similar to: ssh client auto rekey feature.

https://bugzilla.mindrot.org/show_bug.cgi?id=2521 Bug ID: 2521 Summary: subtract buffer size from computed rekey limit to avoid exceeding it Product: Portable OpenSSH Version: 6.8p1 Hardware: amd64 OS: Linux Status: NEW Severity: minor Priority: P5 Component: sshd

I was wondering if there was something specific to the internal chacha20 cipher as opposed to OpenSSL implementation. I can't just change the block size because it breaks compatibility. I can do something like as a hack (though it would probably be better to do it with the compat function): if (strstr(enc->name, "chacha")) *max_blocks = (u_int64_t)1 << (16*2);

https://bugzilla.mindrot.org/show_bug.cgi?id=3524 Bug ID: 3524 Summary: Rekey interval timeout not working when no package is being transfered Product: Portable OpenSSH Version: 8.9p1 Hardware: Other OS: Linux Status: NEW Severity: normal Priority: P5 Component: sshd

On Wed, 29 Mar 2023, Chris Rapier wrote: > I was wondering if there was something specific to the internal chacha20 > cipher as opposed to OpenSSL implementation. > > I can't just change the block size because it breaks compatibility. I can do > something like as a hack (though it would probably be better to do it with the > compat function): > > if

I'm hardly an expert on this, but if I remember correctly, the rekey rate for good security is mostly dependent on the cipher block size. I left my reference books at home; so, I can't come up with a reference for you, but I would take Chris' "I'm deeply unsure of what impact that would have on the security of the cipher" comment seriously and switch to a cipher with a

That's true for block ciphers, but ChaCha20+poly1305 is a stream cipher. On Wed, 29 Mar 2023, Robinson, Herbie wrote: > > I?m hardly an expert on this, but if I remember correctly, the rekey rate > for good security is mostly dependent on the cipher block size.? I left my > reference books at home; so, I can?t come up with a reference for you, but I > would take Chris?

I'm wondering why the ChaCha20 cipher rekeys so frequently. At speed I'm seeing rekeys every second or two. So I'm spending a large amount of time in the rekey process. From what I've read about ChaCha20 it shouldn't need to be rekeyed quite so frequently. Am I missing something obvious? Just curious more than anything else. Chris

Hi, I am using OpenSSH_5.2p1. It seems ssh server doesn't support key regeneration after a specified amount of time. I manually verified the OpenSSH_5.2p1 and OpenSSH-6.2 source codes and haven?t found any code support for session rekeying in both releases. SSH2 supports session rekeying using the parameter ?RekeyIntervalSeconds? with default value 3600 seconds (one hour) in both

Dear all, while playing around with openssh-4.1p1 (trying to add AFS token forwarding in SSH-2), I noticed that agressive rekeying (as e.g. employed by regress/rekey.sh, rekeying every 16bytes) seems to disturb the various forwardings (X11, agent) set up at the beginning of the session. These do not trigger regression test errors, since the client does not ask for confirmation from the server for

https://bugzilla.mindrot.org/show_bug.cgi?id=2252 Bug ID: 2252 Summary: RekeyLimit breaks ClientAlive Product: Portable OpenSSH Version: 6.6p1 Hardware: All OS: All Status: NEW Severity: normal Priority: P5 Component: sshd Assignee: unassigned-bugs at mindrot.org

https://bugzilla.mindrot.org/show_bug.cgi?id=2573 Bug ID: 2573 Summary: dead sessions cannot be closed with ~. Product: Portable OpenSSH Version: 3.7.1p2 Hardware: Other OS: Linux Status: NEW Severity: normal Priority: P5 Component: ssh Assignee: unassigned-bugs at mindrot.org

Hello, I'm trying to configure the openssh sftp server to perform re-keying. On the client side I've found the RekeyLimit parameter. But I am unable to find an equivalent for the server side. Is it currently not possible to configure the sftp server to perform re-keying? Or have I overlooked something. -- R _________________________________________________________________ Snygga till

https://bugzilla.mindrot.org/show_bug.cgi?id=2572 Bug ID: 2572 Summary: dead sessions aren't closed despite ClientAlive enabled Product: Portable OpenSSH Version: 3.7.1p2 Hardware: All OS: Linux Status: NEW Severity: major Priority: P5 Component: sshd

Ah, with an internal block size [Is that what one calls it?] of 64 bytes. From: Damien Miller <djm at mindrot.org> Sent: Wednesday, March 29, 2023 3:08 PM To: Robinson, Herbie <Herbie.Robinson at stratus.com> Cc: Chris Rapier <rapier at psc.edu>; Christian Weisgerber <naddy at mips.inka.de>; openssh-unix-dev at mindrot.org Subject: RE: [EXTERNAL] Re: ChaCha20 Rekey

https://bugzilla.mindrot.org/show_bug.cgi?id=2929 Bug ID: 2929 Summary: OpenSSH server should not send the SSH_MSG_EXT_INFO message after rekeying Product: Portable OpenSSH Version: 7.7p1 Hardware: Other OS: Linux Status: NEW Severity: enhancement Priority: P5

Hi Damien, >This is what I'm playing with at the moment: if you?re playing with this currently anyway, shouldn?t? >+ /* >+ * Otherwise, use the RFC4344 s3.2 recommendation of 2**(L/4) blocks >+ * before rekeying where L is the blocksize in bits. >+ * Most other ciphers have a 128 bit blocksize, so this equates to >+ * 2**32 blocks / 64GB data. >+ */ >+ return

> Portable OpenSSH is also available via [...] Github: https://github.com/openssh/openssh-portable > > Running the regression tests supplied with Portable OpenSSH does not require installation and is a simply: > > $ ./configure && make tests I was going to try this on Kali Linux (latest version), but ran into trouble right away. No "configure" script exists

https://bugzilla.mindrot.org/show_bug.cgi?id=2726 Bug ID: 2726 Summary: Uploading of large files (1GB+) fails when using SFTP in chrooted configuration Product: Portable OpenSSH Version: 7.3p1 Hardware: amd64 OS: Linux Status: NEW Severity: normal Priority: P5

On Fri, 9 Jun 2023, Chris Rapier wrote: > Hi all, > > When a client requests dynamic remote forwarding with -R it delays forking > into the background. In ssh.c we see > > if (options.fork_after_authentication) { > if (options.exit_on_forward_failure && > options.num_remote_forwards > 0) { > debug("deferring postauth fork until

https://bugzilla.mindrot.org/show_bug.cgi?id=3692 Bug ID: 3692 Summary: rekey.sh doesn't actually test different algorithms Product: Portable OpenSSH Version: 9.7p1 Hardware: Other OS: Linux Status: NEW Severity: enhancement Priority: P5 Component: Regression tests