/* 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;
}
/*
* Function: server_establish_context
*
* Purpose: establishses a GSS-API context as a specified service with
* an incoming client, and returns the context handle and associated
* client name
*
* Arguments:
*
* s (r) an established TCP connection to the client
* service_creds (r) server credentials, from gss_acquire_cred
* context (w) the established GSS-API context
* client_name (w) the client's ASCII name
*
* Returns: 0 on success, -1 on failure
*
* Effects:
*
* Any valid client request is accepted. If a context is established,
* its handle is returned in context and the client name is returned
* in client_name and 0 is returned. If unsuccessful, an error
* message is displayed and -1 is returned.
*/
static int
server_establish_context(int s, gss_cred_id_t server_creds,
gss_ctx_id_t *context, gss_buffer_t client_name,
OM_uint32 *ret_flags)
{
gss_buffer_desc send_tok, recv_tok;
gss_name_t client;
gss_OID doid;
OM_uint32 maj_stat, min_stat, acc_sec_min_stat;
gss_buffer_desc oid_name;
int token_flags;
if (recv_token(s, &token_flags, &recv_tok) < 0)
return -1;
if (recv_tok.value) {
free(recv_tok.value);
recv_tok.value = NULL;
}
if (!(token_flags & TOKEN_NOOP)) {
if (logfile)
fprintf(logfile, "Expected NOOP token, got %d token instead\n",
token_flags);
return -1;
}
*context = GSS_C_NO_CONTEXT;
if (token_flags & TOKEN_CONTEXT_NEXT) {
do {
if (recv_token(s, &token_flags, &recv_tok) < 0)
return -1;
if (verbose && logfile) {
fprintf(logfile, "Received token (size=%d): \n",
(int) recv_tok.length);
print_token(&recv_tok);
}
maj_stat = gss_accept_sec_context(&acc_sec_min_stat, context,
server_creds, &recv_tok,
GSS_C_NO_CHANNEL_BINDINGS,
&client, &doid, &send_tok,
ret_flags,
NULL, /* time_rec */
NULL); /* del_cred_handle */
if (recv_tok.value) {
free(recv_tok.value);
recv_tok.value = NULL;
}
if (send_tok.length != 0) {
if (verbose && logfile) {
fprintf(logfile,
"Sending accept_sec_context token (size=%d):\n",
(int) send_tok.length);
print_token(&send_tok);
}
if (send_token(s, TOKEN_CONTEXT, &send_tok) < 0) {
if (logfile)
fprintf(logfile, "failure sending token\n");
return -1;
}
(void) gss_release_buffer(&min_stat, &send_tok);
}
if (maj_stat != GSS_S_COMPLETE
&& maj_stat != GSS_S_CONTINUE_NEEDED) {
display_status("accepting context", maj_stat,
acc_sec_min_stat);
if (*context != GSS_C_NO_CONTEXT)
gss_delete_sec_context(&min_stat, context,
GSS_C_NO_BUFFER);
return -1;
}
if (verbose && logfile) {
if (maj_stat == GSS_S_CONTINUE_NEEDED)
fprintf(logfile, "continue needed...\n");
else
fprintf(logfile, "\n");
fflush(logfile);
}
} while (maj_stat == GSS_S_CONTINUE_NEEDED);
/* display the flags */
display_ctx_flags(*ret_flags);
if (verbose && logfile) {
maj_stat = gss_oid_to_str(&min_stat, doid, &oid_name);
if (maj_stat != GSS_S_COMPLETE) {
display_status("converting oid->string", maj_stat, min_stat);
return -1;
}
fprintf(logfile, "Accepted connection using mechanism OID %.*s.\n",
(int) oid_name.length, (char *) oid_name.value);
(void) gss_release_buffer(&min_stat, &oid_name);
}
maj_stat = gss_display_name(&min_stat, client, client_name, &doid);
if (maj_stat != GSS_S_COMPLETE) {
display_status("displaying name", maj_stat, min_stat);
return -1;
}
enumerateAttributes(&min_stat, client, TRUE);
showLocalIdentity(&min_stat, client);
maj_stat = gss_release_name(&min_stat, &client);
if (maj_stat != GSS_S_COMPLETE) {
display_status("releasing name", maj_stat, min_stat);
return -1;
}
} else {
client_name->length = *ret_flags = 0;
if (logfile)
fprintf(logfile, "Accepted unauthenticated connection.\n");
}
return 0;
}