rexec.c

   1 /*
   2  * Copyright (c) 1980, 1993
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  * 4. Neither the name of the University nor the names of its contributors
  14  *    may be used to endorse or promote products derived from this software
  15  *    without specific prior written permission.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  27  * SUCH DAMAGE.
  28  */
  29
  30 #define __FORCE_GLIBC
  31 #include <features.h>
  32 #include <sys/types.h>
  33 #include <sys/socket.h>
  34
  35 #include <netinet/in.h>
  36
  37 #include <alloca.h>
  38 #include <stdio.h>
  39 #include <netdb.h>
  40 #include <errno.h>
  41 #include <stdlib.h>
  42 #include <string.h>
  43 #include <unistd.h>
  44
  45 # define __TEMP_FAILURE_RETRY(expression) \
  46   (__extension__                                                              \
  47     ({ long int __result;                                                     \
  48        do __result = (long int) (expression);                                 \
  49        while (__result == -1L && errno == EINTR);                             \
  50        __result; }))
  51
  52 #define SA_LEN(_x)      __libc_sa_len((_x)->sa_family)
  53 extern int __libc_sa_len(sa_family_t __af) __THROW attribute_hidden;
  54
  55 /* int rexecoptions; - google does not know it */
  56 static char ahostbuf[NI_MAXHOST];
  57
  58 int
  59 rexec_af(char **ahost, int rport, const char *name, const char *pass, const char *cmd, int *fd2p, sa_family_t af)
  60 {
  61         struct sockaddr_storage sa2, from;
  62         struct addrinfo hints, *res0;
  63         const char *orig_name = name;
  64         const char *orig_pass = pass;
  65         u_short port = 0;
  66         int s, timo = 1, s3;
  67         char c;
  68         int gai;
  69         char servbuff[NI_MAXSERV];
  70
  71         if (sizeof(servbuff) < sizeof(int)*3 + 2) {
  72                 snprintf(servbuff, sizeof(servbuff), "%d", ntohs(rport));
  73                 servbuff[sizeof(servbuff) - 1] = '\0';
  74         } else {
  75                 sprintf(servbuff, "%d", ntohs(rport));
  76         }
  77
  78         memset(&hints, '\0', sizeof(hints));
  79         hints.ai_family = af;
  80         hints.ai_socktype = SOCK_STREAM;
  81         hints.ai_flags = AI_CANONNAME;
  82         gai = getaddrinfo(*ahost, servbuff, &hints, &res0);
  83         if (gai) {
  84                 /* XXX: set errno? */
  85                 return -1;
  86         }
  87
  88         if (res0->ai_canonname) {
  89                 strncpy(ahostbuf, res0->ai_canonname, sizeof(ahostbuf));
  90                 ahostbuf[sizeof(ahostbuf)-1] = '\0';
  91                 *ahost = ahostbuf;
  92         }
  93         else {
  94                 *ahost = NULL;
  95                 __set_errno(ENOENT);
  96                 return -1;
  97         }
  98         ruserpass(res0->ai_canonname, &name, &pass);
  99 retry:
 100         s = socket(res0->ai_family, res0->ai_socktype, 0);
 101         if (s < 0) {
 102                 perror("rexec: socket");
 103                 return -1;
 104         }
 105         if (connect(s, res0->ai_addr, res0->ai_addrlen) < 0) {
 106                 if (errno == ECONNREFUSED && timo <= 16) {
 107                         (void) close(s);
 108                         sleep(timo);
 109                         timo *= 2;
 110                         goto retry;
 111                 }
 112                 perror(res0->ai_canonname);
 113                 return -1;
 114         }
 115         if (fd2p == 0) {
 116                 (void) write(s, "", 1);
 117                 port = 0;
 118         } else {
 119                 char num[32];
 120                 int s2;
 121                 socklen_t sa2len;
 122
 123                 s2 = socket(res0->ai_family, res0->ai_socktype, 0);
 124                 if (s2 < 0) {
 125                         (void) close(s);
 126                         return -1;
 127                 }
 128                 listen(s2, 1);
 129                 sa2len = sizeof(sa2);
 130                 if (getsockname(s2, (struct sockaddr *)&sa2, &sa2len) < 0) {
 131                         perror("getsockname");
 132                         (void) close(s2);
 133                         goto bad;
 134                 } else if (sa2len != SA_LEN((struct sockaddr *)&sa2)) {
 135                         __set_errno(EINVAL);
 136                         (void) close(s2);
 137                         goto bad;
 138                 }
 139                 port = 0;
 140                 if (!getnameinfo((struct sockaddr *)&sa2, sa2len,
 141                                  NULL, 0, servbuff, sizeof(servbuff),
 142                                  NI_NUMERICSERV))
 143                         port = atoi(servbuff);
 144                 (void) sprintf(num, "%u", port);
 145                 (void) write(s, num, strlen(num)+1);
 146                 {
 147                         socklen_t len = sizeof(from);
 148                         s3 = __TEMP_FAILURE_RETRY(accept(s2,
 149                                         (struct sockaddr *)&from, &len));
 150                         close(s2);
 151                         if (s3 < 0) {
 152                                 perror("accept");
 153                                 port = 0;
 154                                 goto bad;
 155                         }
 156                 }
 157                 *fd2p = s3;
 158         }
 159         (void) write(s, name, strlen(name) + 1);
 160         /* should public key encypt the password here */
 161         (void) write(s, pass, strlen(pass) + 1);
 162         (void) write(s, cmd, strlen(cmd) + 1);
 163
 164         /* We don't need the memory allocated for the name and the password
 165            in ruserpass anymore.  */
 166         if (name != orig_name)
 167                 free((char *) name);
 168         if (pass != orig_pass)
 169                 free((char *) pass);
 170
 171         if (read(s, &c, 1) != 1) {
 172                 perror(*ahost);
 173                 goto bad;
 174         }
 175         if (c != 0) {
 176                 while (read(s, &c, 1) == 1) {
 177                         (void) write(2, &c, 1);
 178                         if (c == '\n')
 179                                 break;
 180                 }
 181                 goto bad;
 182         }
 183         freeaddrinfo(res0);
 184         return s;
 185 bad:
 186         if (port)
 187                 (void) close(*fd2p);
 188         (void) close(s);
 189         freeaddrinfo(res0);
 190         return -1;
 191 }
 192 libc_hidden_def(rexec_af)
 193
 194 int
 195 rexec(char **ahost, int rport, const char *name, const char *pass,
 196           const char *cmd, int *fd2p)
 197 {
 198         return rexec_af(ahost, rport, name, pass, cmd, fd2p, AF_INET);
 199 }