/**
* imap_auth_gss - GSS Authentication support
* @param adata Imap Account data
* @param method Name of this authentication method
* @retval enum Result, e.g. #IMAP_AUTH_SUCCESS
*/
enum ImapAuthRes imap_auth_gss(struct ImapAccountData *adata, const char *method)
{
gss_buffer_desc request_buf, send_token;
gss_buffer_t sec_token;
gss_name_t target_name;
gss_ctx_id_t context;
gss_OID mech_name;
char server_conf_flags;
gss_qop_t quality;
int cflags;
OM_uint32 maj_stat, min_stat;
unsigned long buf_size;
int rc, retval = IMAP_AUTH_FAILURE;
if (!(adata->capabilities & IMAP_CAP_AUTH_GSSAPI))
return IMAP_AUTH_UNAVAIL;
if (mutt_account_getuser(&adata->conn->account) < 0)
return IMAP_AUTH_FAILURE;
struct Buffer *buf1 = mutt_buffer_pool_get();
struct Buffer *buf2 = mutt_buffer_pool_get();
/* get an IMAP service ticket for the server */
mutt_buffer_printf(buf1, "imap@%s", adata->conn->account.host);
request_buf.value = buf1->data;
request_buf.length = mutt_buffer_len(buf1);
maj_stat = gss_import_name(&min_stat, &request_buf, gss_nt_service_name, &target_name);
if (maj_stat != GSS_S_COMPLETE)
{
mutt_debug(LL_DEBUG2, "Couldn't get service name for [%s]\n", buf1);
retval = IMAP_AUTH_UNAVAIL;
goto cleanup;
}
else if (C_DebugLevel >= 2)
{
gss_display_name(&min_stat, target_name, &request_buf, &mech_name);
mutt_debug(LL_DEBUG2, "Using service name [%s]\n", (char *) request_buf.value);
gss_release_buffer(&min_stat, &request_buf);
}
/* Acquire initial credentials - without a TGT GSSAPI is UNAVAIL */
sec_token = GSS_C_NO_BUFFER;
context = GSS_C_NO_CONTEXT;
/* build token */
maj_stat = gss_init_sec_context(&min_stat, GSS_C_NO_CREDENTIAL, &context, target_name,
GSS_C_NO_OID, GSS_C_MUTUAL_FLAG | GSS_C_SEQUENCE_FLAG,
0, GSS_C_NO_CHANNEL_BINDINGS, sec_token, NULL,
&send_token, (unsigned int *) &cflags, NULL);
if ((maj_stat != GSS_S_COMPLETE) && (maj_stat != GSS_S_CONTINUE_NEEDED))
{
print_gss_error(maj_stat, min_stat);
mutt_debug(LL_DEBUG1, "Error acquiring credentials - no TGT?\n");
gss_release_name(&min_stat, &target_name);
retval = IMAP_AUTH_UNAVAIL;
goto cleanup;
}
/* now begin login */
mutt_message(_("Authenticating (GSSAPI)..."));
imap_cmd_start(adata, "AUTHENTICATE GSSAPI");
/* expect a null continuation response ("+") */
do
rc = imap_cmd_step(adata);
while (rc == IMAP_CMD_CONTINUE);
if (rc != IMAP_CMD_RESPOND)
{
mutt_debug(LL_DEBUG2, "Invalid response from server: %s\n", buf1);
gss_release_name(&min_stat, &target_name);
goto bail;
}
/* now start the security context initialisation loop... */
mutt_debug(LL_DEBUG2, "Sending credentials\n");
mutt_b64_buffer_encode(buf1, send_token.value, send_token.length);
gss_release_buffer(&min_stat, &send_token);
mutt_buffer_addstr(buf1, "\r\n");
mutt_socket_send(adata->conn, mutt_b2s(buf1));
while (maj_stat == GSS_S_CONTINUE_NEEDED)
{
/* Read server data */
do
rc = imap_cmd_step(adata);
while (rc == IMAP_CMD_CONTINUE);
if (rc != IMAP_CMD_RESPOND)
{
mutt_debug(LL_DEBUG1, "#1 Error receiving server response\n");
gss_release_name(&min_stat, &target_name);
goto bail;
}
if (mutt_b64_buffer_decode(buf2, adata->buf + 2) < 0)
{
mutt_debug(LL_DEBUG1, "Invalid base64 server response\n");
gss_release_name(&min_stat, &target_name);
goto err_abort_cmd;
}
request_buf.value = buf2->data;
request_buf.length = mutt_buffer_len(buf2);
sec_token = &request_buf;
/* Write client data */
maj_stat = gss_init_sec_context(
&min_stat, GSS_C_NO_CREDENTIAL, &context, target_name, GSS_C_NO_OID,
GSS_C_MUTUAL_FLAG | GSS_C_SEQUENCE_FLAG, 0, GSS_C_NO_CHANNEL_BINDINGS,
sec_token, NULL, &send_token, (unsigned int *) &cflags, NULL);
if ((maj_stat != GSS_S_COMPLETE) && (maj_stat != GSS_S_CONTINUE_NEEDED))
{
print_gss_error(maj_stat, min_stat);
mutt_debug(LL_DEBUG1, "Error exchanging credentials\n");
gss_release_name(&min_stat, &target_name);
goto err_abort_cmd;
}
mutt_b64_buffer_encode(buf1, send_token.value, send_token.length);
gss_release_buffer(&min_stat, &send_token);
mutt_buffer_addstr(buf1, "\r\n");
mutt_socket_send(adata->conn, mutt_b2s(buf1));
}
gss_release_name(&min_stat, &target_name);
/* get security flags and buffer size */
do
rc = imap_cmd_step(adata);
while (rc == IMAP_CMD_CONTINUE);
if (rc != IMAP_CMD_RESPOND)
{
mutt_debug(LL_DEBUG1, "#2 Error receiving server response\n");
goto bail;
}
if (mutt_b64_buffer_decode(buf2, adata->buf + 2) < 0)
{
mutt_debug(LL_DEBUG1, "Invalid base64 server response\n");
goto err_abort_cmd;
}
request_buf.value = buf2->data;
request_buf.length = mutt_buffer_len(buf2);
maj_stat = gss_unwrap(&min_stat, context, &request_buf, &send_token, &cflags, &quality);
if (maj_stat != GSS_S_COMPLETE)
{
print_gss_error(maj_stat, min_stat);
mutt_debug(LL_DEBUG2, "Couldn't unwrap security level data\n");
gss_release_buffer(&min_stat, &send_token);
goto err_abort_cmd;
}
mutt_debug(LL_DEBUG2, "Credential exchange complete\n");
/* first octet is security levels supported. We want NONE */
server_conf_flags = ((char *) send_token.value)[0];
if (!(((char *) send_token.value)[0] & GSS_AUTH_P_NONE))
{
mutt_debug(LL_DEBUG2, "Server requires integrity or privacy\n");
gss_release_buffer(&min_stat, &send_token);
goto err_abort_cmd;
}
/* we don't care about buffer size if we don't wrap content. But here it is */
((char *) send_token.value)[0] = '\0';
buf_size = ntohl(*((long *) send_token.value));
gss_release_buffer(&min_stat, &send_token);
mutt_debug(LL_DEBUG2, "Unwrapped security level flags: %c%c%c\n",
(server_conf_flags & GSS_AUTH_P_NONE) ? 'N' : '-',
(server_conf_flags & GSS_AUTH_P_INTEGRITY) ? 'I' : '-',
(server_conf_flags & GSS_AUTH_P_PRIVACY) ? 'P' : '-');
mutt_debug(LL_DEBUG2, "Maximum GSS token size is %ld\n", buf_size);
/* agree to terms (hack!) */
buf_size = htonl(buf_size); /* not relevant without integrity/privacy */
mutt_buffer_reset(buf1);
mutt_buffer_addch(buf1, GSS_AUTH_P_NONE);
mutt_buffer_addstr_n(buf1, ((char *) &buf_size) + 1, 3);
/* server decides if principal can log in as user */
mutt_buffer_addstr(buf1, adata->conn->account.user);
request_buf.value = buf1->data;
request_buf.length = mutt_buffer_len(buf1);
maj_stat = gss_wrap(&min_stat, context, 0, GSS_C_QOP_DEFAULT, &request_buf,
&cflags, &send_token);
if (maj_stat != GSS_S_COMPLETE)
{
mutt_debug(LL_DEBUG2, "Error creating login request\n");
goto err_abort_cmd;
}
mutt_b64_buffer_encode(buf1, send_token.value, send_token.length);
mutt_debug(LL_DEBUG2, "Requesting authorisation as %s\n", adata->conn->account.user);
mutt_buffer_addstr(buf1, "\r\n");
mutt_socket_send(adata->conn, mutt_b2s(buf1));
/* Joy of victory or agony of defeat? */
do
rc = imap_cmd_step(adata);
while (rc == IMAP_CMD_CONTINUE);
if (rc == IMAP_CMD_RESPOND)
{
mutt_debug(LL_DEBUG1, "Unexpected server continuation request\n");
goto err_abort_cmd;
}
if (imap_code(adata->buf))
{
/* flush the security context */
mutt_debug(LL_DEBUG2, "Releasing GSS credentials\n");
maj_stat = gss_delete_sec_context(&min_stat, &context, &send_token);
if (maj_stat != GSS_S_COMPLETE)
mutt_debug(LL_DEBUG1, "Error releasing credentials\n");
/* send_token may contain a notification to the server to flush
* credentials. RFC1731 doesn't specify what to do, and since this
* support is only for authentication, we'll assume the server knows
* enough to flush its own credentials */
gss_release_buffer(&min_stat, &send_token);
retval = IMAP_AUTH_SUCCESS;
goto cleanup;
}
else
goto bail;
err_abort_cmd:
mutt_socket_send(adata->conn, "*\r\n");
do
rc = imap_cmd_step(adata);
while (rc == IMAP_CMD_CONTINUE);
bail:
mutt_error(_("GSSAPI authentication failed"));
retval = IMAP_AUTH_FAILURE;
cleanup:
mutt_buffer_pool_release(&buf1);
mutt_buffer_pool_release(&buf2);
return retval;
}
/* imap_auth_gss: AUTH=GSSAPI support. */
imap_auth_res_t imap_auth_gss (IMAP_DATA* idata, const char* method)
{
gss_buffer_desc request_buf, send_token;
gss_buffer_t sec_token;
gss_name_t target_name;
gss_ctx_id_t context;
#ifdef DEBUG
gss_OID mech_name;
#endif
gss_qop_t quality;
int cflags;
OM_uint32 maj_stat, min_stat;
char buf1[GSS_BUFSIZE], buf2[GSS_BUFSIZE], server_conf_flags;
unsigned long buf_size;
int rc;
if (!mutt_bit_isset (idata->capabilities, AGSSAPI))
return IMAP_AUTH_UNAVAIL;
if (mutt_account_getuser (&idata->conn->account))
return IMAP_AUTH_FAILURE;
/* get an IMAP service ticket for the server */
snprintf (buf1, sizeof (buf1), "imap@%s", idata->conn->account.host);
request_buf.value = buf1;
request_buf.length = strlen (buf1) + 1;
maj_stat = gss_import_name (&min_stat, &request_buf, gss_nt_service_name,
&target_name);
if (maj_stat != GSS_S_COMPLETE)
{
dprint (2, (debugfile, "Couldn't get service name for [%s]\n", buf1));
return IMAP_AUTH_UNAVAIL;
}
#ifdef DEBUG
else if (debuglevel >= 2)
{
maj_stat = gss_display_name (&min_stat, target_name, &request_buf,
&mech_name);
dprint (2, (debugfile, "Using service name [%s]\n",
(char*) request_buf.value));
maj_stat = gss_release_buffer (&min_stat, &request_buf);
}
#endif
/* Acquire initial credentials - without a TGT GSSAPI is UNAVAIL */
sec_token = GSS_C_NO_BUFFER;
context = GSS_C_NO_CONTEXT;
/* build token */
maj_stat = gss_init_sec_context (&min_stat, GSS_C_NO_CREDENTIAL, &context,
target_name, GSS_C_NO_OID, GSS_C_MUTUAL_FLAG | GSS_C_SEQUENCE_FLAG, 0,
GSS_C_NO_CHANNEL_BINDINGS, sec_token, NULL, &send_token,
(unsigned int*) &cflags, NULL);
if (maj_stat != GSS_S_COMPLETE && maj_stat != GSS_S_CONTINUE_NEEDED)
{
print_gss_error(maj_stat, min_stat);
dprint (1, (debugfile, "Error acquiring credentials - no TGT?\n"));
gss_release_name (&min_stat, &target_name);
return IMAP_AUTH_UNAVAIL;
}
/* now begin login */
mutt_message _("Authenticating (GSSAPI)...");
imap_cmd_start (idata, "AUTHENTICATE GSSAPI");
/* expect a null continuation response ("+") */
do
rc = imap_cmd_step (idata);
while (rc == IMAP_CMD_CONTINUE);
if (rc != IMAP_CMD_RESPOND)
{
dprint (2, (debugfile, "Invalid response from server: %s\n", buf1));
gss_release_name (&min_stat, &target_name);
goto bail;
}
/* now start the security context initialisation loop... */
dprint (2, (debugfile, "Sending credentials\n"));
mutt_to_base64 ((unsigned char*) buf1, send_token.value, send_token.length,
sizeof (buf1) - 2);
gss_release_buffer (&min_stat, &send_token);
safe_strcat (buf1, sizeof (buf1), "\r\n");
mutt_socket_write (idata->conn, buf1);
while (maj_stat == GSS_S_CONTINUE_NEEDED)
{
/* Read server data */
do
rc = imap_cmd_step (idata);
while (rc == IMAP_CMD_CONTINUE);
if (rc != IMAP_CMD_RESPOND)
{
dprint (1, (debugfile, "Error receiving server response.\n"));
gss_release_name (&min_stat, &target_name);
goto bail;
}
request_buf.length = mutt_from_base64 (buf2, idata->buf + 2);
request_buf.value = buf2;
sec_token = &request_buf;
/* Write client data */
maj_stat = gss_init_sec_context (&min_stat, GSS_C_NO_CREDENTIAL, &context,
target_name, GSS_C_NO_OID, GSS_C_MUTUAL_FLAG | GSS_C_SEQUENCE_FLAG, 0,
GSS_C_NO_CHANNEL_BINDINGS, sec_token, NULL, &send_token,
(unsigned int*) &cflags, NULL);
if (maj_stat != GSS_S_COMPLETE && maj_stat != GSS_S_CONTINUE_NEEDED)
{
print_gss_error(maj_stat, min_stat);
dprint (1, (debugfile, "Error exchanging credentials\n"));
gss_release_name (&min_stat, &target_name);
goto err_abort_cmd;
}
mutt_to_base64 ((unsigned char*) buf1, send_token.value,
send_token.length, sizeof (buf1) - 2);
gss_release_buffer (&min_stat, &send_token);
safe_strcat (buf1, sizeof (buf1), "\r\n");
mutt_socket_write (idata->conn, buf1);
}
gss_release_name (&min_stat, &target_name);
/* get security flags and buffer size */
do
rc = imap_cmd_step (idata);
while (rc == IMAP_CMD_CONTINUE);
if (rc != IMAP_CMD_RESPOND)
{
dprint (1, (debugfile, "Error receiving server response.\n"));
goto bail;
}
request_buf.length = mutt_from_base64 (buf2, idata->buf + 2);
request_buf.value = buf2;
maj_stat = gss_unwrap (&min_stat, context, &request_buf, &send_token,
&cflags, &quality);
if (maj_stat != GSS_S_COMPLETE)
{
print_gss_error(maj_stat, min_stat);
dprint (2, (debugfile, "Couldn't unwrap security level data\n"));
gss_release_buffer (&min_stat, &send_token);
goto err_abort_cmd;
}
dprint (2, (debugfile, "Credential exchange complete\n"));
/* first octet is security levels supported. We want NONE */
server_conf_flags = ((char*) send_token.value)[0];
if ( !(((char*) send_token.value)[0] & GSS_AUTH_P_NONE) )
{
dprint (2, (debugfile, "Server requires integrity or privacy\n"));
gss_release_buffer (&min_stat, &send_token);
goto err_abort_cmd;
}
/* we don't care about buffer size if we don't wrap content. But here it is */
((char*) send_token.value)[0] = 0;
buf_size = ntohl (*((long *) send_token.value));
gss_release_buffer (&min_stat, &send_token);
dprint (2, (debugfile, "Unwrapped security level flags: %c%c%c\n",
server_conf_flags & GSS_AUTH_P_NONE ? 'N' : '-',
server_conf_flags & GSS_AUTH_P_INTEGRITY ? 'I' : '-',
server_conf_flags & GSS_AUTH_P_PRIVACY ? 'P' : '-'));
dprint (2, (debugfile, "Maximum GSS token size is %ld\n", buf_size));
/* agree to terms (hack!) */
buf_size = htonl (buf_size); /* not relevant without integrity/privacy */
memcpy (buf1, &buf_size, 4);
buf1[0] = GSS_AUTH_P_NONE;
/* server decides if principal can log in as user */
strncpy (buf1 + 4, idata->conn->account.user, sizeof (buf1) - 4);
request_buf.value = buf1;
request_buf.length = 4 + strlen (idata->conn->account.user) + 1;
maj_stat = gss_wrap (&min_stat, context, 0, GSS_C_QOP_DEFAULT, &request_buf,
&cflags, &send_token);
if (maj_stat != GSS_S_COMPLETE)
{
dprint (2, (debugfile, "Error creating login request\n"));
goto err_abort_cmd;
}
mutt_to_base64 ((unsigned char*) buf1, send_token.value, send_token.length,
sizeof (buf1) - 2);
dprint (2, (debugfile, "Requesting authorisation as %s\n",
idata->conn->account.user));
safe_strcat (buf1, sizeof (buf1), "\r\n");
mutt_socket_write (idata->conn, buf1);
/* Joy of victory or agony of defeat? */
do
rc = imap_cmd_step (idata);
while (rc == IMAP_CMD_CONTINUE);
if (rc == IMAP_CMD_RESPOND)
{
dprint (1, (debugfile, "Unexpected server continuation request.\n"));
goto err_abort_cmd;
}
if (imap_code (idata->buf))
{
/* flush the security context */
dprint (2, (debugfile, "Releasing GSS credentials\n"));
maj_stat = gss_delete_sec_context (&min_stat, &context, &send_token);
if (maj_stat != GSS_S_COMPLETE)
dprint (1, (debugfile, "Error releasing credentials\n"));
/* send_token may contain a notification to the server to flush
* credentials. RFC 1731 doesn't specify what to do, and since this
* support is only for authentication, we'll assume the server knows
* enough to flush its own credentials */
gss_release_buffer (&min_stat, &send_token);
return IMAP_AUTH_SUCCESS;
}
else
goto bail;
err_abort_cmd:
mutt_socket_write (idata->conn, "*\r\n");
do
rc = imap_cmd_step (idata);
while (rc == IMAP_CMD_CONTINUE);
bail:
mutt_error _("GSSAPI authentication failed.");
mutt_sleep (2);
return IMAP_AUTH_FAILURE;
}
