23:39 +0800	[thread overview]
Message-ID: <20181016072340.22068-10-hao.a.wu@intel.com> (raw)
In-Reply-To: <20181016072340.22068-1-hao.a.wu@intel.com>

REF:https://bugzilla.tianocore.org/show_bug.cgi?id=1254

This commit will add an additional check within function GetPdFromLongAd()
when getting a Partition Descriptor from given a Long Allocation
Descriptor.

According to UDF 2.60 Spec, Section 2.2.13:

> The partition reference numbers used are determined by the order of the
> Partition Maps in the LVD.

(Also the picture comes before the above contents)

And a more detailed explanation of the partition reference numbers is at
https://sites.google.com/site/udfintro/ (seems not a formal documentation
though), Section 5.3.6.

Based on the above findings, the 'PartitionReferenceNumber' field in a
Long Allocation Descriptor is used as an index to access the Partition
Maps data within a Logical Volume Descriptor.

Hence, the new check focuses on the validity of this
'PartitionReferenceNumber' field in a Long Allocation Descriptor. Since
the current implementation of UdfDxe driver supports only one partition on
a Logical Volume, so the value of 'PartitionReferenceNumber' should be 0.

Cc: Paulo Alcantara <paulo@paulo.ac>
Cc: Ruiyu Ni <ruiyu.ni@intel.com>
Cc: Star Zeng <star.zeng@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Hao Wu <hao.a.wu@intel.com>
---
 MdeModulePkg/Universal/Disk/UdfDxe/FileSystemOperations.c | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/MdeModulePkg/Universal/Disk/UdfDxe/FileSystemOperations.c b/MdeModulePkg/Universal/Disk/UdfDxe/FileSystemOperations.c
index 562a7d983c..7526de79b2 100644
--- a/MdeModulePkg/Universal/Disk/UdfDxe/FileSystemOperations.c
+++ b/MdeModulePkg/Universal/Disk/UdfDxe/FileSystemOperations.c
@@ -241,11 +241,16 @@ GetPdFromLongAd (
     //
     // NOTE: Only one Type 1 (Physical) Partition is supported. It has been
     // checked already in Partition driver for existence of a single Type 1
-    // Partition map, so we don't have to double check here.
+    // Partition map. Hence, the 'PartitionReferenceNumber' field (the index
+    // used to access Partition Maps data within the Logical Volume Descriptor)
+    // in the Long Allocation Descriptor should be 0 to indicate there is only
+    // one partition.
     //
-    // Partition reference number can also be retrieved from
-    // LongAd->ExtentLocation.PartitionReferenceNumber, however the spec says
-    // it may be 0, so let's not rely on it.
+    if (LongAd->ExtentLocation.PartitionReferenceNumber != 0) {
+      return NULL;
+    }
+    //
+    // Since only one partition, get the first one directly.
     //
     PartitionNum = *(UINT16 *)((UINTN)&LogicalVolDesc->PartitionMaps[4]);
     break;
-- 
2.12.0.windows.1



  parent reply	other threads:[~2018-10-16  7:23 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-10-16  7:23 [PATCH v1 00/10] UDF: Bugfixes Hao Wu
2018-10-16  7:23 ` [PATCH v1 01/10] MdeModulePkg/PartitionDxe: Add check for underlying device block size Hao Wu
2018-10-16  7:23 ` [PATCH v1 02/10] MdeModulePkg/UdfDxe: Refine boundary checks for file/path name string Hao Wu
2018-10-16  7:23 ` [PATCH v1 03/10] MdeModulePkg/UdfDxe: Add boundary check the read of FE/EFE Hao Wu
2018-10-16  7:23 ` [PATCH v1 04/10] MdeModulePkg/UdfDxe: Add boundary check for ComponentIdentifier decode Hao Wu
2018-10-16  7:23 ` [PATCH v1 05/10] MdeModulePkg/UdfDxe: Add boundary check for getting volume (free) size Hao Wu
2018-10-16  7:23 ` [PATCH v1 06/10] MdeModulePkg/UdfDxe: Correct behavior for UdfSetPosition() Hao Wu
2018-10-16  7:23 ` [PATCH v1 07/10] MdeModulePkg/UdfDxe: Fix a typo within SetFileInfo() Hao Wu
2018-10-16  7:23 ` [PATCH v1 08/10] MdeModulePkg/UdfDxe: Update GetInfo() for FS VolumeLabel info request Hao Wu
2018-10-16  7:23 ` Hao Wu [this message]
2018-10-16  7:23 ` [PATCH v1 10/10] MdeModulePkg/UdfDxe: Avoid possible use of already-freed data Hao Wu
2018-10-22 14:39 ` [PATCH v1 00/10] UDF: Bugfixes Paulo Alcantara
2018-10-23  5:45   ` Zeng, Star
2018-10-23  6:10     ` Wu, Hao A
2018-10-23 12:28       ` Wu, Hao A

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