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-rw-r--r--lib/utmp.c434
1 files changed, 434 insertions, 0 deletions
diff --git a/lib/utmp.c b/lib/utmp.c
new file mode 100644
index 0000000..08e9b62
--- /dev/null
+++ b/lib/utmp.c
@@ -0,0 +1,434 @@
+/*
+ * SPDX-FileCopyrightText: 1989 - 1994, Julianne Frances Haugh
+ * SPDX-FileCopyrightText: 1996 - 1999, Marek Michałkiewicz
+ * SPDX-FileCopyrightText: 2001 - 2005, Tomasz Kłoczko
+ * SPDX-FileCopyrightText: 2008 - 2009, Nicolas François
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <config.h>
+
+#include "defines.h"
+#include "prototypes.h"
+#include "getdef.h"
+
+#include <utmpx.h>
+#include <assert.h>
+#include <sys/param.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <netdb.h>
+#include <stdio.h>
+#include <fcntl.h>
+
+#include "alloc.h"
+#include "sizeof.h"
+#include "string/strncpy.h"
+#include "string/strtcpy.h"
+#include "string/zustr2stp.h"
+
+#ident "$Id$"
+
+
+#define UTX_LINESIZE NITEMS(memberof(struct utmpx, ut_line))
+
+
+/*
+ * is_my_tty -- determine if "tty" is the same TTY stdin is using
+ */
+static bool
+is_my_tty(const char tty[UTX_LINESIZE])
+{
+ char full_tty[STRLEN("/dev/") + UTX_LINESIZE + 1];
+ /* tmptty shall be bigger than full_tty */
+ static char tmptty[sizeof(full_tty) + 1];
+
+ full_tty[0] = '\0';
+ if (tty[0] != '/')
+ strcpy (full_tty, "/dev/");
+ strncat(full_tty, tty, UTX_LINESIZE);
+
+ if ('\0' == tmptty[0]) {
+ const char *tname = ttyname (STDIN_FILENO);
+ if (NULL != tname)
+ STRTCPY(tmptty, tname);
+ }
+
+ if ('\0' == tmptty[0]) {
+ (void) puts (_("Unable to determine your tty name."));
+ exit (EXIT_FAILURE);
+ }
+
+ return strcmp (full_tty, tmptty) == 0;
+}
+
+
+/*
+ * failtmp - update the cumulative failure log
+ *
+ * failtmp updates the (struct utmpx) formatted failure log which
+ * maintains a record of all login failures.
+ */
+static void
+failtmp(const char *username, const struct utmpx *failent)
+{
+ const char *ftmp;
+ int fd;
+
+ /*
+ * Get the name of the failure file. If no file has been defined
+ * in login.defs, don't do this.
+ */
+
+ ftmp = getdef_str ("FTMP_FILE");
+ if (NULL == ftmp) {
+ return;
+ }
+
+ /*
+ * Open the file for append. It must already exist for this
+ * feature to be used.
+ */
+
+ fd = open (ftmp, O_WRONLY | O_APPEND);
+ if (-1 == fd) {
+ if (errno != ENOENT) {
+ SYSLOG ((LOG_WARN,
+ "Can't append failure of user %s to %s: %m",
+ username, ftmp));
+ }
+ return;
+ }
+
+ /*
+ * Append the new failure record and close the log file.
+ */
+
+ if (write_full(fd, failent, sizeof *failent) == -1) {
+ goto err_write;
+ }
+
+ if (close (fd) != 0 && errno != EINTR) {
+ goto err_close;
+ }
+
+ return;
+
+err_write:
+ {
+ int saved_errno = errno;
+ (void) close (fd);
+ errno = saved_errno;
+ }
+err_close:
+ SYSLOG ((LOG_WARN,
+ "Can't append failure of user %s to %s: %m",
+ username, ftmp));
+}
+
+
+/*
+ * get_current_utmp - return the most probable utmp entry for the current
+ * session
+ *
+ * The utmp file is scanned for an entry with the same process ID.
+ * The line entered by the *getty / telnetd, etc. should also match
+ * the current terminal.
+ *
+ * When an entry is returned by get_current_utmp, and if the utmpx
+ * structure has a ut_id field, this field should be used to update
+ * the entry information.
+ *
+ * Return NULL if no entries exist in utmp for the current process.
+ */
+static /*@null@*/ /*@only@*/struct utmpx *
+get_current_utmp(void)
+{
+ struct utmpx *ut;
+ struct utmpx *ret = NULL;
+
+ setutxent();
+
+ /* First, try to find a valid utmp entry for this process. */
+ while ((ut = getutxent()) != NULL) {
+ if ( (ut->ut_pid == getpid ())
+ && ('\0' != ut->ut_id[0])
+ && ( (LOGIN_PROCESS == ut->ut_type)
+ || (USER_PROCESS == ut->ut_type))
+ /* A process may have failed to close an entry
+ * Check if this entry refers to the current tty */
+ && is_my_tty(ut->ut_line))
+ {
+ break;
+ }
+ }
+
+ if (NULL != ut) {
+ ret = XMALLOC(1, struct utmpx);
+ memcpy (ret, ut, sizeof (*ret));
+ }
+
+ endutxent();
+
+ return ret;
+}
+
+
+int
+get_session_host(char **out)
+{
+ int ret = 0;
+ struct utmpx *ut;
+
+ ut = get_current_utmp();
+
+#if defined(HAVE_STRUCT_UTMPX_UT_HOST)
+ if ((ut != NULL) && (ut->ut_host[0] != '\0')) {
+ char *hostname;
+
+ hostname = XMALLOC(sizeof(ut->ut_host) + 1, char);
+ ZUSTR2STP(hostname, ut->ut_host);
+ *out = hostname;
+ free (ut);
+ } else {
+ *out = NULL;
+ ret = -2;
+ }
+#else
+ *out = NULL;
+ ret = -2;
+#endif
+
+ return ret;
+}
+
+
+#if !defined(USE_PAM) && !defined(HAVE_UPDWTMPX)
+/*
+ * Some systems already have updwtmpx(). Others
+ * don't, so we re-implement these functions if necessary.
+ */
+static void
+updwtmpx(const char *filename, const struct utmpx *ut)
+{
+ int fd;
+
+ fd = open (filename, O_APPEND | O_WRONLY, 0);
+ if (fd >= 0) {
+ write_full(fd, ut, sizeof(*ut));
+ close (fd);
+ }
+}
+#endif
+
+
+/*
+ * prepare_utmp - prepare an utmp entry so that it can be logged in a
+ * utmp/wtmp file.
+ *
+ * It accepts an utmp entry in input (ut) to return an entry with
+ * the right ut_id. This is typically an entry returned by
+ * get_current_utmp
+ * If ut is NULL, ut_id will be forged based on the line argument.
+ *
+ * The ut_host field of the input structure may also be kept, and is
+ * used to define the ut_addr/ut_addr_v6 fields. (if these fields
+ * exist)
+ *
+ * Other fields are discarded and filed with new values (if they
+ * exist).
+ *
+ * The returned structure shall be freed by the caller.
+ */
+static /*@only@*/struct utmpx *
+prepare_utmp(const char *name, const char *line, const char *host,
+ /*@null@*/const struct utmpx *ut)
+{
+ char *hostname = NULL;
+ struct utmpx *utent;
+ struct timeval tv;
+
+ assert (NULL != name);
+ assert (NULL != line);
+
+
+
+ if ( (NULL != host)
+ && ('\0' != host[0])) {
+ hostname = XMALLOC(strlen(host) + 1, char);
+ strcpy (hostname, host);
+#if defined(HAVE_STRUCT_UTMPX_UT_HOST)
+ } else if ( (NULL != ut)
+ && ('\0' != ut->ut_host[0])) {
+ hostname = XMALLOC(NITEMS(ut->ut_host) + 1, char);
+ ZUSTR2STP(hostname, ut->ut_host);
+#endif
+ }
+
+ if (strncmp(line, "/dev/", 5) == 0) {
+ line += 5;
+ }
+
+
+ utent = XCALLOC(1, struct utmpx);
+
+
+ utent->ut_type = USER_PROCESS;
+ utent->ut_pid = getpid ();
+ STRNCPY(utent->ut_line, line);
+ if (NULL != ut) {
+ STRNCPY(utent->ut_id, ut->ut_id);
+ } else {
+ /* XXX - assumes /dev/tty?? */
+ STRNCPY(utent->ut_id, line + 3);
+ }
+#if defined(HAVE_STRUCT_UTMPX_UT_NAME)
+ STRNCPY(utent->ut_name, name);
+#endif
+ STRNCPY(utent->ut_user, name);
+ if (NULL != hostname) {
+ struct addrinfo *info = NULL;
+#if defined(HAVE_STRUCT_UTMPX_UT_HOST)
+ STRNCPY(utent->ut_host, hostname);
+#endif
+#if defined(HAVE_STRUCT_UTMPX_UT_SYSLEN)
+ utent->ut_syslen = MIN (strlen (hostname),
+ sizeof (utent->ut_host));
+#endif
+#if defined(HAVE_STRUCT_UTMPX_UT_ADDR) || defined(HAVE_STRUCT_UTMPX_UT_ADDR_V6)
+ if (getaddrinfo (hostname, NULL, NULL, &info) == 0) {
+ /* getaddrinfo might not be reliable.
+ * Just try to log what may be useful.
+ */
+ if (info->ai_family == AF_INET) {
+ struct sockaddr_in *sa =
+ (struct sockaddr_in *) info->ai_addr;
+# if defined(HAVE_STRUCT_UTMPX_UT_ADDR)
+ memcpy (&(utent->ut_addr),
+ &(sa->sin_addr),
+ MIN (sizeof (utent->ut_addr),
+ sizeof (sa->sin_addr)));
+# endif
+# if defined(HAVE_STRUCT_UTMPX_UT_ADDR_V6)
+ memcpy (utent->ut_addr_v6,
+ &(sa->sin_addr),
+ MIN (sizeof (utent->ut_addr_v6),
+ sizeof (sa->sin_addr)));
+ } else if (info->ai_family == AF_INET6) {
+ struct sockaddr_in6 *sa =
+ (struct sockaddr_in6 *) info->ai_addr;
+ memcpy (utent->ut_addr_v6,
+ &(sa->sin6_addr),
+ MIN (sizeof (utent->ut_addr_v6),
+ sizeof (sa->sin6_addr)));
+# endif
+ }
+ freeaddrinfo (info);
+ }
+#endif
+ free (hostname);
+ }
+ /* ut_exit is only for DEAD_PROCESS */
+ utent->ut_session = getsid (0);
+ if (gettimeofday (&tv, NULL) == 0) {
+#if defined(HAVE_STRUCT_UTMPX_UT_TIME)
+ utent->ut_time = tv.tv_sec;
+#endif
+#if defined(HAVE_STRUCT_UTMPX_UT_XTIME)
+ utent->ut_xtime = tv.tv_usec;
+#endif
+ utent->ut_tv.tv_sec = tv.tv_sec;
+ utent->ut_tv.tv_usec = tv.tv_usec;
+ }
+
+ return utent;
+}
+
+
+/*
+ * setutmp - Update an entry in utmp and log an entry in wtmp
+ *
+ * Return 1 on failure and 0 on success.
+ */
+static int
+setutmp(struct utmpx *ut)
+{
+ int err = 0;
+
+ assert (NULL != ut);
+
+ setutxent();
+ if (pututxline(ut) == NULL) {
+ err = 1;
+ }
+ endutxent();
+
+#if !defined(USE_PAM)
+ /* This is done by pam_lastlog */
+ updwtmpx(_WTMP_FILE, ut);
+#endif
+
+ return err;
+}
+
+
+int
+update_utmp(const char *user, const char *tty, const char *host)
+{
+ struct utmpx *utent, *ut;
+
+ utent = get_current_utmp ();
+ ut = prepare_utmp (user, tty, host, utent);
+
+ (void) setutmp (ut); /* make entry in the utmp & wtmp files */
+
+ free(utent);
+ free(ut);
+
+ return 0;
+}
+
+
+void
+record_failure(const char *failent_user, const char *tty, const char *hostname)
+{
+ struct utmpx *utent, *failent;
+
+ if (getdef_str ("FTMP_FILE") != NULL) {
+ utent = get_current_utmp ();
+ failent = prepare_utmp (failent_user, tty, hostname, utent);
+ failtmp (failent_user, failent);
+ free (utent);
+ free (failent);
+ }
+}
+
+
+unsigned long
+active_sessions_count(const char *name, unsigned long limit)
+{
+ struct utmpx *ut;
+ unsigned long count = 0;
+
+ setutxent();
+ while ((ut = getutxent()))
+ {
+ if (USER_PROCESS != ut->ut_type) {
+ continue;
+ }
+ if ('\0' == ut->ut_user[0]) {
+ continue;
+ }
+ if (strncmp (name, ut->ut_user, sizeof (ut->ut_user)) != 0) {
+ continue;
+ }
+ count++;
+ if (count > limit) {
+ break;
+ }
+ }
+ endutxent();
+
+ return count;
+}
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