Yomi sandbox: presume attachment is clean on "Maximum hash retransmits exceeded"

andre8244 commented 2 years ago

In rare and currently unknown circumstances an email is never delivered because yomi plugin continuously reaches Maximum hash retransmits exceeded and performs a soft-reject.

Proposed solution

This issue seems to happen with clean attachments only. Avoid soft-reject and mark the e-mail with YOMI_UNKNOWN when Maximum hash retransmits exceeded is reached

gsanchietti commented 2 years ago

In nethesis-testing:

nethserver-yomi-2.1.1-1.1.g91b4735.ns7.noarch.rpm

andre8244 commented 2 years ago

Test case

Edit /usr/share/rspamd/lualib/lua_scanners/yomi.lua and set hash_retransmits = 0 (https://github.com/nethesis/yomi-rspamd/blob/master/yomi.lua#L37) to simulate the issue
Run signal-event -j nethserver-yomi-update to apply the change
Send and e-mail to this server with an attachment unknown to the sandbox (e.g. a binary file generated with head -c 100K < /dev/urandom > binary_file)
Verify that this line is printed in /var/log/maillog: Maximum hash retransmits exceeded for <ATTACHMENT_NAME>, presuming attachment is clean
Verify that the e-mail has been delivered with symbol: YOMI_UNKNOWN(0.00)[Maximum hash retransmits exceeded for <ATTACHMENT_NAME>, presuming attachment is clean]
Reset hash_retransmits = 7 in yomi.lua
Re-run signal-event -j nethserver-yomi-update to apply the change

lucagasparini commented 2 years ago

Test passed successfully :+1:

lucagasparini commented 2 years ago

Test passed successfully :+1:

gsanchietti commented 2 years ago

Released: nethserver-yomi-2.2.0-1.ns7.noarch.rpm

nethesis / dev

Yomi sandbox: presume attachment is clean on "Maximum hash retransmits exceeded" #6130