Messages in this thread | | | Date | Tue, 31 May 2022 07:54:43 -0300 | Subject | Re: PROBLEM: with daemon.c after y2038 on 32-bits Kernel | From | Adhemerval Zanella <> |
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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? >> >>> 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.
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