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[NTOSKRNL] Handle symlink parsing when it's bound to a specific object

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Pierre Schweitzer 2019-08-19 10:44:56 +02:00
parent e85664a3d8
commit e12abf63c5
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GPG key ID: 7545556C3D585B0B
1 changed files with 93 additions and 1 deletions
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94
ntoskrnl/ob/oblink.c
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@ -5,6 +5,7 @@
* PURPOSE: Implements symbolic links
* PROGRAMMERS: Alex Ionescu (alex@relsoft.net)
* David Welch (welch@mcmail.com)
* Pierre Schweitzer
*/
/* INCLUDES *****************************************************************/
@ -481,7 +482,98 @@ ObpParseSymbolicLink(IN PVOID ParsedObject,
/* Check if this symlink is bound to a specific object */
if (SymlinkObject->LinkTargetObject)
{
UNIMPLEMENTED;
/* No name to reparse, directly reparse the object */
if (!SymlinkObject->LinkTargetRemaining.Length)
{
*NextObject = SymlinkObject->LinkTargetObject;
return STATUS_REPARSE_OBJECT;
}
TempLength = SymlinkObject->LinkTargetRemaining.Length;
/* The target and remaining names aren't empty, so check for slashes */
if (SymlinkObject->LinkTargetRemaining.Buffer[TempLength / sizeof(WCHAR) - 1] == OBJ_NAME_PATH_SEPARATOR &&
RemainingName->Buffer[0] == OBJ_NAME_PATH_SEPARATOR)
{
/* Reduce the length by one to cut off the extra '\' */
TempLength -= sizeof(OBJ_NAME_PATH_SEPARATOR);
}
/* Calculate the new length */
LengthUsed = TempLength + RemainingName->Length;
LengthUsed += (sizeof(WCHAR) * (RemainingName->Buffer - FullPath->Buffer));
/* Check if it's not too much */
if (LengthUsed > 0xFFF0)
return STATUS_NAME_TOO_LONG;
/* If FullPath is enough, use it */
if (FullPath->MaximumLength > LengthUsed)
{
/* Update remaining length if appropriate */
if (RemainingName->Length)
{
RtlMoveMemory((PVOID)((ULONG_PTR)RemainingName->Buffer + TempLength),
RemainingName->Buffer,
RemainingName->Length);
}
/* And move the target object name */
RtlCopyMemory(RemainingName->Buffer,
SymlinkObject->LinkTargetRemaining.Buffer,
TempLength);
/* Finally update the full path with what we parsed */
FullPath->Length += SymlinkObject->LinkTargetRemaining.Length;
RemainingName->Length += SymlinkObject->LinkTargetRemaining.Length;
RemainingName->MaximumLength += RemainingName->Length + sizeof(WCHAR);
FullPath->Buffer[FullPath->Length / sizeof(WCHAR)] = UNICODE_NULL;
/* And reparse */
*NextObject = SymlinkObject->LinkTargetObject;
return STATUS_REPARSE_OBJECT;
}
/* FullPath is not enough, we'll have to reallocate */
MaximumLength = LengthUsed + sizeof(WCHAR);
NewTargetPath = ExAllocatePoolWithTag(NonPagedPool,
MaximumLength,
OB_NAME_TAG);
if (!NewTargetPath) return STATUS_INSUFFICIENT_RESOURCES;
/* Copy path begin */
RtlCopyMemory(NewTargetPath,
FullPath->Buffer,
sizeof(WCHAR) * (RemainingName->Buffer - FullPath->Buffer));
/* Copy path end (if any) */
if (RemainingName->Length)
{
RtlCopyMemory((PVOID)((ULONG_PTR)&NewTargetPath[RemainingName->Buffer - FullPath->Buffer] + TempLength),
RemainingName->Buffer,
RemainingName->Length);
}
/* And finish path with bound object */
RtlCopyMemory(&NewTargetPath[RemainingName->Buffer - FullPath->Buffer],
SymlinkObject->LinkTargetRemaining.Buffer,
TempLength);
/* Free old buffer */
ExFreePool(FullPath->Buffer);
/* Set new buffer in FullPath */
FullPath->Buffer = NewTargetPath;
FullPath->MaximumLength = MaximumLength;
FullPath->Length = LengthUsed;
/* Update remaining with what we handled */
RemainingName->Length = LengthUsed + (ULONG_PTR)NewTargetPath - (ULONG_PTR)&NewTargetPath[RemainingName->Buffer - FullPath->Buffer];
RemainingName->Buffer = &NewTargetPath[RemainingName->Buffer - FullPath->Buffer];
RemainingName->MaximumLength = RemainingName->Length + sizeof(WCHAR);
/* Reparse! */
*NextObject = SymlinkObject->LinkTargetObject;
return STATUS_REPARSE_OBJECT;
}
/* Set the target path and length */