remove rhosts, PAM, client host and port checks; some code cleanup and cosmetic changes

1 files changed, 88 insertions, 259 deletions

diff --git a/src/urshd.c b/src/urshd.c
index 9aa7234..3c43194 100644
--- a/src/urshd.c
+++ b/src/urshd.c
@@ -33,10 +33,6 @@
 
 #define PROG "urshd"
 
-/*
- * PAM modifications by Michael K. Johnson <johnsonm@redhat.com>
- */
-
 char copyright[] =
  "@(#) Copyright (c) 1988, 1989 The Regents of the University of California.\n"
  "All rights reserved.\n";
@@ -82,26 +78,21 @@ char rcsid[] =
 #include <ctype.h>
 #include <assert.h>
 #include <sched.h>
+#include <getopt.h>
 
 #include <urshd_config.h>
 
-#if defined(__GLIBC__) && (__GLIBC__ >= 2)
-#define _check_rhosts_file  __check_rhosts_file
-#endif
+#define	OPTIONS	"np:P:"
 
-#ifdef USE_PAM
-#include <security/pam_appl.h>
-#include <security/pam_misc.h>
-static pam_handle_t *pamh;
-#endif /* USE_PAM */
-
-#define	OPTIONS	"ahlLnp:P:"
+static struct option long_options[] = {
+	{"disable-keepalive", no_argument, 0, 'n' },
+	{"priority", required_argument, 0, 'p' },
+	{"command-priority", required_argument, 0, 'P' },
+	{0, 0, 0, 0}
+};
 
 static int keepalive = 1;
-static int check_all = 0;
-static int paranoid = 0;
 static int sent_null;
-static int allow_root_rhosts=0;
 static int priority = 0;
 static int cmd_priority = 0;
 
@@ -117,7 +108,34 @@ static void error(const char *fmt, ...);
 static void doit(struct sockaddr_in *fromp);
 static void getstr(char *buf, int cnt, const char *err);
 
-extern int _check_rhosts_file;
+static void
+set_priority(int sched_priority)
+{
+	struct sched_param schedp;
+
+	memset(&schedp, 0, sizeof(schedp));
+	schedp.sched_priority = sched_priority;
+	sched_setscheduler(0, SCHED_FIFO, &schedp);
+}
+
+static void
+usage(void)
+{
+	syslog(LOG_ERR, "usage: " PROG " [-%s]", OPTIONS);
+	exit(2);
+}
+
+static void
+fatal(const char *fmt, ...)
+{
+	va_list ap;
+
+	va_start(ap, fmt);
+	vsyslog(LOG_ERR, fmt, ap);
+	va_end(ap);
+
+	exit(1);
+}
 
 /*
  * Report error to client.
@@ -126,33 +144,25 @@ extern int _check_rhosts_file;
  * for that connection first.
  */
 static void
-error(const char *fmt, ...) {
+error(const char *fmt, ...)
+{
     va_list ap;
     char buf[BUFSIZ], *bp = buf;
-    
-    if (sent_null == 0)	*bp++ = 1;
+
+    if (sent_null == 0) {
+	    *bp++ = 1;
+    }
+
     va_start(ap, fmt);
-    vsnprintf(bp, sizeof(buf)-1, fmt, ap);
+    vsnprintf(bp, sizeof(buf) - 1, fmt, ap);
     va_end(ap);
+
     write(2, buf, strlen(buf));
 }
 
-static void fail(const char *errorstr, 
-		 const char *remuser, const char *hostname, 
-		 const char *locuser,
-		 const char *cmdbuf) 
+static void
+getstr(char *buf, int cnt, const char *err)
 {
-	/* log the (failed) rsh request */
-	syslog(LOG_INFO|LOG_AUTH, "rsh denied to %s@%s as %s: %s",
-	       remuser, hostname, locuser, errorstr);
-	if (paranoid) {
-	    syslog(LOG_INFO|LOG_AUTH, "rsh command was '%s'", cmdbuf);
-	}
-	error(errorstr, hostname);
-	exit(1);
-}
-
-static void getstr(char *buf, int cnt, const char *err) {
     char c;
     do {
 	if (read(0, &c, 1) != 1) exit(1);
@@ -164,7 +174,9 @@ static void getstr(char *buf, int cnt, const char *err) {
     } while (c != 0);
 }
 
-static int getint(void) {
+static int
+getint(void)
+{
     int port = 0;
     char c;
     do {
@@ -174,7 +186,9 @@ static int getint(void) {
     return port;
 }
 
-static void stderr_parent(int sock, int pype, int pid) {
+static void
+stderr_parent(int sock, int pype, int pid)
+{
     fd_set ready, readfrom;
     char buf[BUFSIZ], sig;
     int one = 1;
@@ -215,126 +229,8 @@ static void stderr_parent(int sock, int pype, int pid) {
 	    else write(sock, buf, cc);
 	}
     }
-    
-#ifdef USE_PAM
-    /*
-     * This does not strike me as the right place for this; this is
-     * in a child process... what does this need to accomplish?
-     *
-     * No, it's not the child process, the code is just confusing.
-     */
-    pam_close_session(pamh, 0);
-    pam_end(pamh, PAM_SUCCESS);
-#endif
-    exit(0);
-}
-
 
-static struct passwd *doauth(const char *remuser, 
-			     const char *hostname, 
-			     const char *locuser)
-{
-#ifdef USE_PAM
-    static struct pam_conv conv = { misc_conv, NULL };
-    int retcode;
-#endif
-    struct passwd *pwd = getpwnam(locuser);
-    if (pwd == NULL) return NULL;
-    if (pwd->pw_uid==0) paranoid = 1;
-
-#ifdef USE_PAM
-    retcode = pam_start("rsh", locuser, &conv, &pamh);
-    if (retcode != PAM_SUCCESS) {
-	syslog(LOG_ERR, "pam_start: %s\n", pam_strerror(pamh, retcode));
-	exit (1);
-    }
-    pam_set_item (pamh, PAM_RUSER, remuser);
-    pam_set_item (pamh, PAM_RHOST, hostname);
-    pam_set_item (pamh, PAM_TTY, "tty");
-    
-    retcode = pam_authenticate(pamh, 0);
-    if (retcode == PAM_SUCCESS) {
-	retcode = pam_acct_mgmt(pamh, 0);
-    }
-    if (retcode == PAM_SUCCESS) {
-	/*
-	 * Why do we need to set groups here?
-	 * Also, this stuff should be moved down near where the setuid() is.
-	 */
-	if (setgid(pwd->pw_gid) != 0) {
-	    pam_end(pamh, PAM_SYSTEM_ERR);
-	    return NULL;
-	}
-	if (initgroups(locuser, pwd->pw_gid) != 0) {
-	    pam_end(pamh, PAM_SYSTEM_ERR);
-	    return NULL;
-	}
-	retcode = pam_setcred(pamh, PAM_ESTABLISH_CRED);
-    }
-    
-    if (retcode == PAM_SUCCESS) {
-	retcode = pam_open_session(pamh,0);
-    }
-    if (retcode != PAM_SUCCESS) {
-	pam_end(pamh, retcode);
-	return NULL;
-    }
-    return pwd;
-#else
-    if (pwd->pw_uid==0 && !allow_root_rhosts) return NULL;
-    if (_check_rhosts_file) {
-	if (ruserok(hostname, pwd->pw_uid==0, remuser, locuser) < 0) {
-	    return NULL;
-	}
-    }
-    return pwd;
-#endif
-}
-
-static const char *findhostname(struct sockaddr_in *fromp,
-				const char *remuser, const char *locuser,
-				const char *cmdbuf) 
-{
-	struct hostent *hp;
-	const char *hostname;
-
-	hp = gethostbyaddr((char *)&fromp->sin_addr, sizeof (struct in_addr),
-			   fromp->sin_family);
-
-	errno = ENOMEM; /* malloc (thus strdup) may not set it */
-	if (hp) hostname = strdup(hp->h_name);
-	else hostname = strdup(inet_ntoa(fromp->sin_addr));
-
-	if (hostname==NULL) {
-	    /* out of memory? */
-	    error("strdup: %s\n", strerror(errno));
-	    exit(1);
-	}
-
-	/*
-	 * Attempt to confirm the DNS. 
-	 */
-#ifdef	RES_DNSRCH
-	_res.options &= ~RES_DNSRCH;
-#endif
-	hp = gethostbyname(hostname);
-	if (hp == NULL) {
-	    syslog(LOG_INFO, "Couldn't look up address for %s", hostname);
-	    fail("Couldn't get address for your host (%s)\n", 
-		 remuser, inet_ntoa(fromp->sin_addr), locuser, cmdbuf);
-	} 
-	while (hp->h_addr_list[0] != NULL) {
-	    if (!memcmp(hp->h_addr_list[0], &fromp->sin_addr,
-			sizeof(fromp->sin_addr))) {
-		return hostname;
-	    }
-	    hp->h_addr_list++;
-	}
-	syslog(LOG_NOTICE, "Host addr %s not listed for host %s",
-	       inet_ntoa(fromp->sin_addr), hp->h_name);
-	fail("Host address mismatch for %s\n", 
-	     remuser, inet_ntoa(fromp->sin_addr), locuser, cmdbuf);
-	return NULL; /* not reachable */
+    exit(0);
 }
 
 static void
@@ -345,7 +241,6 @@ doit(struct sockaddr_in *fromp)
 	char locuser[16], remuser[16];
 	struct passwd *pwd;
 	int sock = -1;
-	const char *hostname;
 	u_short port;
 	int pv[2], pid, ifd;
 
@@ -376,25 +271,18 @@ doit(struct sockaddr_in *fromp)
 		}
 	}
 
-#if 0
-	/* We're running from inetd; socket is already on 0, 1, 2 */
-	dup2(f, 0);
-	dup2(f, 1);
-	dup2(f, 2);
-#endif
-
 	getstr(remuser, sizeof(remuser), "remuser");
 	getstr(locuser, sizeof(locuser), "locuser");
 	getstr(cmdbuf, sizeof(cmdbuf), "command");
-	if (!strcmp(locuser, "root")) paranoid = 1;
-
-	hostname = findhostname(fromp, remuser, locuser, cmdbuf);
 
 	setpwent();
-	pwd = doauth(remuser, hostname, locuser);
+	pwd = getpwnam(locuser);
 	if (pwd == NULL) {
-		fail("Permission denied.\n", 
-		     remuser, hostname, locuser, cmdbuf);
+		syslog(LOG_INFO|LOG_AUTH, PROG " permission denied to %s as %s.",
+		       remuser, locuser);
+		syslog(LOG_INFO|LOG_AUTH, PROG " command was '%s'", cmdbuf);
+		error("Permission denied.\n");
+		exit(1);
 	}
 
 	if (chdir(pwd->pw_dir) < 0) {
@@ -449,8 +337,6 @@ doit(struct sockaddr_in *fromp)
 	    syslog(LOG_ERR, "setlogin() failed: %m");
 	}
 #endif
-#ifndef USE_PAM
-	/* if PAM, already done */
 	if (setgid(pwd->pw_gid)) {
 		syslog(LOG_ERR, "setgid: %m");
 		exit(1);
@@ -459,7 +345,6 @@ doit(struct sockaddr_in *fromp)
 		syslog(LOG_ERR, "initgroups: %m");
 		exit(1);
 	}
-#endif
 	if (setuid(pwd->pw_uid)) {
 		syslog(LOG_ERR, "setuid: %m");
 		exit(1);
@@ -482,9 +367,8 @@ doit(struct sockaddr_in *fromp)
 	else shellname = theshell;
 
 	endpwent();
-	if (paranoid) {
-	    syslog(LOG_INFO|LOG_AUTH, "%s@%s as %s: cmd='%s'",
-		   remuser, hostname, locuser, cmdbuf);
+	if (0) {
+	    syslog(LOG_INFO|LOG_AUTH, "%s as %s: cmd='%s'", remuser, locuser, cmdbuf);
 	}
 
 	/*
@@ -494,23 +378,20 @@ doit(struct sockaddr_in *fromp)
 	for (ifd = getdtablesize()-1; ifd > 2; ifd--) close(ifd);
 
 	if (cmd_priority) {
-		struct sched_param schedp;
-
-		memset(&schedp, 0, sizeof(schedp));
-		schedp.sched_priority = cmd_priority;
-		sched_setscheduler(0, SCHED_FIFO, &schedp);
+		set_priority(cmd_priority);
 	}
+
 	execl(theshell, shellname, "-c", cmdbuf, NULL);
 	perror(theshell);
 	exit(1);
 }
 
-static void network_init(int fd, struct sockaddr_in *fromp)
+static void
+network_init(int fd, struct sockaddr_in *fromp)
 {
 	struct linger linger;
 	socklen_t fromlen;
 	int on=1;
-	int port;
 
 	fromlen = sizeof(*fromp);
 	if (getpeername(fd, (struct sockaddr *) fromp, &fromlen) < 0) {
@@ -527,11 +408,6 @@ static void network_init(int fd, struct sockaddr_in *fromp)
 	    sizeof (linger)) < 0)
 		syslog(LOG_WARNING, "setsockopt (SO_LINGER): %m");
 
-	if (fromp->sin_family != AF_INET) {
-	    syslog(LOG_ERR, "malformed \"from\" address (af %d)\n",
-		   fromp->sin_family);
-	    exit(1);
-	}
 #ifdef IP_OPTIONS
       {
 	u_char optbuf[BUFSIZ/3], *cp;
@@ -568,19 +444,10 @@ static void network_init(int fd, struct sockaddr_in *fromp)
 	}
       }
 #endif
-
-	/*
-	 * Check originating port for validity.
-	 */
-	port = ntohs(fromp->sin_port);
-	if (port >= IPPORT_RESERVED || port < IPPORT_RESERVED/2) {
-	    syslog(LOG_NOTICE|LOG_AUTH, "Connection from %s on illegal port",
-		   inet_ntoa(fromp->sin_addr));
-	    exit(1);
-	}
 }
 
-int mainloop(char *port)
+static int
+mainloop(char *port)
 {
 	int s;
 	struct servent *sp;
@@ -591,65 +458,54 @@ int mainloop(char *port)
 	sn.sin_family = AF_INET;
 
 	if (priority) {
-		struct sched_param schedp;
-
-		memset(&schedp, 0, sizeof(schedp));
-		schedp.sched_priority = priority;
-		sched_setscheduler(0, SCHED_FIFO, &schedp);
+		set_priority(priority);
 	}
 
 	if (port) {
-		if ((sp = getservbyname(port, "tcp"))!=NULL) {
+		if ((sp = getservbyname(port, "tcp")) != NULL) {
 			sn.sin_port = sp->s_port;
-		}
-		else {
+		} else {
 			int pt = atoi(port);
 			if (pt <= 0) {
-				fprintf(stderr, "telnetd: %s: bad port number\n",
-					port);
-				exit(1);
+				fatal("%s: bad port number", port);
 			}
 			sn.sin_port = htons(pt);
 		}
 	} else {
 		sp = getservbyname("shell", "tcp");
 		if (sp == 0) {
-			fprintf(stderr, PROG ": tcp/shell: unknown service\n");
-			exit(1);
+			fatal("tcp/shell: unknown service");
 		}
 		sn.sin_port = sp->s_port;
 	}
 
 	s = socket(AF_INET, SOCK_STREAM, 0);
 	if (s < 0) {
-		perror(PROG ": socket");;
-		exit(1);
+		fatal("socket: %s", strerror(errno));
 	}
 	(void) setsockopt(s, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on));
 	if (bind(s, (struct sockaddr *)&sn, sizeof(sn)) < 0) {
-		perror(PROG ": bind");
-		exit(1);
+		fatal("bind: %s", strerror(errno));
 	}
 	if (listen(s, 1) < 0) {
-		perror(PROG ": listen");
-		exit(1);
+		fatal("listen: %s", strerror(errno));
 	}
 	while (1) {
 		socklen_t len;
 		int ns, pid;
 		struct sockaddr_in from;
 
-		fprintf(stderr, PROG ": waiting for connections.\n");
+		syslog(LOG_INFO, "Waiting for connections.");
+
 		len = sizeof(sn);
 		ns = accept(s, (struct sockaddr *)&sn, &len);
 		if (ns < 0) {
-			perror(PROG ": accept");
-			exit(1);
+			fatal("accept: %s", strerror(errno));
 		}
+
 		if ((pid = fork()) < 0) {
-			perror(PROG ": fork");
-		}
-		else if (pid == 0) {
+			fatal("fork: %s", strerror(errno));
+		} else if (pid == 0) {
 			close(s);
 			dup2(ns, 0);
 			dup2(ns, 1);
@@ -657,8 +513,7 @@ int mainloop(char *port)
 			close(ns);
 			network_init(0, &from);
 			doit(&from);
-		}
-		else {
+		} else {
 			close(ns);
 		}
 	}
@@ -668,33 +523,16 @@ int
 main(int argc, char *argv[])
 {
 	int ch;
-	_check_rhosts_file=1;
 
 	openlog(PROG, LOG_PID | LOG_ODELAY, LOG_DAEMON);
 
 	opterr = 0;
-	while ((ch = getopt(argc, argv, OPTIONS)) != EOF) {
+	while ((ch = getopt_long(argc, argv, OPTIONS, long_options, NULL)) != EOF) {
 		switch (ch) {
-		case 'a':
-			check_all = 1;
-			break;
-
-		case 'h':
-			allow_root_rhosts = 1;
-			break;
-
-		case 'l':
-			_check_rhosts_file = 0;
-			break;
-
 		case 'n':
 			keepalive = 0;
 			break;
 
-		case 'L':
-			paranoid = 1;
-			break;
-
 		case 'p':
 			priority = atoi(optarg);
 			break;
@@ -705,23 +543,14 @@ main(int argc, char *argv[])
 
 		case '?':
 		default:
-			syslog(LOG_ERR, "usage: " PROG " [-%s]", OPTIONS);
-			exit(2);
+			usage();
 		}
 	}
-	argc -= optind;
-	argv += optind;
 
-#ifdef USE_PAM
-       if (_check_rhosts_file == 0 || allow_root_rhosts)
-               syslog(LOG_ERR, "-l and -h functionality has been moved to "
-                               "pam_rhosts_auth in /etc/pam.conf");
-#endif /* USE_PAM */
+	if (optind < argc) {
+		usage();
+	}
 
 	mainloop(0);
 	return 0;
 }
-
-
-
-