rsync/access.c

/* 
   Copyright (C) Andrew Tridgell 1998
   
   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2 of the License, or
   (at your option) any later version.
   
   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.
   
   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/

/*
  hosts allow/deny code for rsync

  */

#include "rsync.h"


static int match_hostname(char *host, char *tok)
{
	if (!host || !*host) return 0;
	return wildmatch(tok, host);
}

static int match_binary(char *b1, char *b2, char *mask, int addrlen)
{
	int i;

	for (i=0; i<addrlen; i++) {
		if ((b1[i]^b2[i])&mask[i]) {
			return 0;
		}
	}

	return 1;
}

static void make_mask(char *mask, int plen, int addrlen) {
	int w, b;

	w = plen >> 3;
	b = plen & 0x7;

	if (w)
		memset(mask, 0xff, w);
	if (w < addrlen)
		mask[w] = 0xff & (0xff<<(8-b));
	if (w+1 < addrlen)
		memset(mask+w+1, 0, addrlen-w-1);

	return;
}

static int match_address(char *addr, char *tok)
{
	char *p;
	struct addrinfo hints, *resa, *rest;
	int gai;
	int ret = 0;
	int addrlen = 0;
#ifdef HAVE_STRTOL
	long int bits;
#else
	int bits;
#endif
	char mask[16];
	char *a = NULL, *t = NULL;
	unsigned int len;

	if (!addr || !*addr) return 0;

	p = strchr(tok,'/');
	if (p) {
		*p = '\0';
		len = p - tok;
	}
	else
		len = strlen(tok);

	/* Fail quietly if tok is a hostname (not an address) */
	if (strspn(tok, ".0123456789") != len
#ifdef INET6
	 && !strchr(tok, ':')
#endif
		) return 0;

	memset(&hints, 0, sizeof(hints));
	hints.ai_family = PF_UNSPEC;
	hints.ai_socktype = SOCK_STREAM;
#ifdef AI_NUMERICHOST
	hints.ai_flags = AI_NUMERICHOST;
#endif

	gai = getaddrinfo(addr, NULL, &hints, &resa);
	if (gai) return 0;

	gai = getaddrinfo(tok, NULL, &hints, &rest);
	if (p)
		*p++ = '/';
	if (gai) {
		rprintf(FERROR,
			"error matching address %s: %s\n",
			tok,
			gai_strerror(gai));
		freeaddrinfo(resa);
		return 0;
	}

	if (rest->ai_family != resa->ai_family) {
		ret = 0;
		goto out;
	}

	switch(resa->ai_family) {
	case PF_INET:
		a = (char *)&((struct sockaddr_in *)resa->ai_addr)->sin_addr;
		t = (char *)&((struct sockaddr_in *)rest->ai_addr)->sin_addr;
		addrlen = 4;

		break;

#ifdef INET6
	case PF_INET6:
	    {
		struct sockaddr_in6 *sin6a, *sin6t;

		sin6a = (struct sockaddr_in6 *)resa->ai_addr;
		sin6t = (struct sockaddr_in6 *)rest->ai_addr;

		a = (char *)&sin6a->sin6_addr;
		t = (char *)&sin6t->sin6_addr;

		addrlen = 16;

#ifdef HAVE_SOCKADDR_IN6_SCOPE_ID
		if (sin6t->sin6_scope_id &&
		    sin6a->sin6_scope_id != sin6t->sin6_scope_id) {
			ret = 0;
			goto out;
		}
#endif

		break;
	    }
#endif
	default:
	    rprintf(FERROR,"unknown family %u\n", rest->ai_family);
	    ret = 0;
	    goto out;
	}

	bits = -1;
	if (p) {
		if (inet_pton(resa->ai_addr->sa_family, p, mask) <= 0) {
#ifdef HAVE_STRTOL
			char *ep = NULL;
#else
			unsigned char *pp;
#endif

#ifdef HAVE_STRTOL
			bits = strtol(p, &ep, 10);
			if (!*p || *ep) {
				rprintf(FERROR,"malformed mask in %s\n", tok);
				ret = 0;
				goto out;
			}
#else
			for (pp = (unsigned char *)p; *pp; pp++) {
				if (!isascii(*pp) || !isdigit(*pp)) {
					rprintf(FERROR,"malformed mask in %s\n", tok);
					ret = 0;
					goto out;
				}
			}
			bits = atoi(p);
#endif
			if (bits == 0) {
				ret = 1;
				goto out;
			}
			if (bits < 0 || bits > (addrlen << 3)) {
				rprintf(FERROR,"malformed mask in %s\n", tok);
				ret = 0;
				goto out;
			}
		}
	} else {
		bits = 128;
	}

	if (bits >= 0)
		make_mask(mask, bits, addrlen);

	ret = match_binary(a, t, mask, addrlen);

out:
	freeaddrinfo(resa);
	freeaddrinfo(rest);
	return ret;
}

static int access_match(char *list, char *addr, char *host)
{
	char *tok;
	char *list2 = strdup(list);

	if (!list2) out_of_memory("access_match");

	strlower(list2);
	if (host) strlower(host);

	for (tok=strtok(list2," ,\t"); tok; tok=strtok(NULL," ,\t")) {
		if (match_hostname(host, tok) || match_address(addr, tok)) {
			free(list2);
			return 1;
		}
	}

	free(list2);
	return 0;
}

int allow_access(char *addr, char *host, char *allow_list, char *deny_list)
{
	/* if theres no deny list and no allow list then allow access */
	if ((!deny_list || !*deny_list) && (!allow_list || !*allow_list))
		return 1;

	/* if there is an allow list but no deny list then allow only hosts
	   on the allow list */
	if (!deny_list || !*deny_list)
		return(access_match(allow_list, addr, host));

	/* if theres a deny list but no allow list then allow
	   all hosts not on the deny list */
	if (!allow_list || !*allow_list)
		return(!access_match(deny_list,addr,host));

	/* if there are both type of list then allow all hosts on the
           allow list */
	if (access_match(allow_list,addr,host))
		return 1;

	/* if there are both type of list and it's not on the allow then
	   allow it if its not on the deny */
	if (access_match(deny_list,addr,host))
		return 0;

	return 1;
}