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[Bug]: Uploading files larger than 2GB to SFTP external storage backend fails #49229

Closed
Bug
#48183
Closed
[Bug]: Uploading files larger than 2GB to SFTP external storage backend fails#49229
Bug
#48183
Labels
1. to developAccepted and waiting to be taken care of29-feedbackbugdependenciesfeature: external storagehelp wanted

Description

@chaosgrid
chaosgrid
opened on Nov 12, 2024

⚠️ This issue respects the following points: ⚠️

Bug description

Uploading files larger than 2GB to SFTP external storage backend fails. This is on a docker install using the official Nextcloud image version 29.0.9-apache.

Steps to reproduce

  1. Connect sftp storage backend space
  2. Upload or copy file larger than 2GB to it.
  3. It fails.

Expected behavior

Successful file upload.

Nextcloud Server version

29

Operating system

Other

PHP engine version

None

Web server

None

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?

None

What user-backends are you using?

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

Configuration report



List of activated Apps




Nextcloud Signing status




Nextcloud Logs


The log has these entries:

[PHP] Info: Invalid HMAC at /var/www/html/3rdparty/phpseclib/phpseclib/phpseclib/Net/SSH2.php#3717
	COPY /remote.php/dav/files/redacted/test_file_over2gb.dat

[PHP] Info: Connection closed by server at /var/www/html/3rdparty/phpseclib/phpseclib/phpseclib/Net/SSH2.php#4069
	COPY /remote.php/dav/files/redacted/test_file_over2gb.dat

[no app in context] Warning: Failed to copy stream to storage
	COPY /remote.php/dav/files/redacted/test_file_over2gb.dat


Additional info


This issue is probably related to or the same as #48231


It happens on a docker container install using the official Nextcloud image with version 29.0.9-apache


According to Claude, it might be that the packaged phpseclib version is too old. In fact, checking the composer.json in my docker container, it says: "phpseclib/phpseclib": "^2.0.45"


Claude says:




That explains the issue! You're using phpseclib 2.x which has known limitations with files larger than 2GB due to how it handles HMAC calculations with 32-bit integers.




Is this plausible?


When I connect the same storage via FTPS, uploads above 2GB succeed.

I am not sure when this bug was introduced since it definitely worked in the past, we uploaded >2GB files to the storage using the SFTP backend before.
Activity
  1. chaosgrid
    added 
    0. Needs triagePending check for reproducibility or if it fits our roadmap
     
    bug
     on Nov 12, 2024
  2. szaimen
    added 
    29-feedback
     on Nov 12, 2024
  3. chaosgrid commented on Nov 13, 2024 
    @chaosgrid
    chaosgrid
    on Nov 13, 2024
    Author
    Update: This also happens when downloading a file from sftp backend that is bigger than 2GB. It fails right at the 2GB mark and the Nextcloud client simply says "Connection closed"..
  4. chaosgrid commented on Nov 13, 2024 
    @chaosgrid
    chaosgrid
    on Nov 13, 2024
    Author
    I also found this forum post, seems related (though it is not the SFTP backend): https://help.nextcloud.com/t/unable-to-upload-files-larger-than-2gb-via-webdav/200157
  5. chaosgrid commented on Nov 14, 2024 
    @chaosgrid
    chaosgrid
    on Nov 14, 2024
    Author
    Updated to Nextcloud docker image v30.0.2
    

    Same issues. When downloading a file over 2GB from sftp backend, right around the 2GB mark it fails and the debug output is this:
    

    Image
  6. joshtrichards
    added 
    feature: external storage
     
    dependencies
     on Nov 15, 2024
  7. joshtrichards commented on Nov 18, 2024 
    @joshtrichards
    joshtrichards
    on Nov 18, 2024
    Member
    I see you're working the issue a bit over at phpseclib, but wanted to check on this comment:
    

    

    When I connect the same storage via FTPS, uploads above 2GB succeed.
    

    

    Was that a typo or did you really test using FTPS instead of SFTP?
  8. chaosgrid commented on Nov 19, 2024 
    @chaosgrid
    chaosgrid
    on Nov 19, 2024
    Author
    

    I see you're working the issue a bit over at phpseclib, but wanted to check on this comment:
    

    

    When I connect the same storage via FTPS, uploads above 2GB succeed.
    

    

    Was that a typo or did you really test using FTPS instead of SFTP?
    

    

    Yes, not a typo. I tested the same storage server via the FTPS Nextcloud storage backend and using that, there are no issues with files over 2GB. Also, directly connecting to the storage server using an SFTP tool (like WinSCP) also does not produce these bugs.
  9. chaosgrid commented on Dec 17, 2024 
    @chaosgrid
    chaosgrid
    on Dec 17, 2024
    Author
    @joshtrichards
    

    Hey there, so we concluded the issue over at phpseclib: The error originated from a bug in phpseclib when talking to ProFTPd servers.
    
phpseclib has been updated and it would be great to update the phpseclib dependency ASAP:
    
2.0.48 and 3.0.43 have the fix.
    

    Also, @terrafrost phpseclib dev said:
    

    

    That said, if Nextcloud is using phpseclib 2.0, they would do well to upgrade to 3.0. 3.0 introduces support for newer best practices algorithms that phpseclib 2.0 doesn't have.
    

  10. joshtrichards commented on Dec 17, 2024 
    @joshtrichards
    joshtrichards
    on Dec 17, 2024
    Member
    Thanks for the update, @chaosgrid. Definitely helpful!
    

    We should get a notification from the bot soon for 2.0.48 to bump to it in our 3rdparty repo.
    

    Re: 3.x - already in progress, but currently stalled until someone has a chance to look into why some of the unit tests are unexpectedly failing. See #48183.
    

    Cc: @susnux
  11. joshtrichards
    added 
    1. to developAccepted and waiting to be taken care of
     and removed 
    0. Needs triagePending check for reproducibility or if it fits our roadmap
     on Dec 17, 2024
  12. didierm commented on Mar 2, 2025 
    @didierm
    didierm
    on Mar 2, 2025
    As the 3.x phpseclib upgrade has been stalled for the past 2 months :
    
any chance of upgrading from 2.0.47 to 2.0.48 ?
    

    (not being able to transfer files > 2 GB is a bit of a blocker)
  13. susnux commented on Mar 3, 2025 
    @susnux
    susnux
    on Mar 3, 2025
    Contributor
    Yes any help with #48183 would be highly appreciated!
  14. susnux
    added this to  🧑‍🤝‍🧑 Community triageon Mar 27, 2025
  15. susnux
    moved this to Backlog in  🧑‍🤝‍🧑 Community triageon Mar 27, 2025
  16. joshtrichards
    added 
    help wanted
     on May 26, 2025
  17. chaosgrid commented on Jun 17, 2025 
    @chaosgrid
    chaosgrid
    on Jun 17, 2025
    Author
    Since phpseclib v3 upgrade has been stalled for 6+ months, can at least the v2 library be updated? Should be trivial, no?
  18. joshtrichards
    linked a pull request that will close this issuefeat(deps): Upgrade phpseclib to v3 #48183on Jul 8, 2025
  19. susnux
    added the
    Bug
    issue type on Feb 6, 2026
  20. susnux
    closed this as completedin #48183on Jul 21, 2026
  21. github-project-automation
    moved this from Backlog to Done in  🧑‍🤝‍🧑 Community triageon Jul 21, 2026
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