For further information, this bug is a breaking change between 20.04 and 22.04. Version 20.04 FIPS has been working well for the past few years.
It is good that we tried deploying a new Azure VM on 22.04 FIPS before running do-release-upgrade on one of our existing VMs as that would have resulted in an unexpectedly broken system. I do understand that this is a very niche bug that slipped through the cracks. Thank you for the quick attention to the issue and the PRs pending review and approval. -- 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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