firefox won't start (Permission denied) if $PWD is a NFS share in /mnt

[Chris Guiver]

This started with a https://askubuntu.com/questions/1428384/snap-firefox-cant-open-url-when-started-within-a-nfs-shared-directory

** Description

I have some NFS shares mounted in /mnt, if I try and run a snap with those directories as $PWD I get permission denied errors

this appears to occur with all snaps (wethr, firefox, chromium tested)

** Actual Outcome

guiverc@d960-ubu2:/mnt/de2900$ wethr
cannot open path of the current working directory: Permission denied
guiverc@d960-ubu2:/mnt/de2900$ firefox
cannot open path of the current working directory: Permission denied
guiverc@d960-ubu2:/mnt/de2900$

OP on askubuntu got same from `firefox "www.duckduckgo.com"`

** Expected outcome

If I run those apps from $HOME they'll start normally, and I can access the directory without issue once chromium/firefox has started (for upload of pics etc). I'd expect them to start even if my $PWD is a network NFS share.

** Complication in my own setup?

guiverc@d960-ubu2:/mnt/de2900$ touch mail/blah
touch: cannot touch 'mail/blah': Read-only file system

I access those directories via a different location when I want write access; but I have a RO mount just so I can access them in browsers (chromium/firefox)... I don't know about the OP/end-user on askubuntu.com

My fstab entry was (NOTE: RO)

de2900:/home/shared /mnt/de2900 nfs ro,rsize=8192,wsize=8192,timeo=14,intr,auto,user 0 2

To explore that I switched that fstab entry to be RW, and re-mounted...

guiverc@d960-ubu2:/mnt/de2900/lan$ touch blah
guiverc@d960-ubu2:/mnt/de2900/lan$ firefox
cannot open path of the current working directory: Permission denied
guiverc@d960-ubu2:/mnt/de2900/lan$ rm blah
guiverc@d960-ubu2:/mnt/de2900/lan$

so (my default) RO setup likely isn't an issue (I can create file 'blah' so have write access now but firefox still fails to start, so I remove 'blah.

ProblemType: Bug
DistroRelease: Ubuntu 22.10
Package: snapd 2.57.1+22.10.1
ProcVersionSignature: Ubuntu 5.19.0-15.15-generic 5.19.0
Uname: Linux 5.19.0-15-generic x86_64
ApportVersion: 2.23.0-0ubuntu1
Architecture: amd64
CasperMD5CheckResult: unknown
CurrentDesktop: LXQt
Date: Fri Sep 9 10:12:56 2022
EcryptfsInUse: Yes
InstallationDate: Installed on 2017-11-16 (1757 days ago)
InstallationMedia: Ubuntu 17.10 "Artful Aardvark" - Release amd64 (20171018)
RebootRequiredPkgs: Error: path contained symlinks.
SourcePackage: snapd
UpgradeStatus: No upgrade log present (probably fresh install)

[Alberto Mardegan (mardy)]

Thanks Chris for reporting this bug! I'll mark as a duplicate of https://bugs.launchpad.net/snapd/+bug/1973321, even though that bug was about SSHfs originally.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.