Bug 3329

Summary:

Certificate validity dates greater than 32bit are truncated to 2038-01-19T03:14:07

Product:

Portable OpenSSH

Reporter:

Anthony J. Martinez <anthony>

Component:

ssh-keygen

Assignee:

Assigned to nobody <unassigned-bugs>

Status:

CLOSED FIXED

Severity:

normal

CC:

dtucker

Priority:

Version:

8.4p1

Hardware:

All

OS:

Linux

Bug Depends on:

Bug Blocks:

3302

Attachments:

Description	Flags
allow formatting dates >INT_MAX	none
allow formatting dates >INT_MAX	none

Description Anthony J. Martinez 2021-07-01 22:20:08 AEST

Creation of certificates with validity dates beyond the 32-bit limit are truncated to the edge.

Example from 8.4p1:

[user@disp8853 ~]$ ssh-keygen -t ecdsa -N "" -q -f ca
[user@disp8853 ~]$ ssh-keygen -t ecdsa -N "" -q -f user
[user@disp8853 ~]$ ssh-keygen -s ca -I bug-report -z 911 -n 32bitdates -V always:20390101 user.pub
Signed user key user-cert.pub: id "bug-report" serial 911 for 32bitdates valid before 2038-01-19T03:14:07
[user@disp8853 ~]$ ssh -V
OpenSSH_8.4p1, OpenSSL 1.1.1k  FIPS 25 Mar 2021

This has been observed in several versions from 7.x to 8.x on x86_64 (Windows and Linux), and armv7 (Linux)

Comment 1 Darren Tucker 2021-07-02 13:25:53 AEST

It looks like the cert validity is fine, it's the formatting function that has the limit:

        if (cert->valid_after != 0) {
                /* XXX revisit INT_MAX in 2038 :) */
                tt = cert->valid_after > INT_MAX ?
                    INT_MAX : cert->valid_after;
                tm = localtime(&tt);
                strftime(from, sizeof(from), "%Y-%m-%dT%H:%M:%S", tm);
        }

Unfortunately there's no TIME_T_MAX, and while we can figure out how big time_t is but there's nothing specifying whether it's signed or unsigned.

Anyway there's a format_absolute_time in misc.c, we should factor these out of sshkey.c and fix it in format_absolute_time.

Comment 2 Darren Tucker 2021-07-02 13:57:57 AEST

Created attachment 3531 [details]
allow formatting dates >INT_MAX

This patch ought to fix it on platforms with 64bit time_t, although it'll also require some work in configure to be correct on other systems.

Comment 3 Darren Tucker 2021-07-02 14:00:25 AEST

Created attachment 3532 [details]
allow formatting dates >INT_MAX

Comment 4 Anthony J. Martinez 2021-07-02 16:35:21 AEST

That makes a lot more sense. I'm not a C programmer by any means, but I saw uint64 in the cert creation code and the protocol spec and was baffled by this output from ssh-keygen. Thanks for finding the root cause!

Comment 5 Darren Tucker 2021-07-13 11:07:34 AEST

The fixes have gone in and will be in the next major release.  Thanks for the report.

https://github.com/openssh/openssh-portable/commit/6c29b387cd64a57b0ec8ae7d2c8d02789d88fcc3
and
https://github.com/openssh/openssh-portable/commit/f5fc6a4c3404bbf65c21ca6361853b33d78aa87e

Comment 6 Damien Miller 2022-02-25 13:57:56 AEDT

closing bugs resolved before openssh-8.9