Description

This change prevents operations applied to both files that adjusts their mtime attribute which sometimes results in the same timestamp which causes Dovecot to log errors.

Functionally there doesn't appear to be any issue. After logging the error, the existing svbin is used and works correctly.

This does help avoid false-positives in the test-suite that are asserting for errors in a log.

Fixes: #3558 (comment)

Context

This fix prevents the two error log lines below that are preceding the log where the sieve script is run successfully regardless:

# Each logline prefixed with
Jan  8 02:13:59 mail dovecot: lmtp([email protected])<1319><34kpAWdam2UnBQAAUi6ngw>: 

$ grep -i junk /var/log/mail/mail.log
Error: sieve: binary /usr/lib/dovecot/sieve-global/after/spam_to_junk.svbin: save: failed to create temporary file: open(/usr/lib/dovecot/sieve-global/after/spam_to_junk.svbin.) failed: Permission denied (euid=5000(docker) egid=5000(docker) missing +w perm: /usr/lib/dovecot/sieve-global/after, dir owned by 110:0 mode=0755)
Error: sieve: The LDA Sieve plugin does not have permission to save global Sieve script binaries; global Sieve scripts like `/usr/lib/dovecot/sieve-global/after/spam_to_junk.sieve' need to be pre-compiled using the sievec tool

sieve: msgid=<[email protected]>: fileinto action: stored mail into mailbox 'Junk'

I've only witnessed this personally on my current system (AMD 7940HS with Windows 11 + WSL2), it's possibly related to the filesystem layer and changes happening within a certain window to be coalesced into the same timestamp as an optimization? 🤷‍♂️

If the .sieve file is newer (or the same timestamp in this case), Dovecot will try compile a new .svbin (and presumably fallback to the existing one when that fails).

We can see that the failure is due to the VMail user docker:docker / 5000:5000 lacking permissions to write .svbin as the directory ownership is dovecot:root / 110:0 with 755 permissions.

• As misc.sh, dovecot.sh, rspamd.sh all run sievec for .sieve files in either /usr/lib/dovecot/sieve-pipe or /usr/lib/dovecot/sieve-global. As such, while we could adjust the permission for the VMail static user, it won't support deployments with accounts that have their own unique UID (some LDAP users are known to have this setup).
• Instead it seems correct to ensure the mtime is adjusted as this PR does, as we are intentionally compiling these during startup scripts and there should be no need to compile again afterwards when mail is received and processed by these scripts.

Type of change

• Bug fix (non-breaking change which fixes an issue)
• Improvement (non-breaking change that does improve existing functionality)

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• New and existing unit tests pass locally with my changes
• I have added information about changes made in this PR to CHANGELOG.md