Hello
On 31/05/2022 10:33, Arnd Bergmann wrote:
(cc correct libc-alpha list, sorry for the typo)
On Tue, May 31, 2022 at 10:24 AM Arnd Bergmannarnd@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'm using Buildroot, I added it to TARGET_CPPFLAGS (also used by TARGET_CLAGS) and HOST_CPPFLAGS (used by HOST_CFLAGS) in buildroot/package/Makefile.in
Then all packages are built with the option (unless the package filter it out, I had to create patches for few of them).
Extracts of logs while rebuild openssh:
/home/arnaud/devenv/branches/kernel510/output/host/bin/i686-buildroot-linux-gnu-gcc -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64 -D_TIME_BITS=64 -Os -g0 -D_FORTIFY_SOURCE=1 -pipe -Wno-error=format-truncation -Wall -Wextra -Wpointer-arith -Wuninitialized -Wsign-compare -Wformat-security -Wsizeof-pointer-memaccess -Wno-pointer-sign -Wno-unused-parameter -Wno-unused-result -Wimplicit-fallthrough -fno-strict-aliasing -ftrapv -fno-builtin-memset -fstack-protector-strong -fPIC -I. -I.. -I. -I./.. -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64 -D_TIME_BITS=64 -D_XOPEN_SOURCE=600 -D_BSD_SOURCE -D_DEFAULT_SOURCE -DHAVE_CONFIG_H -c daemon.c
/home/arnaud/devenv/branches/kernel510/output/host/bin/i686-buildroot-linux-gnu-gcc -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64 -D_TIME_BITS=64 -Os -g0 -D_FORTIFY_SOURCE=1 -pipe -Wno-error=format-truncation -Wall -Wextra -Wpointer-arith -Wuninitialized -Wsign-compare -Wformat-security -Wsizeof-pointer-memaccess -Wno-pointer-sign -Wno-unused-parameter -Wno-unused-result -Wimplicit-fallthrough -fno-strict-aliasing -ftrapv -fno-builtin-memset -fstack-protector-strong -fPIE -I. -I. -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64 -D_TIME_BITS=64 -D_XOPEN_SOURCE=600 -D_BSD_SOURCE -D_DEFAULT_SOURCE -DSSHDIR="/etc/ssh" -D_PATH_SSH_PROGRAM="/usr/bin/ssh" -D_PATH_SSH_ASKPASS_DEFAULT="/usr/libexec/ssh-askpass" -D_PATH_SFTP_SERVER="/usr/libexec/sftp-server" -D_PATH_SSH_KEY_SIGN="/usr/libexec/ssh-keysign" -D_PATH_SSH_PKCS11_HELPER="/usr/libexec/ssh-pkcs11-helper" -D_PATH_SSH_SK_HELPER="/usr/libexec/ssh-sk-helper" -D_PATH_SSH_PIDDIR="/var/run" -D_PATH_PRIVSEP_CHROOT_DIR="/var/empty" -DHAVE_CONFIG_H -c sshd.c -o sshd.o
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?
I'd tried previously to build the entire distro with musl without success, not sure I can do it only for openssh.
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.
--
*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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