In function FindFileEntry(): Instead of using the function parameter 'FileEntry', use a local variable to store the buffer allocated for disk read operation.
For the below calling stack: UdfOpenVolume() -> FindRootDirectory() -> FindFileEntry() In FindFileEntry(), the call to 'DiskIo->ReadDisk()' is possible (e.g. media change for a CD/DVD ROM device) to trigger a re-install of the BlockIO(2) protocol which will further lead to a call of the BindingStop() & BingdingStart() of the UdfDxe driver. Meanwhile, for the above listed calling stack, the '**FileEntry' parameter passed into FindFileEntry() is '&PrivFsData->Root'. 'PrivFsData' is a driver-managed private data, it will be freed in BindingStop() and re-allocate in BingdingStart(). In such case, if '*FileEntry' is used to store the allocated buffer, the information will be lost if 'DiskIo->ReadDisk()' triggers a re-install of the BlockIO(2) protocol. The subsequent call of the FreePool API: FreePool (*FileEntry); will cause issues. This commit uses a local variable to store the allocated buffer. Cc: Paulo Alcantara <pca...@zytor.com> Cc: Ruiyu Ni <ruiyu...@intel.com> Cc: Star Zeng <star.z...@intel.com> Cc: Eric Dong <eric.d...@intel.com> Contributed-under: TianoCore Contribution Agreement 1.1 Signed-off-by: Hao Wu <hao.a...@intel.com> --- MdeModulePkg/Universal/Disk/UdfDxe/FileSystemOperations.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-) diff --git a/MdeModulePkg/Universal/Disk/UdfDxe/FileSystemOperations.c b/MdeModulePkg/Universal/Disk/UdfDxe/FileSystemOperations.c index e048d95d31..ecc172303e 100644 --- a/MdeModulePkg/Universal/Disk/UdfDxe/FileSystemOperations.c +++ b/MdeModulePkg/Universal/Disk/UdfDxe/FileSystemOperations.c @@ -1615,12 +1615,13 @@ FindFileEntry ( UINT64 Lsn; UINT32 LogicalBlockSize; UDF_DESCRIPTOR_TAG *DescriptorTag; + VOID *ReadBuffer; Lsn = GetLongAdLsn (Volume, Icb); LogicalBlockSize = Volume->LogicalVolDesc.LogicalBlockSize; - *FileEntry = AllocateZeroPool (Volume->FileEntrySize); - if (*FileEntry == NULL) { + ReadBuffer = AllocateZeroPool (Volume->FileEntrySize); + if (ReadBuffer == NULL) { return EFI_OUT_OF_RESOURCES; } @@ -1632,13 +1633,13 @@ FindFileEntry ( BlockIo->Media->MediaId, MultU64x32 (Lsn, LogicalBlockSize), Volume->FileEntrySize, - *FileEntry + ReadBuffer ); if (EFI_ERROR (Status)) { goto Error_Read_Disk_Blk; } - DescriptorTag = *FileEntry; + DescriptorTag = ReadBuffer; // // Check if the read extent contains a valid Tag Identifier for the expected @@ -1650,11 +1651,12 @@ FindFileEntry ( goto Error_Invalid_Fe; } + *FileEntry = ReadBuffer; return EFI_SUCCESS; Error_Invalid_Fe: Error_Read_Disk_Blk: - FreePool (*FileEntry); + FreePool (ReadBuffer); return Status; } -- 2.12.0.windows.1 _______________________________________________ edk2-devel mailing list edk2-devel@lists.01.org https://lists.01.org/mailman/listinfo/edk2-devel