loginrec.c

OpenSSL Source code for SFTP, SSH, and many others

/*
 * 'line' string utility functions
 *
 * These functions process the 'line' string into one of three forms:
 *
 * 1. The full filename (including '/dev')
 * 2. The stripped name (excluding '/dev')
 * 3. The abbreviated name (e.g. /dev/ttyp00 -> yp00
 *                               /dev/pts/1  -> ts/1 )
 *
 * Form 3 is used on some systems to identify a .tmp.? entry when
 * attempting to remove it. Typically both addition and removal is
 * performed by one application - say, sshd - so as long as the choice
 * uniquely identifies a terminal it's ok.
 */


/* line_fullname(): add the leading '/dev/' if it doesn't exist make
 * sure dst has enough space, if not just copy src (ugh) */
char *
line_fullname(char *dst, const char *src, int dstsize)
{
	memset(dst, '\0', dstsize);
	if ((strncmp(src, "/dev/", 5) == 0) || (dstsize < (strlen(src) + 5))) {
		strlcpy(dst, src, dstsize);
	} else {
		strlcpy(dst, "/dev/", dstsize);
		strlcat(dst, src, dstsize);
	}
	return dst;
}

/* line_stripname(): strip the leading '/dev' if it exists, return dst */
char *
line_stripname(char *dst, const char *src, int dstsize)
{
	memset(dst, '\0', dstsize);
	if (strncmp(src, "/dev/", 5) == 0)
		strlcpy(dst, src + 5, dstsize);
	else
		strlcpy(dst, src, dstsize);
	return dst;
}

/* line_abbrevname(): Return the abbreviated (usually four-character)
 * form of the line (Just use the last <dstsize> characters of the
 * full name.)
 *
 * NOTE: use strncpy because we do NOT necessarily want zero
 * termination */
char *
line_abbrevname(char *dst, const char *src, int dstsize)
{
	size_t len;

	memset(dst, '\0', dstsize);

	/* Always skip prefix if present */
	if (strncmp(src, "/dev/", 5) == 0)
		src += 5;

#ifdef WITH_ABBREV_NO_TTY
	if (strncmp(src, "tty", 3) == 0)
		src += 3;
#endif

	len = strlen(src);

	if (len > 0) {
		if (((int)len - dstsize) > 0)
			src +=  ((int)len - dstsize);

		/* note: _don't_ change this to strlcpy */
		strncpy(dst, src, (size_t)dstsize);
	}

	return dst;
}

/**
 ** utmp utility functions
 **
 ** These functions manipulate struct utmp, taking system differences
 ** into account.
 **/

#if defined(USE_UTMP) || defined (USE_WTMP) || defined (USE_LOGIN)

/* build the utmp structure */
void
set_utmp_time(struct logininfo *li, struct utmp *ut)
{
# ifdef HAVE_TV_IN_UTMP
	ut->ut_tv.tv_sec = li->tv_sec;
	ut->ut_tv.tv_usec = li->tv_usec;
# else
#  ifdef HAVE_TIME_IN_UTMP
	ut->ut_time = li->tv_sec;
#  endif
# endif
}

void
construct_utmp(struct logininfo *li,
		    struct utmp *ut)
{
	memset(ut, '\0', sizeof(*ut));

	/* First fill out fields used for both logins and logouts */

# ifdef HAVE_ID_IN_UTMP
	line_abbrevname(ut->ut_id, li->line, sizeof(ut->ut_id));
# endif

# ifdef HAVE_TYPE_IN_UTMP
	/* This is done here to keep utmp constants out of struct logininfo */
	switch (li->type) {
	case LTYPE_LOGIN:
		ut->ut_type = USER_PROCESS;
#ifdef _CRAY
		cray_set_tmpdir(ut);
#endif
		break;
	case LTYPE_LOGOUT:
		ut->ut_type = DEAD_PROCESS;
#ifdef _CRAY
		cray_retain_utmp(ut, li->pid);
#endif
		break;
	}
# endif
	set_utmp_time(li, ut);

	line_stripname(ut->ut_line, li->line, sizeof(ut->ut_line));

# ifdef HAVE_PID_IN_UTMP
	ut->ut_pid = li->pid;
# endif

	/* If we're logging out, leave all other fields blank */
	if (li->type == LTYPE_LOGOUT)
	  return;

	/*
	 * These fields are only used when logging in, and are blank
	 * for logouts.
	 */

	/* Use strncpy because we don't necessarily want null termination */
	strncpy(ut->ut_name, li->username, MIN_SIZEOF(ut->ut_name, li->username));
# ifdef HAVE_HOST_IN_UTMP
	strncpy(ut->ut_host, li->hostname, MIN_SIZEOF(ut->ut_host, li->hostname));
# endif
# ifdef HAVE_ADDR_IN_UTMP
	/* this is just a 32-bit IP address */
	if (li->hostaddr.sa.sa_family == AF_INET)
		ut->ut_addr = li->hostaddr.sa_in.sin_addr.s_addr;
# endif
}
#endif /* USE_UTMP || USE_WTMP || USE_LOGIN */

/**
 ** utmpx utility functions
 **
 ** These functions manipulate struct utmpx, accounting for system
 ** variations.
 **/

#if defined(USE_UTMPX) || defined (USE_WTMPX)
/* build the utmpx structure */
void
set_utmpx_time(struct logininfo *li, struct utmpx *utx)
{
# ifdef HAVE_TV_IN_UTMPX
	utx->ut_tv.tv_sec = li->tv_sec;
	utx->ut_tv.tv_usec = li->tv_usec;
# else /* HAVE_TV_IN_UTMPX */
#  ifdef HAVE_TIME_IN_UTMPX
	utx->ut_time = li->tv_sec;
#  endif /* HAVE_TIME_IN_UTMPX */
# endif /* HAVE_TV_IN_UTMPX */
}

void
construct_utmpx(struct logininfo *li, struct utmpx *utx)
{
	memset(utx, '\0', sizeof(*utx));
# ifdef HAVE_ID_IN_UTMPX
	line_abbrevname(utx->ut_id, li->line, sizeof(utx->ut_id));
# endif

	/* this is done here to keep utmp constants out of loginrec.h */
	switch (li->type) {
	case LTYPE_LOGIN:
		utx->ut_type = USER_PROCESS;
		break;
	case LTYPE_LOGOUT:
		utx->ut_type = DEAD_PROCESS;
		break;
	}
	line_stripname(utx->ut_line, li->line, sizeof(utx->ut_line));
	set_utmpx_time(li, utx);
	utx->ut_pid = li->pid;
	/* strncpy(): Don't necessarily want null termination */
	strncpy(utx->ut_name, li->username, MIN_SIZEOF(utx->ut_name, li->username));

	if (li->type == LTYPE_LOGOUT)
		return;

	/*
	 * These fields are only used when logging in, and are blank
	 * for logouts.
	 */

# ifdef HAVE_HOST_IN_UTMPX
	strncpy(utx->ut_host, li->hostname, MIN_SIZEOF(utx->ut_host, li->hostname));
# endif
# ifdef HAVE_ADDR_IN_UTMPX
	/* this is just a 32-bit IP address */
	if (li->hostaddr.sa.sa_family == AF_INET)
		utx->ut_addr = li->hostaddr.sa_in.sin_addr.s_addr;
# endif
# ifdef HAVE_SYSLEN_IN_UTMPX
	/* ut_syslen is the length of the utx_host string */
	utx->ut_syslen = MIN(strlen(li->hostname), sizeof(utx->ut_host));
# endif
}
#endif /* USE_UTMPX || USE_WTMPX */

/**
 ** Low-level utmp functions
 **/

/* FIXME: (ATL) utmp_write_direct needs testing */
#ifdef USE_UTMP

/* if we can, use pututline() etc. */
# if !defined(DISABLE_PUTUTLINE) && defined(HAVE_SETUTENT) && \
	defined(HAVE_PUTUTLINE)
#  define UTMP_USE_LIBRARY
# endif


/* write a utmp entry with the system's help (pututline() and pals) */
# ifdef UTMP_USE_LIBRARY
static int
utmp_write_library(struct logininfo *li, struct utmp *ut)
{
	setutent();
	pututline(ut);

#  ifdef HAVE_ENDUTENT
	endutent();
#  endif
	return 1;
}
# else /* UTMP_USE_LIBRARY */

/* write a utmp entry direct to the file */
/* This is a slightly modification of code in OpenBSD's login.c */
static int
utmp_write_direct(struct logininfo *li, struct utmp *ut)
{
	struct utmp old_ut;
	register int fd;
	int tty;

	/* FIXME: (ATL) ttyslot() needs local implementation */

#if defined(HAVE_GETTTYENT)
	register struct ttyent *ty;

	tty=0;

	setttyent();
	while ((struct ttyent *)0 != (ty = getttyent())) {
		tty++;
		if (!strncmp(ty->ty_name, ut->ut_line, sizeof(ut->ut_line)))
			break;
	}
	endttyent();

	if((struct ttyent *)0 == ty) {
		log("utmp_write_entry: tty not found");
		return(1);
	}
#else /* FIXME */

	tty = ttyslot(); /* seems only to work for /dev/ttyp? style names */

#endif /* HAVE_GETTTYENT */

	if (tty > 0 && (fd = open(UTMP_FILE, O_RDWR|O_CREAT, 0644)) >= 0) {
		(void)lseek(fd, (off_t)(tty * sizeof(struct utmp)), SEEK_SET);
		/*
		 * Prevent luser from zero'ing out ut_host.
		 * If the new ut_line is empty but the old one is not
		 * and ut_line and ut_name match, preserve the old ut_line.
		 */
		if (atomicio(read, fd, &old_ut, sizeof(old_ut)) == sizeof(old_ut) &&
			(ut->ut_host[0] == '\0') && (old_ut.ut_host[0] != '\0') &&
			(strncmp(old_ut.ut_line, ut->ut_line, sizeof(ut->ut_line)) == 0) &&
			(strncmp(old_ut.ut_name, ut->ut_name, sizeof(ut->ut_name)) == 0)) {
			(void)memcpy(ut->ut_host, old_ut.ut_host, sizeof(ut->ut_host));
		}

		(void)lseek(fd, (off_t)(tty * sizeof(struct utmp)), SEEK_SET);
		if (atomicio(write, fd, ut, sizeof(*ut)) != sizeof(*ut))
			log("utmp_write_direct: error writing %s: %s",
			    UTMP_FILE, strerror(errno));

		(void)close(fd);
		return 1;
	} else {
		return 0;
	}
}
# endif /* UTMP_USE_LIBRARY */

static int
utmp_perform_login(struct logininfo *li)
{
	struct utmp ut;

	construct_utmp(li, &ut);
# ifdef UTMP_USE_LIBRARY
	if (!utmp_write_library(li, &ut)) {
		log("utmp_perform_login: utmp_write_library() failed");
		return 0;
	}
# else
	if (!utmp_write_direct(li, &ut)) {
		log("utmp_perform_login: utmp_write_direct() failed");
		return 0;
	}
# endif
	return 1;
}


static int
utmp_perform_logout(struct logininfo *li)
{
	struct utmp ut;

	construct_utmp(li, &ut);
# ifdef UTMP_USE_LIBRARY
	if (!utmp_write_library(li, &ut)) {
		log("utmp_perform_logout: utmp_write_library() failed");
		return 0;
	}
# else
	if (!utmp_write_direct(li, &ut)) {
		log("utmp_perform_logout: utmp_write_direct() failed");
		return 0;
	}
# endif
	return 1;
}


int
utmp_write_entry(struct logininfo *li)
{
	switch(li->type) {
	case LTYPE_LOGIN:
		return utmp_perform_login(li);

	case LTYPE_LOGOUT:
		return utmp_perform_logout(li);

	default:
		log("utmp_write_entry: invalid type field");
		return 0;
	}
}
#endif /* USE_UTMP */


/**
 ** Low-level utmpx functions
 **/

/* not much point if we don't want utmpx entries */
#ifdef USE_UTMPX

/* if we have the wherewithall, use pututxline etc. */
# if !defined(DISABLE_PUTUTXLINE) && defined(HAVE_SETUTXENT) && \
	defined(HAVE_PUTUTXLINE)
#  define UTMPX_USE_LIBRARY
# endif


/* write a utmpx entry with the system's help (pututxline() and pals) */
# ifdef UTMPX_USE_LIBRARY
static int
utmpx_write_library(struct logininfo *li, struct utmpx *utx)
{
	setutxent();
	pututxline(utx);

#  ifdef HAVE_ENDUTXENT
	endutxent();
#  endif
	return 1;
}

# else /* UTMPX_USE_LIBRARY */

/* write a utmp entry direct to the file */
static int
utmpx_write_direct(struct logininfo *li, struct utmpx *utx)
{
	log("utmpx_write_direct: not implemented!");
	return 0;
}
# endif /* UTMPX_USE_LIBRARY */

static int
utmpx_perform_login(struct logininfo *li)
{
	struct utmpx utx;

	construct_utmpx(li, &utx);
# ifdef UTMPX_USE_LIBRARY
	if (!utmpx_write_library(li, &utx)) {
		log("utmpx_perform_login: utmp_write_library() failed");
		return 0;
	}
# else
	if (!utmpx_write_direct(li, &ut)) {
		log("utmpx_perform_login: utmp_write_direct() failed");
		return 0;
	}
# endif
	return 1;
}


static int
utmpx_perform_logout(struct logininfo *li)
{
	struct utmpx utx;

	construct_utmpx(li, &utx);
# ifdef HAVE_ID_IN_UTMPX
	line_abbrevname(utx.ut_id, li->line, sizeof(utx.ut_id));
# endif
# ifdef HAVE_TYPE_IN_UTMPX
	utx.ut_type = DEAD_PROCESS;
# endif

# ifdef UTMPX_USE_LIBRARY
	utmpx_write_library(li, &utx);
# else
	utmpx_write_direct(li, &utx);
# endif
	return 1;
}

int
utmpx_write_entry(struct logininfo *li)
{
	switch(li->type) {
	case LTYPE_LOGIN:
		return utmpx_perform_login(li);
	case LTYPE_LOGOUT:
		return utmpx_perform_logout(li);
	default:
		log("utmpx_write_entry: invalid type field");
		return 0;
	}
}
#endif /* USE_UTMPX */


/**
 ** Low-level wtmp functions
 **/

#ifdef USE_WTMP

/* write a wtmp entry direct to the end of the file */
/* This is a slight modification of code in OpenBSD's logwtmp.c */
static int
wtmp_write(struct logininfo *li, struct utmp *ut)
{
	struct stat buf;
	int fd, ret = 1;

	if ((fd = open(WTMP_FILE, O_WRONLY|O_APPEND, 0)) < 0) {
		log("wtmp_write: problem writing %s: %s",
		    WTMP_FILE, strerror(errno));
		return 0;
	}
	if (fstat(fd, &buf) == 0)
		if (atomicio(write, fd, ut, sizeof(*ut)) != sizeof(*ut)) {
			ftruncate(fd, buf.st_size);
			log("wtmp_write: problem writing %s: %s",
			    WTMP_FILE, strerror(errno));
			ret = 0;
		}
	(void)close(fd);