Bug 1042833 - ssh-add should prefer ecdsa
Summary: ssh-add should prefer ecdsa
Keywords:
Status: CLOSED EOL
Alias: None
Product: Fedora
Classification: Fedora
Component: openssh
Version: 19
Hardware: Unspecified
OS: Unspecified
unspecified
unspecified
Target Milestone: ---
Assignee: Petr Lautrbach
QA Contact: Fedora Extras Quality Assurance
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2013-12-13 13:41 UTC by Harald Reindl
Modified: 2015-02-18 11:00 UTC (History)
4 users (show)

Fixed In Version:
Clone Of:
Environment:
Last Closed: 2015-02-18 11:00:55 UTC
Type: Bug
Embargoed:


Attachments (Terms of Use)

Description Harald Reindl 2013-12-13 13:41:02 UTC
* fully patched Fedora 19
* openssh-clients-6.2p2-7.fc19.x86_64
* ~/.ssh/config
  IdentityFile ~/.ssh/id_ecdsa
  IdentityFile ~/.ssh/id_rsa
* both keys have the same password

i call "ssh-add" in KDE's autostart to unlock my keys
connecting to a RHEL7-Beta shows in /var/log/secure that id_rsa is used while from machines connecting via unencrypted private key per cronjob you can see there ECDSA

Dec 13 14:36:55 hosting sshd[14110]: Accepted publickey for root from *.*.*.* port 51522 ssh2: RSA 81:15:32:31:87:78:2f:ad:e8:ba:78:b5:34:3a:b3:fc

according to the manpage it should unlock both kyes and IMHO respect the order in ~/.ssh/config since we need both key-types as long not all servers and clients support ECDSA

> ssh-add adds private key identities to the authentication 
> agent, ssh-agent(1).  When run without arguments, it adds
> the files ~/.ssh/id_rsa, ~/.ssh/id_dsa, ~/.ssh/id_ecdsa and 
> ~/.ssh/identity.  After loading a private key, ssh-add
> will try to load corresponding certificate information from 
> the filename obtained by appending -cert.pub to the name
> of the private key file. Alternative file names can be given 
> on the command line. If any file requires a passphrase, ssh-add 
> asks for the passphrase from the user.  The passphrase is read 
> from the user's tty.  ssh-add retries the last passphrase if 
> multiple identity files are given.

Comment 1 Petr Lautrbach 2013-12-13 14:33:43 UTC
ssh-add doesn't read config file. ssh client gets a list of keys from ssh-agent in order how they were added to the agent. If you want to prefer one key then add this key first:

$ ssh-add .ssh/id_ecdsa .ssh/id_rsa
Enter passphrase for .ssh/id_ecdsa: 
Identity added: .ssh/id_ecdsa (.ssh/id_ecdsa)
Identity added: .ssh/id_rsa (.ssh/id_rsa)

$ ssh-add -L
ecdsa-sha2-nistp256 AAAAE2VjZHNhLXNoYTItbmlzdHAyNTYAAAAIbmlzdHAyNTYAAABBBAM9ObyBQNDv5nBeVfTA8qTfaqAlHOSmHeTv5YmiHhhI5XTSnhc/mKItd1djQVCYUPYOSGuAzEJPRETamBH/kdE= .ssh/id_ecdsa
ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQCqmBxx8ghdl8mTB2fbfvoJLK16MOtf0SeE70D6zcp0mLxu9J2u4mUU91ME+VZIgxX2oE04oLRg+e8nJVgfoPjOiZx5bvm0IMdqiPPE8qu9eiqqLVU5M385/ckHRzr1qG9Y29DwI2v9WhTxCkihAd5boTQz9eqrGB2luFiQoi2xeVvN12evDCiuVMkKQHPkz5fP49STP2Jsmh9CinRYmKbb9GSODrVAja2wqrlvyWbI3Ap7vTSlgc3wZvdYrHQb7tirl739b8EyprjjXp/PQzqzue18X1NUEzVhpy+mkp36RsUD0a1fUfAMst6j7a8QA5yrpGEK18JfZYKLBQ89ECtt .ssh/id_rsa

$ ssh-add -D
All identities removed.

$ ssh-add .ssh/id_rsa .ssh/id_ecdsa 
Enter passphrase for .ssh/id_rsa: 
Identity added: .ssh/id_rsa (.ssh/id_rsa)
Identity added: .ssh/id_ecdsa (.ssh/id_ecdsa)

$ ssh-add -L
ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQCqmBxx8ghdl8mTB2fbfvoJLK16MOtf0SeE70D6zcp0mLxu9J2u4mUU91ME+VZIgxX2oE04oLRg+e8nJVgfoPjOiZx5bvm0IMdqiPPE8qu9eiqqLVU5M385/ckHRzr1qG9Y29DwI2v9WhTxCkihAd5boTQz9eqrGB2luFiQoi2xeVvN12evDCiuVMkKQHPkz5fP49STP2Jsmh9CinRYmKbb9GSODrVAja2wqrlvyWbI3Ap7vTSlgc3wZvdYrHQb7tirl739b8EyprjjXp/PQzqzue18X1NUEzVhpy+mkp36RsUD0a1fUfAMst6j7a8QA5yrpGEK18JfZYKLBQ89ECtt .ssh/id_rsa
ecdsa-sha2-nistp256 AAAAE2VjZHNhLXNoYTItbmlzdHAyNTYAAAAIbmlzdHAyNTYAAABBBAM9ObyBQNDv5nBeVfTA8qTfaqAlHOSmHeTv5YmiHhhI5XTSnhc/mKItd1djQVCYUPYOSGuAzEJPRETamBH/kdE= .ssh/id_ecdsa

Comment 2 Harald Reindl 2013-12-13 14:59:33 UTC
that's not what the documentation promises
it says they will be all added and ~/.ssh/config should be respected

in fact if i start it with "ssh-add .ssh/id_ecdsa .ssh/id_rsa" terminal programs will use ECDSA, in the reverted order they use RSA, well the main-problem here seems to be the idiotic rewrite of the KDE sftp-ioslave which does not support ECDSA at all *and* asks for the rsa-key-password even if the ssh-cli falls back to the RSA-Key in case a server does not support ECDSA

in older KDE releases they used the openssh-clients via pipe and so implicitly supported anything of new openssh-releases while you now permanently have to verify that your configurations are working for CLI and GUI at the same time

https://bugzilla.redhat.com/show_bug.cgi?id=1042833

throw away this crap and restore the pipe-behavior and please do not come again up with exuses about performance - the pipe in case of  a networ protocol is *for sure* not the part responsible for performance

Comment 3 Harald Reindl 2013-12-13 15:00:43 UTC
argh - wrong cross-refrence - sorry

https://bugzilla.redhat.com/show_bug.cgi?id=1033370

Comment 4 Fedora End Of Life 2015-01-09 22:22:49 UTC
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Comment 5 Fedora End Of Life 2015-02-18 11:00:55 UTC
Fedora 19 changed to end-of-life (EOL) status on 2015-01-06. Fedora 19 is
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