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* scod - a minimal sasl implementation for jabberd2
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* Copyright (c) 2003 Robert Norris
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.See the
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* GNU General Public License for more details.
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA02111-1307USA
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/* DIGEST-MD5 mechanism */
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/* unions to comply with strict-alias rules for gcc3 */
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static char *_opt_quote(char *in) {
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if(*r == '"' || *r == '\\')
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out = (char *) malloc(sizeof(char) * (strlen(in) + nesc + 3));
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if(*r == '"' || *r == '\\') {
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log_debug(ZONE, "escaped '%s' into '%s'", in, out);
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/** the list parser is based on code from cyrus-sasl. I love open source ;) */
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static char *_opt_skip_lws(char *c) {
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while(*c == ' ' || *c == HT || *c == CR || *c == LF) {
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static char *_opt_skip_token(char *c, int ci) {
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if(*c == DEL || *c == '(' || *c == ')' || *c == '<' || *c == '>' ||
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*c == '@' || *c == ',' || *c == ';' || *c == ':' || *c == '\\' ||
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*c == '\'' || *c == '/' || *c == '[' || *c == ']' || *c == '?' ||
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*c == '=' || *c == '{' || *c == '}') {
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if(!isupper((unsigned char) *c))
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static char *_opt_unquote(char *in) {
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/* if its not quoted, there's nothing to do */
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return _opt_skip_token(in, 0);
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for(end = in; *end != '\0'; end++, out++) {
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else if(*end == '\\') {
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static void _opt_get_pair(char **in, char **key, char **val) {
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char *end, *cur = *in;
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cur = _opt_skip_lws(cur);
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cur = _opt_skip_token(cur, 1);
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if(*cur != '=' && *cur != '\0') {
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cur = _opt_skip_lws(cur);
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cur = _opt_skip_lws(cur);
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*val = (*cur == '"') ? cur + 1 : cur;
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end = _opt_unquote(cur);
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if(*end != ',' && *end != '\0') {
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end = _opt_skip_lws(end);
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else if(*end != '\0') {
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static xht _digest_md5_parse_options(const char *buf, int buflen) {
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char *nbuf, *in, *key, *val;
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nbuf = (char *) malloc(sizeof(char) * (buflen + 1));
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strncpy(nbuf, buf, buflen);
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hash = xhash_new(101);
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_opt_get_pair(&in, &key, &val);
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sub = xhash_get(hash, key);
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xhash_put(hash, pstrdup(xhash_pool(hash), key), sub);
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pool_cleanup(xhash_pool(hash), (void (*)(void *)) xhash_free, sub);
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xhash_put(sub, pstrdup(xhash_pool(hash), val), (void *) 1);
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log_debug(ZONE, "got key '%s' val '%s'", key, val);
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static char *_digest_md5_gen_nonce(void) {
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char nonce[65], hnonce[41];
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for(i = 0; i < 64; i++) {
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r = (int) (36.0 * rand() / RAND_MAX);
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nonce[i] = (r >= 0 && r <= 9) ? (r + 48) : (r + 87);
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shahash_r(nonce, hnonce);
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log_debug(ZONE, "generated nonce: %s", hnonce);
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return strdup(hnonce);
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typedef struct _digest_md5_st {
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static int _digest_md5_client_start(scod_mech_t mech, scod_t sd, char **resp, int *resplen) {
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log_debug(ZONE, "DIGEST-MD5 client start");
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static int _digest_md5_client_step(scod_mech_t mech, scod_t sd, const char *chal, int challen, char **resp, int *resplen) {
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char *key, *realm, *nonce, *qop, *charset, *algorithm, *cnonce, *c;
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char ha1[33], ha2[33], hrsp[33];
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log_debug(ZONE, "DIGEST-MD5 client step; challenge: %.*s", challen, chal);
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if(sd->mech_data != NULL) {
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/* !!! check rspauth */
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sd->mech_data = NULL;
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realm = nonce = qop = charset = algorithm = NULL;
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attrs = _digest_md5_parse_options(chal, challen);
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if(xhash_iter_first(attrs))
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xhash_iter_get(attrs, (const char **) &key, xhv.val);
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log_debug(ZONE, "extracting '%s'", key);
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if(xhash_iter_first(sub)) {
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if(strcmp(key, "realm") == 0) {
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su.char_val = &realm;
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(mech->ctx->cb)(sd, sd_cb_DIGEST_MD5_CHOOSE_REALM, (void *) sub, su.val, mech->ctx->cbarg);
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else if(strcmp(key, "nonce") == 0)
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xhash_iter_get(sub, (const char **) &nonce, NULL);
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else if(strcmp(key, "qop") == 0)
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xhash_iter_get(sub, (const char **) &qop, NULL);
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else if(strcmp(key, "charset") == 0)
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xhash_iter_get(sub, (const char **) &charset, NULL);
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else if(strcmp(key, "algorithm") == 0)
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xhash_iter_get(sub, (const char **) &algorithm, NULL);
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} while(xhash_iter_next(attrs));
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if(nonce == NULL || qop == NULL || charset == NULL || algorithm == NULL) {
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log_debug(ZONE, "missing attribute");
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return sd_auth_MALFORMED_DATA;
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cnonce = _digest_md5_gen_nonce();
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md5_append(&md5, sd->authnid, strlen(sd->authnid));
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md5_append(&md5, ":", 1);
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if(realm != NULL) md5_append(&md5, realm, strlen(realm));
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md5_append(&md5, ":", 1);
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md5_append(&md5, sd->pass, strlen(sd->pass));
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md5_finish(&md5, hash);
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md5_append(&md5, hash, 16);
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md5_append(&md5, ":", 1);
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md5_append(&md5, nonce, strlen(nonce));
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md5_append(&md5, ":", 1);
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md5_append(&md5, cnonce, 40);
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if(sd->authzid != NULL) {
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md5_append(&md5, ":", 1);
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md5_append(&md5, sd->authzid, strlen(sd->authzid));
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md5_finish(&md5, hash); /* A1 */
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hex_from_raw(hash, 16, ha1);
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log_debug(ZONE, "HEX(H(A1)) = %s", ha1);
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md5_append(&md5, "AUTHENTICATE:", 13);
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md5_append(&md5, "xmpp/", 5); /* !!! make this configurable */
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md5_finish(&md5, hash); /* A2 */
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hex_from_raw(hash, 16, ha2);
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log_debug(ZONE, "HEX(H(A2)) = %s", ha2);
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md5_append(&md5, ha1, 32);
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md5_append(&md5, ":", 1);
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md5_append(&md5, nonce, strlen(nonce));
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md5_append(&md5, ":", 1);
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md5_append(&md5, "00000001", 8);
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md5_append(&md5, ":", 1);
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md5_append(&md5, cnonce, 40);
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md5_append(&md5, ":auth:", 6);
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md5_append(&md5, ha2, 32);
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md5_finish(&md5, hash); /* KD(HA1, foo, HA2) */
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hex_from_raw(hash, 16, hrsp);
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log_debug(ZONE, "response is %s", hrsp);
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/* !!! generate rspauth and save it for later so we can validate */
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c = _opt_quote(sd->authnid);
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spooler(s, "username=", c, ",", s);
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c = _opt_quote(nonce);
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spooler(s, "nonce=", c, ",", s);
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c = _opt_quote(cnonce);
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spooler(s, "cnonce=", c, ",", s);
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if(sd->authzid != NULL) {
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c = _opt_quote(sd->authzid);
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spooler(s, "authzid=", c, ",", s);
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c = _opt_quote(realm);
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spooler(s, "realm=", c, ",", s);
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spooler(s, "nc=00000001,qop=auth,digest-uri=\"xmpp/\",charset=utf-8,response=", hrsp, s);
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*resp = strdup(spool_print(s));
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*resplen = strlen(*resp);
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log_debug(ZONE, "generated initial response: %.*s", *resplen, *resp);
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sd->mech_data = (void *) 1;
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static int _digest_md5_server_start(scod_mech_t mech, scod_t sd, const char *resp, int resplen, char **chal, int *challen) {
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log_debug(ZONE, "DIGEST-MD5 server start");
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md = (digest_md5_t) pmalloco(p, sizeof(struct _digest_md5_st));
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if(sd->realm != NULL) {
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c = _opt_quote(sd->realm);
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spooler(s, "realm=", c, ",", s);
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nonce = _digest_md5_gen_nonce();
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md->nonce = pstrdup(md->p, nonce);
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c = _opt_quote(md->nonce);
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spooler(s, "nonce=", c, ",qop=\"auth\",charset=utf-8,algorithm=md5-sess", s);
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*chal = strdup(spool_print(s));
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*challen = strlen(*chal);
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log_debug(ZONE, "generated initial challenge: %.*s", *challen, *chal);
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static int _digest_md5_server_step(scod_mech_t mech, scod_t sd, const char *resp, int resplen, char **chal, int *challen) {
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digest_md5_t md = (digest_md5_t) sd->mech_data;
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char *key, *username, *realm, *nonce, *cnonce, *nc, *qop, *digest_uri, *response, *charset, *pass, buf[257], *c, authzid[3072];
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char ha1[33], ha2[33], hrsp[33];
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struct _scod_cb_creds_st creds;
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log_debug(ZONE, "DIGEST-MD5 server step; response: %.*s", resplen, resp);
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sd->mech_data = NULL;
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username = realm = nonce = cnonce = nc = qop = digest_uri = response = charset = NULL;
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attrs = _digest_md5_parse_options(resp, resplen);
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if(xhash_iter_first(attrs))
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xhash_iter_get(attrs, (const char **) &key, xhv.val);
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log_debug(ZONE, "extracting '%s'", key);
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if(xhash_iter_first(sub)) {
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if(strcmp(key, "username") == 0)
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xhash_iter_get(sub, (const char **) &username, NULL);
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else if(strcmp(key, "realm") == 0)
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xhash_iter_get(sub, (const char **) &realm, NULL);
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else if(strcmp(key, "nonce") == 0)
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xhash_iter_get(sub, (const char **) &nonce, NULL);
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else if(strcmp(key, "cnonce") == 0)
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xhash_iter_get(sub, (const char **) &cnonce, NULL);
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else if(strcmp(key, "nc") == 0)
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xhash_iter_get(sub, (const char **) &nc, NULL);
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else if(strcmp(key, "qop") == 0)
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xhash_iter_get(sub, (const char **) &qop, NULL);
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else if(strcmp(key, "digest-uri") == 0)
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xhash_iter_get(sub, (const char **) &digest_uri, NULL);
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else if(strcmp(key, "response") == 0)
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xhash_iter_get(sub, (const char **) &response, NULL);
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else if(strcmp(key, "charset") == 0)
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xhash_iter_get(sub, (const char **) &charset, NULL);
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else if(strcmp(key, "authzid") == 0) {
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xhash_iter_get(sub, (const char **) &c, NULL);
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strncpy(authzid, c, sizeof(authzid));
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} while(xhash_iter_next(attrs));
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if(username == NULL || nonce == NULL || cnonce == NULL || nc == NULL || qop == NULL || digest_uri == NULL || response == NULL)
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err = sd_auth_MALFORMED_DATA;
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else if(strcmp(nonce, md->nonce) != 0)
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err = sd_auth_MISMATCH;
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else if(strcmp(qop, "auth") != 0)
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err = sd_auth_NOT_OFFERED;
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if(err != sd_SUCCESS) {
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log_debug(ZONE, "returning error %d", err);
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sd->mech_data = NULL;
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/* !!! verify realm? */
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creds.authnid = username;
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if((mech->ctx->cb)(sd, sd_cb_GET_PASS, &creds, su.val, mech->ctx->cbarg) != 0) {
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log_debug(ZONE, "user not found (or some other error getting password), failing");
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sd->mech_data = NULL;
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return sd_auth_USER_UNKNOWN;
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md->cnonce = pstrdup(md->p, cnonce);
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md->nc = pstrdup(md->p, nc);
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md5_append(&md5, username, strlen(username));
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md5_append(&md5, ":", 1);
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if(realm != NULL) md5_append(&md5, realm, strlen(realm));
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md5_append(&md5, ":", 1);
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if(pass != NULL) md5_append(&md5, pass, strlen(pass));
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md5_finish(&md5, hash);
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md5_append(&md5, hash, 16);
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md5_append(&md5, ":", 1);
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md5_append(&md5, md->nonce, strlen(md->nonce));
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md5_append(&md5, ":", 1);
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md5_append(&md5, md->cnonce, strlen(md->cnonce));
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if(authzid[0] != '\0') {
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md5_append(&md5, ":", 1);
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md5_append(&md5, authzid, strlen(authzid));
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md5_finish(&md5, hash); /* A1 */
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hex_from_raw(hash, 16, ha1);
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log_debug(ZONE, "HEX(H(A1)) = %s", ha1);
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md5_append(&md5, "AUTHENTICATE:", 13);
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md5_append(&md5, digest_uri, strlen(digest_uri));
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md5_finish(&md5, hash); /* A2 */
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hex_from_raw(hash, 16, ha2);
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log_debug(ZONE, "HEX(H(A2)) = %s", ha2);
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md5_append(&md5, ha1, 32);
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md5_append(&md5, ":", 1);
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md5_append(&md5, nonce, strlen(nonce));
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md5_append(&md5, ":", 1);
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md5_append(&md5, nc, strlen(nc));
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md5_append(&md5, ":", 1);
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md5_append(&md5, cnonce, strlen(cnonce));
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md5_append(&md5, ":auth:", 6);
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md5_append(&md5, ha2, 32);
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md5_finish(&md5, hash); /* KD(HA1, foo, HA2) */
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hex_from_raw(hash, 16, hrsp);
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log_debug(ZONE, "our response is %s, theirs is %s", hrsp, response);
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if(strcmp(hrsp, response) != 0) {
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log_debug(ZONE, "not matched, denied");
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sd->mech_data = NULL;
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return sd_auth_AUTH_FAILED;
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log_debug(ZONE, "matched, they're authenticated");
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creds.authnid = username;
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creds.authzid = authzid;
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if((mech->ctx->cb)(sd, sd_cb_CHECK_AUTHZID, &creds, NULL, mech->ctx->cbarg) != 0) {
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log_debug(ZONE, "authzid is invalid (app policy said so)");
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sd->mech_data = NULL;
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return sd_auth_AUTHZID_POLICY;
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sd->authzid = strdup(creds.authzid);
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md5_append(&md5, ":", 1);
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md5_append(&md5, digest_uri, strlen(digest_uri));
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md5_finish(&md5, hash); /* rspauth A2 */
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hex_from_raw(hash, 16, ha2);
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log_debug(ZONE, "HEX(H(rspauth A2)) = %s", ha2);
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md5_append(&md5, ha1, 32);
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md5_append(&md5, ":", 1);
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md5_append(&md5, nonce, strlen(nonce));
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md5_append(&md5, ":", 1);
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md5_append(&md5, nc, strlen(nc));
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md5_append(&md5, ":", 1);
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md5_append(&md5, cnonce, strlen(cnonce));
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md5_append(&md5, ":auth:", 6);
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md5_append(&md5, ha2, 32);
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md5_finish(&md5, hash); /* KD(HA1, foo, HA2) */
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hex_from_raw(hash, 16, hrsp);
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log_debug(ZONE, "rspauth: %s", hrsp);
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*chal = (char *) malloc(sizeof(char) * 41);
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snprintf(*chal, 41, "rspauth=%s", hrsp);
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log_debug(ZONE, "generated final challenge: %.*s", *challen, *chal);
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static void _digest_md5_free(scod_mech_t mech) {
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xhash_free((xht) mech->private);
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int scod_mech_digest_md5_init(scod_mech_t mech) {
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log_debug(ZONE, "initialising DIGEST-MD5 mechanism");
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mech->name = "DIGEST-MD5";
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mech->flags = sd_flag_GET_PASS;
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mech->client_start = _digest_md5_client_start;
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mech->client_step = _digest_md5_client_step;
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mech->server_start = _digest_md5_server_start;
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mech->server_step = _digest_md5_server_step;
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mech->free = _digest_md5_free;
added
removed
scod/mech_digest_md5.c
