Re: [ptxdist] OpenSSH patches
On Tue, Jul 14, 2015 at 12:03:47PM +0200, Michael Olbrich wrote: On Tue, Jul 07, 2015 at 10:52:52AM +0200, Clemens Gruber wrote: what do you think about my recent OpenSSH patches (not the version bumps) but enabling the sandbox per default (to use seccomp if available) and the switch from DSA to Ed25519. ArchLinux and current Debian both generate Ed25519 pubkeys by default and add them as HostKey to sshd_config. They keep DSA and ECDSA but as they fall apart completely if the random numbers used are not good, I am not sure this is a good idea for embedded systems where entropy is often very scarce. Ed25519 is not that sensitive to entropy problems. I looked at what Debian is doing, and I liked it: Basically, the postinst script checks the sshd_config and generated the needed keys. I think we can do the same in the ssh rc-once script. Then we can choose more restrictive defaults. Then those that need other keys just need to overwrite sshd_config in the BSP. Michael Hi Michael, what do you think about my recent patch (openssh: improve rc.once.d script and harden sshd_config) from July 17th? I tried to follow what Debian is doing for key generation and I also hardened the default config. Regards, Clemens -- ptxdist mailing list ptxdist@pengutronix.de
Re: [ptxdist] OpenSSH patches
On Tue, Jul 07, 2015 at 10:52:52AM +0200, Clemens Gruber wrote: what do you think about my recent OpenSSH patches (not the version bumps) but enabling the sandbox per default (to use seccomp if available) and the switch from DSA to Ed25519. ArchLinux and current Debian both generate Ed25519 pubkeys by default and add them as HostKey to sshd_config. They keep DSA and ECDSA but as they fall apart completely if the random numbers used are not good, I am not sure this is a good idea for embedded systems where entropy is often very scarce. Ed25519 is not that sensitive to entropy problems. I looked at what Debian is doing, and I liked it: Basically, the postinst script checks the sshd_config and generated the needed keys. I think we can do the same in the ssh rc-once script. Then we can choose more restrictive defaults. Then those that need other keys just need to overwrite sshd_config in the BSP. Michael -- Pengutronix e.K. | | Industrial Linux Solutions | http://www.pengutronix.de/ | Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0| Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917- | -- ptxdist mailing list ptxdist@pengutronix.de
Re: [ptxdist] OpenSSH patches
Hey Clemens, what do you think about my recent OpenSSH patches (not the version bumps) but enabling the sandbox per default (to use seccomp if available) and the switch from DSA to Ed25519. ArchLinux and current Debian both generate Ed25519 pubkeys by default and add them as HostKey to sshd_config. They keep DSA and ECDSA but as they fall apart completely if the random numbers used are not good, I am not sure this is a good idea for embedded systems where entropy is often very scarce. Ed25519 is not that sensitive to entropy problems. I agree, when possible we should use ed25519. Adam Langley blog entry[1]. /Bruno [1] https://www.imperialviolet.org/2013/06/15/suddendeathentropy.html -- ptxdist mailing list ptxdist@pengutronix.de
