/*    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.*/ /* support rsync authentication */#include "rsync.h" /***************************************************************************encode a buffer using base64 - simple and slow algorithm. null terminatesthe result.  ***************************************************************************/static void base64_encode(char *buf, int len, char *out){	char *b64 = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";	int bit_offset, byte_offset, idx, i;	unsigned char *d = (unsigned char *)buf;	int bytes = (len*8 + 5)/6; 	memset(out, 0, bytes+1); 	for (i=0;i<bytes;i++) {		byte_offset = (i*6)/8;		bit_offset = (i*6)%8;		if (bit_offset < 3) {			idx = (d[byte_offset] >> (2-bit_offset)) & 0x3F;		} else {			idx = (d[byte_offset] << (bit_offset-2)) & 0x3F;			if (byte_offset+1 < len) {				idx |= (d[byte_offset+1] >> (8-(bit_offset-2)));			}		}		out[i] = b64[idx];	}} /* create a 16 byte challenge buffer */static void gen_challenge(char *addr, char *challenge){	char input[32];	struct timeval tv; 	memset(input, 0, sizeof(input)); 	strlcpy((char *)input, addr, 16);	gettimeofday(&tv, NULL);	SIVAL(input, 16, tv.tv_sec);	SIVAL(input, 20, tv.tv_usec);	SIVAL(input, 24, getpid()); 	sum_init();	sum_update(input, sizeof(input));	sum_end(challenge);}  /* return the secret for a user from the sercret file. maximum length   is len. null terminate it */static int get_secret(int module, char *user, char *secret, int len){	char *fname = lp_secrets_file(module);	int fd, found=0;	char line[MAXPATHLEN];	char *p, *pass=NULL; 	if (!fname || !*fname) return 0; 	fd = open(fname,O_RDONLY);	if (fd == -1) return 0; 	while (!found) {		int i = 0;		memset(line, 0, sizeof(line));		while (i<(sizeof(line)-1)) {			if (read(fd, &line[i], 1) != 1) {				memset(line, 0, sizeof(line));				close(fd);				return 0;			}			if (line[i] == '\r') continue;			if (line[i] == '\n') break;			i++;		}		line[i] = 0;		if (line[0] == '#') continue;		p = strchr(line,':');		if (!p) continue;		*p = 0;		if (strcmp(user, line)) continue;		pass = p+1;		found = 1;	} 	close(fd);	if (!found) return 0; 	strlcpy(secret, pass, len);	return 1;} /* generate a 16 byte hash from a password and challenge */void generate_hash(char *in, char *challenge, char *out){	char buf[16]; 	sum_init();	sum_update(in, strlen(in));	sum_update(challenge, strlen(challenge));	sum_end(buf); 	base64_encode(buf, 16, out);} /* possible negotiate authentication with the client. Use "leader" to   start off the auth if necessary     return NULL if authentication failed    return "" if anonymous access    otherwise return username*/char *auth_server(int fd, int module, char *addr, char *leader){	char *users = lp_auth_users(module);	char challenge[16];	char b64_challenge[30];	char line[MAXPATHLEN];	static char user[100];	char secret[100];	char pass[30];	char pass2[30];	char *tok; 	/* if no auth list then allow anyone in! */	if (!users || !*users) return ""; 	gen_challenge(addr, challenge);		base64_encode(challenge, 16, b64_challenge); 	io_printf(fd,"%s%s\n", leader, b64_challenge); 	if (!read_line(fd, line, sizeof(line)-1)) {		return NULL;	} 	memset(user, 0, sizeof(user));	memset(pass, 0, sizeof(pass)); 	if (sscanf(line,"%99s %29s", user, pass) != 2) {		return NULL;	} 	users = strdup(users);	if (!users) return NULL; 	for (tok=strtok(users," ,\t"); tok; tok = strtok(NULL," ,\t")) {		if (strcmp(tok, user) == 0) break;	}	free(users); 	if (!tok) {		return NULL;	}		memset(secret, 0, sizeof(secret));	if (!get_secret(module, user, secret, sizeof(secret)-1)) {		memset(secret, 0, sizeof(secret));		return NULL;	} 	generate_hash(secret, b64_challenge, pass2);	memset(secret, 0, sizeof(secret));		if (strcmp(pass, pass2) == 0)		return user; 	return NULL;}  void auth_client(int fd, char *user, char *challenge){	char *pass;	char pass2[30]; 	if (!user || !*user) return; 	if (!(pass=getenv("RSYNC_PASSWORD"))) {		pass = getpass("Password: ");	} 	if (!pass || !*pass) {		pass = "";	} 	generate_hash(pass, challenge, pass2);		io_printf(fd, "%s %s\n", user, pass2);}