On 17/05/2022 09:51, Arnaud Panaïotis wrote:
> Hello,
>
> I'm working for a client to generate embedded 32-bits Linux Kernel working after y2038 issue.
>
> 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).
To clarify: did you build just openssh with -D_TIME_BITS=64, or did
you build the user space
this way?
> After 2038, /usr/sbin/sshd does not create an error but it child does generate this one:
> 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));
My guess is that there are parts of glibc that are not fully
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);
}
__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.
(cc correct libc-alpha list, sorry for the typo)
On Tue, May 31, 2022 at 10:24 AM Arnd Bergmann <[email protected]> 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.
> >
> > 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).
>
> To clarify: did you build just openssh with -D_TIME_BITS=64, or did
> you build the entire user space this way?
>
> > After 2038, /usr/sbin/sshd does not create an error but it child does generate this one:
> > 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));
>
> My guess is that there are parts of glibc that are not fully
> 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);
> }
>
> __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.
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 <[email protected]> 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.
>>>
>>> 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).
>>
>> To clarify: did you build just openssh with -D_TIME_BITS=64, or did
>> you build the entire user space this way?
>>
>>> After 2038, /usr/sbin/sshd does not create an error but it child does generate this one:
>>> 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));
>>
>> My guess is that there are parts of glibc that are not fully
>> 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);
>> }
Thanks for catching it, I have opened a bug report for it [1] and I will fix
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.
Hello,
On 31/05/2022 12:54, Adhemerval Zanella wrote:
>
> 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 <[email protected]> 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.
>>>>
>>>> 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).
>>> To clarify: did you build just openssh with -D_TIME_BITS=64, or did
>>> you build the entire user space this way?
I made a patch for the whole Builroot, this way all packages are built
with it (unless it is filter-out, I had to make few patches).
Option is present in build log for daemon.c and sshd.c
>>>
>>>> After 2038, /usr/sbin/sshd does not create an error but it child does generate this one:
>>>> 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));
>>> My guess is that there are parts of glibc that are not fully
>>> 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);
>>> }
> Thanks for catching it, I have opened a bug report for it [1] and I will fix
> and backport to 2.34 and 2.35.
>
> [1] https://sourceware.org/bugzilla/show_bug.cgi?id=29203
Thanks, I'll watch this.
>
>>> __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?
Musl did not worked previously for me, not sure for openssh only within
Buildroot.
I'll test the patch from ticket 29203, probably the easiest solution for me.
>>>
>>> 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.
--
*Arnaud PANAÏOTIS* | Lead Developer Freelance
+33 6 34 82 12 62 | [email protected] <mailto:Arnaud Panaïotis
<[email protected]>>
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--
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