Initial integration of a much cleaned up libwrap.

1 files changed, 629 insertions, 0 deletions

diff --git a/lib/libwrap/options.c b/lib/libwrap/options.c
new file mode 100644
index 00000000000..30e456f3887
--- /dev/null
+++ b/lib/libwrap/options.c
@@ -0,0 +1,629 @@
+/*	$OpenBSD: options.c,v 1.1 1997/02/26 03:06:54 downsj Exp $	*/
+
+ /*
+  * General skeleton for adding options to the access control language. The
+  * features offered by this module are documented in the hosts_options(5)
+  * manual page (source file: hosts_options.5, "nroff -man" format).
+  * 
+  * Notes and warnings for those who want to add features:
+  * 
+  * In case of errors, abort options processing and deny access. There are too
+  * many irreversible side effects to make error recovery feasible. For
+  * example, it makes no sense to continue after we have already changed the
+  * userid.
+  * 
+  * In case of errors, do not terminate the process: the routines might be
+  * called from a long-running daemon that should run forever. Instead, call
+  * tcpd_jump() which does a non-local goto back into the hosts_access()
+  * routine.
+  * 
+  * In case of severe errors, use clean_exit() instead of directly calling
+  * exit(), or the inetd may loop on an UDP request.
+  * 
+  * In verification mode (for example, with the "tcpdmatch" command) the
+  * "dry_run" flag is set. In this mode, an option function should just "say"
+  * what it is going to do instead of really doing it.
+  * 
+  * Some option functions do not return (for example, the twist option passes
+  * control to another program). In verification mode (dry_run flag is set)
+  * such options should clear the "dry_run" flag to inform the caller of this
+  * course of action.
+  */
+
+#ifndef lint
+#if 0
+static char sccsid[] = "@(#) options.c 1.17 96/02/11 17:01:31";
+#else
+static char rcsid[] = "$OpenBSD: options.c,v 1.1 1997/02/26 03:06:54 downsj Exp $";
+#endif
+#endif
+
+/* System libraries. */
+
+#include <sys/types.h>
+#include <sys/param.h>
+#include <sys/socket.h>
+#include <sys/stat.h>
+#include <netinet/in.h>
+#include <netdb.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <syslog.h>
+#include <pwd.h>
+#include <grp.h>
+#include <ctype.h>
+#include <setjmp.h>
+#include <string.h>
+#include <unistd.h>
+
+#ifndef MAXPATHNAMELEN
+#define MAXPATHNAMELEN  BUFSIZ
+#endif
+
+/* Local stuff. */
+
+#include "tcpd.h"
+
+/* Options runtime support. */
+
+int     dry_run = 0;			/* flag set in verification mode */
+extern jmp_buf tcpd_buf;		/* tcpd_jump() support */
+
+/* Options parser support. */
+
+static char whitespace_eq[] = "= \t\r\n";
+#define whitespace (whitespace_eq + 1)
+
+static char *get_field();		/* chew :-delimited field off string */
+static char *chop_string();		/* strip leading and trailing blanks */
+
+/* List of functions that implement the options. Add yours here. */
+
+static void user_option();		/* execute "user name.group" option */
+static void group_option();		/* execute "group name" option */
+static void umask_option();		/* execute "umask mask" option */
+static void linger_option();		/* execute "linger time" option */
+static void keepalive_option();		/* execute "keepalive" option */
+static void spawn_option();		/* execute "spawn command" option */
+static void twist_option();		/* execute "twist command" option */
+static void rfc931_option();		/* execute "rfc931" option */
+static void setenv_option();		/* execute "setenv name value" */
+static void nice_option();		/* execute "nice" option */
+static void severity_option();		/* execute "severity value" */
+static void allow_option();		/* execute "allow" option */
+static void deny_option();		/* execute "deny" option */
+static void banners_option();		/* execute "banners path" option */
+
+/* Structure of the options table. */
+
+struct option {
+    char   *name;			/* keyword name, case is ignored */
+    void  (*func) ();			/* function that does the real work */
+    int     flags;			/* see below... */
+};
+
+#define NEED_ARG	(1<<1)		/* option requires argument */
+#define USE_LAST	(1<<2)		/* option must be last */
+#define OPT_ARG		(1<<3)		/* option has optional argument */
+#define EXPAND_ARG	(1<<4)		/* do %x expansion on argument */
+
+#define need_arg(o)	((o)->flags & NEED_ARG)
+#define opt_arg(o)	((o)->flags & OPT_ARG)
+#define permit_arg(o)	((o)->flags & (NEED_ARG | OPT_ARG))
+#define use_last(o)	((o)->flags & USE_LAST)
+#define expand_arg(o)	((o)->flags & EXPAND_ARG)
+
+/* List of known keywords. Add yours here. */
+
+static struct option option_table[] = {
+    "user", user_option, NEED_ARG,
+    "group", group_option, NEED_ARG,
+    "umask", umask_option, NEED_ARG,
+    "linger", linger_option, NEED_ARG,
+    "keepalive", keepalive_option, 0,
+    "spawn", spawn_option, NEED_ARG | EXPAND_ARG,
+    "twist", twist_option, NEED_ARG | EXPAND_ARG | USE_LAST,
+    "rfc931", rfc931_option, OPT_ARG,
+    "setenv", setenv_option, NEED_ARG | EXPAND_ARG,
+    "nice", nice_option, OPT_ARG,
+    "severity", severity_option, NEED_ARG,
+    "allow", allow_option, USE_LAST,
+    "deny", deny_option, USE_LAST,
+    "banners", banners_option, NEED_ARG,
+    0,
+};
+
+/* process_options - process access control options */
+
+void    process_options(options, request)
+char   *options;
+struct request_info *request;
+{
+    char   *key;
+    char   *value;
+    char   *curr_opt;
+    char   *next_opt;
+    struct option *op;
+    char    bf[BUFSIZ];
+
+    for (curr_opt = get_field(options); curr_opt; curr_opt = next_opt) {
+	next_opt = get_field((char *) 0);
+
+	/*
+	 * Separate the option into name and value parts. For backwards
+	 * compatibility we ignore exactly one '=' between name and value.
+	 */
+	curr_opt = chop_string(curr_opt);
+	if (*(value = curr_opt + strcspn(curr_opt, whitespace_eq))) {
+	    if (*value != '=') {
+		*value++ = 0;
+		value += strspn(value, whitespace);
+	    }
+	    if (*value == '=') {
+		*value++ = 0;
+		value += strspn(value, whitespace);
+	    }
+	}
+	if (*value == 0)
+	    value = 0;
+	key = curr_opt;
+
+	/*
+	 * Disallow missing option names (and empty option fields).
+	 */
+	if (*key == 0)
+	    tcpd_jump("missing option name");
+
+	/*
+	 * Lookup the option-specific info and do some common error checks.
+	 * Delegate option-specific processing to the specific functions.
+	 */
+
+	for (op = option_table; op->name && STR_NE(op->name, key); op++)
+	     /* VOID */ ;
+	if (op->name == 0)
+	    tcpd_jump("bad option name: \"%s\"", key);
+	if (!value && need_arg(op))
+	    tcpd_jump("option \"%s\" requires value", key);
+	if (value && !permit_arg(op))
+	    tcpd_jump("option \"%s\" requires no value", key);
+	if (next_opt && use_last(op))
+	    tcpd_jump("option \"%s\" must be at end", key);
+	if (value && expand_arg(op))
+	    value = chop_string(percent_x(bf, sizeof(bf), value, request));
+	if (hosts_access_verbose)
+	    syslog(LOG_DEBUG, "option:   %s %s", key, value ? value : "");
+	(*(op->func)) (value, request);
+    }
+}
+
+/* allow_option - grant access */
+
+/* ARGSUSED */
+
+static void allow_option(value, request)
+char   *value;
+struct request_info *request;
+{
+    longjmp(tcpd_buf, AC_PERMIT);
+}
+
+/* deny_option - deny access */
+
+/* ARGSUSED */
+
+static void deny_option(value, request)
+char   *value;
+struct request_info *request;
+{
+    longjmp(tcpd_buf, AC_DENY);
+}
+
+/* banners_option - expand %<char>, terminate each line with CRLF */
+
+static void banners_option(value, request)
+char   *value;
+struct request_info *request;
+{
+    char    path[MAXPATHNAMELEN];
+    char    ibuf[BUFSIZ];
+    char    obuf[2 * BUFSIZ];
+    struct stat st;
+    int     ch;
+    FILE   *fp;
+
+    sprintf(path, "%s/%s", value, eval_daemon(request));
+    if ((fp = fopen(path, "r")) != 0) {
+	while ((ch = fgetc(fp)) == 0)
+	    write(request->fd, "", 1);
+	ungetc(ch, fp);
+	while (fgets(ibuf, sizeof(ibuf) - 1, fp)) {
+	    if (split_at(ibuf, '\n'))
+		strcat(ibuf, "\r\n");
+	    percent_x(obuf, sizeof(obuf), ibuf, request);
+	    write(request->fd, obuf, strlen(obuf));
+	}
+	fclose(fp);
+    } else if (stat(value, &st) < 0) {
+	tcpd_warn("%s: %m", value);
+    }
+}
+
+/* group_option - switch group id */
+
+/* ARGSUSED */
+
+static void group_option(value, request)
+char   *value;
+struct request_info *request;
+{
+    struct group *grp;
+    struct group *getgrnam();
+
+    if ((grp = getgrnam(value)) == 0)
+	tcpd_jump("unknown group: \"%s\"", value);
+    endgrent();
+
+    if (dry_run == 0 && setgid(grp->gr_gid))
+	tcpd_jump("setgid(%s): %m", value);
+}
+
+/* user_option - switch user id */
+
+/* ARGSUSED */
+
+static void user_option(value, request)
+char   *value;
+struct request_info *request;
+{
+    struct passwd *pwd;
+    struct passwd *getpwnam();
+    char   *group;
+
+    if ((group = split_at(value, '.')) != 0)
+	group_option(group, request);
+    if ((pwd = getpwnam(value)) == 0)
+	tcpd_jump("unknown user: \"%s\"", value);
+    endpwent();
+
+    if (dry_run == 0 && setuid(pwd->pw_uid))
+	tcpd_jump("setuid(%s): %m", value);
+}
+
+/* umask_option - set file creation mask */
+
+/* ARGSUSED */
+
+static void umask_option(value, request)
+char   *value;
+struct request_info *request;
+{
+    unsigned mask;
+    char    junk;
+
+    if (sscanf(value, "%o%c", &mask, &junk) != 1 || (mask & 0777) != mask)
+	tcpd_jump("bad umask value: \"%s\"", value);
+    (void) umask(mask);
+}
+
+/* spawn_option - spawn a shell command and wait */
+
+/* ARGSUSED */
+
+static void spawn_option(value, request)
+char   *value;
+struct request_info *request;
+{
+    if (dry_run == 0)
+	shell_cmd(value);
+}
+
+/* linger_option - set the socket linger time (Marc Boucher <marc@cam.org>) */
+
+/* ARGSUSED */
+
+static void linger_option(value, request)
+char   *value;
+struct request_info *request;
+{
+    struct linger linger;
+    char    junk;
+
+    if (sscanf(value, "%d%c", &linger.l_linger, &junk) != 1
+	|| linger.l_linger < 0)
+	tcpd_jump("bad linger value: \"%s\"", value);
+    if (dry_run == 0) {
+	linger.l_onoff = (linger.l_linger != 0);
+	if (setsockopt(request->fd, SOL_SOCKET, SO_LINGER, (char *) &linger,
+		       sizeof(linger)) < 0)
+	    tcpd_warn("setsockopt SO_LINGER %d: %m", linger.l_linger);
+    }
+}
+
+/* keepalive_option - set the socket keepalive option */
+
+/* ARGSUSED */
+
+static void keepalive_option(value, request)
+char   *value;
+struct request_info *request;
+{
+    static int on = 1;
+
+    if (dry_run == 0 && setsockopt(request->fd, SOL_SOCKET, SO_KEEPALIVE,
+				   (char *) &on, sizeof(on)) < 0)
+	tcpd_warn("setsockopt SO_KEEPALIVE: %m");
+}
+
+/* nice_option - set nice value */
+
+/* ARGSUSED */
+
+static void nice_option(value, request)
+char   *value;
+struct request_info *request;
+{
+    int     niceval = 10;
+    char    junk;
+
+    if (value != 0 && sscanf(value, "%d%c", &niceval, &junk) != 1)
+	tcpd_jump("bad nice value: \"%s\"", value);
+    if (dry_run == 0 && nice(niceval) < 0)
+	tcpd_warn("nice(%d): %m", niceval);
+}
+
+/* twist_option - replace process by shell command */
+
+static void twist_option(value, request)
+char   *value;
+struct request_info *request;
+{
+    char   *error;
+
+    if (dry_run != 0) {
+	dry_run = 0;
+    } else {
+	if (resident > 0)
+	    tcpd_jump("twist option in resident process");
+
+	syslog(deny_severity, "twist %s to %s", eval_client(request), value);
+
+	/* Before switching to the shell, set up stdin, stdout and stderr. */
+
+#define maybe_dup2(from, to) ((from == to) ? to : (close(to), dup(from)))
+
+	if (maybe_dup2(request->fd, 0) != 0 ||
+	    maybe_dup2(request->fd, 1) != 1 ||
+	    maybe_dup2(request->fd, 2) != 2) {
+	    error = "twist_option: dup: %m";
+	} else {
+	    if (request->fd > 2)
+		close(request->fd);
+	    (void) execl("/bin/sh", "sh", "-c", value, (char *) 0);
+	    error = "twist_option: /bin/sh: %m";
+	}
+
+	/* Something went wrong: we MUST terminate the process. */
+
+	tcpd_warn(error);
+	clean_exit(request);
+    }
+}
+
+/* rfc931_option - look up remote user name */
+
+static void rfc931_option(value, request)
+char   *value;
+struct request_info *request;
+{
+    int     timeout;
+    char    junk;
+
+    if (value != 0) {
+	if (sscanf(value, "%d%c", &timeout, &junk) != 1 || timeout <= 0)
+	    tcpd_jump("bad rfc931 timeout: \"%s\"", value);
+	rfc931_timeout = timeout;
+    }
+    (void) eval_user(request);
+}
+
+/* setenv_option - set environment variable */
+
+/* ARGSUSED */
+
+static void setenv_option(value, request)
+char   *value;
+struct request_info *request;
+{
+    char   *var_value;
+
+    if (*(var_value = value + strcspn(value, whitespace)))
+	*var_value++ = 0;
+    if (setenv(chop_string(value), chop_string(var_value), 1))
+	tcpd_jump("memory allocation failure");
+}
+
+ /*
+  * The severity option goes last because it comes with a huge amount of ugly
+  * #ifdefs and tables.
+  */
+
+struct syslog_names {
+    char   *name;
+    int     value;
+};
+
+static struct syslog_names log_fac[] = {
+#ifdef LOG_KERN
+    "kern", LOG_KERN,
+#endif
+#ifdef LOG_USER
+    "user", LOG_USER,
+#endif
+#ifdef LOG_MAIL
+    "mail", LOG_MAIL,
+#endif
+#ifdef LOG_DAEMON
+    "daemon", LOG_DAEMON,
+#endif
+#ifdef LOG_AUTH
+    "auth", LOG_AUTH,
+#endif
+#ifdef LOG_LPR
+    "lpr", LOG_LPR,
+#endif
+#ifdef LOG_NEWS
+    "news", LOG_NEWS,
+#endif
+#ifdef LOG_UUCP
+    "uucp", LOG_UUCP,
+#endif
+#ifdef LOG_CRON
+    "cron", LOG_CRON,
+#endif
+#ifdef LOG_LOCAL0
+    "local0", LOG_LOCAL0,
+#endif
+#ifdef LOG_LOCAL1
+    "local1", LOG_LOCAL1,
+#endif
+#ifdef LOG_LOCAL2
+    "local2", LOG_LOCAL2,
+#endif
+#ifdef LOG_LOCAL3
+    "local3", LOG_LOCAL3,
+#endif
+#ifdef LOG_LOCAL4
+    "local4", LOG_LOCAL4,
+#endif
+#ifdef LOG_LOCAL5
+    "local5", LOG_LOCAL5,
+#endif
+#ifdef LOG_LOCAL6
+    "local6", LOG_LOCAL6,
+#endif
+#ifdef LOG_LOCAL7
+    "local7", LOG_LOCAL7,
+#endif
+    0,
+};
+
+static struct syslog_names log_sev[] = {
+#ifdef LOG_EMERG
+    "emerg", LOG_EMERG,
+#endif
+#ifdef LOG_ALERT
+    "alert", LOG_ALERT,
+#endif
+#ifdef LOG_CRIT
+    "crit", LOG_CRIT,
+#endif
+#ifdef LOG_ERR
+    "err", LOG_ERR,
+#endif
+#ifdef LOG_WARNING
+    "warning", LOG_WARNING,
+#endif
+#ifdef LOG_NOTICE
+    "notice", LOG_NOTICE,
+#endif
+#ifdef LOG_INFO
+    "info", LOG_INFO,
+#endif
+#ifdef LOG_DEBUG
+    "debug", LOG_DEBUG,
+#endif
+    0,
+};
+
+/* severity_map - lookup facility or severity value */
+
+static int severity_map(table, name)
+struct syslog_names *table;
+char   *name;
+{
+    struct syslog_names *t;
+
+    for (t = table; t->name; t++)
+	if (STR_EQ(t->name, name))
+	    return (t->value);
+    tcpd_jump("bad syslog facility or severity: \"%s\"", name);
+    /* NOTREACHED */
+}
+
+/* severity_option - change logging severity for this event (Dave Mitchell) */
+
+/* ARGSUSED */
+
+static void severity_option(value, request)
+char   *value;
+struct request_info *request;
+{
+    char   *level = split_at(value, '.');
+
+    allow_severity = deny_severity = level ?
+	severity_map(log_fac, value) | severity_map(log_sev, level) :
+	severity_map(log_sev, value);
+}
+
+/* get_field - return pointer to next field in string */
+
+static char *get_field(string)
+char   *string;
+{
+    static char *last = "";
+    char   *src;
+    char   *dst;
+    char   *ret;
+    int     ch;
+
+    /*
+     * This function returns pointers to successive fields within a given
+     * string. ":" is the field separator; warn if the rule ends in one. It
+     * replaces a "\:" sequence by ":", without treating the result of
+     * substitution as field terminator. A null argument means resume search
+     * where the previous call terminated. This function destroys its
+     * argument.
+     * 
+     * Work from explicit source or from memory. While processing \: we
+     * overwrite the input. This way we do not have to maintain buffers for
+     * copies of input fields.
+     */
+
+    src = dst = ret = (string ? string : last);
+    if (src[0] == 0)
+	return (0);
+
+    while ((ch = *src)) {
+	if (ch == ':') {
+	    if (*++src == 0)
+		tcpd_warn("rule ends in \":\"");
+	    break;
+	}
+	if (ch == '\\' && src[1] == ':')
+	    src++;
+	*dst++ = *src++;
+    }
+    last = src;
+    *dst = 0;
+    return (ret);
+}
+
+/* chop_string - strip leading and trailing blanks from string */
+
+static char *chop_string(string)
+register char *string;
+{
+    char   *start = 0;
+    char   *end;
+    char   *cp;
+
+    for (cp = string; *cp; cp++) {
+	if (!isspace(*cp)) {
+	    if (start == 0)
+		start = cp;
+	    end = cp;
+	}
+    }
+    return (start ? (end[1] = 0, start) : cp);
+}