complete config reset with filled disk

[noerw]

Steps to reproduce

1. Fill entire available diskspace
2. Visit instance landingpage (might need to repeat this step a couple of times, not sure if instantly reproducible)

Expected behaviour

Config should never be reset, even in edgecases.
Config should never ever be opened with write-permission from a public / non-admin endpoint.

Actual behaviour

Find your config/config.php truncated to a minimal config file with only the instanceid key filled in. This is serious.

Landing page says something like "Looks like you're trying to reinstall nextcloud but file CAN_INSTALL was not found"

Server configuration

Operating system: debian 9

Web server: nginx

Database: mysql

PHP version: 7.3

Nextcloud version: (see Nextcloud admin page) 17.0.1

Updated from an older Nextcloud/ownCloud or fresh install: updated since NC 15

Where did you install Nextcloud from: source tarball

Signing status:

Signing status

No errors have been found.

List of activated apps:

App list

Enabled:
  - accessibility: 1.3.0
  - apporder: 0.8.0
  - audioplayer: 2.8.4
  - calendar: 1.7.1
  - cloud_federation_api: 1.0.0
  - contacts: 3.1.6
  - dav: 1.13.0
  - deck: 0.7.0
  - encryption: 2.5.0
  - federatedfilesharing: 1.7.0
  - files: 1.12.0
  - files_linkeditor: 1.0.11
  - files_markdown: 2.1.0
  - files_pdfviewer: 1.6.0
  - files_readmemd: 1.1.3
  - files_rightclick: 0.15.1
  - files_sharing: 1.9.0
  - files_videoplayer: 1.6.0
  - gallery: 18.4.0
  - logreader: 2.2.0
  - lookup_server_connector: 1.5.0
  - nextcloud_announcements: 1.6.0
  - notes: 3.0.3
  - notifications: 2.5.0
  - oauth2: 1.5.0
  - password_policy: 1.7.0
  - polls: 0.10.4
  - privacy: 1.1.0
  - provisioning_api: 1.7.0
  - recommendations: 0.5.0
  - serverinfo: 1.7.0
  - sharebymail: 1.7.0
  - sharerenamer: 2.7.2
  - survey_client: 1.5.0
  - tasks: 0.11.3
  - text: 1.1.1
  - theming: 1.8.0
  - twofactor_backupcodes: 1.6.0
  - updatenotification: 1.7.0
  - viewer: 1.2.0
  - workflowengine: 1.7.0

Nextcloud configuration:

Config report

{
    "system": {
        "instanceid": "***REMOVED SENSITIVE VALUE***",
        "passwordsalt": "***REMOVED SENSITIVE VALUE***",
        "secret": "***REMOVED SENSITIVE VALUE***",
        "trusted_proxies": "***REMOVED SENSITIVE VALUE***",
        "trusted_domains": [
            "***REMOVED SENSITIVE VALUE***"",
            "***REMOVED SENSITIVE VALUE***"",
            "***REMOVED SENSITIVE VALUE***""
        ],
        "datadirectory": "***REMOVED SENSITIVE VALUE***",
        "dbtype": "mysql",
        "version": "17.0.1.1",
        "overwrite.cli.url": "***REMOVED SENSITIVE VALUE***",
        "dbname": "***REMOVED SENSITIVE VALUE***",
        "dbhost": "***REMOVED SENSITIVE VALUE***",
        "dbport": "",
        "dbtableprefix": "oc_",
        "dbuser": "***REMOVED SENSITIVE VALUE***",
        "dbpassword": "***REMOVED SENSITIVE VALUE***",
        "logtimezone": "UTC",
        "installed": true,
        "mail_from_address": "***REMOVED SENSITIVE VALUE***",
        "mail_smtpmode": "smtp",
        "mail_domain": "***REMOVED SENSITIVE VALUE***",
        "appstore.experimental.enabled": true,
        "loglevel": 2,
        "maintenance": false,
        "default_language": "de",
        "theme": "",
        "updater.release.channel": "stable",
        "mail_smtpauthtype": "LOGIN",
        "mail_smtpauth": 1,
        "mail_smtphost": "***REMOVED SENSITIVE VALUE***",
        "mail_smtpport": "587",
        "mail_smtpname": "***REMOVED SENSITIVE VALUE***",
        "mail_smtppassword": "***REMOVED SENSITIVE VALUE***",
        "mail_smtpsecure": "tls",
        "memcache.distributed": "\\OC\\Memcache\\Redis",
        "memcache.locking": "\\OC\\Memcache\\Redis",
        "memcache.local": "\\OC\\Memcache\\APCu",
        "redis": {
            "host": "***REMOVED SENSITIVE VALUE***",
            "port": 6379,
            "timeout": 0,
            "dbindex": 0
        },
        "mysql.utf8mb4": true
    }
}

Are you using external storage, if yes which one: no
Are you using encryption: yes
Are you using an external user-backend, if yes which one: no

Client configuration

Browser: latest firefox

Operating system: linux

Logs

Web server error log

Web server error log

Insert your webserver log here

Nextcloud log (data/nextcloud.log)

Nextcloud log

At the point of config-reset, nothing is logged. Beforehand, redis complains about unavailable storage

[solracsf]

When you say "entire disk space" are you talking about server space (can't write anything) or data folder only?

[noerw]

All available system storage full, though I have both on the same file system

[solracsf]

Being able to reproduce here.

• Mounted a WebDAV share trough davfs2
• Installed NC 17.0.2 and place data-dir under /mnt/davfs2/data
• Uploaded some files
• Shut down davfs2 mount (so emulating system storage "full")
• Try to access Nexcloud URL
• Message about CAN_INSTALL not on the config folder
• Check config.php:

cat config.php

<?php
$CONFIG = array (
  'instanceid' => 'ocd1zu1a7a',
); 

[szaimen]

Is this Issue still valid? If not, please close this issue. Thanks! :)

This issue has been automatically marked as stale because it has not had recent activity and seems to be missing some essential information. It will be closed if no further activity occurs. Thank you for your contributions.

[BENETNATH]

Gasp. Happened to me right now.
Back from vacation. the disk was filled and my nextcloud is dead, saying : "it looks like you are trying to reinstall nextcloud but CAN_INSTALL is absent"
my config.php is now 62 bytes and contains only the instanceid

I don't have a backup of this config file !! How can I get it back ?

[noerw]

Can we please reopen this?
How can such a critical failure mode (DoS + potential data loss) be missed for years? How can the report on such a problem be closed just in case, because *waves hands* magic could have solved this in the meantime?

(To clarify, I'm not angry at anyone personally; from my own work I know well enough that important tickets can slip. Just want to draw attention to a triaging fail like this, so processes can be improved).

I don't have a backup of this config file !! How can I get it back ?

@BENETNATH You can try and see if $nc-data/updater-*/backups/nextcloud-*/config/config.php exists. If not, I guess you're out of luck.

[szaimen]

@BENETNATH don't want to hate here but how can you self host any service without creating a regular backup?