glibc/inet/rcmd.c

775 lines
19 KiB
C

/*
* Copyright (C) 1998 WIDE Project.
* 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. Neither the name of the project 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 PROJECT 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 PROJECT 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.
*/
/*
* 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.
* 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 sccsid[] = "@(#)rcmd.c 8.3 (Berkeley) 3/26/94";
#endif /* LIBC_SCCS and not lint */
#include <sys/param.h>
#include <sys/poll.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <alloca.h>
#include <signal.h>
#include <fcntl.h>
#include <netdb.h>
#include <unistd.h>
#include <pwd.h>
#include <errno.h>
#include <stdio.h>
#include <ctype.h>
#include <string.h>
#include <libintl.h>
#include <stdlib.h>
int __ivaliduser __P ((FILE *, u_int32_t, const char *, const char *));
static int __validuser2_sa __P ((FILE *, struct sockaddr *, size_t,
const char *, const char *, const char *));
static int ruserok2_sa (struct sockaddr *ra, size_t ralen,
int superuser, const char *ruser,
const char *luser, const char *rhost);
static int ruserok_sa (struct sockaddr *ra, size_t ralen,
int superuser, const char *ruser,
const char *luser);
int iruserok_af (const void *raddr, int superuser, const char *ruser,
const char *luser, sa_family_t af);
int iruserok (u_int32_t raddr, int superuser, const char *ruser,
const char *luser);
static char ahostbuf[NI_MAXHOST];
int
rcmd_af(ahost, rport, locuser, remuser, cmd, fd2p, af)
char **ahost;
u_short rport;
const char *locuser, *remuser, *cmd;
int *fd2p;
sa_family_t af;
{
char paddr[INET6_ADDRSTRLEN];
size_t hstbuflen;
char *tmphstbuf;
struct addrinfo hints, *res, *ai;
struct sockaddr_storage from;
struct pollfd pfd[2];
int32_t oldmask;
pid_t pid;
int s, lport, timo, error;
char c;
int refused;
char num[8];
if (af != AF_INET && af != AF_INET6)
{
__set_errno (EAFNOSUPPORT);
return -1;
}
pid = __getpid();
memset(&hints, '\0', sizeof(hints));
hints.ai_flags = AI_CANONNAME;
hints.ai_family = af;
hints.ai_socktype = SOCK_STREAM;
(void)snprintf(num, sizeof(num), "%d", ntohs(rport));
error = getaddrinfo(*ahost, num, &hints, &res);
if (error) {
fprintf(stderr, "rcmd: getaddrinfo: %s\n",
gai_strerror(error));
return (-1);
}
pfd[0].events = POLLIN;
pfd[1].events = POLLIN;
if (res->ai_canonname){
strncpy(ahostbuf, res->ai_canonname, sizeof(ahostbuf));
ahostbuf[sizeof(ahostbuf)-1] = '\0';
*ahost = ahostbuf;
}
else
*ahost = NULL;
ai = res;
refused = 0;
oldmask = __sigblock(sigmask(SIGURG));
for (timo = 1, lport = IPPORT_RESERVED - 1;;) {
s = rresvport_af(&lport, ai->ai_family);
if (s < 0) {
if (errno == EAGAIN)
fprintf(stderr,
_("rcmd: socket: All ports in use\n"));
else
fprintf(stderr, "rcmd: socket: %m\n");
__sigsetmask(oldmask);
freeaddrinfo(res);
return -1;
}
__fcntl(s, F_SETOWN, pid);
if (__connect(s, ai->ai_addr, ai->ai_addrlen) >= 0)
break;
(void)__close(s);
if (errno == EADDRINUSE) {
lport--;
continue;
}
if (errno == ECONNREFUSED)
refused = 1;
if (ai->ai_next != NULL) {
int oerrno = errno;
getnameinfo(ai->ai_addr, ai->ai_addrlen,
paddr, sizeof(paddr),
NULL, 0,
NI_NUMERICHOST);
fprintf(stderr, "connect to address %s: ", paddr);
__set_errno (oerrno);
perror(0);
ai = ai->ai_next;
getnameinfo(ai->ai_addr, ai->ai_addrlen,
paddr, sizeof(paddr),
NULL, 0,
NI_NUMERICHOST);
fprintf(stderr, "Trying %s...\n", paddr);
continue;
}
if (refused && timo <= 16) {
(void)sleep(timo);
timo *= 2;
ai = res;
refused = 0;
continue;
}
freeaddrinfo(res);
(void)fprintf(stderr, "%s: %s\n", *ahost, strerror(errno));
__sigsetmask(oldmask);
return -1;
}
lport--;
if (fd2p == 0) {
__write(s, "", 1);
lport = 0;
} else {
char num[8];
int s2 = rresvport_af(&lport, ai->ai_family), s3;
size_t len = ai->ai_addrlen;
if (s2 < 0)
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): %m\n"));
(void)__close(s2);
goto bad;
}
pfd[0].fd = s;
pfd[1].fd = s2;
__set_errno (0);
if (__poll (pfd, 2, -1) < 1 || (pfd[1].revents & POLLIN) == 0){
if (errno != 0)
(void)fprintf(stderr,
_("rcmd: poll (setting up stderr): %m\n"));
else
(void)fprintf(stderr,
_("poll: protocol failure in circuit setup\n"));
(void)__close(s2);
goto bad;
}
s3 = accept(s2, (struct sockaddr *)&from, &len);
switch (from.__ss_family) {
case AF_INET:
rport = ntohs(((struct sockaddr_in *)&from)->sin_port);
break;
case AF_INET6:
rport = ntohs(((struct sockaddr_in6 *)&from)->sin6_port);
break;
default:
rport = 0;
break;
}
(void)__close(s2);
if (s3 < 0) {
(void)fprintf(stderr,
"rcmd: accept: %m\n");
lport = 0;
goto bad;
}
*fd2p = s3;
if (rport >= IPPORT_RESERVED || rport < 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: %m\n", *ahost);
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);
freeaddrinfo(res);
return s;
bad2:
if (lport)
(void)__close(*fd2p);
bad:
(void)__close(s);
__sigsetmask(oldmask);
freeaddrinfo(res);
return -1;
}
int
rcmd(ahost, rport, locuser, remuser, cmd, fd2p)
char **ahost;
u_short rport;
const char *locuser, *remuser, *cmd;
int *fd2p;
{
return rcmd_af (ahost, rport, locuser, remuser, cmd, fd2p, AF_INET);
}
int
rresvport_af(alport, family)
int *alport;
sa_family_t family;
{
struct sockaddr_storage ss;
int s;
size_t len;
uint16_t *sport, i;
switch(family){
case AF_INET:
len = sizeof(struct sockaddr_in);
sport = &((struct sockaddr_in *)&ss)->sin_port;
break;
case AF_INET6:
len = sizeof(struct sockaddr_in6);
sport = &((struct sockaddr_in6 *)&ss)->sin6_port;
break;
default:
__set_errno (EAFNOSUPPORT);
return -1;
}
s = socket(family, SOCK_STREAM, 0);
if (s < 0)
return -1;
memset (&ss, '\0', sizeof(ss));
#ifdef SALEN
ss.__ss_len = len;
#endif
ss.__ss_family = family;
for (;;) {
*sport = htons(i);
if (bind(s, (struct sockaddr *)&ss, len) >= 0){
*alport = i;
return s;
}
if (errno != EADDRINUSE) {
(void)__close(s);
return -1;
}
(*alport)--;
if (*alport == IPPORT_RESERVED/2)
break;
}
(void)__close(s);
__set_errno (EAGAIN);
return -1;
}
int
rresvport(alport)
int *alport;
{
return rresvport_af(alport, AF_INET);
}
int __check_rhosts_file = 1;
char *__rcmd_errstr;
int
ruserok_af(rhost, superuser, ruser, luser, af)
const char *rhost, *ruser, *luser;
int superuser;
sa_family_t af;
{
struct addrinfo hints, *res, *res0;
int gai;
int ret;
memset (&hints, '\0', sizeof(hints));
hints.ai_family = af;
gai = getaddrinfo(rhost, NULL, &hints, &res0);
if (gai)
return -1;
ret = -1;
for (res=res0; res; res=res->ai_next)
if (ruserok2_sa(res->ai_addr, res->ai_addrlen,
superuser, ruser, luser, rhost) == 0){
ret = 0;
break;
}
freeaddrinfo(res0);
return (ret);
}
int
ruserok(rhost, superuser, ruser, luser)
const char *rhost, *ruser, *luser;
int superuser;
{
return ruserok_af(rhost, superuser, ruser, luser, AF_INET);
}
/* Extremely paranoid file open function. */
static FILE *
iruserfopen (char *file, uid_t okuser)
{
struct stat st;
char *cp = NULL;
FILE *res = NULL;
/* If not a regular file, if owned by someone other than user or
root, if writeable by anyone but the owner, or if hardlinked
anywhere, quit. */
cp = NULL;
if (__lxstat (_STAT_VER, file, &st))
cp = _("lstat failed");
else if (!S_ISREG (st.st_mode))
cp = _("not regular file");
else
{
res = fopen (file, "r");
if (!res)
cp = _("cannot open");
else if (__fxstat (_STAT_VER, fileno (res), &st) < 0)
cp = _("fstat failed");
else if (st.st_uid && st.st_uid != okuser)
cp = _("bad owner");
else if (st.st_mode & (S_IWGRP|S_IWOTH))
cp = _("writeable by other than owner");
else if (st.st_nlink > 1)
cp = _("hard linked somewhere");
}
/* If there were any problems, quit. */
if (cp != NULL)
{
__rcmd_errstr = cp;
if (res)
fclose (res);
return NULL;
}
return res;
}
/*
* 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.
*/
static int
ruserok2_sa (ra, ralen, superuser, ruser, luser, rhost)
struct sockaddr *ra;
size_t ralen;
int superuser;
const char *ruser, *luser, *rhost;
{
FILE *hostf = NULL;
int isbad = -1;
if (!superuser)
hostf = iruserfopen (_PATH_HEQUIV, 0);
if (hostf)
{
isbad = __validuser2_sa (hostf, ra, ralen, luser, ruser, rhost);
fclose (hostf);
if (!isbad)
return 0;
}
if (__check_rhosts_file || superuser)
{
char *pbuf;
struct passwd pwdbuf, *pwd;
size_t dirlen;
size_t buflen = __sysconf (_SC_GETPW_R_SIZE_MAX);
char *buffer = __alloca (buflen);
uid_t uid;
if (__getpwnam_r (luser, &pwdbuf, buffer, buflen, &pwd) != 0
|| pwd == NULL)
return -1;
dirlen = strlen (pwd->pw_dir);
pbuf = alloca (dirlen + sizeof "/.rhosts");
__mempcpy (__mempcpy (pbuf, pwd->pw_dir, dirlen),
"/.rhosts", sizeof "/.rhosts");
/* Change effective uid while reading .rhosts. If root and
reading an NFS mounted file system, can't read files that
are protected read/write owner only. */
uid = __geteuid ();
seteuid (pwd->pw_uid);
hostf = iruserfopen (pbuf, pwd->pw_uid);
if (hostf != NULL)
{
isbad = __validuser2_sa (hostf, ra, ralen, luser, ruser, rhost);
fclose (hostf);
}
seteuid (uid);
return isbad;
}
return -1;
}
/*
* ruserok_sa() is now discussed on ipng, so
* currently disabled for external use
*/
static int ruserok_sa(ra, ralen, superuser, ruser, luser)
struct sockaddr *ra;
size_t ralen;
int superuser;
const char *ruser, *luser;
{
ruserok2_sa(ra, ralen, superuser, ruser, luser, "-");
}
/* This is the exported version. */
int
iruserok_af (raddr, superuser, ruser, luser, af)
const void *raddr;
int superuser;
const char *ruser, *luser;
sa_family_t af;
{
struct sockaddr_storage ra;
size_t ralen;
memset (&ra, '\0', sizeof(ra));
switch (af){
case AF_INET:
((struct sockaddr_in *)&ra)->sin_family = AF_INET;
memcpy (&(((struct sockaddr_in *)&ra)->sin_addr), raddr,
sizeof(struct in_addr));
ralen = sizeof(struct sockaddr_in);
break;
case AF_INET6:
((struct sockaddr_in6 *)&ra)->sin6_family = AF_INET6;
memcpy (&(((struct sockaddr_in6 *)&ra)->sin6_addr), raddr,
sizeof(struct in6_addr));
ralen = sizeof(struct sockaddr_in6);
break;
default:
return 0;
}
return ruserok_sa ((struct sockaddr *)&ra, ralen, superuser, ruser, luser);
}
int
iruserok (raddr, superuser, ruser, luser)
u_int32_t raddr;
int superuser;
const char *ruser, *luser;
{
return iruserok_af (&raddr, superuser, ruser, luser, AF_INET);
}
/*
* XXX
* Don't make static, used by lpd(8).
*
* This function is not used anymore. It is only present because lpd(8)
* calls it (!?!). We simply call __invaliduser2() with an illegal rhost
* argument. This means that netgroups won't work in .rhost/hosts.equiv
* files. If you want lpd to work with netgroups, fix lpd to use ruserok()
* or PAM.
* Returns 0 if ok, -1 if not ok.
*/
int
__ivaliduser(hostf, raddr, luser, ruser)
FILE *hostf;
u_int32_t raddr;
const char *luser, *ruser;
{
struct sockaddr_in ra;
memset(&ra, '\0', sizeof(ra));
ra.sin_family = AF_INET;
ra.sin_addr.s_addr = raddr;
return __validuser2_sa(hostf, (struct sockaddr *)&ra, sizeof(ra),
luser, ruser, "-");
}
/* Returns 1 on positive match, 0 on no match, -1 on negative match. */
static int
internal_function
__checkhost_sa (ra, ralen, lhost, rhost)
struct sockaddr *ra;
size_t ralen;
char *lhost;
const char *rhost;
{
struct addrinfo hints, *res0, *res;
int herr;
int save_errno;
char raddr[INET6_ADDRSTRLEN];
int match;
int negate=1; /* Multiply return with this to get -1 instead of 1 */
char *user;
/* Check nis netgroup. */
if (strncmp ("+@", lhost, 2) == 0)
return innetgr (&lhost[2], rhost, NULL, NULL);
if (strncmp ("-@", lhost, 2) == 0)
return -innetgr (&lhost[2], rhost, NULL, NULL);
/* -host */
if (strncmp ("-", lhost,1) == 0) {
negate = -1;
lhost++;
} else if (strcmp ("+",lhost) == 0) {
return 1; /* asking for trouble, but ok.. */
}
/* Try for raw ip address first. */
/* XXX */
if (getnameinfo(ra, ralen,
raddr, sizeof(raddr), NULL, 0,
NI_NUMERICHOST) == 0)
return negate * (strcmp(raddr, lhost) == 0);
/* Better be a hostname. */
match = 0;
memset(&hints, '\0', sizeof(hints));
hints.ai_family = ra->sa_family;
if (getaddrinfo(lhost, NULL, &hints, &res0) == 0){
/* Spin through ip addresses. */
for (res=res0; res; res->ai_next){
if (res->ai_family == ra->sa_family &&
!memcmp(res->ai_addr, ra, res->ai_addrlen)){
match = 1;
break;
}
}
freeaddrinfo(res0);
}
return (negate * match);
}
/* Returns 1 on positive match, 0 on no match, -1 on negative match. */
static int
internal_function
__icheckuser (luser, ruser)
const char *luser, *ruser;
{
/*
luser is user entry from .rhosts/hosts.equiv file
ruser is user id on remote host
*/
char *user;
/* [-+]@netgroup */
if (strncmp ("+@", luser, 2) == 0)
return innetgr (&luser[2], NULL, ruser, NULL);
if (strncmp ("-@", luser,2) == 0)
return -innetgr (&luser[2], NULL, ruser, NULL);
/* -user */
if (strncmp ("-", luser, 1) == 0)
return -(strcmp (&luser[1], ruser) == 0);
/* + */
if (strcmp ("+", luser) == 0)
return 1;
/* simple string match */
return strcmp (ruser, luser) == 0;
}
/*
* Returns 1 for blank lines (or only comment lines) and 0 otherwise
*/
static int
__isempty(p)
char *p;
{
while (*p && isspace (*p)) {
++p;
}
return (*p == '\0' || *p == '#') ? 1 : 0 ;
}
/*
* Returns 0 if positive match, -1 if _not_ ok.
*/
static int
__validuser2_sa(hostf, ra, ralen, luser, ruser, rhost)
FILE *hostf;
struct sockaddr *ra;
size_t ralen;
const char *luser, *ruser, *rhost;
{
register const char *user;
register char *p;
int hcheck, ucheck;
char *buf = NULL;
size_t bufsize = 0;
int retval = -1;
while (__getline (&buf, &bufsize, hostf) > 0) {
buf[bufsize - 1] = '\0'; /* Make sure it's terminated. */
p = buf;
/* Skip empty or comment lines */
if (__isempty (p)) {
continue;
}
/* Skip lines that are too long. */
if (strchr (p, '\n') == NULL) {
int ch = getc_unlocked (hostf);
while (ch != '\n' && ch != EOF)
ch = getc_unlocked (hostf);
continue;
}
for (;*p && !isspace(*p); ++p) {
*p = _tolower (*p);
}
/* Next we want to find the permitted name for the remote user. */
if (*p == ' ' || *p == '\t') {
/* <nul> terminate hostname and skip spaces */
for (*p++='\0'; *p && isspace (*p); ++p);
user = p; /* this is the user's name */
while (*p && !isspace (*p))
++p; /* find end of user's name */
} else
user = p;
*p = '\0'; /* <nul> terminate username (+host?) */
/* buf -> host(?) ; user -> username(?) */
/* First check host part */
hcheck = __checkhost_sa (ra, ralen, buf, rhost);
if (hcheck < 0)
break;
if (hcheck) {
/* Then check user part */
if (! (*user))
user = luser;
ucheck = __icheckuser (user, ruser);
/* Positive 'host user' match? */
if (ucheck > 0) {
retval = 0;
break;
}
/* Negative 'host -user' match? */
if (ucheck < 0)
break;
/* Neither, go on looking for match */
}
}
if (buf != NULL)
free (buf);
return retval;
}