Error: 0x80040305

[Bryce-Dixon]

• Your Windows build number: 10.0.17604.1000

• What you're doing and what's happening: I noticed that my default user had changed to root (I don't remember if I had done that or if I had just never noticed it before. I ran cut -d: -f1 /etc/passwd to get a list of all users and saw "bryce" at the bottom. I wanted my user to be "bthedestroyer" so I ran usermod -l bthedestroyer bryce and checked /etc/passwd again to find it changed. I then closed ubuntu and ran ubuntu config --default-user bthedestroyer from the command line and got a confirmation message, but when I went back in I was still root. I then restarted my computer and when I tried to run ubuntu this time, I get the error 0x80040305 and it instantly closes. I tried changing the default user back to root hoping that'd fix the issue but now I get Failed to set default user to: root

• What's wrong / what should be happening instead: I should be able to open Ubuntu or at least change the user back to root.

lxcore_kernel.zip

[benhillis]

@BtheDestroyer - When you attempted to change the default UID back to root was there an error?

Took a look through this path and I think failing to launch anything if the default UID is not found seems overly harsh. This made more sense back when we were in charge of the install / configuration but now that there are multiple distros all in charge of managing their own default user info I think we should relax this error path. Falling back to root if the default user does not exist seems like the best thing to do here.

[Bryce-Dixon]

I agree. The only error I got was Failed to set default user to: root unless there is some other error I can find somehow

[therealkenc]

I think we should relax this error path

That or add a --userspec commandline parameter. Which gets you another step closer.

[benhillis]

@BtheDestroyer - I'm not sure where that error message is coming from, I guess ubuntu.exe's code.

[Bryce-Dixon]

I'd strings it but it seems to be 0 bytes (unless I need to log into Administrator to view it or something)

[Bryce-Dixon]

My solution to get Ubuntu back running again was to copy out the files I needed from C:\Users\%USERNAME%\AppData\Local\Packages\CanonicalGroupLimited.UbuntuonWindows_79rhkp1fndgsc\LocalState\rootfs, uninstall Ubuntu, reinstall it, and copy the files back in. Works, but this probably shouldn't be something that happens in the first place.

[benhillis]

Agreed. I submitted a mitigation for this yesterday which will fall back to root if there is a problem with parsing the /etc/passwd file.

[Biswa96]

Can bash run without /etc/passwd?

[benhillis]

Yes, but the way WSL sets up environment uses /etc/passwd similar to the login binary. After my change a missing passwd file won't prevent launching.

[Biswa96]

Can you share what do you change? Or close-source 🤐

[benhillis]

The change is in our init daemon which is closed-source, maybe someday we can open it up. I can describe the change at a high level though:

1. Call getpwuid for default UID, if success goto 4
2. Call getpwuid for root UID, if success goto 4
3. Initialize a default passwd structure with some sane defaults (root, /bin/sh, etc).
4. Launch shell from passwd structure

[Brian-Perkins]

This change is now available in the Skip-ahead 17627 build.

[Biswa96]

wsl.exe can't open without passwd but bash.exe can. Is it normal?

[benhillis]

Yes but there is a change coming to Insider builds soon that will allow WSL.exe launch without the passwd file.

[michaelrothkopf]

I had a similar issue. I set it to root to reset my Kali password, then I went to set it back. I ran cat /etc/passwd to get my user ID, then I went to the registry editor and changed the default UID to 1000. Of course, it didn't work, and I got error 0x80040305. So I went back, switched it to decimal, not hexadecimal 1000, and it worked. I know hex 0 and decimal 0 are the same but that might fix it.