release/src/router/dropbear/compat.c

   1 /*
   2  * Dropbear - a SSH2 server
   3  *
   4  * Copyright (c) 2002,2003 Matt Johnston
   5  * All rights reserved.
   6  *
   7  * Permission is hereby granted, free of charge, to any person obtaining a copy
   8  * of this software and associated documentation files (the "Software"), to deal
   9  * in the Software without restriction, including without limitation the rights
  10  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  11  * copies of the Software, and to permit persons to whom the Software is
  12  * furnished to do so, subject to the following conditions:
  13  *
  14  * The above copyright notice and this permission notice shall be included in
  15  * all copies or substantial portions of the Software.
  16  *
  17  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  18  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  20  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  21  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  22  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  23  * SOFTWARE.
  24  *
  25  * strlcat() is copyright as follows:
  26  * Copyright (c) 1998 Todd C. Miller <Todd.Miller@courtesan.com>
  27  * All rights reserved.
  28  *
  29  * Redistribution and use in source and binary forms, with or without
  30  * modification, are permitted provided that the following conditions
  31  * are met:
  32  * 1. Redistributions of source code must retain the above copyright
  33  *    notice, this list of conditions and the following disclaimer.
  34  * 2. Redistributions in binary form must reproduce the above copyright
  35  *    notice, this list of conditions and the following disclaimer in the
  36  *    documentation and/or other materials provided with the distribution.
  37  * 3. The name of the author may not be used to endorse or promote products
  38  *    derived from this software without specific prior written permission.
  39  *
  40  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
  41  * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
  42  * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL
  43  * THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  44  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  45  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
  46  * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
  47  * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
  48  * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
  49  * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  50  *
  51  * daemon() and getusershell() is copyright as follows:
  52  *
  53  * Copyright (c) 1990, 1993
  54  *      The Regents of the University of California.  All rights reserved.
  55  *
  56  * Redistribution and use in source and binary forms, with or without
  57  * modification, are permitted provided that the following conditions
  58  * are met:
  59  * 1. Redistributions of source code must retain the above copyright
  60  *    notice, this list of conditions and the following disclaimer.
  61  * 2. Redistributions in binary form must reproduce the above copyright
  62  *    notice, this list of conditions and the following disclaimer in the
  63  *    documentation and/or other materials provided with the distribution.
  64  * 3. Neither the name of the University nor the names of its contributors
  65  *    may be used to endorse or promote products derived from this software
  66  *    without specific prior written permission.
  67  *
  68  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  69  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  70  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  71  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  72  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  73 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  74                 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  75 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  76 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  77 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  78 * SUCH DAMAGE.
  79 *
  80 * Modifications for Dropbear to getusershell() are by Paul Marinceu
  81 */
  82
  83 #include "includes.h"
  84
  85 #ifndef HAVE_GETUSERSHELL
  86 static char **curshell, **shells, *strings;
  87 static char **initshells();
  88 #endif
  89
  90 #ifndef HAVE_STRLCPY
  91 /* Implemented by matt as specified in freebsd 4.7 manpage.
  92  * We don't require great speed, is simply for use with sshpty code */
  93 size_t strlcpy(char *dst, const char *src, size_t size) {
  94
  95         size_t i;
  96
  97         /* this is undefined, though size==0 -> return 0 */
  98         if (size < 1) {
  99                 return 0;
 100         }
 101
 102         for (i = 0; i < size-1; i++) {
 103                 if (src[i] == '\0') {
 104                         break;
 105                 } else {
 106                         dst[i] = src[i];
 107                 }
 108         }
 109
 110         dst[i] = '\0';
 111         return strlen(src);
 112
 113 }
 114 #endif /* HAVE_STRLCPY */
 115
 116 #ifndef HAVE_STRLCAT
 117 /* taken from openbsd-compat for OpenSSH 3.6.1p1 */
 118 /* "$OpenBSD: strlcat.c,v 1.8 2001/05/13 15:40:15 deraadt Exp $"
 119  *
 120  * Appends src to string dst of size siz (unlike strncat, siz is the
 121  * full size of dst, not space left).  At most siz-1 characters
 122  * will be copied.  Always NUL terminates (unless siz <= strlen(dst)).
 123  * Returns strlen(src) + MIN(siz, strlen(initial dst)).
 124  * If retval >= siz, truncation occurred.
 125  */
 126         size_t
 127 strlcat(dst, src, siz)
 128         char *dst;
 129         const char *src;
 130         size_t siz;
 131 {
 132         register char *d = dst;
 133         register const char *s = src;
 134         register size_t n = siz;
 135         size_t dlen;
 136
 137         /* Find the end of dst and adjust bytes left but don't go past end */
 138         while (n-- != 0 && *d != '\0')
 139                 d++;
 140         dlen = d - dst;
 141         n = siz - dlen;
 142
 143         if (n == 0)
 144                 return(dlen + strlen(s));
 145         while (*s != '\0') {
 146                 if (n != 1) {
 147                         *d++ = *s;
 148                         n--;
 149                 }
 150                 s++;
 151         }
 152         *d = '\0';
 153
 154         return(dlen + (s - src));       /* count does not include NUL */
 155 }
 156 #endif /* HAVE_STRLCAT */
 157
 158 #ifndef HAVE_DAEMON
 159 /* From NetBSD - daemonise a process */
 160
 161 int daemon(int nochdir, int noclose) {
 162
 163         int fd;
 164
 165         switch (fork()) {
 166                 case -1:
 167                         return (-1);
 168                 case 0:
 169                         break;
 170                 default:
 171                         _exit(0);
 172         }
 173
 174         if (setsid() == -1)
 175                 return -1;
 176
 177         if (!nochdir)
 178                 (void)chdir("/");
 179
 180         if (!noclose && (fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) {
 181                 (void)dup2(fd, STDIN_FILENO);
 182                 (void)dup2(fd, STDOUT_FILENO);
 183                 (void)dup2(fd, STDERR_FILENO);
 184                 if (fd > STDERR_FILENO)
 185                         (void)close(fd);
 186         }
 187         return 0;
 188 }
 189 #endif /* HAVE_DAEMON */
 190
 191 #ifndef HAVE_BASENAME
 192
 193 char *basename(const char *path) {
 194
 195         char *foo = strrchr(path, '/');
 196         if (!foo)
 197         {
 198                 return path;
 199         }
 200         return ++foo;
 201 }
 202
 203 #endif /* HAVE_BASENAME */
 204
 205 #ifndef HAVE_GETUSERSHELL
 206
 207 /*
 208  * Get a list of shells from /etc/shells, if it exists.
 209  */
 210 char * getusershell() {
 211         char *ret;
 212
 213         if (curshell == NULL)
 214                 curshell = initshells();
 215         ret = *curshell;
 216         if (ret != NULL)
 217                 curshell++;
 218         return (ret);
 219 }
 220
 221 void endusershell() {
 222
 223         if (shells != NULL)
 224                 free(shells);
 225         shells = NULL;
 226         if (strings != NULL)
 227                 free(strings);
 228         strings = NULL;
 229         curshell = NULL;
 230 }
 231
 232 void setusershell() {
 233         curshell = initshells();
 234 }
 235
 236 static char **initshells() {
 237         /* don't touch this list. */
 238         static const char *okshells[] = { "/bin/sh", "/bin/csh", NULL };
 239         register char **sp, *cp;
 240         register FILE *fp;
 241         struct stat statb;
 242         int flen;
 243
 244         if (shells != NULL)
 245                 free(shells);
 246         shells = NULL;
 247         if (strings != NULL)
 248                 free(strings);
 249         strings = NULL;
 250         if ((fp = fopen("/etc/shells", "rc")) == NULL)
 251                 return (char **) okshells;
 252         if (fstat(fileno(fp), &statb) == -1) {
 253                 (void)fclose(fp);
 254                 return (char **) okshells;
 255         }
 256         if ((strings = malloc((u_int)statb.st_size + 1)) == NULL) {
 257                 (void)fclose(fp);
 258                 return (char **) okshells;
 259         }
 260         shells = calloc((unsigned)statb.st_size / 3, sizeof (char *));
 261         if (shells == NULL) {
 262                 (void)fclose(fp);
 263                 free(strings);
 264                 strings = NULL;
 265                 return (char **) okshells;
 266         }
 267         sp = shells;
 268         cp = strings;
 269         flen = statb.st_size;
 270         while (fgets(cp, flen - (cp - strings), fp) != NULL) {
 271                 while (*cp != '#' && *cp != '/' && *cp != '\0')
 272                         cp++;
 273                 if (*cp == '#' || *cp == '\0')
 274                         continue;
 275                 *sp++ = cp;
 276                 while (!isspace(*cp) && *cp != '#' && *cp != '\0')
 277                         cp++;
 278                 *cp++ = '\0';
 279         }
 280         *sp = NULL;
 281         (void)fclose(fp);
 282         return (shells);
 283 }
 284
 285 #endif /* HAVE_GETUSERSHELL */