I am not an expert on how to run dovecot. I was able to reproduce your steps to get to the error so that I could find the correct fix.
Running in non-FIPS mode is required so that old passwords (with the shorter 8 byte salt) will still work. Once all passwords have been changed (to the new longer 16 byte salt), then FIPS mode can be enabled. Once the patch is in place, it may require some experimentation to document the proper steps to give to a customer. -- You received this bug notification because you are a member of Ubuntu Touch seeded packages, which is subscribed to openssl in Ubuntu. https://bugs.launchpad.net/bugs/2107773 Title: Enabling FIPS causes SALT to be 8 bytes, but OpenSSL 3.0.2 checks if SALT is < 16 bytes, breaking Dovecot and possibly other packages. Status in openssl package in Ubuntu: New Bug description: [ Impact ] * When one enables FIPS mode on a Jammy system and then attempts to use Dovecot to create an encrypted mailbox, the module returns a invalid salt length error. * FIPS mode requires a 16 byte salt for PBEKDF2 and Dovecot is only requesting 8 bytes of salt. The solution is to modify Dovecot to request 16 bytes of salt. [ Test Plan ] * Install Dovecot on the system - sudo apt install dovecot-auth-lua dovecot-core dovecot-gssapi dovecot-imapd dovecot-ldap dovecot-lmtpd dovecot-managesieved dovecot-mysql dovecot-pgsql dovecot-pop3d dovecot-sieve dovecot-solr dovecot-sqlite dovecot-submissiond * Enable mailbox encryption. - Add /etc/dovecot/conf.d//mail-crypt.conf to enable mailbox encryption: mail_location = mbox:~/mail:INBOX=/var/mail/%u listen = * mbox_write_locks = fcntl namespace inbox { inbox = yes location = mailbox Drafts { special_use = \Drafts } mailbox Junk { special_use = \Junk } mailbox Sent { special_use = \Sent } mailbox "Sent Messages" { special_use = \Sent } mailbox Trash { special_use = \Trash } prefix = } passdb { driver = pam } userdb { driver = passwd } mail_plugins = $mail_plugins mail_crypt plugin { mail_crypt_curve = secp521r1 mail_crypt_save_version=2 } mail_attribute_dict = file:%h/Maildir/dovecot-attributes imap_metadata = yes * Issue the following command to create an encrypted mailbox: - sudo doveadm -o plugin/mail_crypt_private_password=e32f1f174d7576716d5df899e7d5cb6b64cdb33584c71882e9f7e1f79f2e695e mailbox cryptokey generate -u <username> * Verify that no error occurs. * Enable FIPS on a Jammy system. - sudo pro attach <token> - sudo pro enable fips-updates - sudo reboot (To test FIPS on a Noble system) - sudo add-apt-repository ppa:fips-cc-stig/fips-under-certification - sudo apt install -y ubuntu-fips openssh-server=1:9.6p1-3ubuntu13+Fips1~rc0 \ openssh-client=1:9.6p1-3ubuntu13+Fips1~rc0 \ openssh-sftp-server=1:9.6p1-3ubuntu13+Fips1~rc0 \ --allow-downgrades --yes * Reboot * Delete the mailbox - rm -rf ~/mail * Issue the following command to create an encrypted mailbox: - sudo doveadm -o plugin/mail_crypt_private_password=e32f1f174d7576716d5df899e7d5cb6b64cdb33584c71882e9f7e1f79f2e695e mailbox cryptokey generate -u <username> * Verify that an error occurs. * Update Dovecot to the fixed version. * Repeat the commands to delete the mailbox and to create an encrypted mailbox. * After installing the fix, verify that no error occurs. [ Where problems could occur ] * The increased salt size of 16 bytes could potentially cause issues in allocated data structures, but I've attempted to mitigate this by increasing the size of potentially problematic data structures. [ Other Info ] This is really only needed on systems where FIPS is supported, i.e. Jammy and Noble and 26.04. -------------- We deployed Ubuntu Server 22.04 FIPS on Azure as it is now a FIPS Certified release. See https://ubuntu.com/blog/fips-140-3-for-ubuntu-22-04lts ~# lsb_release -rd Description: Ubuntu 22.04.5 LTS Release: 22.04 After installing Ubuntu Server 22.04 FIPS, we then deployed Dovecot modules as shown here: -------------- # apt search dovecot | grep "install" WARNING: apt does not have a stable CLI interface. Use with caution in scripts. dovecot-core/jammy-updates,jammy-security,now 1:2.3.16+dfsg1-3ubuntu2.4 amd64 [installed] dovecot-imapd/jammy-updates,jammy-security,now 1:2.3.16+dfsg1-3ubuntu2.4 amd64 [installed] dovecot-lmtpd/jammy-updates,jammy-security,now 1:2.3.16+dfsg1-3ubuntu2.4 amd64 [installed] dovecot-managesieved/jammy-updates,jammy-security,now 1:2.3.16+dfsg1-3ubuntu2.4 amd64 [installed] dovecot-mysql/jammy-updates,jammy-security,now 1:2.3.16+dfsg1-3ubuntu2.4 amd64 [installed] dovecot-pop3d/jammy-updates,jammy-security,now 1:2.3.16+dfsg1-3ubuntu2.4 amd64 [installed] dovecot-sieve/jammy-updates,jammy-security,now 1:2.3.16+dfsg1-3ubuntu2.4 amd64 [installed] ~# apt-cache policy dovecot-core dovecot-core: Installed: 1:2.3.16+dfsg1-3ubuntu2.4 Candidate: 1:2.3.16+dfsg1-3ubuntu2.4 Version table: *** 1:2.3.16+dfsg1-3ubuntu2.4 500 500 http://azure.archive.ubuntu.com/ubuntu jammy-updates/main amd64 Packages 500 http://azure.archive.ubuntu.com/ubuntu jammy-security/main amd64 Packages 100 /var/lib/dpkg/status 1:2.3.16+dfsg1-3ubuntu2 500 500 http://azure.archive.ubuntu.com/ubuntu jammy/main amd64 Packages ------------- We attempted to add a mailbox with encryption: ------------- sudo -u vmail doveadm -o plugin/mail_crypt_private_password=e32f1f174d7576716d5df899e7d5cb6b64cdb33584c71882e9f7e1f79f2e695e mailbox cryptokey generate -u u...@domain.com doveadm(u...@domain.com): Error: mail_crypt_user_generate_keypair(u...@domain.com) failed: error:1C800070:Provider routines::invalid salt length doveadm(u...@domain.com): Warning: mailbox cryptokey generate: Nothing was matched. Use -U or specify mask? Folder Public ID x ERROR: error:1C800070:Provider routines::invalid salt length Segmentation fault ------------- After researching the error, I found a single note in the OpenSSL bug tracker referencing the error. https://github.com/openssl/openssl/issues/24962 The suggested options are not available as they defeat the purpose of being FIPS compliant and certified. As a result, Dovecot is completely broken on 22.04 FIPS if using encrypted mailboxes. (At least in our testing) Expected behavior: The SALT length should match what the required check is, which is 16 bytes. Dovecot should utilize an appropriate version to produce encryption keys using the required SALT length. 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