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[FASTFAT]

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- Fix memory corruption if long file name entry is invalid.
- Minor improvements.

See issue #6546 for more details.

svn path=/trunk/; revision=54222
This commit is contained in:
Rafal Harabien 2011-10-21 13:21:56 +00:00
parent 06c9dfcef7
commit 7940686557
2 changed files with 36 additions and 16 deletions
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37
reactos/drivers/filesystems/fastfat/direntry.c
View file

@ -181,7 +181,8 @@ FATGetNextDirEntry(PVOID *pContext,
BOOLEAN Valid = TRUE;
BOOLEAN Back = FALSE;
DirContext->LongNameU.Buffer[0] = 0;
DirContext->LongNameU.Length = 0;
DirContext->LongNameU.Buffer[0] = UNICODE_NULL;
FileOffset.u.HighPart = 0;
FileOffset.u.LowPart = ROUND_DOWN(DirContext->DirIndex * sizeof(FAT_DIR_ENTRY), PAGE_SIZE);
@ -304,14 +305,30 @@ FATGetNextDirEntry(PVOID *pContext,
6, longNameEntry->name5_10,
2, longNameEntry->name11_12);
index = (longNameEntry->id & 0x1f) - 1;
dirMap |= 1 << index;
pName = DirContext->LongNameU.Buffer + 13 * index;
index = longNameEntry->id & 0x3f; // Note: it can be 0 for corrupted FS
/* Make sure index is valid and we have enaugh space in buffer
(we count one char for \0) */
if (index > 0 &&
index * 13 < DirContext->LongNameU.MaximumLength / sizeof(WCHAR))
{
index--; // make index 0 based
dirMap |= 1 << index;
pName = DirContext->LongNameU.Buffer + index * 13;
RtlCopyMemory(pName, longNameEntry->name0_4, 5 * sizeof(WCHAR));
RtlCopyMemory(pName + 5, longNameEntry->name5_10, 6 * sizeof(WCHAR));
RtlCopyMemory(pName + 11, longNameEntry->name11_12, 2 * sizeof(WCHAR));
if (longNameEntry->id & 0x40)
{
/* It's last LFN entry. Terminate filename with \0 */
pName[13] = UNICODE_NULL;
}
}
else
DPRINT1("Long name entry has invalid index: %x!\n", longNameEntry->id);
DPRINT (" longName: [%S]\n", DirContext->LongNameU.Buffer);
if (CheckSum != longNameEntry->alias_checksum)
@ -372,13 +389,17 @@ FATGetNextDirEntry(PVOID *pContext,
}
}
/* Make sure filename is NULL terminate and calculate length */
DirContext->LongNameU.Buffer[DirContext->LongNameU.MaximumLength / sizeof(WCHAR) - 1]
= UNICODE_NULL;
DirContext->LongNameU.Length = wcslen(DirContext->LongNameU.Buffer) * sizeof(WCHAR);
/* Init short name */
vfat8Dot3ToString(&DirContext->DirEntry.Fat, &DirContext->ShortNameU);
/* If we found no LFN, use short name as long */
if (DirContext->LongNameU.Length == 0)
{
RtlCopyUnicodeString(&DirContext->LongNameU, &DirContext->ShortNameU);
}
return STATUS_SUCCESS;
}
@ -405,7 +426,7 @@ NTSTATUS FATXGetNextDirEntry(PVOID * pContext,
{
DirContext->ShortNameU.Buffer[0] = 0;
DirContext->ShortNameU.Length = 0;
DirContext->LongNameU.Buffer[0] = L'.';
wcscpy(DirContext->LongNameU.Buffer, L".");
DirContext->LongNameU.Length = sizeof(WCHAR);
RtlCopyMemory(&DirContext->DirEntry.FatX, &pDirFcb->entry.FatX, sizeof(FATX_DIR_ENTRY));
DirContext->DirEntry.FatX.Filename[0] = '.';
@ -417,7 +438,7 @@ NTSTATUS FATXGetNextDirEntry(PVOID * pContext,
{
DirContext->ShortNameU.Buffer[0] = 0;
DirContext->ShortNameU.Length = 0;
DirContext->LongNameU.Buffer[0] = DirContext->LongNameU.Buffer[1] = L'.';
wcscpy(DirContext->LongNameU.Buffer, L"..");
DirContext->LongNameU.Length = 2 * sizeof(WCHAR);
RtlCopyMemory(&DirContext->DirEntry.FatX, &pDirFcb->entry.FatX, sizeof(FATX_DIR_ENTRY));
DirContext->DirEntry.FatX.Filename[0] = DirContext->DirEntry.FatX.Filename[1] = '.';

3
reactos/drivers/filesystems/fastfat/fcb.c
View file

@ -604,8 +604,7 @@ vfatDirFindFile (
DPRINT (" Index:%d longName:%wZ\n",
DirContext.DirIndex,
&DirContext.LongNameU);
DirContext.LongNameU.Buffer[DirContext.LongNameU.Length / sizeof(WCHAR)] = 0;
DirContext.ShortNameU.Buffer[DirContext.ShortNameU.Length / sizeof(WCHAR)] = 0;
if (!ENTRY_VOLUME(pDeviceExt, &DirContext.DirEntry))
{
FoundLong = RtlEqualUnicodeString(FileToFindU, &DirContext.LongNameU, TRUE);