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sys,dll: FspFileSystemResolveReparsePoints: use IO_REPARSE_TAG_SYMLINK instead of IO_REPARSE for symlink resolution

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- FspFsvolCreateComplete STATUS_REPARSE handling changed to support device-relative symlink reparse points
This commit is contained in:
Bill Zissimopoulos 2016-09-14 22:16:40 -07:00
parent 46a29f663a
commit 5771eedc45
2 changed files with 63 additions and 31 deletions
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55
src/dll/fsop.c
View File

@ -1057,6 +1057,7 @@ FSP_API NTSTATUS FspFileSystemResolveReparsePoints(FSP_FILE_SYSTEM *FileSystem,
PWSTR FileName, UINT32 ReparsePointIndex, BOOLEAN ResolveLastPathComponent0,
PIO_STATUS_BLOCK PIoStatus, PVOID Buffer, PSIZE_T PSize)
{
PREPARSE_DATA_BUFFER OutputReparseData;
PWSTR TargetPath, RemainderPath, LastPathComponent, NewRemainderPath, ReparseTargetPath;
WCHAR RemainderChar;
union
@ -1070,10 +1071,17 @@ FSP_API NTSTATUS FspFileSystemResolveReparsePoints(FSP_FILE_SYSTEM *FileSystem,
ULONG MaxTries = 32;
NTSTATUS Result;
TargetPath = Buffer;
RemainderPathSize = (lstrlenW(FileName) + 1) * sizeof(WCHAR);
if (RemainderPathSize > *PSize)
if (FIELD_OFFSET(REPARSE_DATA_BUFFER, SymbolicLinkReparseBuffer.PathBuffer) +
RemainderPathSize > *PSize)
return STATUS_REPARSE_POINT_NOT_RESOLVED;
OutputReparseData = Buffer;
memset(OutputReparseData, 0,
FIELD_OFFSET(REPARSE_DATA_BUFFER, SymbolicLinkReparseBuffer.PathBuffer));
OutputReparseData->ReparseTag = IO_REPARSE_TAG_SYMLINK;
OutputReparseData->SymbolicLinkReparseBuffer.Flags = SYMLINK_FLAG_RELATIVE;
TargetPath = OutputReparseData->SymbolicLinkReparseBuffer.PathBuffer;
memcpy(TargetPath, FileName, RemainderPathSize);
ResolveLastPathComponent = ResolveLastPathComponent0;
@ -1089,7 +1097,7 @@ FSP_API NTSTATUS FspFileSystemResolveReparsePoints(FSP_FILE_SYSTEM *FileSystem,
if (L'\0' == *RemainderPath)
{
if (!ResolveLastPathComponent)
goto exit;
goto symlink_exit;
ResolveLastPathComponent = FALSE;
break;
}
@ -1164,44 +1172,57 @@ FSP_API NTSTATUS FspFileSystemResolveReparsePoints(FSP_FILE_SYSTEM *FileSystem,
if (IO_REPARSE_TAG_SYMLINK != ReparseData->ReparseTag)
goto reparse_data_exit;
if (0 == --MaxTries)
return STATUS_REPARSE_POINT_NOT_RESOLVED;
ReparseTargetPath = ReparseData->SymbolicLinkReparseBuffer.PathBuffer +
ReparseData->SymbolicLinkReparseBuffer.SubstituteNameOffset / sizeof(WCHAR);
ReparseTargetPathLength = ReparseData->SymbolicLinkReparseBuffer.SubstituteNameLength;
/* if an absolute (in the NT namespace) symlink return the full reparse point */
if (0 == (ReparseData->SymbolicLinkReparseBuffer.Flags & SYMLINK_FLAG_RELATIVE) &&
ReparseTargetPathLength >= sizeof(WCHAR) && L'\\' == ReparseTargetPath[0])
goto reparse_data_exit;
if (0 == --MaxTries)
return STATUS_REPARSE_POINT_NOT_RESOLVED;
/* if device relative symlink replace whole path; else replace last path component */
NewRemainderPath = ReparseTargetPathLength >= sizeof(WCHAR) && L'\\' == ReparseTargetPath[0] ?
TargetPath : LastPathComponent;
reparse:
RemainderPathSize = (lstrlenW(RemainderPath) + 1) * sizeof(WCHAR);
if (NewRemainderPath + (ReparseTargetPathLength + RemainderPathSize) / sizeof(WCHAR) >
TargetPath + *PSize / sizeof(WCHAR))
if ((PUINT8)NewRemainderPath + ReparseTargetPathLength + RemainderPathSize >
(PUINT8)Buffer + *PSize)
return STATUS_REPARSE_POINT_NOT_RESOLVED;
/* move remainder path to its new position */
memmove(NewRemainderPath + ReparseTargetPathLength / sizeof(WCHAR),
memmove((PUINT8)NewRemainderPath + ReparseTargetPathLength,
RemainderPath, RemainderPathSize);
/* copy symlink target */
memcpy(NewRemainderPath, ReparseTargetPath, ReparseTargetPathLength);
/* if an absolute (in the NT namespace) symlink exit now */
if (0 != ReparseTargetPath /* ensure we are not doing dot handling */ &&
0 == (ReparseData->SymbolicLinkReparseBuffer.Flags & SYMLINK_FLAG_RELATIVE) &&
ReparseTargetPathLength >= sizeof(WCHAR) && L'\\' == ReparseTargetPath[0])
{
OutputReparseData->SymbolicLinkReparseBuffer.Flags = 0;
goto symlink_exit;
}
ResolveLastPathComponent = ResolveLastPathComponent0;
RemainderPath = NewRemainderPath;
}
exit:
*PSize = (PUINT8)RemainderPath - (PUINT8)TargetPath;
symlink_exit:
OutputReparseData->SymbolicLinkReparseBuffer.SubstituteNameLength =
OutputReparseData->SymbolicLinkReparseBuffer.PrintNameLength =
(USHORT)lstrlenW(OutputReparseData->SymbolicLinkReparseBuffer.PathBuffer) * sizeof(WCHAR);
OutputReparseData->ReparseDataLength =
FIELD_OFFSET(REPARSE_DATA_BUFFER, SymbolicLinkReparseBuffer.PathBuffer) -
FIELD_OFFSET(REPARSE_DATA_BUFFER, SymbolicLinkReparseBuffer) +
OutputReparseData->SymbolicLinkReparseBuffer.SubstituteNameLength;
*PSize = FIELD_OFFSET(REPARSE_DATA_BUFFER, SymbolicLinkReparseBuffer) +
OutputReparseData->ReparseDataLength;
PIoStatus->Status = STATUS_REPARSE;
PIoStatus->Information = 0/*IO_REPARSE*/;
PIoStatus->Information = ReparseData->ReparseTag;
return STATUS_REPARSE;
reparse_data_exit:

39
src/sys/create.c
View File

@ -510,22 +510,24 @@ NTSTATUS FspFsvolCreateComplete(
IO_REPARSE_TAG_SYMLINK == Response->IoStatus.Information)
{
/*
* IO_REPARSE means that the user-mode file system has returned a device-relative
* (absolute in the device namespace) path. Prefix it with our device name/prefix
* and send it to the IO Manager.
* IO_REPARSE means that the user-mode file system has returned an absolute (in
* the device namespace) path. Send it as is to the IO Manager.
*
* IO_REPARSE_TAG_SYMLINK means that the user-mode file system has returned a full
* symbolic link reparse buffer with an absolute (in the NT namespace) path. Send
* it as is to the IO Manager. The FSD cannot handle relative symbolic links, so
* it is the responsibility of the user-mode file system to resolve them.
* symbolic link reparse buffer. If the symbolic link is absolute send it to the
* IO Manager as is. If the symbolic link is device-relative (absolute in the
* device namespace) prefix it with our volume name/prefix and then send it to the
* IO Manager.
*
* We do our own handling of IO_REPARSE_TAG_SYMLINK reparse points because
* experimentation with handling them directly to the IO Manager revealed problems
* with UNC paths (\??\UNC\{VolumePrefix}\{FilePath}).
*/
if (IO_REPARSE == Response->IoStatus.Information)
{
RtlCopyMemory(&ReparseTargetPrefix0, &FsvolDeviceExtension->VolumeName,
sizeof ReparseTargetPrefix0);
RtlCopyMemory(&ReparseTargetPrefix1, &FsvolDeviceExtension->VolumePrefix,
sizeof ReparseTargetPrefix1);
RtlZeroMemory(&ReparseTargetPrefix0, sizeof ReparseTargetPrefix0);
RtlZeroMemory(&ReparseTargetPrefix1, sizeof ReparseTargetPrefix1);
ReparseTargetPath.Length = ReparseTargetPath.MaximumLength =
Response->Rsp.Create.Reparse.Buffer.Size;
@ -552,16 +554,25 @@ NTSTATUS FspFsvolCreateComplete(
if (!NT_SUCCESS(Result))
FSP_RETURN(Result = STATUS_REPARSE_POINT_NOT_RESOLVED);
RtlZeroMemory(&ReparseTargetPrefix0, sizeof ReparseTargetPrefix0);
RtlZeroMemory(&ReparseTargetPrefix1, sizeof ReparseTargetPrefix1);
if (!FlagOn(ReparseData->SymbolicLinkReparseBuffer.Flags, SYMLINK_FLAG_RELATIVE))
{
RtlZeroMemory(&ReparseTargetPrefix0, sizeof ReparseTargetPrefix0);
RtlZeroMemory(&ReparseTargetPrefix1, sizeof ReparseTargetPrefix1);
}
else
{
RtlCopyMemory(&ReparseTargetPrefix0, &FsvolDeviceExtension->VolumeName,
sizeof ReparseTargetPrefix0);
RtlCopyMemory(&ReparseTargetPrefix1, &FsvolDeviceExtension->VolumePrefix,
sizeof ReparseTargetPrefix1);
}
ReparseTargetPath.Buffer = ReparseData->SymbolicLinkReparseBuffer.PathBuffer +
ReparseData->SymbolicLinkReparseBuffer.SubstituteNameOffset / sizeof(WCHAR);
ReparseTargetPath.Length = ReparseTargetPath.MaximumLength =
ReparseData->SymbolicLinkReparseBuffer.SubstituteNameLength;
if (FlagOn(ReparseData->SymbolicLinkReparseBuffer.Flags, SYMLINK_FLAG_RELATIVE) ||
ReparseTargetPath.Length < sizeof(WCHAR) || L'\\' != ReparseTargetPath.Buffer[0])
if (ReparseTargetPath.Length < sizeof(WCHAR) || L'\\' != ReparseTargetPath.Buffer[0])
FSP_RETURN(Result = STATUS_REPARSE_POINT_NOT_RESOLVED);
}