On 31/05/2022 05:33, Arnd Bergmann via Libc-alpha wrote:
(cc correct libc-alpha list, sorry for the typo)
On Tue, May 31, 2022 at 10:24 AM Arnd Bergmann <arnd@xxxxxxxxxx> wrote:
On 17/05/2022 09:51, Arnaud Panaïotis wrote:
I'm working for a client to generate embedded 32-bits Linux Kernel working after y2038 issue.To clarify: did you build just openssh with -D_TIME_BITS=64, or did
I generated a 5.15 Kernel thought Buildroot with Coreutils 9.0, GCC 11.2.0, Binutils 2.37, Glibc 2.34-9 and CFLAGS -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64 -D_TIME_BITS=64.
I encounter an issue while working with OpenSSH (I initially contacted them before).
you build the entire user space this way?
Thanks, I'll watch this.Thanks for catching it, I have opened a bug report for it [1] and I will fix
After 2038, /usr/sbin/sshd does not create an error but it child does generate this one:My guess is that there are parts of glibc that are not fully
daemon() failed: Value too large for defined data type
This happend here in sshd.c:
2019 /*
2020 * If not in debugging mode, not started from inetd and not already
2021 * daemonized (eg re-exec via SIGHUP), disconnect from the controlling
2022 * terminal, and fork. The original process exits.
2023 */
2024 already_daemon = daemonized();
2025 if (!(debug_flag || inetd_flag || no_daemon_flag || already_daemon)) {
2026
2027 if (daemon(0, 0) == -1)
2028 fatal("daemon() failed: %.200s", strerror(errno));
y2038-safe at the moment, but
merely provide the interfaces for time64 applications.
In the glibc code, I see
int
daemon (int nochdir, int noclose)
{
...
if ((fd = __open_nocancel(_PATH_DEVNULL, O_RDWR, 0)) != -1
&& (__builtin_expect (__fstat64 (fd, &st), 0)
== 0)) {
...
} else {
__close_nocancel_nostatus (fd);
return -1;
}
return (0);
}
and backport to 2.34 and 2.35.
[1] https://sourceware.org/bugzilla/show_bug.cgi?id=29203
__fstatat64 (int fd, const char *file, struct stat64 *buf, int flags)
{
struct __stat64_t64 st_t64;
return __fstatat64_time64 (fd, file, &st_t64, flags)
?: __cp_stat64_t64_stat64 (&st_t64, buf);
}
If I'm reading this correctly, daemon() internally uses the time32
version of 'stat', which fails for files with out-of-range timestamps.
Are you able to rebuild the ssh binary (or your entire distro, if that's
easier) against musl-1.2.x instead of glibc to see if the same thing
happens there?
--
Arnd
To reproduce:
# date -s "2040-05-12"
# hwclock --systohc
# reboot
# /usr/sbin/sshd
Note this error occurs only after the reboot, and setting a date before 2038 also require a reboot to remove the error.
strace and gdb trace linked.
Let me know if you need additional information.