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Default umask (permissions) is not applied #352

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simonbuchan opened this issue May 12, 2016 · 36 comments
Closed

Default umask (permissions) is not applied #352

simonbuchan opened this issue May 12, 2016 · 36 comments
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@simonbuchan
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@simonbuchan simonbuchan commented May 12, 2016

Reference: http://www.cyberciti.biz/tips/understanding-linux-unix-umask-value-usage.html

My current install has this in /etc/profile:

# The default umask is now handled by pam_umask.
# See pam_umask(8) and /etc/login.defs.

And, indeed /etc/profile has UMASK> > 022, but:

simon@QOF:~$ umask
0000

The effect of this is that new files are created with 666 and dirs with 777 permissions:

simon@QOF:~$ touch file
simon@QOF:~$ mkdir dir
simon@QOF:~$ ll -d file dir
drwxrwxrwx 2 simon simon 0 May 12 22:54 dir/
-rw-rw-rw- 1 simon simon 0 May 12 22:54 file

This mostly isn't a real problem since UoW doesn't have to care about multiple users, it largely shows up as ls showing dirs with an ugly green background, but it could freak out some tools, similar to ssh wanting 600 on your private keys.

Simplest fix would probably be to dump a umask 022 in /etc/profile, but it seems there's a bunch of stuff in that /etc/login.defs

Easy workaound is to add a umask to your ~/.bashrc

@simonbuchan
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@simonbuchan simonbuchan commented May 13, 2016

May be somewhat related to #167 , /etc/profile is supposed to be read if bash is a login shell - but even bash.exe --login doesn't seem to use pam_umask

@benhillis
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@benhillis benhillis commented May 13, 2016

@simonbuchan Thanks for reporting this. I think there are a couple things going on here. I verified that when bash.exe --login is launched /bin/bash does read from /etc/profile. I dumped my default /etc/profile and noticed a comment that:

# The default umask is now handled by pam_umask.
# See pam_umask(8) and /etc/login.defs.

When you run "bash.exe --login" that translates into "/bin/bash --login". We don't run the /bin/login binary and I'm assuming that's what normally sets up pam_umask. Did you try adding a new umask to value to your /etc/profile? It should work (when using bash.exe --login).

@simonbuchan
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@simonbuchan simonbuchan commented May 13, 2016

Yep, umask in both /etc/profile and ~/.profile run with both bash.exe --login and bash -c "bash --login".
Interestingly, if I revert the umask command and do bash.exe -c "sudo login" then umask is 0002 - no idea where that is coming from!

@0xMF
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@0xMF 0xMF commented May 26, 2016

Please ensure umask is never 0000 no matter how bash is started.

I understand users can set umask to saner defaults in their own bashrc files but it means whatever directories and files auto-installed by scripts after WSL setup and user first bash run till the bad umask was discovered now have to be changed to sane defaults. This is exacerbated in git-based repos because git will track the change of perms to saner defaults as a (needless) change thereby status of git repo becomes dirty which simply put is both: confusing and annoying.

@simonbuchan
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@simonbuchan simonbuchan commented May 26, 2016

@0xMF don't worry, git only tracks +x, and the .bashrc changes are mentioned as a workaround

@neurogenesis
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@neurogenesis neurogenesis commented Oct 16, 2016

This also causes problems for zsh (compinit/compaudit). If you use a tool like antigen the directory permissions will throw shell errors when compinit/compaudit (command completion) is loaded.

Essentially any tool that performs basic checking for "other" write/read permissions will fail.

For anyone else trying to use dropbox, careful with symlinks to the windows /mnt/c/.... You'll likely run into a lot of problems. Unfortunately, dropbox for linux doesn't work yet either (because of the /proc/vmstat issue: #1071 ).

This was referenced Oct 16, 2016
@zhangxj5
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@zhangxj5 zhangxj5 commented Oct 23, 2016

Hello, It's very strange. If I run ./configure, I found that the Makefile in the dir and sub dir only has permission rw no x. So some middle product didn't output, ./configure is right, but can't do make.

It's a big problem.

@zhangxj5
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@zhangxj5 zhangxj5 commented Oct 24, 2016

/usr/bin/m4: m4_esyscmd subprocess failed: Operation not permitted
/usr/bin/m4:configure.ac:489: cannot run command `./scripts/version.sh': Operation not permitted

@lilred
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@lilred lilred commented Dec 1, 2016

I have put this in my ~/.profile in the meantime:

# Note: Bash on Windows does not currently apply umask properly.
if [ "$(umask)" = "0000" ]; then
>   umask 022
fi

@benhillis: if you have time to entertain my curiosity - is there a particular reason you don't run /bin/login?

@benhillis
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@benhillis benhillis commented Dec 1, 2016

@lilred - good question. Historically there have been a couple of reasons. When we first released /bin/bash worked but other shells (zsh for example) didn't work very well and we didn't want users to set their default shell to something that didn't work and get into a bad state. There's also potential strangeness around running bash.exe and zsh being launched.

That being said, running login would actually make a lot of things simpler for us.  Currently our init daemon has to do many of the things that /bin/login normally does. We're doing some design for the next release of Windows and I'll take a look at this and see if it would make sense to potentially switch things over now.

If you'd like to play around with using login there's a way you can use it now.

lxrun.exe /setdefaultuser root
bash.exe -c "/bin/login -f username"

@lilred
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@lilred lilred commented Dec 1, 2016

This is fantastic, thanks for the insight. I will change my Bash shortcut to this and report back if I hit any issues.

@simonbuchan
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@simonbuchan simonbuchan commented Dec 1, 2016

With /bin/login I do get umask returning 002, which is probably "good enough" to close this, but it's still not getting the "correct" default value 022 from /etc/login.defs line 151, which may be a thing.

Also it seems to start faster?!

@simonbuchan
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@simonbuchan simonbuchan commented Dec 1, 2016

One thing to be aware of is it doesn't extend PATH with the windows path.

@simonbuchan
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@simonbuchan simonbuchan commented Feb 15, 2017

@jackchammons Does closing this mean the default setup will now set a umask? /bin/login is not a default setup.

@jackchammons
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@jackchammons jackchammons commented Feb 15, 2017

The current behavior is expected. We will be reevaluating where umask gets set in an future release.

@hughbe
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@hughbe hughbe commented Mar 23, 2017

This is breaking unit tests for swift-llbuild, part of the Swift.org project:

$ umask 22
$ umask
0022
$ mkdir foo
$ ls -l
drwxrwxrwx 2 root root 0 Mar 23 16:47 foo

@benhillis
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@benhillis benhillis commented Jun 27, 2019

Thanks for your patience. I'm adding a default umask of 022, with an /etc/wsl.conf setting to override it:

[filesystem]
umask = 02
@benhillis benhillis self-assigned this Jun 27, 2019
@simonbuchan
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@simonbuchan simonbuchan commented Jun 28, 2019

Woo! My ls will finally be cured of it's horrifying green miasma!

@radusuciu
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@radusuciu radusuciu commented Oct 25, 2019

Had a nice surprise today when I built a static site using Hugo in WSL from /mnt/d/ and saw that my published site had 777 permissions..

None of the workarounds mentioned here seem to have any effect. While it's possible to set umask to 022, everything is still created as 777 and worse, is immune to chmod!

Re-cloned the repo in my home folder and everything is behaving as expected there.

@dgw
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@dgw dgw commented Oct 25, 2019

@radusuciu You probably won't ever be able to chmod stuff in /mnt/ drives. The permission models are completely different between Linux and Windows filesystems, so everything just appears as 777.

@therealkenc
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@therealkenc therealkenc commented Oct 26, 2019

You probably won't ever be able to chmod stuff in /mnt/ drives

You've been able to do that since 17063 circa Christmas of 2017.

image

@dgw
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@dgw dgw commented Oct 26, 2019

And the permissions stick? I'll have to play with that.

yous added a commit to yous/dotfiles that referenced this issue Nov 6, 2019
@itolosa
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@itolosa itolosa commented Jan 17, 2020

My workaround was:

  • Start linux using: "wsl.exe -u root -- /bin/login -f username"
  • Change /etc/passwd to use zsh: sudo usermod -s /bin/zsh username

Using that, default umask is set to 0002


If you want to use umask 022 you have two options:

  • Set the variable "USERGROUPS_ENAB" to "no" in /etc/login.defs, and then use UMASK 022.
  • Add umask 022 in /etc/profile or .bashrc
@therealkenc
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@therealkenc therealkenc commented Jan 17, 2020

Ben's login(1) musing can fight another day a new issue/ask for wsl.exe --login or somesuch. This one deemed fixinbound last June with the umask configurable in wsl.conf. Applicable in both WSL1 and WSL2.

@mohd-akram
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@mohd-akram mohd-akram commented Jan 26, 2020

I just updated to 1909 and this problem is still there.

deas added a commit to deas/dotfiles that referenced this issue Feb 3, 2020
@Ifiht
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@Ifiht Ifiht commented Feb 6, 2020

image
Confirming that with 1909 and a fresh install of Ubuntu. 000 is still the default umask.

@Twanislas
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@Twanislas Twanislas commented Feb 6, 2020

This is how I workaround it in my dotfiles, if it helps anyone ;)

@therealkenc
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@therealkenc therealkenc commented Feb 6, 2020

I just updated to 1909 and this problem is still there.

Right; it looks like Ben's fix shipped in 18945. 18945 > 18363 (aka 1909 aka 19H2). Which is to say, it appears a number of issues that were addressed in spring/summer 2019 never made it into the November 2019 Windows 10 release. [Or, at least on best evidence.] I'll bounce the tag on this one, but to be honest I'm hoping the fine-grained fixed-in tags die this spring in favour of whatever version is cited in the issue (presupposing they're cited). Here, 18945.

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