From f954a53a9a7dced3fb4c80b1e8dd267981ae025d Mon Sep 17 00:00:00 2001 From: cvs2svn Date: Mon, 19 Oct 1998 21:47:13 +0000 Subject: This commit was manufactured by cvs2git to create branch 'OPENBSD_2_4'. --- src/lib/libc/net/rcmd.c | 607 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 607 insertions(+) create mode 100644 src/lib/libc/net/rcmd.c (limited to 'src/lib/libc/net/rcmd.c') diff --git a/src/lib/libc/net/rcmd.c b/src/lib/libc/net/rcmd.c new file mode 100644 index 0000000000..c933f5b447 --- /dev/null +++ b/src/lib/libc/net/rcmd.c @@ -0,0 +1,607 @@ +/* + * Copyright (c) 1995, 1996, 1998 Theo de Raadt. All rights reserved. + * Copyright (c) 1983, 1993, 1994 + * The Regents of the University of California. All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * 3. All advertising materials mentioning features or use of this software + * must display the following acknowledgement: + * This product includes software developed by the University of + * California, Berkeley and its contributors. + * This product includes software developed by Theo de Raadt. + * 4. Neither the name of the University nor the names of its contributors + * may be used to endorse or promote products derived from this software + * without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + */ + +#if defined(LIBC_SCCS) && !defined(lint) +static char *rcsid = "$OpenBSD: rcmd.c,v 1.31 1998/03/19 00:30:05 millert Exp $"; +#endif /* LIBC_SCCS and not lint */ + +#include +#include +#include + +#include +#include + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +int __ivaliduser __P((FILE *, in_addr_t, const char *, const char *)); +static int __icheckhost __P((u_int32_t, const char *)); +static char *__gethostloop __P((u_int32_t)); + +int +rcmd(ahost, rport, locuser, remuser, cmd, fd2p) + char **ahost; + in_port_t rport; + const char *locuser, *remuser, *cmd; + int *fd2p; +{ + struct hostent *hp; + struct sockaddr_in sin, from; + fd_set *readsp = NULL; + int oldmask; + pid_t pid; + int s, lport, timo; + char c, *p; + + /* call rcmdsh() with specified remote shell if appropriate. */ + if (!issetugid() && (p = getenv("RSH"))) { + struct servent *sp = getservbyname("shell", "tcp"); + + if (sp && sp->s_port == rport) + return (rcmdsh(ahost, rport, locuser, remuser, + cmd, p)); + } + + /* use rsh(1) if non-root and remote port is shell. */ + if (geteuid()) { + struct servent *sp = getservbyname("shell", "tcp"); + + if (sp && sp->s_port == rport) + return (rcmdsh(ahost, rport, locuser, remuser, + cmd, NULL)); + } + + pid = getpid(); + hp = gethostbyname(*ahost); + if (hp == NULL) { + herror(*ahost); + return (-1); + } + *ahost = hp->h_name; + + oldmask = sigblock(sigmask(SIGURG)); + for (timo = 1, lport = IPPORT_RESERVED - 1;;) { + s = rresvport(&lport); + if (s < 0) { + if (errno == EAGAIN) + (void)fprintf(stderr, + "rcmd: socket: All ports in use\n"); + else + (void)fprintf(stderr, "rcmd: socket: %s\n", + strerror(errno)); + sigsetmask(oldmask); + return (-1); + } + fcntl(s, F_SETOWN, pid); + bzero(&sin, sizeof sin); + sin.sin_len = sizeof(struct sockaddr_in); + sin.sin_family = hp->h_addrtype; + sin.sin_port = rport; + bcopy(hp->h_addr_list[0], &sin.sin_addr, hp->h_length); + if (connect(s, (struct sockaddr *)&sin, sizeof(sin)) >= 0) + break; + (void)close(s); + if (errno == EADDRINUSE) { + lport--; + continue; + } + if (errno == ECONNREFUSED && timo <= 16) { + (void)sleep(timo); + timo *= 2; + continue; + } + if (hp->h_addr_list[1] != NULL) { + int oerrno = errno; + + (void)fprintf(stderr, "connect to address %s: ", + inet_ntoa(sin.sin_addr)); + errno = oerrno; + perror(0); + hp->h_addr_list++; + bcopy(hp->h_addr_list[0], &sin.sin_addr, hp->h_length); + (void)fprintf(stderr, "Trying %s...\n", + inet_ntoa(sin.sin_addr)); + continue; + } + (void)fprintf(stderr, "%s: %s\n", hp->h_name, strerror(errno)); + sigsetmask(oldmask); + return (-1); + } +#if 0 + /* + * try to rresvport() to the same port. This will make rresvport() + * fail it's first bind, resulting in it choosing a random port. + */ + lport--; +#endif + if (fd2p == 0) { + write(s, "", 1); + lport = 0; + } else { + char num[8]; + int s2 = rresvport(&lport), s3; + int len = sizeof(from); + int fdssize = howmany(MAX(s, s2)+1, NFDBITS) * sizeof(fd_mask); + + if (s2 < 0) + goto bad; + readsp = (fd_set *)malloc(fdssize); + if (readsp == NULL) + goto bad; + listen(s2, 1); + (void)snprintf(num, sizeof(num), "%d", lport); + if (write(s, num, strlen(num)+1) != strlen(num)+1) { + (void)fprintf(stderr, + "rcmd: write (setting up stderr): %s\n", + strerror(errno)); + (void)close(s2); + goto bad; + } +again: + bzero(readsp, fdssize); + FD_SET(s, readsp); + FD_SET(s2, readsp); + errno = 0; + if (select(MAX(s, s2) + 1, readsp, 0, 0, 0) < 1 || + !FD_ISSET(s2, readsp)) { + if (errno != 0) + (void)fprintf(stderr, + "rcmd: select (setting up stderr): %s\n", + strerror(errno)); + else + (void)fprintf(stderr, + "select: protocol failure in circuit setup\n"); + (void)close(s2); + goto bad; + } + s3 = accept(s2, (struct sockaddr *)&from, &len); + /* + * XXX careful for ftp bounce attacks. If discovered, shut them + * down and check for the real auxiliary channel to connect. + */ + if (from.sin_family == AF_INET && from.sin_port == htons(20)) { + close(s3); + goto again; + } + (void)close(s2); + if (s3 < 0) { + (void)fprintf(stderr, + "rcmd: accept: %s\n", strerror(errno)); + lport = 0; + goto bad; + } + *fd2p = s3; + from.sin_port = ntohs(from.sin_port); + if (from.sin_family != AF_INET || + from.sin_port >= IPPORT_RESERVED || + from.sin_port < IPPORT_RESERVED / 2) { + (void)fprintf(stderr, + "socket: protocol failure in circuit setup.\n"); + goto bad2; + } + } + (void)write(s, locuser, strlen(locuser)+1); + (void)write(s, remuser, strlen(remuser)+1); + (void)write(s, cmd, strlen(cmd)+1); + if (read(s, &c, 1) != 1) { + (void)fprintf(stderr, + "rcmd: %s: %s\n", *ahost, strerror(errno)); + goto bad2; + } + if (c != 0) { + while (read(s, &c, 1) == 1) { + (void)write(STDERR_FILENO, &c, 1); + if (c == '\n') + break; + } + goto bad2; + } + sigsetmask(oldmask); + free(readsp); + return (s); +bad2: + if (lport) + (void)close(*fd2p); +bad: + if (readsp) + free(readsp); + (void)close(s); + sigsetmask(oldmask); + return (-1); +} + +int +rresvport(alport) + int *alport; +{ + struct sockaddr_in sin; + int s; + + bzero(&sin, sizeof sin); + sin.sin_len = sizeof(struct sockaddr_in); + sin.sin_family = AF_INET; + sin.sin_addr.s_addr = INADDR_ANY; + s = socket(AF_INET, SOCK_STREAM, 0); + if (s < 0) + return (-1); + sin.sin_port = htons((in_port_t)*alport); + if (*alport < IPPORT_RESERVED - 1) { + if (bind(s, (struct sockaddr *)&sin, sizeof(sin)) >= 0) + return (s); + if (errno != EADDRINUSE) { + (void)close(s); + return (-1); + } + } + sin.sin_port = 0; + if (bindresvport(s, &sin) == -1) { + (void)close(s); + return (-1); + } + *alport = (int)ntohs(sin.sin_port); + return (s); +} + +int __check_rhosts_file = 1; +char *__rcmd_errstr; + +int +ruserok(rhost, superuser, ruser, luser) + const char *rhost, *ruser, *luser; + int superuser; +{ + struct hostent *hp; + char **ap; + int i; +#define MAXADDRS 35 + u_int32_t addrs[MAXADDRS + 1]; + + if ((hp = gethostbyname(rhost)) == NULL) + return (-1); + for (i = 0, ap = hp->h_addr_list; *ap && i < MAXADDRS; ++ap, ++i) + bcopy(*ap, &addrs[i], sizeof(addrs[i])); + addrs[i] = 0; + + for (i = 0; i < MAXADDRS && addrs[i]; i++) + if (iruserok((in_addr_t)addrs[i], superuser, ruser, luser) == 0) + return (0); + return (-1); +} + +/* + * New .rhosts strategy: We are passed an ip address. We spin through + * hosts.equiv and .rhosts looking for a match. When the .rhosts only + * has ip addresses, we don't have to trust a nameserver. When it + * contains hostnames, we spin through the list of addresses the nameserver + * gives us and look for a match. + * + * Returns 0 if ok, -1 if not ok. + */ +int +iruserok(raddr, superuser, ruser, luser) + u_int32_t raddr; + int superuser; + const char *ruser, *luser; +{ + register char *cp; + struct stat sbuf; + struct passwd *pwd; + FILE *hostf; + uid_t uid; + int first; + char pbuf[MAXPATHLEN]; + + first = 1; + hostf = superuser ? NULL : fopen(_PATH_HEQUIV, "r"); +again: + if (hostf) { + if (__ivaliduser(hostf, raddr, luser, ruser) == 0) { + (void)fclose(hostf); + return (0); + } + (void)fclose(hostf); + } + if (first == 1 && (__check_rhosts_file || superuser)) { + first = 0; + if ((pwd = getpwnam(luser)) == NULL) + return (-1); + (void)strcpy(pbuf, pwd->pw_dir); + (void)strcat(pbuf, "/.rhosts"); + + /* + * Change effective uid while opening .rhosts. If root and + * reading an NFS mounted file system, can't read files that + * are protected read/write owner only. + */ + uid = geteuid(); + (void)seteuid(pwd->pw_uid); + hostf = fopen(pbuf, "r"); + (void)seteuid(uid); + + if (hostf == NULL) + return (-1); + /* + * If not a regular file, or is owned by someone other than + * user or root or if writeable by anyone but the owner, quit. + */ + cp = NULL; + if (lstat(pbuf, &sbuf) < 0) + cp = ".rhosts lstat failed"; + else if (!S_ISREG(sbuf.st_mode)) + cp = ".rhosts not regular file"; + else if (fstat(fileno(hostf), &sbuf) < 0) + cp = ".rhosts fstat failed"; + else if (sbuf.st_uid && sbuf.st_uid != pwd->pw_uid) + cp = "bad .rhosts owner"; + else if (sbuf.st_mode & (S_IWGRP|S_IWOTH)) + cp = ".rhosts writeable by other than owner"; + /* If there were any problems, quit. */ + if (cp) { + __rcmd_errstr = cp; + (void)fclose(hostf); + return (-1); + } + goto again; + } + return (-1); +} + +/* + * XXX + * Don't make static, used by lpd(8). + * + * Returns 0 if ok, -1 if not ok. + */ +int +__ivaliduser(hostf, raddrl, luser, ruser) + FILE *hostf; + in_addr_t raddrl; + const char *luser, *ruser; +{ + register char *user, *p; + char *buf; + const char *auser, *ahost; + int hostok, userok; + char *rhost = (char *)-1; + char domain[MAXHOSTNAMELEN]; + u_int32_t raddr = (u_int32_t)raddrl; + size_t buflen; + + getdomainname(domain, sizeof(domain)); + + while ((buf = fgetln(hostf, &buflen))) { + p = buf; + if (*p == '#') + continue; + while (*p != '\n' && *p != ' ' && *p != '\t' && p < buf + buflen) { + if (!isprint(*p)) + goto bail; + *p = isupper(*p) ? tolower(*p) : *p; + p++; + } + if (p >= buf + buflen) + continue; + if (*p == ' ' || *p == '\t') { + *p++ = '\0'; + while ((*p == ' ' || *p == '\t') && p < buf + buflen) + p++; + if (p >= buf + buflen) + continue; + user = p; + while (*p != '\n' && *p != ' ' && + *p != '\t' && p < buf + buflen) { + if (!isprint(*p)) + goto bail; + p++; + } + } else + user = p; + *p = '\0'; + + if (p == buf) + continue; + + auser = *user ? user : luser; + ahost = buf; + + if (strlen(ahost) >= MAXHOSTNAMELEN) + continue; + + /* + * innetgr() must lookup a hostname (we do not attempt + * to change the semantics so that netgroups may have + * #.#.#.# addresses in the list.) + */ + if (ahost[0] == '+') + switch (ahost[1]) { + case '\0': + hostok = 1; + break; + case '@': + if (rhost == (char *)-1) + rhost = __gethostloop(raddr); + hostok = 0; + if (rhost) + hostok = innetgr(&ahost[2], rhost, + NULL, domain); + break; + default: + hostok = __icheckhost(raddr, &ahost[1]); + break; + } + else if (ahost[0] == '-') + switch (ahost[1]) { + case '\0': + hostok = -1; + break; + case '@': + if (rhost == (char *)-1) + rhost = __gethostloop(raddr); + hostok = 0; + if (rhost) + hostok = -innetgr(&ahost[2], rhost, + NULL, domain); + break; + default: + hostok = -__icheckhost(raddr, &ahost[1]); + break; + } + else + hostok = __icheckhost(raddr, ahost); + + + if (auser[0] == '+') + switch (auser[1]) { + case '\0': + userok = 1; + break; + case '@': + userok = innetgr(&auser[2], NULL, ruser, + domain); + break; + default: + userok = strcmp(ruser, &auser[1]) ? 0 : 1; + break; + } + else if (auser[0] == '-') + switch (auser[1]) { + case '\0': + userok = -1; + break; + case '@': + userok = -innetgr(&auser[2], NULL, ruser, + domain); + break; + default: + userok = strcmp(ruser, &auser[1]) ? 0 : -1; + break; + } + else + userok = strcmp(ruser, auser) ? 0 : 1; + + /* Check if one component did not match */ + if (hostok == 0 || userok == 0) + continue; + + /* Check if we got a forbidden pair */ + if (userok <= -1 || hostok <= -1) + return (-1); + + /* Check if we got a valid pair */ + if (hostok >= 1 && userok >= 1) + return (0); + } +bail: + return (-1); +} + +/* + * Returns "true" if match, 0 if no match. If we do not find any + * semblance of an A->PTR->A loop, allow a simple #.#.#.# match to work. + */ +static int +__icheckhost(raddr, lhost) + u_int32_t raddr; + const char *lhost; +{ + register struct hostent *hp; + register char **pp; + struct in_addr in; + + hp = gethostbyname(lhost); + if (hp != NULL) { + /* Spin through ip addresses. */ + for (pp = hp->h_addr_list; *pp; ++pp) + if (!bcmp(&raddr, *pp, sizeof(raddr))) + return (1); + } + + in.s_addr = raddr; + if (strcmp(lhost, inet_ntoa(in)) == 0) + return (1); + return (0); +} + +/* + * Return the hostname associated with the supplied address. + * Do a reverse lookup as well for security. If a loop cannot + * be found, pack the result of inet_ntoa() into the string. + */ +static char * +__gethostloop(raddr) + u_int32_t raddr; +{ + static char remotehost[MAXHOSTNAMELEN]; + struct hostent *hp; + struct in_addr in; + + hp = gethostbyaddr((char *) &raddr, sizeof(raddr), AF_INET); + if (hp == NULL) + return (NULL); + + /* + * Look up the name and check that the supplied + * address is in the list + */ + strncpy(remotehost, hp->h_name, sizeof(remotehost) - 1); + remotehost[sizeof(remotehost) - 1] = '\0'; + hp = gethostbyname(remotehost); + if (hp == NULL) + return (NULL); + + for (; hp->h_addr_list[0] != NULL; hp->h_addr_list++) + if (!bcmp(hp->h_addr_list[0], (caddr_t)&raddr, sizeof(raddr))) + return (remotehost); + + /* + * either the DNS adminstrator has made a configuration + * mistake, or someone has attempted to spoof us + */ + in.s_addr = raddr; + syslog(LOG_NOTICE, "rcmd: address %s not listed for host %s", + inet_ntoa(in), hp->h_name); + return (NULL); +} -- cgit v1.2.3-55-g6feb