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Writing our own FltGetDestinationFileNameInformation?
Dejan_Maksimovic
Member - All Emails Posts: 373
Has anyone done it?
There are too many cases now, even with the most current MS OS/FS
combinations, that it is a total shame such an API is even out...
E.g. we just found that using symbolic links to a mapped network drive
causes FGDFNI to fail with STATUS_INVALID_PARAMETER... not an atypical
scenario as much as some might think. On the contrary, it is heavily
used in some cloud solutions.
There are too many cases now, even with the most current MS OS/FS
combinations, that it is a total shame such an API is even out...
E.g. we just found that using symbolic links to a mapped network drive
causes FGDFNI to fail with STATUS_INVALID_PARAMETER... not an atypical
scenario as much as some might think. On the contrary, it is heavily
used in some cloud solutions.
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Comments
Ouch.... so in this particular case, not only does FGDFNI fail with INV_PARAM, but whatever I try to do myself fails the same..
IoCreateFileEx(IO_OPEN_TARGET_DIRECTORY).. opens the target directory. ALL other file open APIs fail with STATUS_INVALID_PARAMETER! (IoCreateFile/FltCreateFileEx - Nt/ZwCreateFile don't have a way to open the target folder, or I am missing something)
Then I try to query the file name. NtQueryInformationFIle would fail with ACC_VIOLATION because I am passing a kernel buffer of course.
ZwQueryInformationFile fails with STATUS_INVALID_PARAMETER, regardless of whether I ask for a FileNormalizedNameInformation or FileNameInformation..
There seems to be no way of getting the file name in this situation!
Any ideas?
Funny.. as soon as I wrote the message, after struggling two days to figure a combination that works... solved by opening the directory directly and querying the file name.
Strange, this is a rare case where the issue occurs on Server 2016/Win10, but not on earlier versions!
Note: It is not possible to query Normalized file name, it fails with STATUS_INVALID_PARAMETER. Only FileNameInformation can be queried.