compat.c - third_party/dropbear - Git at Google

 /*
  * Dropbear - a SSH2 server
  *
  * Copyright (c) 2002,2003 Matt Johnston
  * All rights reserved.
  *
  * Permission is hereby granted, free of charge, to any person obtaining a copy
  * of this software and associated documentation files (the "Software"), to deal
  * in the Software without restriction, including without limitation the rights
  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  * copies of the Software, and to permit persons to whom the Software is
  * furnished to do so, subject to the following conditions:
  *
  * The above copyright notice and this permission notice shall be included in
  * all copies or substantial portions of the Software.
  *
  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  * SOFTWARE.
  *
  * strlcat() is copyright as follows:
  * Copyright (c) 1998 Todd C. Miller <Todd.Miller@courtesan.com>
  * 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. The name of the author may not be used to endorse or promote products
  *    derived from this software without specific prior written permission.
  *
  * THIS SOFTWARE IS PROVIDED ``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 AUTHOR 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.
  *
  * daemon() and getusershell() is copyright as follows:
  *
  * Copyright (c) 1990, 1993
  *      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. 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.
 *
 * Modifications for Dropbear to getusershell() are by Paul Marinceu
 */

 #include "includes.h"

 #ifndef HAVE_GETUSERSHELL
 static char **curshell, **shells, *strings;
 static char **initshells();
 #endif

 #ifndef HAVE_STRLCPY
 /* Implemented by matt as specified in freebsd 4.7 manpage.
  * We don't require great speed, is simply for use with sshpty code */
 size_t strlcpy(char *dst, const char *src, size_t size) {

 	size_t i;

 	/* this is undefined, though size==0 -> return 0 */
 	if (size < 1) {
 		return 0;
 	}

 	for (i = 0; i < size-1; i++) {
 		if (src[i] == '\0') {
 			break;
 		} else {
 			dst[i] = src[i];
 		}
 	}

 	dst[i] = '\0';
 	return strlen(src);

 }
 #endif /* HAVE_STRLCPY */

 #ifndef HAVE_STRLCAT
 /* taken from openbsd-compat for OpenSSH 3.6.1p1 */
 /* "$OpenBSD: strlcat.c,v 1.8 2001/05/13 15:40:15 deraadt Exp $"
  *
  * Appends src to string dst of size siz (unlike strncat, siz is the
  * full size of dst, not space left).  At most siz-1 characters
  * will be copied.  Always NUL terminates (unless siz <= strlen(dst)).
  * Returns strlen(src) + MIN(siz, strlen(initial dst)).
  * If retval >= siz, truncation occurred.
  */
 	size_t
 strlcat(dst, src, siz)
 	char *dst;
 	const char *src;
 	size_t siz;
 {
 	register char *d = dst;
 	register const char *s = src;
 	register size_t n = siz;
 	size_t dlen;

 	/* Find the end of dst and adjust bytes left but don't go past end */
 	while (n-- != 0 && *d != '\0')
 		d++;
 	dlen = d - dst;
 	n = siz - dlen;

 	if (n == 0)
 		return(dlen + strlen(s));
 	while (*s != '\0') {
 		if (n != 1) {
 			*d++ = *s;
 			n--;
 		}
 		s++;
 	}
 	*d = '\0';

 	return(dlen + (s - src));	/* count does not include NUL */
 }
 #endif /* HAVE_STRLCAT */

 #ifndef HAVE_DAEMON
 /* From NetBSD - daemonise a process */

 int daemon(int nochdir, int noclose) {

 	int fd;

 	switch (fork()) {
 		case -1:
 			return (-1);
 		case 0:
 			break;
 		default:
 			_exit(0);
 	}

 	if (setsid() == -1)
 		return -1;

 	if (!nochdir)
 		(void)chdir("/");

 	if (!noclose && (fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) {
 		(void)dup2(fd, STDIN_FILENO);
 		(void)dup2(fd, STDOUT_FILENO);
 		(void)dup2(fd, STDERR_FILENO);
 		if (fd > STDERR_FILENO)
 			(void)close(fd);
 	}
 	return 0;
 }
 #endif /* HAVE_DAEMON */

 #ifndef HAVE_BASENAME

 char *basename(const char *path) {

 	char *foo = strrchr(path, '/');
 	return ++foo;
 }

 #endif /* HAVE_BASENAME */

 #ifndef HAVE_GETUSERSHELL

 /*
  * Get a list of shells from /etc/shells, if it exists.
  */
 char * getusershell() {
 	char *ret;

 	if (curshell == NULL)
 		curshell = initshells();
 	ret = *curshell;
 	if (ret != NULL)
 		curshell++;
 	return (ret);
 }

 void endusershell() {

 	if (shells != NULL)
 		free(shells);
 	shells = NULL;
 	if (strings != NULL)
 		free(strings);
 	strings = NULL;
 	curshell = NULL;
 }

 void setusershell() {
 	curshell = initshells();
 }

 static char **initshells() {
 	/* don't touch this list. */
 	const char *okshells[] = { "/bin/sh", "/bin/csh", NULL };
 	register char **sp, *cp;
 	register FILE *fp;
 	struct stat statb;
 	int flen;

 	if (shells != NULL)
 		free(shells);
 	shells = NULL;
 	if (strings != NULL)
 		free(strings);
 	strings = NULL;
 	if ((fp = fopen("/etc/shells", "rc")) == NULL)
 		return (char **) okshells;
 	if (fstat(fileno(fp), &statb) == -1) {
 		(void)fclose(fp);
 		return (char **) okshells;
 	}
 	if ((strings = malloc((u_int)statb.st_size + 1)) == NULL) {
 		(void)fclose(fp);
 		return (char **) okshells;
 	}
 	shells = calloc((unsigned)statb.st_size / 3, sizeof (char *));
 	if (shells == NULL) {
 		(void)fclose(fp);
 		free(strings);
 		strings = NULL;
 		return (char **) okshells;
 	}
 	sp = shells;
 	cp = strings;
 	flen = statb.st_size;
 	while (fgets(cp, flen - (cp - strings), fp) != NULL) {
 		while (*cp != '#' && *cp != '/' && *cp != '\0')
 			cp++;
 		if (*cp == '#' || *cp == '\0')
 			continue;
 		*sp++ = cp;
 		while (!isspace(*cp) && *cp != '#' && *cp != '\0')
 			cp++;
 		*cp++ = '\0';
 	}
 	*sp = NULL;
 	(void)fclose(fp);
 	return (shells);
 }

 #endif /* HAVE_GETUSERSHELL */
	/*
	* Dropbear - a SSH2 server
	*
	* Copyright (c) 2002,2003 Matt Johnston
	* All rights reserved.
	*
	* Permission is hereby granted, free of charge, to any person obtaining a copy
	* of this software and associated documentation files (the "Software"), to deal
	* in the Software without restriction, including without limitation the rights
	* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
	* copies of the Software, and to permit persons to whom the Software is
	* furnished to do so, subject to the following conditions:
	*
	* The above copyright notice and this permission notice shall be included in
	* all copies or substantial portions of the Software.
	*
	* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
	* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
	* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
	* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
	* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
	* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
	* SOFTWARE.
	*
	* strlcat() is copyright as follows:
	* Copyright (c) 1998 Todd C. Miller <Todd.Miller@courtesan.com>
	* 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. The name of the author may not be used to endorse or promote products
	* derived from this software without specific prior written permission.
	*
	* THIS SOFTWARE IS PROVIDED ``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 AUTHOR 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.
	*
	* daemon() and getusershell() is copyright as follows:
	*
	* Copyright (c) 1990, 1993
	* 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. 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.
	*
	* Modifications for Dropbear to getusershell() are by Paul Marinceu
	*/

	#include "includes.h"

	#ifndef HAVE_GETUSERSHELL
	static char curshell, shells, *strings;
	static char **initshells();
	#endif

	#ifndef HAVE_STRLCPY
	/* Implemented by matt as specified in freebsd 4.7 manpage.
	* We don't require great speed, is simply for use with sshpty code */
	size_t strlcpy(char dst, const char src, size_t size) {

	size_t i;

	/* this is undefined, though size==0 -> return 0 */
	if (size < 1) {
	return 0;
	}

	for (i = 0; i < size-1; i++) {
	if (src[i] == '\0') {
	break;
	} else {
	dst[i] = src[i];
	}
	}

	dst[i] = '\0';
	return strlen(src);

	}
	#endif /* HAVE_STRLCPY */

	#ifndef HAVE_STRLCAT
	/* taken from openbsd-compat for OpenSSH 3.6.1p1 */
	/* "$OpenBSD: strlcat.c,v 1.8 2001/05/13 15:40:15 deraadt Exp $"
	*
	* Appends src to string dst of size siz (unlike strncat, siz is the
	* full size of dst, not space left). At most siz-1 characters
	* will be copied. Always NUL terminates (unless siz <= strlen(dst)).
	* Returns strlen(src) + MIN(siz, strlen(initial dst)).
	* If retval >= siz, truncation occurred.
	*/
	size_t
	strlcat(dst, src, siz)
	char *dst;
	const char *src;
	size_t siz;
	{
	register char *d = dst;
	register const char *s = src;
	register size_t n = siz;
	size_t dlen;

	/* Find the end of dst and adjust bytes left but don't go past end */
	while (n-- != 0 && *d != '\0')
	d++;
	dlen = d - dst;
	n = siz - dlen;

	if (n == 0)
	return(dlen + strlen(s));
	while (*s != '\0') {
	if (n != 1) {
	d++ = s;
	n--;
	}
	s++;
	}
	*d = '\0';

	return(dlen + (s - src)); /* count does not include NUL */
	}
	#endif /* HAVE_STRLCAT */

	#ifndef HAVE_DAEMON
	/* From NetBSD - daemonise a process */

	int daemon(int nochdir, int noclose) {

	int fd;

	switch (fork()) {
	case -1:
	return (-1);
	case 0:
	break;
	default:
	_exit(0);
	}

	if (setsid() == -1)
	return -1;

	if (!nochdir)
	(void)chdir("/");

	if (!noclose && (fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) {
	(void)dup2(fd, STDIN_FILENO);
	(void)dup2(fd, STDOUT_FILENO);
	(void)dup2(fd, STDERR_FILENO);
	if (fd > STDERR_FILENO)
	(void)close(fd);
	}
	return 0;
	}
	#endif /* HAVE_DAEMON */

	#ifndef HAVE_BASENAME

	char basename(const char path) {

	char *foo = strrchr(path, '/');
	return ++foo;
	}

	#endif /* HAVE_BASENAME */

	#ifndef HAVE_GETUSERSHELL

	/*
	* Get a list of shells from /etc/shells, if it exists.
	*/
	char * getusershell() {
	char *ret;

	if (curshell == NULL)
	curshell = initshells();
	ret = *curshell;
	if (ret != NULL)
	curshell++;
	return (ret);
	}

	void endusershell() {

	if (shells != NULL)
	free(shells);
	shells = NULL;
	if (strings != NULL)
	free(strings);
	strings = NULL;
	curshell = NULL;
	}

	void setusershell() {
	curshell = initshells();
	}

	static char **initshells() {
	/* don't touch this list. */
	const char *okshells[] = { "/bin/sh", "/bin/csh", NULL };
	register char *sp, cp;
	register FILE *fp;
	struct stat statb;
	int flen;

	if (shells != NULL)
	free(shells);
	shells = NULL;
	if (strings != NULL)
	free(strings);
	strings = NULL;
	if ((fp = fopen("/etc/shells", "rc")) == NULL)
	return (char **) okshells;
	if (fstat(fileno(fp), &statb) == -1) {
	(void)fclose(fp);
	return (char **) okshells;
	}
	if ((strings = malloc((u_int)statb.st_size + 1)) == NULL) {
	(void)fclose(fp);
	return (char **) okshells;
	}
	shells = calloc((unsigned)statb.st_size / 3, sizeof (char *));
	if (shells == NULL) {
	(void)fclose(fp);
	free(strings);
	strings = NULL;
	return (char **) okshells;
	}
	sp = shells;
	cp = strings;
	flen = statb.st_size;
	while (fgets(cp, flen - (cp - strings), fp) != NULL) {
	while (cp != '#' && cp != '/' && *cp != '\0')
	cp++;
	if (cp == '#' \|\| cp == '\0')
	continue;
	*sp++ = cp;
	while (!isspace(cp) && cp != '#' && *cp != '\0')
	cp++;
	*cp++ = '\0';
	}
	*sp = NULL;
	(void)fclose(fp);
	return (shells);
	}

	#endif /* HAVE_GETUSERSHELL */