[Bug]: Spike in CPU usage when editing calendar in Thunderbird CalDAV

[MannyAdumbire]

⚠️ This issue respects the following points: ⚠️

• This is a bug, not a question or a configuration/webserver/proxy issue.
• This issue is not already reported on Github OR Nextcloud Community Forum (I've searched it).
• Nextcloud Server is up to date. See Maintenance and Release Schedule for supported versions.
• I agree to follow Nextcloud's Code of Conduct.

Bug description

When adding a making any edits to calendars to ThunderBird calendar app, there is a 5-10 second delay in the UI per-event. CPU usage spikes to full usage. Trying to delete 10 or so events can take over a minute to complete.

Doing a PHP profile revealed a large chuck of time spent running hash-pbkdf2
We are using php-fpm and seeing several new child processes spawned whenever editing calendar.

Steps to reproduce

1. Sync with Thunderbird using your preferred method. All methods seem to have this issue.*
2. Add an event to Thunderbird and select one of the Calendars on the user used to sync in Step 1.
3. Track how long it takes for the event to be added. If it takes several seconds, it may be due to this bug.

*I was not able to reproduce the issue when using other email clients, only seeing this behavior when using Thunderbird.

Expected behavior

Events should reflect on the Thunderbird calendar within a second or two when added.
CPU use shouldn't spike because someone added or deleted a couple appointments.

Installation method

None

Nextcloud Server version

28

Operating system

None

PHP engine version

PHP 8.2

Web server

Nginx

Database engine version

None

Is this bug present after an update or on a fresh install?

None

Are you using the Nextcloud Server Encryption module?

Yes

What user-backends are you using?

• Default user-backend (database)
• LDAP/ Active Directory
• SSO - SAML
• Other

Configuration report

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}

List of activated Apps

No response

Nextcloud Signing status

No errors have been found.

Nextcloud Logs

No response

Additional info

[ChristophWurst]

Doing a PHP profile revealed a large chuck of time spent running hash-pbkdf2

Nice finding! Does the profile show the callers of the function?

[MannyAdumbire]

@ChristophWurst ohh good question.
It appears the closest call is Crypt::generatePasswordHash, but not sure which fn kicks off the whole process.

server/apps/encryption/lib/Crypto/Crypt.php

Line 304 in 3da69fc

protected function generatePasswordHash(string $password, string $cipher, string $uid = '', int $iterations = 600000): string {

[ChristophWurst]

Interesting. That is the server-side encryption (encryption app) that is active when the DAV request is authenticating.

[ChristophWurst]

You could try to trace the call

1. Set 'log.backtrace' => true, in your config/config.php
2. Add \OCP\Log\logger('encryption')->critical('Generate password hash'); as first line of the generatePasswordHash method
3. Trigger the code again
4. Grep data/nextcloud.log for Generate password hash and post one of the json rows here
5. Undo 1 & 2

[MannyAdumbire]

@ChristophWurst thanks for clear steps. Here's one of the json rows logged ..

{
  "reqId": "RiehvqBzHpKNfutl1xDh",
  "level": 3,
  "time": "2024-08-08T02:35:01+00:00",
  "remoteAddr": "",
  "user": "--",
  "app": "encryption",
  "method": "",
  "url": "--",
  "message": "Generate password hash",
  "userAgent": "--",
  "version": "28.0.6.1",
  "data": {
    "app": "encryption",
    "backtrace": [
      {
        "file": "/var/www/nextcloud/lib/private/Log.php",
        "line": 139,
        "function": "log",
        "class": "OC\\Log",
        "type": "->"
      },
      {
        "file": "/var/www/nextcloud/lib/private/Log/PsrLoggerAdapter.php",
        "line": 110,
        "function": "critical",
        "class": "OC\\Log",
        "type": "->"
      },
      {
        "file": "/var/www/nextcloud/lib/private/AppFramework/ScopedPsrLogger.php",
        "line": 70,
        "function": "critical",
        "class": "OC\\Log\\PsrLoggerAdapter",
        "type": "->"
      },
      {
        "file": "/var/www/nextcloud/apps/encryption/lib/Crypto/Crypt.php",
        "line": 330,
        "function": "critical",
        "class": "OC\\AppFramework\\ScopedPsrLogger",
        "type": "->"
      },
      {
        "file": "/var/www/nextcloud/apps/encryption/lib/Crypto/Crypt.php",
        "line": 391,
        "function": "generatePasswordHash",
        "class": "OCA\\Encryption\\Crypto\\Crypt",
        "type": "->"
      },
      {
        "file": "/var/www/nextcloud/apps/encryption/lib/KeyManager.php",
        "line": 162,
        "function": "decryptPrivateKey",
        "class": "OCA\\Encryption\\Crypto\\Crypt",
        "type": "->"
      },
      {
        "file": "/var/www/nextcloud/apps/encryption/lib/Users/Setup.php",
        "line": 63,
        "function": "validateMasterKey",
        "class": "OCA\\Encryption\\KeyManager",
        "type": "->"
      },
      {
        "file": "/var/www/nextcloud/apps/encryption/lib/AppInfo/Application.php",
        "line": 56,
        "function": "setupSystem",
        "class": "OCA\\Encryption\\Users\\Setup",
        "type": "->"
      },
      {
        "file": "/var/www/nextcloud/apps/encryption/appinfo/app.php",
        "line": 37,
        "function": "setUp",
        "class": "OCA\\Encryption\\AppInfo\\Application",
        "type": "->"
      },
      {
        "file": "/var/www/nextcloud/lib/private/App/AppManager.php",
        "line": 522,
        "args": [
          "/var/www/nextcloud/apps/encryption/appinfo/app.php"
        ],
        "function": "require_once"
      },
      {
        "file": "/var/www/nextcloud/lib/private/App/AppManager.php",
        "line": 413,
        "function": "requireAppFile",
        "class": "OC\\App\\AppManager",
        "type": "::"
      },
      {
        "file": "/var/www/nextcloud/lib/private/App/AppManager.php",
        "line": 213,
        "function": "loadApp",
        "class": "OC\\App\\AppManager",
        "type": "->"
      },
      {
        "file": "/var/www/nextcloud/lib/private/legacy/OC_App.php",
        "line": 125,
        "function": "loadApps",
        "class": "OC\\App\\AppManager",
        "type": "->"
      },
      {
        "file": "/var/www/nextcloud/cron.php",
        "line": 55,
        "function": "loadApps",
        "class": "OC_App",
        "type": "::"
      }
    ]
  },
  "id": "66b42ed9c45fd"
}

[MannyAdumbire]

I tried also logging with below setting in config file

  'loglevel' => 0,
  'log.condition' => [
    'apps' => [ 'encryption','calendar','dav'],
  ],

I was just looking for events where the client (Thunderbird) was specified, in case there's anything relevant there

{
  "reqId": "Vtn5hLBBNPLvvLpzsWVs",
  "level": 1,
  "time": "2024-08-08T04:56:16+00:00",
  "remoteAddr": "****",
  "user": "calendar_tester",
  "app": "user_ldap",
  "method": "REPORT",
  "url": "/remote.php/dav/calendars/calendar_tester/newnewrouge/",
  "message": "OCA\\User_LDAP\\LoginListener \u2013 calendar_tester postLogin",
  "userAgent": "Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:128.0) Gecko/20100101 Thunderbird/128.0.1",
  "version": "28.0.6.1",
  "data": {
    "app": "user_ldap",
    "backtrace": [
      {
        "file": "/var/www/nextcloud/lib/private/Log.php",
        "line": 189,
        "function": "log",
        "class": "OC\\Log",
        "type": "->"
      },
      {
        "file": "/var/www/nextcloud/lib/private/Log/PsrLoggerAdapter.php",
        "line": 192,
        "function": "info",
        "class": "OC\\Log",
        "type": "->"
      },
      {
        "file": "/var/www/nextcloud/lib/private/AppFramework/ScopedPsrLogger.php",
        "line": 118,
        "function": "info",
        "class": "OC\\Log\\PsrLoggerAdapter",
        "type": "->"
      },
      {
        "file": "/var/www/nextcloud/apps/user_ldap/lib/LoginListener.php",
        "line": 60,
        "function": "info",
        "class": "OC\\AppFramework\\ScopedPsrLogger",
        "type": "->"
      },
      {
        "file": "/var/www/nextcloud/apps/user_ldap/lib/LoginListener.php",
        "line": 55,
        "function": "onPostLogin",
        "class": "OCA\\User_LDAP\\LoginListener",
        "type": "->"
      },
      {
        "file": "/var/www/nextcloud/lib/private/EventDispatcher/ServiceEventListener.php",
        "line": 86,
        "function": "handle",
        "class": "OCA\\User_LDAP\\LoginListener",
        "type": "->"
      },
      {
        "file": "/var/www/nextcloud/3rdparty/symfony/event-dispatcher/EventDispatcher.php",
        "line": 230,
        "function": "__invoke",
        "class": "OC\\EventDispatcher\\ServiceEventListener",
        "type": "->"
      },
      {
        "file": "/var/www/nextcloud/3rdparty/symfony/event-dispatcher/EventDispatcher.php",
        "line": 59,
        "function": "callListeners",
        "class": "Symfony\\Component\\EventDispatcher\\EventDispatcher",
        "type": "->"
      },
      {
        "file": "/var/www/nextcloud/lib/private/EventDispatcher/EventDispatcher.php",
        "line": 94,
        "function": "dispatch",
        "class": "Symfony\\Component\\EventDispatcher\\EventDispatcher",
        "type": "->"
      },
      {
        "file": "/var/www/nextcloud/lib/private/EventDispatcher/EventDispatcher.php",
        "line": 106,
        "function": "dispatch",
        "class": "OC\\EventDispatcher\\EventDispatcher",
        "type": "->"
      },
      {
        "file": "/var/www/nextcloud/lib/private/User/Session.php",
        "line": 392,
        "function": "dispatchTyped",
        "class": "OC\\EventDispatcher\\EventDispatcher",
        "type": "->"
      },
      {
        "file": "/var/www/nextcloud/lib/private/User/Session.php",
        "line": 667,
        "function": "completeLogin",
        "class": "OC\\User\\Session",
        "type": "->"
      },
      {
        "file": "/var/www/nextcloud/lib/private/User/Session.php",
        "line": 354,
        "function": "loginWithToken",
        "class": "OC\\User\\Session",
        "type": "->"
      },
      {
        "file": "/var/www/nextcloud/lib/private/User/Session.php",
        "line": 453,
        "function": "login",
        "class": "OC\\User\\Session",
        "type": "->"
      },
      {
        "file": "/var/www/nextcloud/apps/dav/lib/Connector/Sabre/Auth.php",
        "line": 113,
        "function": "logClientIn",
        "class": "OC\\User\\Session",
        "type": "->"
      },
      {
        "file": "/var/www/nextcloud/3rdparty/sabre/dav/lib/DAV/Auth/Backend/AbstractBasic.php",
        "line": 103,
        "function": "validateUserPass",
        "class": "OCA\\DAV\\Connector\\Sabre\\Auth",
        "type": "->"
      },
      {
        "file": "/var/www/nextcloud/apps/dav/lib/Connector/Sabre/Auth.php",
        "line": 231,
        "function": "check",
        "class": "Sabre\\DAV\\Auth\\Backend\\AbstractBasic",
        "type": "->"
      },
      {
        "file": "/var/www/nextcloud/apps/dav/lib/Connector/Sabre/Auth.php",
        "line": 138,
        "function": "auth",
        "class": "OCA\\DAV\\Connector\\Sabre\\Auth",
        "type": "->"
      },
      {
        "file": "/var/www/nextcloud/3rdparty/sabre/dav/lib/DAV/Auth/Plugin.php",
        "line": 179,
        "function": "check",
        "class": "OCA\\DAV\\Connector\\Sabre\\Auth",
        "type": "->"
      },
      {
        "file": "/var/www/nextcloud/3rdparty/sabre/dav/lib/DAV/Auth/Plugin.php",
        "line": 135,
        "function": "check",
        "class": "Sabre\\DAV\\Auth\\Plugin",
        "type": "->"
      },
      {
        "file": "/var/www/nextcloud/3rdparty/sabre/event/lib/WildcardEmitterTrait.php",
        "line": 89,
        "function": "beforeMethod",
        "class": "Sabre\\DAV\\Auth\\Plugin",
        "type": "->"
      },
      {
        "file": "/var/www/nextcloud/3rdparty/sabre/dav/lib/DAV/Server.php",
        "line": 456,
        "function": "emit",
        "class": "Sabre\\DAV\\Server",
        "type": "->"
      },
      {
        "file": "/var/www/nextcloud/3rdparty/sabre/dav/lib/DAV/Server.php",
        "line": 253,
        "function": "invokeMethod",
        "class": "Sabre\\DAV\\Server",
        "type": "->"
      },
      {
        "file": "/var/www/nextcloud/3rdparty/sabre/dav/lib/DAV/Server.php",
        "line": 321,
        "function": "start",
        "class": "Sabre\\DAV\\Server",
        "type": "->"
      },
      {
        "file": "/var/www/nextcloud/apps/dav/lib/Server.php",
        "line": 373,
        "function": "exec",
        "class": "Sabre\\DAV\\Server",
        "type": "->"
      },
      {
        "file": "/var/www/nextcloud/apps/dav/appinfo/v2/remote.php",
        "line": 35,
        "function": "exec",
        "class": "OCA\\DAV\\Server",
        "type": "->"
      },
      {
        "file": "/var/www/nextcloud/remote.php",
        "line": 172,
        "args": ["/var/www/nextcloud/apps/dav/appinfo/v2/remote.php"],
        "function": "require_once"
      }
    ]
  }
}

As a NextCloud newbie, nothing stuck out to me other than lot of deprecated notices.

[ChristophWurst]

Great insights! I think the expensive routine happens for every login. Arguably, the CalDAV request might not even need file storage access, so the preparation of the server-side encryption could be skipped.

[Phaen]

I'm not sure whether it has anything to do with the routine itself, as the observed 5-10 second request time is ludicrous, and not something that always happens whenever encryption is required. There is definitely some kind of bug where this routine is called excessively in this specific case.