Remove DH-AES/DH-BLOWFISH mechanisms and misc cleanup

- AES and Blowfish mechanisms are deemed insecure and servers
  have removed support for them
- Remove attempts to retry since we only support one mech
- Handle SASL 3.2's new syntax for supported mechs
This commit is contained in:
Patrick Griffis 2016-01-29 17:41:08 -05:00
parent 6b62c4738d
commit 4362085847
7 changed files with 57 additions and 309 deletions

View File

@ -422,9 +422,7 @@ typedef struct session
/* SASL Mechanisms */
#define MECH_PLAIN 0
#define MECH_BLOWFISH 1
#define MECH_AES 2
#define MECH_EXTERNAL 3
#define MECH_EXTERNAL 1
typedef struct server
{
@ -546,7 +544,6 @@ typedef struct server
unsigned int skip_next_whois:1; /* hide whois output */
unsigned int inside_whois:1;
unsigned int doing_dns:1; /* /dns has been done */
unsigned int retry_sasl:1; /* retrying another sasl mech */
unsigned int end_of_motd:1; /* end of motd reached (logged in) */
unsigned int sent_quit:1; /* sent a QUIT already? */
unsigned int use_listargs:1; /* undernet and dalnet need /list >0,<10000 */
@ -570,7 +567,6 @@ typedef struct server
unsigned int have_cert:1; /* have loaded a cert */
unsigned int use_who:1; /* whether to use WHO command to get dcc_ip */
unsigned int sasl_mech; /* mechanism for sasl auth */
unsigned int sent_saslauth:1; /* have sent AUTHENICATE yet */
unsigned int sent_capend:1; /* have sent CAP END yet */
unsigned int waiting_on_cap:1; /* waiting on another line of CAP LS */
#ifdef USE_OPENSSL

View File

@ -1633,6 +1633,12 @@ inbound_identified (server *serv) /* 'MODE +e MYSELF' on freenode */
}
}
static const char *sasl_mechanisms[] =
{
"PLAIN",
"EXTERNAL"
};
static void
inbound_toggle_caps (server *serv, const char *extensions_str, gboolean enable)
{
@ -1666,24 +1672,12 @@ inbound_toggle_caps (server *serv, const char *extensions_str, gboolean enable)
serv->have_sasl = enable;
if (enable)
{
serv->sent_saslauth = FALSE;
#ifdef USE_OPENSSL
if (serv->loginmethod == LOGIN_SASLEXTERNAL)
{
serv->sasl_mech = MECH_EXTERNAL;
tcp_send_len (serv, "AUTHENTICATE EXTERNAL\r\n", 23);
}
else
{
/* default to most secure, it will fallback if not supported */
serv->sasl_mech = MECH_AES;
tcp_send_len (serv, "AUTHENTICATE DH-AES\r\n", 21);
}
#else
serv->sasl_mech = MECH_PLAIN;
tcp_send_len (serv, "AUTHENTICATE PLAIN\r\n", 20);
#endif
/* Mechanism either defaulted to PLAIN or server gave us list */
tcp_sendf (serv, "AUTHENTICATE %s\r\n", sasl_mechanisms[serv->sasl_mech]);
}
}
}
@ -1735,6 +1729,37 @@ static const char * const supported_caps[] = {
"twitch.tv/membership",
};
static int
get_supported_mech (server *serv, const char *list)
{
char **mechs = g_strsplit (list, ",", 0);
gsize i;
int ret = -1;
for (i = 0; mechs[i]; ++i)
{
#ifdef USE_OPENSSL
if (serv->loginmethod == LOGIN_SASLEXTERNAL)
{
if (!strcmp (mechs[i], "EXTERNAL"))
{
ret = MECH_EXTERNAL;
break;
}
}
else
#endif
if (!strcmp (mechs[i], "PLAIN"))
{
ret = MECH_PLAIN;
break;
}
}
g_strfreev (mechs);
return ret;
}
void
inbound_cap_ls (server *serv, char *nick, char *extensions_str,
const message_tags_data *tags_data)
@ -1781,6 +1806,13 @@ inbound_cap_ls (server *serv, char *nick, char *extensions_str,
((serv->loginmethod == LOGIN_SASL && strlen (serv->password) != 0)
|| (serv->loginmethod == LOGIN_SASLEXTERNAL && serv->have_cert)))
{
if (value)
{
int sasl_mech = get_supported_mech (serv, value);
if (sasl_mech == -1) /* No supported mech */
continue;
serv->sasl_mech = sasl_mech;
}
want_cap = TRUE;
want_sasl = TRUE;
g_strlcat (buffer, "sasl ", sizeof(buffer));
@ -1839,40 +1871,6 @@ inbound_cap_list (server *serv, char *nick, char *extensions,
NULL, NULL, 0, tags_data->timestamp);
}
static const char *sasl_mechanisms[] =
{
"PLAIN",
"DH-BLOWFISH",
"DH-AES",
"EXTERNAL"
};
void
inbound_sasl_supportedmechs (server *serv, char *list)
{
int i;
if (serv->sasl_mech != MECH_EXTERNAL)
{
/* Use most secure one supported */
for (i = MECH_AES; i >= MECH_PLAIN; i--)
{
if (strstr (list, sasl_mechanisms[i]) != NULL)
{
serv->sasl_mech = i;
serv->retry_sasl = TRUE;
tcp_sendf (serv, "AUTHENTICATE %s\r\n", sasl_mechanisms[i]);
return;
}
}
}
/* Abort, none supported */
serv->sent_saslauth = TRUE;
tcp_sendf (serv, "AUTHENTICATE *\r\n");
return;
}
void
inbound_sasl_authenticate (server *serv, char *data)
{
@ -1880,12 +1878,10 @@ inbound_sasl_authenticate (server *serv, char *data)
char *user, *pass = NULL;
const char *mech = sasl_mechanisms[serv->sasl_mech];
/* Got a list of supported mechanisms from inspircd */
/* Got a list of supported mechanisms from outdated inspircd
* just ignore it as it goes against spec */
if (strchr (data, ',') != NULL)
{
inbound_sasl_supportedmechs (serv, data);
return;
}
if (net->user && !(net->flags & FLAG_USE_GLOBAL))
user = net->user;
@ -1898,12 +1894,6 @@ inbound_sasl_authenticate (server *serv, char *data)
pass = encode_sasl_pass_plain (user, serv->password);
break;
#ifdef USE_OPENSSL
case MECH_BLOWFISH:
pass = encode_sasl_pass_blowfish (user, serv->password, data);
break;
case MECH_AES:
pass = encode_sasl_pass_aes (user, serv->password, data);
break;
case MECH_EXTERNAL:
pass = g_strdup ("+");
break;
@ -1913,12 +1903,10 @@ inbound_sasl_authenticate (server *serv, char *data)
if (pass == NULL)
{
/* something went wrong abort */
serv->sent_saslauth = TRUE; /* prevent trying PLAIN */
tcp_sendf (serv, "AUTHENTICATE *\r\n");
return;
}
serv->sent_saslauth = TRUE;
tcp_sendf (serv, "AUTHENTICATE %s\r\n", pass);
g_free (pass);
@ -1927,19 +1915,9 @@ inbound_sasl_authenticate (server *serv, char *data)
NULL, NULL, 0, 0);
}
int
void
inbound_sasl_error (server *serv)
{
if (serv->retry_sasl && !serv->sent_saslauth)
return 1;
/* If server sent 904 before we sent password,
* mech not support so fallback to next mech */
if (!serv->sent_saslauth && serv->sasl_mech != MECH_EXTERNAL && serv->sasl_mech != MECH_PLAIN)
{
serv->sasl_mech -= 1;
tcp_sendf (serv, "AUTHENTICATE %s\r\n", sasl_mechanisms[serv->sasl_mech]);
return 1;
}
return 0;
/* Just abort, not much we can do */
tcp_sendf (serv, "AUTHENTICATE *\r\n");
}

View File

@ -98,8 +98,7 @@ void inbound_cap_list (server *serv, char *nick, char *extensions,
void inbound_cap_del (server *serv, char *nick, char *extensions,
const message_tags_data *tags_data);
void inbound_sasl_authenticate (server *serv, char *data);
int inbound_sasl_error (server *serv);
void inbound_sasl_supportedmechs (server *serv, char *list);
void inbound_sasl_error (server *serv);
void do_dns (session *sess, char *nick, char *host,
const message_tags_data *tags_data);
gboolean alert_match_word (char *word, char *masks);

View File

@ -946,10 +946,9 @@ process_numeric (session * sess, int n,
word_eol[6]+1, word[1], word[2], NULL, 0,
tags_data->timestamp);
break;
case 903: /* successful SASL auth */
case 904: /* failed SASL auth */
if (inbound_sasl_error (serv))
break; /* might retry */
inbound_sasl_error (serv);
case 903: /* successful SASL auth */
case 905: /* failed SASL auth */
case 906: /* aborted */
case 907: /* attempting to re-auth after a successful auth */
@ -963,7 +962,7 @@ process_numeric (session * sess, int n,
}
break;
case 908: /* Supported SASL Mechs */
inbound_sasl_supportedmechs (serv, word[4]);
/* ignored for now, SASL 3.2 is a better solution and we only do PLAIN atm */
break;
default:

View File

@ -1727,6 +1727,7 @@ server_set_defaults (server *serv)
serv->chanmodes = g_strdup ("beI,k,l");
serv->nick_prefixes = g_strdup ("@%+");
serv->nick_modes = g_strdup ("ohv");
serv->sasl_mech = MECH_PLAIN;
server_set_encoding (serv, "UTF-8");

View File

@ -56,8 +56,6 @@
#ifdef USE_OPENSSL
#include <openssl/bn.h>
#include <openssl/rand.h>
#include <openssl/blowfish.h>
#include <openssl/aes.h>
#ifndef WIN32
#include <netinet/in.h>
#endif
@ -1393,227 +1391,6 @@ encode_sasl_pass_plain (char *user, char *pass)
return encoded;
}
#ifdef USE_OPENSSL
/* Adapted from ZNC's SASL module */
static int
parse_dh (char *str, DH **dh_out, unsigned char **secret_out, int *keysize_out)
{
DH *dh;
guchar *data, *decoded_data;
guchar *secret = NULL;
gsize data_len;
guint size;
guint16 size16;
BIGNUM *pubkey;
gint key_size;
dh = DH_new();
data = decoded_data = g_base64_decode (str, &data_len);
if (data_len < 2)
goto fail;
/* prime number */
memcpy (&size16, data, sizeof(size16));
size = ntohs (size16);
data += 2;
data_len -= 2;
if (size > data_len)
goto fail;
dh->p = BN_bin2bn (data, size, NULL);
data += size;
/* Generator */
if (data_len < 2)
goto fail;
memcpy (&size16, data, sizeof(size16));
size = ntohs (size16);
data += 2;
data_len -= 2;
if (size > data_len)
goto fail;
dh->g = BN_bin2bn (data, size, NULL);
data += size;
/* pub key */
if (data_len < 2)
goto fail;
memcpy (&size16, data, sizeof(size16));
size = ntohs(size16);
data += 2;
data_len -= 2;
pubkey = BN_bin2bn (data, size, NULL);
if (!(DH_generate_key (dh)))
goto fail;
secret = g_malloc (DH_size (dh));
key_size = DH_compute_key (secret, pubkey, dh);
if (key_size == -1)
goto fail;
g_free (decoded_data);
*dh_out = dh;
*secret_out = secret;
*keysize_out = key_size;
return 1;
fail:
g_free (secret);
g_free (decoded_data);
return 0;
}
char *
encode_sasl_pass_blowfish (char *user, char *pass, char *data)
{
DH *dh;
char *response, *ret = NULL;
unsigned char *secret;
unsigned char *encrypted_pass;
char *plain_pass;
BF_KEY key;
int key_size, length;
int pass_len = strlen (pass) + (8 - (strlen (pass) % 8));
int user_len = strlen (user);
guint16 size16;
char *in_ptr, *out_ptr;
if (!parse_dh (data, &dh, &secret, &key_size))
return NULL;
BF_set_key (&key, key_size, secret);
encrypted_pass = g_malloc0 (pass_len);
plain_pass = g_malloc0 (pass_len);
memcpy (plain_pass, pass, strlen(pass));
out_ptr = (char*)encrypted_pass;
in_ptr = (char*)plain_pass;
for (length = pass_len; length; length -= 8, in_ptr += 8, out_ptr += 8)
BF_ecb_encrypt ((unsigned char*)in_ptr, (unsigned char*)out_ptr, &key, BF_ENCRYPT);
/* Create response */
length = 2 + BN_num_bytes (dh->pub_key) + pass_len + user_len + 1;
response = g_malloc0 (length);
out_ptr = response;
/* our key */
size16 = htons ((guint16)BN_num_bytes (dh->pub_key));
memcpy (out_ptr, &size16, sizeof(size16));
out_ptr += 2;
BN_bn2bin (dh->pub_key, (guchar*)out_ptr);
out_ptr += BN_num_bytes (dh->pub_key);
/* username */
memcpy (out_ptr, user, user_len + 1);
out_ptr += user_len + 1;
/* pass */
memcpy (out_ptr, encrypted_pass, pass_len);
ret = g_base64_encode ((const guchar*)response, length);
g_free (response);
DH_free(dh);
g_free (plain_pass);
g_free (encrypted_pass);
g_free (secret);
return ret;
}
char *
encode_sasl_pass_aes (char *user, char *pass, char *data)
{
DH *dh;
AES_KEY key;
char *response = NULL;
char *out_ptr, *ret = NULL;
unsigned char *secret, *ptr;
unsigned char *encrypted_userpass, *plain_userpass;
int key_size, length;
guint16 size16;
unsigned char iv[16], iv_copy[16];
int user_len = strlen (user) + 1;
int pass_len = strlen (pass) + 1;
int len = user_len + pass_len;
int padlen = 16 - (len % 16);
int userpass_len = len + padlen;
if (!parse_dh (data, &dh, &secret, &key_size))
return NULL;
encrypted_userpass = g_malloc0 (userpass_len);
plain_userpass = g_malloc0 (userpass_len);
/* create message */
/* format of: <username>\0<password>\0<padding> */
ptr = plain_userpass;
memcpy (ptr, user, user_len);
ptr += user_len;
memcpy (ptr, pass, pass_len);
ptr += pass_len;
if (padlen)
{
/* Padding */
unsigned char randbytes[16];
if (!RAND_bytes (randbytes, padlen))
goto end;
memcpy (ptr, randbytes, padlen);
}
if (!RAND_bytes (iv, sizeof (iv)))
goto end;
memcpy (iv_copy, iv, sizeof(iv));
/* Encrypt */
AES_set_encrypt_key (secret, key_size * 8, &key);
AES_cbc_encrypt(plain_userpass, encrypted_userpass, userpass_len, &key, iv_copy, AES_ENCRYPT);
/* Create response */
/* format of: <size pubkey><pubkey><iv (always 16 bytes)><ciphertext> */
length = 2 + key_size + sizeof(iv) + userpass_len;
response = g_malloc (length);
out_ptr = response;
/* our key */
size16 = htons ((guint16)key_size);
memcpy (out_ptr, &size16, sizeof(size16));
out_ptr += 2;
BN_bn2bin (dh->pub_key, (guchar*)out_ptr);
out_ptr += key_size;
/* iv */
memcpy (out_ptr, iv, sizeof(iv));
out_ptr += sizeof(iv);
/* userpass */
memcpy (out_ptr, encrypted_userpass, userpass_len);
ret = g_base64_encode ((const guchar*)response, length);
end:
DH_free (dh);
g_free (plain_userpass);
g_free (encrypted_userpass);
g_free (secret);
g_free (response);
return ret;
}
#endif
#ifdef USE_OPENSSL
static char *
str_sha256hash (char *string)

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@ -76,8 +76,6 @@ void canonalize_key (char *key);
int portable_mode (void);
int unity_mode (void);
char *encode_sasl_pass_plain (char *user, char *pass);
char *encode_sasl_pass_blowfish (char *user, char *pass, char *data);
char *encode_sasl_pass_aes (char *user, char *pass, char *data);
char *challengeauth_response (char *username, char *password, char *challenge);
size_t strftime_validated (char *dest, size_t destsize, const char *format, const struct tm *time);
gsize strftime_utf8 (char *dest, gsize destsize, const char *format, time_t time);