Messages in this thread | | | From | Arnd Bergmann <> | Date | Tue, 31 May 2022 10:33:05 +0200 | Subject | Re: PROBLEM: with daemon.c after y2038 on 32-bits Kernel |
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(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); > } > > __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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