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 arnd@kernel.org 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.
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.
ArndTo 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.
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*Arnaud PANAÏOTIS* | Lead Developer Freelance +33 6 34 82 12 62 | arnaud.panaiotis@gmx.fr <mailto:Arnaud Panaïotis arnaud.panaiotis@gmx.fr>
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