[SSHD-745] KnownHostEntry cannot parse [host]:port or IPv6 with %link entries

• Type: New Feature
• Status: Resolved
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: 1.2.0
• Fix Version/s: 2.1.0
• Assignee: Unassigned
• Reporter: Stephen Connolly
• Created: 09/May/17 09:16
• Updated: 27/Mar/19 13:47
• Resolved: 27/Mar/19 13:47

Description

My known hosts file contains lines like: (note I have sanitized the lines and switched entries to documentation reserved IP addresses and DNS names)

[host.example.com]:7999,[192.0.2.3]:7999 ssh-rsa AAAA...Z45M/
2001:db8:85a3::8a2e:370:7334%en1 ecdsa-sha2-nistp256 AAAAE2...q9zmk=

Both of which will bomb out with errors like:

WARNING: Failed (StreamCorruptedException) to reload server keys from /Users/stephenc/.ssh/known_hosts: Failed (IllegalArgumentException) to parse line #96 '2001:db8:85a3::8a2e:370:7334%en1 ecdsa-sha2-nistp256 AAAAE2...q9zmk=': Invalid host pattern char in 2001:db8:85a3::8a2e:370:7334%en1

or

(This next one is a thrown away ssh server running in docker and the container is gone so I can provide the full unedited line)

WARNING: Failed (StreamCorruptedException) to reload server keys from /Users/stephenc/.ssh/known_hosts: Failed (IllegalArgumentException) to parse line #60 '[127.0.0.1]:49153 ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQC5ntfSGAQOO2O/8ma7mtk9UaC6JWVlJ+6WAjnN3V510wc4nkkUcL66hZZyPLI0TYhk2CHNNQPeXkc6Cq7enSJab7SI06MhCQhF9yeuBQnphNBsUa01twPgycQOdrYey+4hIVXRF5BbckuU5nVAuFsPv7utNROmo+XoWoAdopSiejWs6Mrox+VIwgeN6peJ5l5jPqCjMEBTP9iNWgZMa+wQN7cTWpi7lIbK+a2hnzHz5P8oWFN8j8jREm+/6NK1IdW3c0CsLRWyee50GYYQOEi0zo1FfGweia5CbzfjRtfd0XFtUxGtULJpPoj9x/7xHuFUL1rYoKAGaTPzPdBHJTiJ': Invalid host pattern char in [127.0.0.1]:49153

{/code}

https://en.wikibooks.org/wiki/OpenSSH/Client_Configuration_Files seems to indicate that [host]:port is the syntax for when the ssh server is using a non-standard port

https://serverfault.com/a/771355/147023 reports that the % at the end of the IPv6 address is indicating the local link (in my case %en1 being WIFI on my macbook, but I have seem %eth0 on modern linux servers)

Completely blowing up for these entries seems rather wrong, I would expect either skipping such entries or actually being able to parse them.

Checking the current code on master it seems this issue has not been resolved yet:

IOW https://github.com/apache/mina-sshd/blob/5b0b163c5500fedc2a6bae0fc5e260d64fcf370a/sshd-core/src/main/java/org/apache/sshd/client/config/hosts/HostPatternsHolder.java#L289-L306 still will reject a host name containing either the non-standard port specification or the link specifier

Issue Links

• is related to: SSHD-746 IPv6 addresses are not supported as client sessions connection target
• is related to: SSHD-747 Add support for non-standard port specification in known_hosts file