radius.c

使用最广泛的radius的linux的源码

		}
	}

	memcpy(output, passwd, len);
}

static void make_tunnel_passwd(uint8_t *output, int *outlen,
			       const uint8_t *input, int inlen, int room,
			       const char *secret, const uint8_t *vector)
{
	FR_MD5_CTX context, old;
	uint8_t	digest[AUTH_VECTOR_LEN];
	uint8_t passwd[MAX_STRING_LEN + AUTH_VECTOR_LEN];
	int	i, n;
	int	len;

	/*
	 *	Be paranoid.
	 */
	if (room > 253) room = 253;

	/*
	 *	Account for 2 bytes of the salt, and round the room
	 *	available down to the nearest multiple of 16.  Then,
	 *	subtract one from that to account for the length byte,
	 *	and the resulting number is the upper bound on the data
	 *	to copy.
	 *
	 *	We could short-cut this calculation just be forcing
	 *	inlen to be no more than 239.  It would work for all
	 *	VSA's, as we don't pack multiple VSA's into one
	 *	attribute.
	 *
	 *	However, this calculation is more general, if a little
	 *	complex.  And it will work in the future for all possible
	 *	kinds of weird attribute packing.
	 */
	room -= 2;
	room -= (room & 0x0f);
	room--;

	if (inlen > room) inlen = room;

	/*
	 *	Length of the encrypted data is password length plus
	 *	one byte for the length of the password.
	 */
	len = inlen + 1;
	if ((len & 0x0f) != 0) {
		len += 0x0f;
		len &= ~0x0f;
	}
	*outlen = len + 2;	/* account for the salt */

	/*
	 *	Copy the password over.
	 */
	memcpy(passwd + 3, input, inlen);
	memset(passwd + 3 + inlen, 0, sizeof(passwd) - 3 - inlen);

	/*
	 *	Generate salt.  The RFC's say:
	 *
	 *	The high bit of salt[0] must be set, each salt in a
	 *	packet should be unique, and they should be random
	 *
	 *	So, we set the high bit, add in a counter, and then
	 *	add in some CSPRNG data.  should be OK..
	 */
	passwd[0] = (0x80 | ( ((salt_offset++) & 0x0f) << 3) |
		     (fr_rand() & 0x07));
	passwd[1] = fr_rand();
	passwd[2] = inlen;	/* length of the password string */

	fr_MD5Init(&context);
	fr_MD5Update(&context, (const uint8_t *) secret, strlen(secret));
	old = context;

	fr_MD5Update(&context, vector, AUTH_VECTOR_LEN);
	fr_MD5Update(&context, &passwd[0], 2);

	for (n = 0; n < len; n += AUTH_PASS_LEN) {
		if (n > 0) {
			context = old;
			fr_MD5Update(&context,
				       passwd + 2 + n - AUTH_PASS_LEN,
				       AUTH_PASS_LEN);
		}

		fr_MD5Final(digest, &context);
		for (i = 0; i < AUTH_PASS_LEN; i++) {
			passwd[i + 2 + n] ^= digest[i];
		}
	}
	memcpy(output, passwd, len + 2);
}


/*
 *	Parse a data structure into a RADIUS attribute.
 */
int rad_vp2attr(const RADIUS_PACKET *packet, const RADIUS_PACKET *original,
		const char *secret, const VALUE_PAIR *vp, uint8_t *ptr)
{
	int		vendorcode;
	int		offset, len, total_length;
	uint32_t	lvalue;
	uint8_t		*length_ptr, *vsa_length_ptr;
	const uint8_t	*data = NULL;
	uint8_t		array[4];

	vendorcode = total_length = 0;
	length_ptr = vsa_length_ptr = NULL;

	/*
	 *	For interoperability, always put vendor attributes
	 *	into their own VSA.
	 */
	if ((vendorcode = VENDOR(vp->attribute)) == 0) {
		*(ptr++) = vp->attribute & 0xFF;
		length_ptr = ptr;
		*(ptr++) = 2;
		total_length += 2;

	} else {
		int vsa_tlen = 1;
		int vsa_llen = 1;
		DICT_VENDOR *dv = dict_vendorbyvalue(vendorcode);

		/*
		 *	This must be an RFC-format attribute.  If it
		 *	wasn't, then the "decode" function would have
		 *	made a Vendor-Specific attribute (i.e. type
		 *	26), and we would have "vendorcode == 0" here.
		 */
		if (dv) {
			vsa_tlen = dv->type;
			vsa_llen = dv->length;
		}

		/*
		 *	Build a VSA header.
		 */
		*ptr++ = PW_VENDOR_SPECIFIC;
		vsa_length_ptr = ptr;
		*ptr++ = 6;
		lvalue = htonl(vendorcode);
		memcpy(ptr, &lvalue, 4);
		ptr += 4;
		total_length += 6;

		switch (vsa_tlen) {
		case 1:
			ptr[0] = (vp->attribute & 0xFF);
			break;

		case 2:
			ptr[0] = ((vp->attribute >> 8) & 0xFF);
			ptr[1] = (vp->attribute & 0xFF);
			break;

		case 4:
			ptr[0] = 0;
			ptr[1] = 0;
			ptr[2] = ((vp->attribute >> 8) & 0xFF);
			ptr[3] = (vp->attribute & 0xFF);
			break;

		default:
			return 0; /* silently discard it */
		}
		ptr += vsa_tlen;

		switch (vsa_llen) {
		case 0:
			length_ptr = vsa_length_ptr;
			vsa_length_ptr = NULL;
			break;
		case 1:
			ptr[0] = 0;
			length_ptr = ptr;
			break;
		case 2:
			ptr[0] = 0;
			ptr[1] = 0;
			length_ptr = ptr + 1;
			break;

		default:
			return 0; /* silently discard it */
		}
		ptr += vsa_llen;

		total_length += vsa_tlen + vsa_llen;
		if (vsa_length_ptr) *vsa_length_ptr += vsa_tlen + vsa_llen;
		*length_ptr += vsa_tlen + vsa_llen;
	}

	offset = 0;
	if (vp->flags.has_tag) {
		if (TAG_VALID(vp->flags.tag)) {
			ptr[0] = vp->flags.tag & 0xff;
			offset = 1;

		} else if (vp->flags.encrypt == FLAG_ENCRYPT_TUNNEL_PASSWORD) {
			/*
			 *	Tunnel passwords REQUIRE a tag, even
			 *	if don't have a valid tag.
			 */
			ptr[0] = 0;
			offset = 1;
		} /* else don't write a tag */
	} /* else the attribute doesn't have a tag */

	/*
	 *	Set up the default sources for the data.
	 */
	data = vp->vp_octets;
	len = vp->length;

	switch(vp->type) {
	case PW_TYPE_STRING:
	case PW_TYPE_OCTETS:
	case PW_TYPE_IFID:
	case PW_TYPE_IPV6ADDR:
	case PW_TYPE_IPV6PREFIX:
	case PW_TYPE_ABINARY:
		/* nothing more to do */
		break;

	case PW_TYPE_BYTE:
		len = 1;	/* just in case */
		array[0] = vp->vp_integer & 0xff;
		data = array;
		offset = 0;
		break;


	case PW_TYPE_SHORT:
		len = 2;	/* just in case */
		array[0] = (vp->vp_integer >> 8) & 0xff;
		array[1] = vp->vp_integer & 0xff;
		data = array;
		offset = 0;
		break;

	case PW_TYPE_INTEGER:
		len = 4;	/* just in case */
		lvalue = htonl(vp->vp_integer);
		memcpy(array, &lvalue, sizeof(lvalue));

		/*
		 *	Perhaps discard the first octet.
		 */
		data = &array[offset];
		len -= offset;
		break;

	case PW_TYPE_IPADDR:
		data = (const uint8_t *) &vp->vp_ipaddr;
		len = 4;	/* just in case */
		break;

		/*
		 *  There are no tagged date attributes.
		 */
	case PW_TYPE_DATE:
		lvalue = htonl(vp->vp_date);
		data = (const uint8_t *) &lvalue;
		len = 4;	/* just in case */
		break;

	default:		/* unknown type: ignore it */
		librad_log("ERROR: Unknown attribute type %d", vp->type);
		return -1;
	}

	/*
	 *	Bound the data to 255 bytes.
	 */
	if (len + offset + total_length > 255) {
		len = 255 - offset - total_length;
	}

	/*
	 *	Encrypt the various password styles
	 *
	 *	Attributes with encrypted values MUST be less than
	 *	128 bytes long.
	 */
	switch (vp->flags.encrypt) {
	case FLAG_ENCRYPT_USER_PASSWORD:
		make_passwd(ptr + offset, &len,
			    data, len,
			    secret, packet->vector);
		break;

	case FLAG_ENCRYPT_TUNNEL_PASSWORD:
		/*
		 *	Check if 255 - offset - total_length is less
		 *	than 18.  If so, we can't fit the data into
		 *	the available space, and we discard the
		 *	attribute.
		 *
		 *	This is ONLY a problem if we have multiple VSA's
		 *	in one Vendor-Specific, though.
		 */
		if ((255 - offset - total_length) < 18) return 0;

        	switch (packet->code) {
	        case PW_AUTHENTICATION_ACK:
        	case PW_AUTHENTICATION_REJECT:
        	case PW_ACCESS_CHALLENGE:
        	default:
			if (!original) {
				librad_log("ERROR: No request packet, cannot encrypt %s attribute in the vp.", vp->name);
				return -1;
			}
			make_tunnel_passwd(ptr + offset, &len,
					   data, len, 255 - offset - total_length,
					   secret, original->vector);
                	break;
	        case PW_ACCOUNTING_REQUEST:
        	case PW_DISCONNECT_REQUEST:
	        case PW_COA_REQUEST:
			make_tunnel_passwd(ptr + offset, &len,
					   data, len, 255 - offset - total_length,
					   secret, packet->vector);
	                break;
        	}
		break;

		/*
		 *	The code above ensures that this attribute
		 *	always fits.
		 */
	case FLAG_ENCRYPT_ASCEND_SECRET:
		make_secret(ptr + offset, packet->vector,
			    secret, data);
		len = AUTH_VECTOR_LEN;
		break;


	default:
		/*
		 *	Just copy the data over
		 */
		memcpy(ptr + offset, data, len);
		break;
	} /* switch over encryption flags */

	/*
	 *	Account for the tag (if any).
	 */
	len += offset;

	/*
	 *	RFC 2865 section 5 says that zero-length attributes
	 *	MUST NOT be sent.
	 */
	if (len == 0) return 0;

	/*
	 *	Update the various lengths.
	 */
	*length_ptr += len;
	if (vsa_length_ptr) *vsa_length_ptr += len;
	ptr += len;
	total_length += len;

	return total_length;	/* of attribute */
}


/*
 *	Encode a packet.
 */
int rad_encode(RADIUS_PACKET *packet, const RADIUS_PACKET *original,
	       const char *secret)
{
	radius_packet_t	*hdr;
	uint8_t	        *ptr;
	uint16_t	total_length;
	int		len;
	VALUE_PAIR	*reply;
	const char	*what;
	char		ip_buffer[128];

	/*
	 *	For simplicity in the following logic, we allow
	 *	the attributes to "overflow" the 4k maximum
	 *	RADIUS packet size, by one attribute.
	 *
	 *	It's uint32_t, for alignment purposes.
	 */
	uint32_t	data[(MAX_PACKET_LEN + 256) / 4];

	if ((packet->code > 0) && (packet->code < MAX_PACKET_CODE)) {
		what = packet_codes[packet->code];
	} else {
		what = "Reply";
	}

	DEBUG("Sending %s of id %d to %s port %d\n",
	      what, packet->id,
	      inet_ntop(packet->dst_ipaddr.af,
			&packet->dst_ipaddr.ipaddr,
			ip_buffer, sizeof(ip_buffer)),
	      packet->dst_port);

	/*
	 *	Double-check some things based on packet code.
	 */
	switch (packet->code) {
	case PW_AUTHENTICATION_ACK:
	case PW_AUTHENTICATION_REJECT:
	case PW_ACCESS_CHALLENGE:
		if (!original) {
			librad_log("ERROR: Cannot sign response packet without a request packet.");
			return -1;
		}
		break;

		/*
		 *	These packet vectors start off as all zero.
		 */
	case PW_ACCOUNTING_REQUEST:
	case PW_DISCONNECT_REQUEST:
	case PW_COA_REQUEST:
		memset(packet->vector, 0, sizeof(packet->vector));
		break;

	default:
		break;
	}

	/*
	 *	Use memory on the stack, until we know how
	 *	large the packet will be.
	 */
	hdr = (radius_packet_t *) data;

	/*
	 *	Build standard header
	 */
	hdr->code = packet->code;
	hdr->id = packet->id;

	memcpy(hdr->vector, packet->vector, sizeof(hdr->vector));

	total_length = AUTH_HDR_LEN;

	/*
	 *	Load up the configuration values for the user
	 */
	ptr = hdr->data;
	packet->offset = 0;

	/*
	 *	FIXME: Loop twice over the reply list.  The first time,
	 *	calculate the total length of data.  The second time,
	 *	allocate the memory, and fill in the VP's.
	 *
	 *	Hmm... this may be slower than just doing a small
	 *	memcpy.
	 */

	/*
	 *	Loop over the reply attributes for the packet.
	 */
	for (reply = packet->vps; reply; reply = reply->next) {
		/*
		 *	Ignore non-wire attributes
		 */
		if ((VENDOR(reply->attribute) == 0) &&
		    ((reply->attribute & 0xFFFF) > 0xff)) {
#ifndef NDEBUG
			/*
			 *	Permit the admin to send BADLY formatted
			 *	attributes with a debug build.
			 */
			if (reply->attribute == PW_RAW_ATTRIBUTE) {
				memcpy(ptr, reply->vp_octets, reply->length);
				len = reply->length;
				goto next;
			}
#endif
			continue;
		}

		/*
		 *	Set the Message-Authenticator to the correct
		 *	length and initial value.
		 */
		if (reply->attribute == PW_MESSAGE_AUTHENTICATOR) {
			reply->length = AUTH_VECTOR_LEN;
			memset(reply->vp_strvalue, 0, AUTH_VECTOR_LEN);

			/*
			 *	Cache the offset to the
			 *	Message-Authenticator
			 */
			packet->offset = total_length;
		}

		/*
		 *	Print out ONLY the attributes which
		 *	we're sending over the wire, and print
		 *	them out BEFORE they're encrypted.
		 */
		debug_pair(reply);

		len = rad_vp2attr(packet, original, secret, reply, ptr);

		if (len < 0) return -1;

		/*
		 *	Check that the packet is no more than 4k in
		 *	size, AFTER writing the attribute past the 4k
		 *	boundary, but BEFORE deciding to increase the
		 *	size of the packet. Note that the 'data'
		 *	buffer, above, is one attribute longer than
		 *	necessary, in order to permit this overflow.
		 */
		if ((total_length + len) > MAX_PACKET_LEN) {
			break;
		}

	next:
		ptr += len;
		total_length += len;
	} /* done looping over all attributes */

	/*
	 *	Fill in the rest of the fields, and copy the data over
	 *	from the local stack to the newly allocated memory.
	 *
	 *	Yes, all this 'memcpy' is slow, but it means
	 *	that we only allocate the minimum amount of
	 *	memory for a request.
	 */
	packet->data_len = total_length;
	packet->data = (uint8_t *) malloc(packet->data_len);
	if (!packet->data) {
		librad_log("Out of memory");
		return -1;
	}

	memcpy(packet->data, data, packet->data_len);
	hdr = (radius_packet_t *) packet->data;

	total_length = htons(total_length);
	memcpy(hdr->length, &total_length, sizeof(total_length));

	return 0;
}


/*
 *	Sign a previously encoded packet.
 */
int rad_sign(RADIUS_PACKET *packet, const RADIUS_PACKET *original,