Implement BLOWFISh, AES, and EXTERNAL SASL mechanisms

Closes #657

src/common/util.c

@@ -58,6 +58,17 @@
 #include <socks.h>
 #endif
 
+/* SASL mechanisms */
+#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
+#endif
+
 #ifndef HAVE_SNPRINTF
 #define snprintf g_snprintf
 #endif
@@ -1929,7 +1940,7 @@ get_subdirs (const char *path)
 }
 
 char *
-encode_sasl_pass (char *user, char *pass)
+encode_sasl_pass_plain (char *user, char *pass)
 {
 	int authlen;
 	char *buffer;
@@ -1944,6 +1955,230 @@ encode_sasl_pass (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;
+	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 = (unsigned char*)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:
+	if (decoded_data)
+		g_free (decoded_data);
+	return 0;
+}
+
+char *
+encode_sasl_pass_blowfish (char *user, char *pass, char *data)
+{
+	DH *dh;
+	char *response, *ret;
+	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 = (guchar*)malloc (pass_len);
+	memset (encrypted_pass, 0, pass_len);
+	plain_pass = (char*)malloc (pass_len);
+	memset (plain_pass, 0, pass_len);
+	memcpy (plain_pass, pass, pass_len);
+	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 = (char*)malloc (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);
+
+	DH_free (dh);
+	free (plain_pass);
+	free (encrypted_pass);
+	free (secret);
+	free (response);
+
+	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 = (guchar*)malloc (userpass_len);
+	memset (encrypted_userpass, 0, userpass_len);
+	plain_userpass = (guchar*)malloc (userpass_len);
+	memset (plain_userpass, 0, 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 = (char*)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);
+	free (plain_userpass);
+	free (encrypted_userpass);
+	free (secret);
+	if (response)
+		free (response);
+
+	return ret;
+}
+#endif
+
 #ifdef WIN32
 int
 find_font (const char *fontname)