Internal Server Error: trim(): Argument #1 ($string) must be of type string, null given

[Caliran]

Describe the bug

The Server was unable to complete your request. If This happens again, please send t he technical details below to the server administrator. Technical details: Remote Adress: xxx.xxx.xxx.xxx Requested ID: xxx Message: trim(): Argument #1 ($string) must be of type string, null given

To reproduce

Sign The Document, then confirm the signature.

Environment information

NC 32.0.1
Libresign 12.0.1

[henmohr]

Hey, thanks for reaching out.

Can you provide more details about your setup?

[Caliran]

Sure. Did you have something in mind you need to know? I'm running an apache2 web server with PHP 8.4 on Debian 11.

Operating System: Linux 5.10.0-36-amd64 x86_64
CPU: Intel(R) Xeon(R) CPU E5-2680 0 @ 2.70GHz (32 threads)
Memory: 251.84 GB

PHP
Version: 8.4.13
Memory limit: 2 GB
Max execution time: 3600
Upload max size: 2 GB
OPcache Revalidate Frequency: 2
Extensions: Core, date, libxml, openssl, pcre, zlib, filter, hash, json, random, Reflection, SPL, session, standard, sodium, cgi-fcgi, mysqlnd, PDO, xml, apcu, bcmath, calendar, ctype, curl, dom, mbstring, FFI, fileinfo, ftp, gd, gettext, gmp, iconv, igbinary, imagick, intl, exif, mysqli, pdo_mysql, Phar, posix, readline, shmop, SimpleXML, sockets, sysvmsg, sysvsem, sysvshm, tokenizer, xmlreader, xmlwriter, xsl, zip, redis, Zend OPcache

Database
Type: mysql
Version: 8.0.37

Apps Enabled:

• activity: 5.0.0-dev.0
• admin_audit: 1.22.0
• bruteforcesettings: 5.0.0-dev.0
• calendar: 6.0.2
• camerarawpreviews: 0.8.8
• circles: 32.0.0
• cloud_federation_api: 1.16.0
• comments: 1.22.0
• contacts: 8.0.4
• contactsinteraction: 1.13.1
• cookbook: 0.11.4
• dashboard: 7.12.0
• dav: 1.34.2
• deck: 1.16.0
• federatedfilesharing: 1.22.0
• files: 2.4.0
• files_downloadlimit: 5.0.0-dev.0
• files_external: 1.24.0
• files_pdfviewer: 5.0.0-dev.0
• files_reminders: 1.5.0
• files_sharing: 1.24.0
• files_trashbin: 1.22.0
• files_versions: 1.25.0
• firstrunwizard: 5.0.0-dev.0
• libresign: 12.0.1
• logcleaner: 1.1.9
• logreader: 5.0.0-dev.0
• lookup_server_connector: 1.20.0
• mail: 5.5.11
• nextcloud_announcements: 4.0.0-dev.0
• notes: 4.12.3
• notifications: 5.0.0-dev.0
• oauth2: 1.20.0
• password_policy: 4.0.0-dev.0
• photos: 5.0.0-dev.1
• previewgenerator: 5.10.0
• privacy: 4.0.0-dev.0
• profile: 1.1.0
• provisioning_api: 1.22.0
• recognize: 10.0.4
• recommendations: 5.0.0-dev.0
• registration: 2.8.0
• related_resources: 3.0.0-dev.0
• richdocuments: 9.0.1
• richdocumentscode: 25.4.504
• serverinfo: 4.0.0-dev.0
• settings: 1.15.1
• sharebymail: 1.22.0
• support: 4.0.0-dev.0
• survey_client: 4.0.0-dev.0
• suspicious_login: 10.0.0-dev.0
• systemtags: 1.22.0
• tasks: 0.17.0
• text: 6.0.1
• theming: 2.7.0
• twofactor_backupcodes: 1.21.0
• twofactor_email: 2.8.2
• updatenotification: 1.22.0
• user_status: 1.12.0
• viewer: 5.0.0-dev.0
• weather_status: 1.12.0
• webhook_listeners: 1.3.0
• workflowengine: 2.14.0

[vitormattos]

Did you have the log entry added to your nextcloud.log file when this mestre is generated?

[Caliran]

{"reqId":"i1exIXjUXwtnkTm3bBrW","level":3,"time":"2025-10-24T01:32:48+00:00","remoteAddr":"xxx.xxx.xxx.xxx","user":"--","app":"libresign","method":"POST","url":"/ocs/v2.php/apps/libresign/api/v1/sign/uuid/175e5651-c803-4ff0-b9a3-c97c129f2f7f","message":"trim(): Argument #1 ($string) must be of type string, null given","userAgent":"Mozilla/5.0 (Linux; Android 10; K) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/141.0.0.0 Mobile Safari/537.36","version":"32.0.1.2","exception":{"Exception":"TypeError","Message":"trim(): Argument #1 ($string) must be of type string, null given","Code":0,"Trace":[{"function":"trim","file":"/var/www/nextcloud/apps/libresign/lib/Handler/SignEngine/Pkcs12Handler.php","line":285},{"file":"/var/www/nextcloud/apps/libresign/lib/Handler/SignEngine/Pkcs12Handler.php","line":178,"function":"parseDistinguishedNameWithMultipleValues","class":"OCA\Libresign\Handler\SignEngine\Pkcs12Handler","type":"->"},{"file":"/var/www/nextcloud/apps/libresign/lib/Handler/SignEngine/Pkcs12Handler.php","line":91,"function":"popplerUtilsPdfSignFallback","class":"OCA\Libresign\Handler\SignEngine\Pkcs12Handler","type":"->"},{"file":"/var/www/nextcloud/apps/libresign/lib/Handler/SignEngine/SignEngineHandler.php","line":211,"function":"getCertificateChain","class":"OCA\Libresign\Handler\SignEngine\Pkcs12Handler","type":"->"},{"file":"/var/www/nextcloud/apps/libresign/lib/Service/SignFileService.php","line":337,"function":"getLastSignedDate","class":"OCA\Libresign\Handler\SignEngine\SignEngineHandler","type":"->"},{"file":"/var/www/nextcloud/apps/libresign/lib/Service/SignFileService.php","line":324,"function":"updateSignRequest","class":"OCA\Libresign\Service\SignFileService","type":"->","args":["*** sensitive parameters replaced ***"]},{"file":"/var/www/nextcloud/apps/libresign/lib/Controller/SignFileController.php","line":133,"function":"sign","class":"OCA\Libresign\Service\SignFileService","type":"->"},{"file":"/var/www/nextcloud/apps/libresign/lib/Controller/SignFileController.php","line":95,"function":"sign","class":"OCA\Libresign\Controller\SignFileController","type":"->"},{"file":"/var/www/nextcloud/lib/private/AppFramework/Http/Dispatcher.php","line":204,"function":"signUsingUuid","class":"OCA\Libresign\Controller\SignFileController","type":"->"},{"file":"/var/www/nextcloud/lib/private/AppFramework/Http/Dispatcher.php","line":118,"function":"executeController","class":"OC\AppFramework\Http\Dispatcher","type":"->"},{"file":"/var/www/nextcloud/lib/private/AppFramework/App.php","line":153,"function":"dispatch","class":"OC\AppFramework\Http\Dispatcher","type":"->"},{"file":"/var/www/nextcloud/lib/private/Route/Router.php","line":321,"function":"main","class":"OC\AppFramework\App","type":"::"},{"file":"/var/www/nextcloud/ocs/v1.php","line":61,"function":"match","class":"OC\Route\Router","type":"->"},{"file":"/var/www/nextcloud/ocs/v2.php","line":8,"args":["/var/www/nextcloud/ocs/v1.php"],"function":"require_once"}],"File":"/var/www/nextcloud/apps/libresign/lib/Handler/SignEngine/Pkcs12Handler.php","Line":285,"message":"trim(): Argument #1 ($string) must be of type string, null given","exception":[],"CustomMessage":"trim(): Argument #1 ($string) must be of type string, null given"},"id":"68ff61d621458"}

[vitormattos]

This issue occurs when parsing the signed file and executing the pdfsig command to collect signature data.
This part of the code is already covered by tests, so the problem shouldn't normally occur. It’s likely related to a specific characteristic of your environment or the signed PDF file.

You can help us diagnose it by adding the following line right after the code block below:

libresign/lib/Handler/SignEngine/Pkcs12Handler.php

Lines 185 to 189 in 9ebc9fb

	$content = shell_exec('env TZ=UTC pdfsig ' . $tempFile);
	if (empty($content)) {
	return [];
	}
	$lines = explode("\n", $content);

file_put_contents('/tmp/poppler_output', $content);

Then, reproduce the action that triggered the error and, if possible, share the /tmp/poppler_output file here.
Please make sure it does not contain any sensitive information before sending.

[Caliran]

Digital` Signature Info of: /tmp/oc_tmp_bY17uw3bxhlMw153E3CEIShGHejbgl7q.file.pdf

Signature #1:
  - Signer Certificate Common Name: (null)
  - Signer full Distinguished Name: (null)
  - Signing Time: Jan 01 1970 00:00:00
  - Signing Hash Algorithm: unknown
  - Signature Type: unknown
  - Signature Validation: Signature has not yet been verified.
Signature #2:
  - Signer Certificate Common Name: (null)
  - Signer full Distinguished Name: (null)
  - Signing Time: Jan 01 1970 00:00:00
  - Signing Hash Algorithm: unknown
  - Signature Type: unknown
  - Signature Validation: Signature has not yet been verified.
Signature #3:
  - Signer Certificate Common Name: CERTNAME
  - Signer full Distinguished Name: O=Internet Widgits Pty Ltd,CN=SOMECOMPANY,L=SOMECITY,ST=ASTATESOMEWHEREE,C=US
  - Signing Time: Oct 29 2025 00:18:41
  - Signing Hash Algorithm: SHA-256
  - Signature Type: adbe.pkcs7.detached
  - Signed Ranges: [0 - 2567546], [2597548 - 2604597]
  - Total document signed
  - Signature Validation: Signature is Invalid.

[Caliran]

There was only one signature blank also.

I also see there's a new version. Let me know if I should update before we're done troubleshooting.

[vitormattos]

@Caliran I recommend to update to the newest version, generate again your root certificate (I recommend to use OpenSSL) and test again.

Have strange (invalid) values at two signatures (the null values) at your file.

[vitormattos]

I also recommend to generate your certificate again after generate the root certificate.

[Caliran]

I regenerated the certificate. And updated. I'm still getting the error repeately asking me to confirm. But now I'm getting a document thats signed saved in the folder..

Digital Signature Info of: /tmp/oc_tmp_muCv4Jr75Q40UEWh3JJBnQle7vFrNvXx.file.pdf
Signature #1:
  - Signer Certificate Common Name: (null)
  - Signer full Distinguished Name: (null)
  - Signing Time: Jan 01 1970 00:00:00
  - Signing Hash Algorithm: unknown
  - Signature Type: unknown
  - Signature Validation: Signature has not yet been verified.
Signature #2:
  - Signer Certificate Common Name: (null)
  - Signer full Distinguished Name: (null)
  - Signing Time: Jan 01 1970 00:00:00
  - Signing Hash Algorithm: unknown
  - Signature Type: unknown
  - Signature Validation: Signature has not yet been verified.
Signature #3:
  - Signer Certificate Common Name: xxxxx
  - Signer full Distinguished Name: xxxxxxx
  - Signing Time: Oct 29 2025 03:00:08
  - Signing Hash Algorithm: SHA-256
  - Signature Type: adbe.pkcs7.detached
  - Signed Ranges: [0 - 2589878], [2619880 - 2626937]
  - Not total document signed
  - Signature Validation: Signature is Invalid.
Signature #4:
  - Signer Certificate Common Name: xxxxxx
  - Signer full Distinguished Name: xxxxxxx
  - Signing Time: Oct 29 2025 03:00:11
  - Signing Hash Algorithm: SHA-256
  - Signature Type: adbe.pkcs7.detached
  - Signed Ranges: [0 - 2816151], [2846153 - 2853221]
  - Not total document signed
  - Signature Validation: Signature is Invalid.
Signature #5:
  - Signer Certificate Common Name: xxxxxxx
  - Signer full Distinguished Name: xxxxxxxxxx
  - Signing Time: Oct 29 2025 03:00:14
  - Signing Hash Algorithm: SHA-256
  - Signature Type: adbe.pkcs7.detached
  - Signed Ranges: [0 - 3042438], [3072440 - 3079531]
  - Total document signed
  - Signature Validation: Signature is Invalid.