bec925d29d
utmpx is specified by POSIX as an XSI extension. That's more portable than utmp, which is unavailable for example in musl libc. The manual page specifies that in Linux (but it probably means in glibc), utmp and utmpx (and the functions that use them) are identical, so this commit shouldn't affect glibc systems. Assume utmpx is always present. Also, if utmpx is present, POSIX guarantees that some members exist: - ut_user - ut_id - ut_line - ut_pid - ut_type - ut_tv So, rely on them unconditionally. Fixes:170b76cdd1("Disable utmpx permanently") Closes: <https://github.com/shadow-maint/shadow/issues/945> Reported-by: Firas Khalil Khana <firasuke@gmail.com> Reported-by: "A. Wilfox" <https://github.com/awilfox> Tested-by: Firas Khalil Khana <firasuke@gmail.com> Reviewed-by: Iker Pedrosa <ipedrosa@redhat.com> Signed-off-by: Alejandro Colomar <alx@kernel.org> Cherry-picked-from:64bcb54fa9("lib/, src/, configure.ac: Use utmpx instead of utmp") Signed-off-by: Alejandro Colomar <alx@kernel.org>
94 lines
2.3 KiB
C
94 lines
2.3 KiB
C
/*
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* SPDX-FileCopyrightText: 1989 - 1994, Julianne Frances Haugh
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* SPDX-FileCopyrightText: 1996 - 1998, Marek Michałkiewicz
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* SPDX-FileCopyrightText: 2003 - 2005, Tomasz Kłoczko
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* SPDX-FileCopyrightText: 2008 , Nicolas François
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*
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* SPDX-License-Identifier: BSD-3-Clause
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*/
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#include <config.h>
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#ident "$Id$"
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#include <sys/types.h>
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#include <pwd.h>
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#include <fcntl.h>
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#include <time.h>
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#include "defines.h"
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#include <lastlog.h>
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#include "prototypes.h"
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/*
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* dolastlog - create lastlog entry
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*
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* A "last login" entry is created for the user being logged in. The
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* UID is extracted from the global (struct passwd) entry and the
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* TTY information is gotten from the (struct utmpx).
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*/
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void dolastlog (
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struct lastlog *ll,
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const struct passwd *pw,
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/*@unique@*/const char *line,
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/*@unique@*/const char *host)
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{
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int fd;
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off_t offset;
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struct lastlog newlog;
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time_t ll_time;
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/*
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* If the file does not exist, don't create it.
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*/
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fd = open (LASTLOG_FILE, O_RDWR);
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if (-1 == fd) {
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return;
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}
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/*
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* The file is indexed by UID number. Seek to the record
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* for this UID. Negative UID's will create problems, but ...
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*/
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offset = (off_t) pw->pw_uid * sizeof newlog;
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if (lseek (fd, offset, SEEK_SET) != offset) {
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SYSLOG ((LOG_WARN,
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"Can't read last lastlog entry for UID %lu in %s. Entry not updated.",
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(unsigned long) pw->pw_uid, LASTLOG_FILE));
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(void) close (fd);
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return;
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}
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/*
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* Read the old entry so we can tell the user when they last
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* logged in. Then construct the new entry and write it out
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* the way we read the old one in.
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*/
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if (read (fd, &newlog, sizeof newlog) != (ssize_t) sizeof newlog) {
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memzero (&newlog, sizeof newlog);
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}
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if (NULL != ll) {
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*ll = newlog;
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}
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ll_time = newlog.ll_time;
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(void) time (&ll_time);
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newlog.ll_time = ll_time;
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strncpy (newlog.ll_line, line, sizeof (newlog.ll_line) - 1);
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#if HAVE_LL_HOST
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strncpy (newlog.ll_host, host, sizeof (newlog.ll_host) - 1);
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#endif
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if ( (lseek (fd, offset, SEEK_SET) != offset)
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|| (write_full (fd, &newlog, sizeof newlog) != (ssize_t) sizeof newlog)
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|| (close (fd) != 0)) {
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SYSLOG ((LOG_WARN,
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"Can't write lastlog entry for UID %lu in %s.",
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(unsigned long) pw->pw_uid, LASTLOG_FILE));
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(void) close (fd);
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}
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}
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