WSL symbolic links

[Brian Inglis]

On 2020-03-26 05:00, Corinna Vinschen wrote:
> On Mar 26 10:00, Thomas Wolff wrote:
>> A symbolic link created with WSL is neither interpreted in cygwin nor can it
>> be deleted:
>>> touch file
>>> wsl ln -s file link
>>> wsl ls -l link
>> lrwxrwxrwx    1 towo     towo             1 Mar 26 08:56 link -> file
>>> ls -l link
>> -rw-r----- 1 Unknown+User Unknown+Group 0 Mar 26 00:00 link
> What kind of file are they in the real world?  Reparse points?  If so,
> what content do they have?  I attached a Q&D source from my vault
> of old test apps to check on reparse point content.  Please compile with
>   gcc -g ../src/rd-reparse.c -o rd-reparse -lntdll
> It takes a single native NT path as parameter, kind of like this:
>   ./rd-reparse '\??\C:\cygwin64\home\corinna\link'

They should be WSL or Windows mklink (soft) links, and the reason why mklink was
allowed unelevated in Windows 10 with Developer mode.

In an *elevated* shell:

$ ls -dln u
-rw-r----- 1 4294967295 4294967295 0 Nov  9 06:09 u
$ getfacl u
getfacl: u: Permission denied
$ icacls u
u NULL SID:(DENY)(Rc,S,REA,WEA,X,DC)
  $HOSTNAME\$USER:(F)
  $HOSTNAME\$USER:(RX,W,DC)
  BUILTIN\Users:(Rc,S,RA)
  BUILTIN\Administrators:(RX,W,DC)
  BUILTIN\Users:(DENY)(S,RD,REA,X)
  Everyone:(RX)
  NT AUTHORITY\SYSTEM:(I)(F)
  BUILTIN\Administrators:(I)(F)
  $HOSTNAME\$USER:(I)(F)

Successfully processed 1 files; Failed processing 0 files
$ ./rd-reparse '\??\C:\...\u'
ReparseTag:           0xa000001d
ReparseDataLength:             5
Reserved:                      0
02 00 00 00 75

-- 
Take care. Thanks, Brian Inglis, Calgary, Alberta, Canada

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