/* do the sasl negotiation; return -1 if it fails */
int mysasl_negotiate(FILE *in, FILE *out, sasl_conn_t *conn)
{
char buf[8192];
char chosenmech[128];
const char *data;
int len;
int r = SASL_FAIL;
const char *userid;
#ifdef HAVE_GSS_GET_NAME_ATTRIBUTE
gss_name_t peer = GSS_C_NO_NAME;
#endif
/* generate the capability list */
if (mech) {
dprintf(2, "forcing use of mechanism %s\n", mech);
data = strdup(mech);
len = strlen(data);
} else {
int count;
dprintf(1, "generating client mechanism list... ");
r = sasl_listmech(conn, NULL, NULL, " ", NULL,
&data, (unsigned int *)&len, &count);
if (r != SASL_OK) saslfail(r, "generating mechanism list");
dprintf(1, "%d mechanisms\n", count);
}
/* send capability list to client */
send_string(out, data, len);
dprintf(1, "waiting for client mechanism...\n");
len = recv_string(in, chosenmech, sizeof chosenmech);
if (len <= 0) {
printf("client didn't choose mechanism\n");
fputc('N', out); /* send NO to client */
fflush(out);
return -1;
}
if (mech && strcasecmp(mech, chosenmech)) {
printf("client didn't choose mandatory mechanism\n");
fputc('N', out); /* send NO to client */
fflush(out);
return -1;
}
len = recv_string(in, buf, sizeof(buf));
if(len != 1) {
saslerr(r, "didn't receive first-send parameter correctly");
fprintf(stderr, "%s\n", sasl_errdetail(conn));
fputc('N', out);
fflush(out);
return -1;
}
if(buf[0] == 'Y') {
/* receive initial response (if any) */
len = recv_string(in, buf, sizeof(buf));
/* start libsasl negotiation */
r = sasl_server_start(conn, chosenmech, buf, len,
&data, (unsigned int *)&len);
} else {
r = sasl_server_start(conn, chosenmech, NULL, 0,
&data, (unsigned int *)&len);
}
if (r != SASL_OK && r != SASL_CONTINUE) {
saslerr(r, "starting SASL negotiation");
fprintf(stderr, "%s\n", sasl_errdetail(conn));
fputc('N', out); /* send NO to client */
fflush(out);
return -1;
}
while (r == SASL_CONTINUE) {
if (data) {
dprintf(2, "sending response length %d...\n", len);
fputc('C', out); /* send CONTINUE to client */
send_string(out, data, len);
} else {
dprintf(2, "sending null response...\n");
fputc('C', out); /* send CONTINUE to client */
send_string(out, "", 0);
}
dprintf(1, "waiting for client reply...\n");
len = recv_string(in, buf, sizeof buf);
if (len < 0) {
printf("client disconnected\n");
return -1;
}
r = sasl_server_step(conn, buf, len, &data, (unsigned int *)&len);
if (r != SASL_OK && r != SASL_CONTINUE) {
saslerr(r, "performing SASL negotiation");
fprintf(stderr, "%s\n", sasl_errdetail(conn));
fputc('N', out); /* send NO to client */
fflush(out);
return -1;
}
}
if (r != SASL_OK) {
saslerr(r, "incorrect authentication");
fprintf(stderr, "%s\n", sasl_errdetail(conn));
fputc('N', out); /* send NO to client */
fflush(out);
return -1;
}
fputc('O', out); /* send OK to client */
fflush(out);
dprintf(1, "negotiation complete\n");
r = sasl_getprop(conn, SASL_USERNAME, (const void **) &userid);
printf("successful authentication '%s'\n", userid);
#ifdef HAVE_GSS_GET_NAME_ATTRIBUTE
r = sasl_getprop(conn, SASL_GSS_PEER_NAME, (const void **) &peer);
if (peer != GSS_C_NO_NAME) {
OM_uint32 minor;
enumerateAttributes(&minor, peer, 1);
}
#endif
return 0;
}
void saslfail(int why, const char *what, sasl_conn_t *conn)
{
saslerr(why, what, conn);
exit(-1);
}
