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kike: implement SSL client cert. auth.

tags/v0.9
Přemysl Janouch 5 years ago
parent
commit
34967973aa
2 changed files with 83 additions and 2 deletions
  1. +6
    -0
      README
  2. +77
    -2
      src/kike.c

+ 6
- 0
README View File

@@ -44,6 +44,12 @@ ZyklonB stays running in the foreground, so I recommend launching it inside
a Screen or tmux session. kike, on the other hand, immediately forks into the
background. Use something like `killall' if you want to terminate it.

Client Certificates
-------------------
`kike' uses SHA1 fingerprints of SSL client certificates to authenticate users.
To get the fingerprint from a certificate file, use:
$ openssl x509 -noout -in cert.pem -sha1 -fingerprint

Disclaimer
----------
I am not an antisemitist, I'm just being an offensive asshole with the naming.

+ 77
- 2
src/kike.c View File

@@ -38,6 +38,8 @@ static struct config_item g_config_table[] =
{ "ssl_cert", NULL, "Server SSL certificate (PEM)" },
{ "ssl_key", NULL, "Server SSL private key (PEM)" },

{ "operators", NULL, "IRCop SSL cert. fingerprints" },

{ "max_connections", "0", "Global connection limit" },
{ "ping_interval", "180", "Interval between PING's (sec)" },
{ NULL, NULL, NULL }
@@ -222,6 +224,12 @@ irc_is_valid_key (const char *key)
#undef LE
#undef SP

static bool
irc_is_valid_fingerprint (const char *fp)
{
return irc_regex_match ("^[a-fA-F0-9]{2}(:[a-fA-F0-9]{2}){20}$", fp);
}

// --- Application data --------------------------------------------------------

#define IRC_SUPPORTED_USER_MODES "aiwros"
@@ -251,6 +259,7 @@ struct client
bool ssl_rx_want_tx; ///< SSL_read() wants to write
bool ssl_tx_want_rx; ///< SSL_write() wants to read
SSL *ssl; ///< SSL connection
char *ssl_cert_fingerprint; ///< Client certificate fingerprint

char *nickname; ///< IRC nickname (main identifier)
char *username; ///< IRC username
@@ -435,6 +444,7 @@ struct server_context
unsigned max_connections; ///< Max. connections allowed or 0
struct str_vector motd; ///< MOTD (none if empty)
nl_catd catalog; ///< Message catalog for server msgs
struct str_map operators; ///< SSL cert. fingerprints for IRCops
};

static void
@@ -465,6 +475,9 @@ server_context_init (struct server_context *self)
self->max_connections = 0;
str_vector_init (&self->motd);
self->catalog = (nl_catd) -1;
str_map_init (&self->operators);
// The regular irc_strxfrm() is sufficient for fingerprints
self->operators.key_xfrm = irc_strxfrm;
}

static void
@@ -494,6 +507,7 @@ server_context_free (struct server_context *self)
str_vector_free (&self->motd);
if (self->catalog != (nl_catd) -1)
catclose (self->catalog);
str_map_free (&self->operators);
}

static void
@@ -759,6 +773,35 @@ irc_initiate_quit (struct server_context *ctx)
irc_try_finish_quit (ctx);
}

static char *
client_get_ssl_cert_fingerprint (struct client *c)
{
if (!c->ssl)
return NULL;

X509 *peer_cert = SSL_get_peer_certificate (c->ssl);
if (!peer_cert)
return NULL;

int cert_len = i2d_X509 (peer_cert, NULL);
if (cert_len < 0)
return NULL;

unsigned char cert[cert_len], *p = cert;
if (i2d_X509 (peer_cert, &p) < 0)
return NULL;

unsigned char hash[SHA_DIGEST_LENGTH];
SHA1 (cert, cert_len, hash);

struct str fingerprint;
str_init (&fingerprint);
str_append_printf (&fingerprint, "%02X", hash[0]);
for (size_t i = 0; i < sizeof hash; i++)
str_append_printf (&fingerprint, ":%02X", hash[i]);
return str_steal (&fingerprint);
}

// --- Timers ------------------------------------------------------------------

static void
@@ -1076,6 +1119,12 @@ irc_try_finish_registration (struct client *c)
if (*mode)
irc_send (c, ":%s MODE %s :+%s", c->nickname, c->nickname, mode);
free (mode);

hard_assert (c->ssl_cert_fingerprint == NULL);
if ((c->ssl_cert_fingerprint = client_get_ssl_cert_fingerprint (c)))
irc_send (c, ":%s NOTICE %s :"
"Your SSL client certificate fingerprint is %s",
ctx->server_name, c->nickname, c->ssl_cert_fingerprint);
}

static void
@@ -1367,7 +1416,13 @@ irc_handle_user_mode_change (struct client *c, const char *mode_string)
case 'o':
if (!adding)
irc_modify_mode (&new_mode, IRC_USER_MODE_OPERATOR, false);
// TODO: check public key fingerprint when adding
else if (c->ssl_cert_fingerprint
&& str_map_find (&c->ctx->operators, c->ssl_cert_fingerprint))
irc_modify_mode (&new_mode, IRC_USER_MODE_OPERATOR, true);
else
irc_send (c, ":%s NOTICE %s :Either you're not using an SSL"
" client certificate, or the fingerprint doesn't match",
c->ctx->server_name, c->nickname);
break;
case 's':
irc_modify_mode (&new_mode, IRC_USER_MODE_RX_SERVER_NOTICES, adding);
@@ -2657,7 +2712,27 @@ irc_parse_config (struct server_context *ctx, struct error **e)

PARSE_UNSIGNED (ping_interval, 1, UINT_MAX);
PARSE_UNSIGNED (max_connections, 0, UINT_MAX);
return true;

bool result = true;
struct str_vector fingerprints;
str_vector_init (&fingerprints);
const char *operators = str_map_find (&ctx->config, "operators");
if (operators)
split_str_ignore_empty (operators, ',', &fingerprints);
for (size_t i = 0; i < fingerprints.len; i++)
{
const char *key = fingerprints.vector[i];
if (!irc_is_valid_fingerprint (key))
{
error_set (e, "invalid configuration value for `%s': %s",
"operators", "invalid fingerprint value");
result = false;
break;
}
str_map_set (&ctx->operators, key, (void *) 1);
}
str_vector_free (&fingerprints);
return result;
}

static bool

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