/*
sptps.c -- Simple Peer-to-Peer Security
- Copyright (C) 2011 Guus Sliepen <guus@tinc-vpn.org>,
+ Copyright (C) 2014-2017 Guus Sliepen <guus@meshlink.io>
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
#include "system.h"
-#include "cipher.h"
+#include "chacha-poly1305/chacha-poly1305.h"
#include "crypto.h"
-#include "digest.h"
#include "ecdh.h"
#include "ecdsa.h"
+#include "logger.h"
#include "prf.h"
#include "sptps.h"
Make sure ECC operations are fixed time (aka prevent side-channel attacks).
*/
+void sptps_log_quiet(sptps_t *s, int s_errno, const char *format, va_list ap) {
+ (void)s;
+ (void)s_errno;
+ (void)format;
+ (void)ap;
+
+ assert(format);
+}
+
+void sptps_log_stderr(sptps_t *s, int s_errno, const char *format, va_list ap) {
+ (void)s;
+ (void)s_errno;
+
+ assert(format);
+
+ vfprintf(stderr, format, ap);
+ fputc('\n', stderr);
+}
+
+void (*sptps_log)(sptps_t *s, int s_errno, const char *format, va_list ap) = sptps_log_quiet;
+
// Log an error message.
-static bool error(sptps_t *s, int s_errno, const char *msg) {
- fprintf(stderr, "SPTPS error: %s\n", msg);
+static bool error(sptps_t *s, int s_errno, const char *format, ...) {
+ assert(s_errno);
+ assert(format);
+
+ if(format) {
+ va_list ap;
+ va_start(ap, format);
+ sptps_log(s, s_errno, format, ap);
+ va_end(ap);
+ }
+
errno = s_errno;
return false;
}
+static void warning(sptps_t *s, const char *format, ...) {
+ assert(format);
+
+ va_list ap;
+ va_start(ap, format);
+ sptps_log(s, 0, format, ap);
+ va_end(ap);
+}
+
// Send a record (datagram version, accepts all record types, handles encryption and authentication).
-static bool send_record_priv_datagram(sptps_t *s, uint8_t type, const char *data, uint16_t len) {
- char buffer[len + 23UL];
+static bool send_record_priv_datagram(sptps_t *s, uint8_t type, const void *data, uint16_t len) {
+ char buffer[len + 21UL];
// Create header with sequence number, length and record type
- uint32_t seqno = htonl(s->outseqno++);
- uint16_t netlen = htons(len);
-
- memcpy(buffer, &netlen, 2);
- memcpy(buffer + 2, &seqno, 4);
- buffer[6] = type;
+ uint32_t seqno = s->outseqno++;
+ uint32_t netseqno = ntohl(seqno);
- // Add plaintext (TODO: avoid unnecessary copy)
- memcpy(buffer + 7, data, len);
+ memcpy(buffer, &netseqno, 4);
+ buffer[4] = type;
+ memcpy(buffer + 5, data, len);
if(s->outstate) {
// If first handshake has finished, encrypt and HMAC
- cipher_set_counter(&s->outcipher, &seqno, sizeof seqno);
- if(!cipher_counter_xor(&s->outcipher, buffer + 6, len + 1UL, buffer + 6))
- return false;
-
- if(!digest_create(&s->outdigest, buffer, len + 7UL, buffer + 7UL + len))
- return false;
-
- return s->send_data(s->handle, type, buffer + 2, len + 21UL);
+ chacha_poly1305_encrypt(s->outcipher, seqno, buffer + 4, len + 1, buffer + 4, NULL);
+ return s->send_data(s->handle, type, buffer, len + 21UL);
} else {
// Otherwise send as plaintext
- return s->send_data(s->handle, type, buffer + 2, len + 5UL);
+ return s->send_data(s->handle, type, buffer, len + 5UL);
}
}
// Send a record (private version, accepts all record types, handles encryption and authentication).
-static bool send_record_priv(sptps_t *s, uint8_t type, const char *data, uint16_t len) {
- if(s->datagram)
+static bool send_record_priv(sptps_t *s, uint8_t type, const void *data, uint16_t len) {
+ if(s->datagram) {
return send_record_priv_datagram(s, type, data, len);
+ }
- char buffer[len + 23UL];
+ char buffer[len + 19UL];
// Create header with sequence number, length and record type
- uint32_t seqno = htonl(s->outseqno++);
+ uint32_t seqno = s->outseqno++;
uint16_t netlen = htons(len);
- memcpy(buffer, &seqno, 4);
- memcpy(buffer + 4, &netlen, 2);
- buffer[6] = type;
-
- // Add plaintext (TODO: avoid unnecessary copy)
- memcpy(buffer + 7, data, len);
+ memcpy(buffer, &netlen, 2);
+ buffer[2] = type;
+ memcpy(buffer + 3, data, len);
if(s->outstate) {
// If first handshake has finished, encrypt and HMAC
- if(!cipher_counter_xor(&s->outcipher, buffer + 4, len + 3UL, buffer + 4))
- return false;
-
- if(!digest_create(&s->outdigest, buffer, len + 7UL, buffer + 7UL + len))
- return false;
-
- return s->send_data(s->handle, type, buffer + 4, len + 19UL);
+ chacha_poly1305_encrypt(s->outcipher, seqno, buffer + 2, len + 1, buffer + 2, NULL);
+ return s->send_data(s->handle, type, buffer, len + 19UL);
} else {
// Otherwise send as plaintext
- return s->send_data(s->handle, type, buffer + 4, len + 3UL);
+ return s->send_data(s->handle, type, buffer, len + 3UL);
}
}
// Send an application record.
-bool sptps_send_record(sptps_t *s, uint8_t type, const char *data, uint16_t len) {
+bool sptps_send_record(sptps_t *s, uint8_t type, const void *data, uint16_t len) {
+ assert(!len || data);
+
// Sanity checks: application cannot send data before handshake is finished,
// and only record types 0..127 are allowed.
- if(!s->outstate)
+ if(!s->outstate) {
return error(s, EINVAL, "Handshake phase not finished yet");
+ }
- if(type >= SPTPS_HANDSHAKE)
+ if(type >= SPTPS_HANDSHAKE) {
return error(s, EINVAL, "Invalid application record type");
+ }
return send_record_priv(s, type, data, len);
}
size_t keylen = ECDH_SIZE;
// Make room for our KEX message, which we will keep around since send_sig() needs it.
- if(s->mykex)
- abort();
+ if(s->mykex) {
+ return false;
+ }
+
s->mykex = realloc(s->mykex, 1 + 32 + keylen);
- if(!s->mykex)
+
+ if(!s->mykex) {
return error(s, errno, strerror(errno));
+ }
// Set version byte to zero.
s->mykex[0] = SPTPS_VERSION;
randomize(s->mykex + 1, 32);
// Create a new ECDH public key.
- if(!ecdh_generate_public(&s->ecdh, s->mykex + 1 + 32))
- return false;
+ if(!(s->ecdh = ecdh_generate_public(s->mykex + 1 + 32))) {
+ return error(s, EINVAL, "Failed to generate ECDH public key");
+ }
return send_record_priv(s, SPTPS_HANDSHAKE, s->mykex, 1 + 32 + keylen);
}
// Send a SIGnature record, containing an ECDSA signature over both KEX records.
static bool send_sig(sptps_t *s) {
size_t keylen = ECDH_SIZE;
- size_t siglen = ecdsa_size(&s->mykey);
+ size_t siglen = ecdsa_size(s->mykey);
// Concatenate both KEX messages, plus tag indicating if it is from the connection originator, plus label
char msg[(1 + 32 + keylen) * 2 + 1 + s->labellen];
memcpy(msg + 1 + 2 * (33 + keylen), s->label, s->labellen);
// Sign the result.
- if(!ecdsa_sign(&s->mykey, msg, sizeof msg, sig))
- return false;
+ if(!ecdsa_sign(s->mykey, msg, sizeof(msg), sig)) {
+ return error(s, EINVAL, "Failed to sign SIG record");
+ }
// Send the SIG exchange record.
- return send_record_priv(s, SPTPS_HANDSHAKE, sig, sizeof sig);
+ return send_record_priv(s, SPTPS_HANDSHAKE, sig, sizeof(sig));
}
// Generate key material from the shared secret created from the ECDHE key exchange.
static bool generate_key_material(sptps_t *s, const char *shared, size_t len) {
+ assert(shared);
+ assert(len);
+
// Initialise cipher and digest structures if necessary
if(!s->outstate) {
- bool result
- = cipher_open_by_name(&s->incipher, "aes-256-ecb")
- && cipher_open_by_name(&s->outcipher, "aes-256-ecb")
- && digest_open_by_name(&s->indigest, "sha256", 16)
- && digest_open_by_name(&s->outdigest, "sha256", 16);
- if(!result)
- return false;
+ s->incipher = chacha_poly1305_init();
+ s->outcipher = chacha_poly1305_init();
+
+ if(!s->incipher || !s->outcipher) {
+ return error(s, EINVAL, "Failed to open cipher");
+ }
}
// Allocate memory for key material
- size_t keylen = digest_keylength(&s->indigest) + digest_keylength(&s->outdigest) + cipher_keylength(&s->incipher) + cipher_keylength(&s->outcipher);
+ size_t keylen = 2 * CHACHA_POLY1305_KEYLEN;
s->key = realloc(s->key, keylen);
- if(!s->key)
+
+ if(!s->key) {
return error(s, errno, strerror(errno));
+ }
// Create the HMAC seed, which is "key expansion" + session label + server nonce + client nonce
char seed[s->labellen + 64 + 13];
strcpy(seed, "key expansion");
+
if(s->initiator) {
memcpy(seed + 13, s->mykex + 1, 32);
memcpy(seed + 45, s->hiskex + 1, 32);
memcpy(seed + 13, s->hiskex + 1, 32);
memcpy(seed + 45, s->mykex + 1, 32);
}
- memcpy(seed + 78, s->label, s->labellen);
+
+ memcpy(seed + 77, s->label, s->labellen);
// Use PRF to generate the key material
- if(!prf(shared, len, seed, s->labellen + 64 + 13, s->key, keylen))
- return false;
+ if(!prf(shared, len, seed, s->labellen + 64 + 13, s->key, keylen)) {
+ return error(s, EINVAL, "Failed to generate key material");
+ }
return true;
}
// Receive an ACKnowledgement record.
static bool receive_ack(sptps_t *s, const char *data, uint16_t len) {
- if(len)
+ (void)data;
+
+ if(len) {
return error(s, EIO, "Invalid ACK record length");
+ }
if(s->initiator) {
- bool result
- = cipher_set_counter_key(&s->incipher, s->key)
- && digest_set_key(&s->indigest, s->key + cipher_keylength(&s->incipher), digest_keylength(&s->indigest));
- if(!result)
- return false;
+ if(!chacha_poly1305_set_key(s->incipher, s->key)) {
+ return error(s, EINVAL, "Failed to set counter");
+ }
} else {
- bool result
- = cipher_set_counter_key(&s->incipher, s->key + cipher_keylength(&s->outcipher) + digest_keylength(&s->outdigest))
- && digest_set_key(&s->indigest, s->key + cipher_keylength(&s->outcipher) + digest_keylength(&s->outdigest) + cipher_keylength(&s->incipher), digest_keylength(&s->indigest));
- if(!result)
- return false;
+ if(!chacha_poly1305_set_key(s->incipher, s->key + CHACHA_POLY1305_KEYLEN)) {
+ return error(s, EINVAL, "Failed to set counter");
+ }
}
free(s->key);
// Receive a Key EXchange record, respond by sending a SIG record.
static bool receive_kex(sptps_t *s, const char *data, uint16_t len) {
// Verify length of the HELLO record
- if(len != 1 + 32 + ECDH_SIZE)
+ if(len != 1 + 32 + ECDH_SIZE) {
return error(s, EIO, "Invalid KEX record length");
+ }
// Ignore version number for now.
// Make a copy of the KEX message, send_sig() and receive_sig() need it
- if(s->hiskex)
- abort();
+ if(s->hiskex) {
+ return error(s, EINVAL, "Received a second KEX message before first has been processed");
+ }
+
s->hiskex = realloc(s->hiskex, len);
- if(!s->hiskex)
+
+ if(!s->hiskex) {
return error(s, errno, strerror(errno));
+ }
memcpy(s->hiskex, data, len);
// Receive a SIGnature record, verify it, if it passed, compute the shared secret and calculate the session keys.
static bool receive_sig(sptps_t *s, const char *data, uint16_t len) {
size_t keylen = ECDH_SIZE;
- size_t siglen = ecdsa_size(&s->hiskey);
+ size_t siglen = ecdsa_size(s->hiskey);
// Verify length of KEX record.
- if(len != siglen)
+ if(len != siglen) {
return error(s, EIO, "Invalid KEX record length");
+ }
// Concatenate both KEX messages, plus tag indicating if it is from the connection originator
char msg[(1 + 32 + keylen) * 2 + 1 + s->labellen];
memcpy(msg + 1 + 2 * (33 + keylen), s->label, s->labellen);
// Verify signature.
- if(!ecdsa_verify(&s->hiskey, msg, sizeof msg, data))
- return false;
+ if(!ecdsa_verify(s->hiskey, msg, sizeof(msg), data)) {
+ return error(s, EIO, "Failed to verify SIG record");
+ }
// Compute shared secret.
char shared[ECDH_SHARED_SIZE];
- if(!ecdh_compute_shared(&s->ecdh, s->hiskex + 1 + 32, shared))
- return false;
+
+ if(!ecdh_compute_shared(s->ecdh, s->hiskex + 1 + 32, shared)) {
+ return error(s, EINVAL, "Failed to compute ECDH shared secret");
+ }
+
+ s->ecdh = NULL;
// Generate key material from shared secret.
- if(!generate_key_material(s, shared, sizeof shared))
+ if(!generate_key_material(s, shared, sizeof(shared))) {
return false;
+ }
free(s->mykex);
free(s->hiskex);
s->hiskex = NULL;
// Send cipher change record
- if(s->outstate && !send_ack(s))
+ if(s->outstate && !send_ack(s)) {
return false;
+ }
// TODO: only set new keys after ACK has been set/received
if(s->initiator) {
- bool result
- = cipher_set_counter_key(&s->outcipher, s->key + cipher_keylength(&s->incipher) + digest_keylength(&s->indigest))
- && digest_set_key(&s->outdigest, s->key + cipher_keylength(&s->incipher) + digest_keylength(&s->indigest) + cipher_keylength(&s->outcipher), digest_keylength(&s->outdigest));
- if(!result)
- return false;
+ if(!chacha_poly1305_set_key(s->outcipher, s->key + CHACHA_POLY1305_KEYLEN)) {
+ return error(s, EINVAL, "Failed to set key");
+ }
} else {
- bool result
- = cipher_set_counter_key(&s->outcipher, s->key)
- && digest_set_key(&s->outdigest, s->key + cipher_keylength(&s->outcipher), digest_keylength(&s->outdigest));
- if(!result)
- return false;
+ if(!chacha_poly1305_set_key(s->outcipher, s->key)) {
+ return error(s, EINVAL, "Failed to set key");
+ }
}
return true;
// Force another Key EXchange (for testing purposes).
bool sptps_force_kex(sptps_t *s) {
- if(!s->outstate || s->state != SPTPS_SECONDARY_KEX)
+ if(!s->outstate || s->state != SPTPS_SECONDARY_KEX) {
return error(s, EINVAL, "Cannot force KEX in current state");
+ }
s->state = SPTPS_KEX;
return send_kex(s);
// Receive a handshake record.
static bool receive_handshake(sptps_t *s, const char *data, uint16_t len) {
// Only a few states to deal with handshaking.
- fprintf(stderr, "Received handshake message, current state %d\n", s->state);
switch(s->state) {
- case SPTPS_SECONDARY_KEX:
- // We receive a secondary KEX request, first respond by sending our own.
- if(!send_kex(s))
- return false;
- case SPTPS_KEX:
- // We have sent our KEX request, we expect our peer to sent one as well.
- if(!receive_kex(s, data, len))
- return false;
- s->state = SPTPS_SIG;
- return true;
- case SPTPS_SIG:
- // If we already sent our secondary public ECDH key, we expect the peer to send his.
- if(!receive_sig(s, data, len))
+ case SPTPS_SECONDARY_KEX:
+
+ // We receive a secondary KEX request, first respond by sending our own.
+ if(!send_kex(s)) {
+ return false;
+ }
+
+ // fallthrough
+ case SPTPS_KEX:
+
+ // We have sent our KEX request, we expect our peer to sent one as well.
+ if(!receive_kex(s, data, len)) {
+ return false;
+ }
+
+ s->state = SPTPS_SIG;
+ return true;
+
+ case SPTPS_SIG:
+
+ // If we already sent our secondary public ECDH key, we expect the peer to send his.
+ if(!receive_sig(s, data, len)) {
+ return false;
+ }
+
+ if(s->outstate) {
+ s->state = SPTPS_ACK;
+ } else {
+ s->outstate = true;
+
+ if(!receive_ack(s, NULL, 0)) {
return false;
- if(s->outstate)
- s->state = SPTPS_ACK;
- else {
- s->outstate = true;
- if(!receive_ack(s, NULL, 0))
- return false;
- s->receive_record(s->handle, SPTPS_HANDSHAKE, NULL, 0);
- s->state = SPTPS_SECONDARY_KEX;
}
- return true;
- case SPTPS_ACK:
- // We expect a handshake message to indicate transition to the new keys.
- if(!receive_ack(s, data, len))
- return false;
s->receive_record(s->handle, SPTPS_HANDSHAKE, NULL, 0);
s->state = SPTPS_SECONDARY_KEX;
- return true;
- // TODO: split ACK into a VERify and ACK?
- default:
- return error(s, EIO, "Invalid session state");
+ }
+
+ return true;
+
+ case SPTPS_ACK:
+
+ // We expect a handshake message to indicate transition to the new keys.
+ if(!receive_ack(s, data, len)) {
+ return false;
+ }
+
+ s->receive_record(s->handle, SPTPS_HANDSHAKE, NULL, 0);
+ s->state = SPTPS_SECONDARY_KEX;
+ return true;
+
+ // TODO: split ACK into a VERify and ACK?
+ default:
+ return error(s, EIO, "Invalid session state %d", s->state);
}
}
// Check datagram for valid HMAC
-bool sptps_verify_datagram(sptps_t *s, const char *data, size_t len) {
- if(!s->instate || len < 21)
- return false;
+bool sptps_verify_datagram(sptps_t *s, const void *data, size_t len) {
+ if(!s->instate) {
+ return error(s, EIO, "SPTPS state not ready to verify this datagram");
+ }
- char buffer[len + 23];
- uint16_t netlen = htons(len - 21);
+ if(len < 21) {
+ return error(s, EIO, "Received short packet in sptps_verify_datagram");
+ }
- memcpy(buffer, &netlen, 2);
- memcpy(buffer + 2, data, len);
+ uint32_t seqno;
+ memcpy(&seqno, data, 4);
+ seqno = ntohl(seqno);
+ // TODO: check whether seqno makes sense, to avoid CPU intensive decrypt
- return digest_verify(&s->indigest, buffer, len - 14, buffer + len - 14);
+ return chacha_poly1305_verify(s->incipher, seqno, (const char *)data + 4, len - 4);
}
// Receive incoming data, datagram version.
-static bool sptps_receive_data_datagram(sptps_t *s, const char *data, size_t len) {
- if(len < (s->instate ? 21 : 5))
- return error(s, EIO, "Received short packet");
+static bool sptps_receive_data_datagram(sptps_t *s, const void *vdata, size_t len) {
+ const char *data = vdata;
+
+ if(len < (s->instate ? 21 : 5)) {
+ return error(s, EIO, "Received short packet in sptps_receive_data_datagram");
+ }
uint32_t seqno;
memcpy(&seqno, data, 4);
if(!s->instate) {
if(seqno != s->inseqno) {
- fprintf(stderr, "Received invalid packet seqno: %d != %d\n", seqno, s->inseqno);
- return error(s, EIO, "Invalid packet seqno");
+ return error(s, EIO, "Invalid packet seqno: %d != %d", seqno, s->inseqno);
}
s->inseqno = seqno + 1;
uint8_t type = data[4];
- if(type != SPTPS_HANDSHAKE)
+ if(type != SPTPS_HANDSHAKE) {
return error(s, EIO, "Application record received before handshake finished");
+ }
return receive_handshake(s, data + 5, len - 5);
}
- if(seqno < s->inseqno) {
- fprintf(stderr, "Received late or replayed packet: %d < %d\n", seqno, s->inseqno);
- return true;
- }
+ // Decrypt
- if(seqno > s->inseqno)
- fprintf(stderr, "Missed %d packets\n", seqno - s->inseqno);
+ if(len > s->decrypted_buffer_len) {
+ s->decrypted_buffer_len *= 2;
+ char *new_buffer = realloc(s->decrypted_buffer, s->decrypted_buffer_len);
- s->inseqno = seqno + 1;
+ if(!new_buffer) {
+ return error(s, errno, strerror(errno));
+ }
- uint16_t netlen = htons(len - 21);
+ s->decrypted_buffer = new_buffer;
+ }
- char buffer[len + 23];
+ size_t outlen;
- memcpy(buffer, &netlen, 2);
- memcpy(buffer + 2, data, len);
+ if(!chacha_poly1305_decrypt(s->incipher, seqno, data + 4, len - 4, s->decrypted_buffer, &outlen)) {
+ return error(s, EIO, "Failed to decrypt and verify packet");
+ }
- memcpy(&seqno, buffer + 2, 4);
+ // Replay protection using a sliding window of configurable size.
+ // s->inseqno is expected sequence number
+ // seqno is received sequence number
+ // s->late[] is a circular buffer, a 1 bit means a packet has not been received yet
+ // The circular buffer contains bits for sequence numbers from s->inseqno - s->replaywin * 8 to (but excluding) s->inseqno.
+ if(s->replaywin) {
+ if(seqno != s->inseqno) {
+ if(seqno >= s->inseqno + s->replaywin * 8) {
+ // TODO: Prevent packets that jump far ahead of the queue from causing many others to be dropped.
+ warning(s, "Lost %d packets\n", seqno - s->inseqno);
+ // Mark all packets in the replay window as being late.
+ memset(s->late, 255, s->replaywin);
+ } else if(seqno < s->inseqno) {
+ // If the sequence number is farther in the past than the bitmap goes, or if the packet was already received, drop it.
+ if((s->inseqno >= s->replaywin * 8 && seqno < s->inseqno - s->replaywin * 8) || !(s->late[(seqno / 8) % s->replaywin] & (1 << seqno % 8))) {
+ return error(s, EIO, "Received late or replayed packet, seqno %d, last received %d\n", seqno, s->inseqno);
+ }
+ } else {
+ // We missed some packets. Mark them in the bitmap as being late.
+ for(uint32_t i = s->inseqno; i < seqno; i++) {
+ s->late[(i / 8) % s->replaywin] |= 1 << i % 8;
+ }
+ }
+ }
- // Check HMAC and decrypt.
- if(!digest_verify(&s->indigest, buffer, len - 14, buffer + len - 14))
- return error(s, EIO, "Invalid HMAC");
+ // Mark the current packet as not being late.
+ s->late[(seqno / 8) % s->replaywin] &= ~(1 << seqno % 8);
+ }
- cipher_set_counter(&s->incipher, &seqno, sizeof seqno);
- if(!cipher_counter_xor(&s->incipher, buffer + 6, len - 4, buffer + 6))
- return false;
+ if(seqno >= s->inseqno) {
+ s->inseqno = seqno + 1;
+ }
+
+ if(!s->inseqno) {
+ s->received = 0;
+ } else {
+ s->received++;
+ }
// Append a NULL byte for safety.
- buffer[len - 14] = 0;
+ s->decrypted_buffer[len - 20] = 0;
- uint8_t type = buffer[6];
+ uint8_t type = s->decrypted_buffer[0];
if(type < SPTPS_HANDSHAKE) {
- if(!s->instate)
+ if(!s->instate) {
return error(s, EIO, "Application record received before handshake finished");
- if(!s->receive_record(s->handle, type, buffer + 7, len - 21))
- return false;
+ }
+
+ if(!s->receive_record(s->handle, type, s->decrypted_buffer + 1, len - 21)) {
+ abort();
+ }
} else if(type == SPTPS_HANDSHAKE) {
- if(!receive_handshake(s, buffer + 7, len - 21))
- return false;
+ if(!receive_handshake(s, s->decrypted_buffer + 1, len - 21)) {
+ abort();
+ }
} else {
- return error(s, EIO, "Invalid record type");
+ return error(s, EIO, "Invalid record type %d", type);
}
return true;
}
+
// Receive incoming data. Check if it contains a complete record, if so, handle it.
-bool sptps_receive_data(sptps_t *s, const char *data, size_t len) {
- if(s->datagram)
+bool sptps_receive_data(sptps_t *s, const void *data, size_t len) {
+ if(!s->state) {
+ return error(s, EIO, "Invalid session state zero");
+ }
+
+ if(s->datagram) {
return sptps_receive_data_datagram(s, data, len);
+ }
+
+ const char *ptr = data;
while(len) {
// First read the 2 length bytes.
- if(s->buflen < 6) {
- size_t toread = 6 - s->buflen;
- if(toread > len)
+ if(s->buflen < 2) {
+ size_t toread = 2 - s->buflen;
+
+ if(toread > len) {
toread = len;
+ }
- memcpy(s->inbuf + s->buflen, data, toread);
+ memcpy(s->inbuf + s->buflen, ptr, toread);
s->buflen += toread;
len -= toread;
- data += toread;
-
+ ptr += toread;
+
// Exit early if we don't have the full length.
- if(s->buflen < 6)
+ if(s->buflen < 2) {
return true;
-
- // Decrypt the length bytes
-
- if(s->instate) {
- if(!cipher_counter_xor(&s->incipher, s->inbuf + 4, 2, &s->reclen))
- return false;
- } else {
- memcpy(&s->reclen, s->inbuf + 4, 2);
}
+ // Get the length bytes
+
+ memcpy(&s->reclen, s->inbuf, 2);
s->reclen = ntohs(s->reclen);
// If we have the length bytes, ensure our buffer can hold the whole request.
- s->inbuf = realloc(s->inbuf, s->reclen + 23UL);
- if(!s->inbuf)
- return error(s, errno, strerror(errno));
+ s->inbuf = realloc(s->inbuf, s->reclen + 19UL);
- // Add sequence number.
- uint32_t seqno = htonl(s->inseqno++);
- memcpy(s->inbuf, &seqno, 4);
+ if(!s->inbuf) {
+ return error(s, errno, strerror(errno));
+ }
// Exit early if we have no more data to process.
- if(!len)
+ if(!len) {
return true;
+ }
}
// Read up to the end of the record.
- size_t toread = s->reclen + (s->instate ? 23UL : 7UL) - s->buflen;
- if(toread > len)
+ size_t toread = s->reclen + (s->instate ? 19UL : 3UL) - s->buflen;
+
+ if(toread > len) {
toread = len;
+ }
- memcpy(s->inbuf + s->buflen, data, toread);
+ memcpy(s->inbuf + s->buflen, ptr, toread);
s->buflen += toread;
len -= toread;
- data += toread;
+ ptr += toread;
// If we don't have a whole record, exit.
- if(s->buflen < s->reclen + (s->instate ? 23UL : 7UL))
+ if(s->buflen < s->reclen + (s->instate ? 19UL : 3UL)) {
return true;
+ }
+
+ // Update sequence number.
+
+ uint32_t seqno = s->inseqno++;
// Check HMAC and decrypt.
if(s->instate) {
- if(!digest_verify(&s->indigest, s->inbuf, s->reclen + 7UL, s->inbuf + s->reclen + 7UL))
- return error(s, EIO, "Invalid HMAC");
-
- if(!cipher_counter_xor(&s->incipher, s->inbuf + 6UL, s->reclen + 1UL, s->inbuf + 6UL))
- return false;
+ if(!chacha_poly1305_decrypt(s->incipher, seqno, s->inbuf + 2UL, s->reclen + 17UL, s->inbuf + 2UL, NULL)) {
+ return error(s, EINVAL, "Failed to decrypt and verify record");
+ }
}
// Append a NULL byte for safety.
- s->inbuf[s->reclen + 7UL] = 0;
+ s->inbuf[s->reclen + 3UL] = 0;
- uint8_t type = s->inbuf[6];
+ uint8_t type = s->inbuf[2];
if(type < SPTPS_HANDSHAKE) {
- if(!s->instate)
+ if(!s->instate) {
return error(s, EIO, "Application record received before handshake finished");
- if(!s->receive_record(s->handle, type, s->inbuf + 7, s->reclen))
+ }
+
+ if(!s->receive_record(s->handle, type, s->inbuf + 3, s->reclen)) {
return false;
+ }
} else if(type == SPTPS_HANDSHAKE) {
- if(!receive_handshake(s, s->inbuf + 7, s->reclen))
+ if(!receive_handshake(s, s->inbuf + 3, s->reclen)) {
return false;
+ }
} else {
- return error(s, EIO, "Invalid record type");
+ return error(s, EIO, "Invalid record type %d", type);
}
- s->buflen = 4;
+ s->buflen = 0;
}
return true;
}
// Start a SPTPS session.
-bool sptps_start(sptps_t *s, void *handle, bool initiator, bool datagram, ecdsa_t mykey, ecdsa_t hiskey, const char *label, size_t labellen, send_data_t send_data, receive_record_t receive_record) {
+bool sptps_start(sptps_t *s, void *handle, bool initiator, bool datagram, ecdsa_t *mykey, ecdsa_t *hiskey, const char *label, size_t labellen, send_data_t send_data, receive_record_t receive_record) {
+ if(!s || !mykey || !hiskey || !label || !labellen || !send_data || !receive_record) {
+ return error(s, EINVAL, "Invalid argument to sptps_start()");
+ }
+
// Initialise struct sptps
- memset(s, 0, sizeof *s);
+ memset(s, 0, sizeof(*s));
s->handle = handle;
s->initiator = initiator;
s->datagram = datagram;
s->mykey = mykey;
s->hiskey = hiskey;
+ s->replaywin = 32;
+ s->decrypted_buffer_len = 1024;
+ s->decrypted_buffer = malloc(s->decrypted_buffer_len);
+
+ if(!s->decrypted_buffer) {
+ return error(s, errno, strerror(errno));
+ }
+
+ if(s->replaywin) {
+ s->late = malloc(s->replaywin);
+
+ if(!s->late) {
+ return error(s, errno, strerror(errno));
+ }
+
+ memset(s->late, 0, s->replaywin);
+ }
s->label = malloc(labellen);
- if(!s->label)
+
+ if(!s->label) {
return error(s, errno, strerror(errno));
+ }
if(!datagram) {
s->inbuf = malloc(7);
- if(!s->inbuf)
+
+ if(!s->inbuf) {
return error(s, errno, strerror(errno));
- s->buflen = 4;
- memset(s->inbuf, 0, 4);
+ }
+
+ s->buflen = 0;
}
memcpy(s->label, label, labellen);
// Stop a SPTPS session.
bool sptps_stop(sptps_t *s) {
// Clean up any resources.
- ecdh_free(&s->ecdh);
+ chacha_poly1305_exit(s->incipher);
+ chacha_poly1305_exit(s->outcipher);
+ ecdh_free(s->ecdh);
free(s->inbuf);
- s->inbuf = NULL;
free(s->mykex);
- s->mykex = NULL;
free(s->hiskex);
- s->hiskex = NULL;
free(s->key);
- s->key = NULL;
free(s->label);
- s->label = NULL;
+ free(s->late);
+ memset(s->decrypted_buffer, 0, s->decrypted_buffer_len);
+ free(s->decrypted_buffer);
+ memset(s, 0, sizeof(*s));
return true;
}
projects / meshlink / blobdiff