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Additional extensions and allow sending multiple tickets #328

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Additional extensions and allow sending multiple tickets #328

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4b3644a
add additional extensions to send in NST message
Oct 25, 2020
61dc45c
server can send multiple session tickets
Oct 26, 2020
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4 changes: 4 additions & 0 deletions include/picotls.h
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Original file line number Diff line number Diff line change
Expand Up @@ -830,6 +830,10 @@ typedef struct st_ptls_handshake_properties_t {
* an optional list of additional extensions to send either in CH or EE, terminated by type == UINT16_MAX
*/
ptls_raw_extension_t *additional_extensions;
/**
* an optional list of extensions to send in NST, terminated by type == UINT16_MAX
*/
ptls_raw_extension_t *nst_extensions;
/**
* an optional callback that returns a boolean value indicating if a particular extension should be collected
*/
Expand Down
184 changes: 123 additions & 61 deletions lib/picotls.c
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Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -1069,11 +1069,47 @@ static int derive_resumption_secret(ptls_key_schedule_t *sched, uint8_t *secret,
return ret;
}

static int should_collect_unknown_extension(ptls_t *tls, ptls_handshake_properties_t *properties, uint16_t type)
{
return properties != NULL && properties->collect_extension != NULL && properties->collect_extension(tls, properties, type);
}

static int collect_unknown_extension(ptls_t *tls, uint16_t type, const uint8_t *src, const uint8_t *const end,
ptls_raw_extension_t *slots)
{
size_t i;
for (i = 0; slots[i].type != UINT16_MAX; ++i) {
assert(i < MAX_UNKNOWN_EXTENSIONS);
if (slots[i].type == type)
return PTLS_ALERT_ILLEGAL_PARAMETER;
}
if (i < MAX_UNKNOWN_EXTENSIONS) {
slots[i].type = type;
slots[i].data = ptls_iovec_init(src, end - src);
slots[i + 1].type = UINT16_MAX;
}
return 0;
}

static int report_unknown_extensions(ptls_t *tls, ptls_handshake_properties_t *properties, ptls_raw_extension_t *slots)
{
if (properties != NULL && properties->collect_extension != NULL) {
assert(properties->collected_extensions != NULL);
return properties->collected_extensions(tls, properties, slots);
} else {
return 0;
}
}



static int decode_new_session_ticket(ptls_t *tls, uint32_t *lifetime, uint32_t *age_add, ptls_iovec_t *nonce, ptls_iovec_t *ticket,
uint32_t *max_early_data_size, const uint8_t *src, const uint8_t *const end)
uint32_t *max_early_data_size, const uint8_t *src, const uint8_t *const end, ptls_handshake_properties_t *properties)
{
uint16_t exttype;
int ret;
static const ptls_raw_extension_t no_unknown_extensions = {UINT16_MAX};
ptls_raw_extension_t *unknown_extensions = (ptls_raw_extension_t *)&no_unknown_extensions;

if ((ret = ptls_decode32(lifetime, &src, end)) != 0)
goto Exit;
Expand Down Expand Up @@ -1104,6 +1140,19 @@ static int decode_new_session_ticket(ptls_t *tls, uint32_t *lifetime, uint32_t *
goto Exit;
break;
default:
if (should_collect_unknown_extension(tls, properties, exttype)) {
if (unknown_extensions == &no_unknown_extensions) {
if ((unknown_extensions = malloc(sizeof(*unknown_extensions) * (MAX_UNKNOWN_EXTENSIONS + 1))) == NULL) {
ret = PTLS_ERROR_NO_MEMORY;
goto Exit;
}
unknown_extensions[0].type = UINT16_MAX;
}
if ((ret = collect_unknown_extension(tls, exttype, src, end, unknown_extensions)) != 0)
goto Exit;
if ((ret = report_unknown_extensions(tls, properties, unknown_extensions)) != 0)
goto Exit;
}
src = end;
break;
}
Expand All @@ -1116,7 +1165,7 @@ static int decode_new_session_ticket(ptls_t *tls, uint32_t *lifetime, uint32_t *

static int decode_stored_session_ticket(ptls_t *tls, ptls_key_exchange_algorithm_t **key_share, ptls_cipher_suite_t **cs,
ptls_iovec_t *secret, uint32_t *obfuscated_ticket_age, ptls_iovec_t *ticket,
uint32_t *max_early_data_size, const uint8_t *src, const uint8_t *const end)
uint32_t *max_early_data_size, const uint8_t *src, const uint8_t *const end, ptls_handshake_properties_t *properties)
{
uint16_t kxid, csid;
uint32_t lifetime, age_add;
Expand All @@ -1132,7 +1181,7 @@ static int decode_stored_session_ticket(ptls_t *tls, ptls_key_exchange_algorithm
if ((ret = ptls_decode16(&csid, &src, end)) != 0)
goto Exit;
ptls_decode_open_block(src, end, 3, {
if ((ret = decode_new_session_ticket(tls, &lifetime, &age_add, &nonce, ticket, max_early_data_size, src, end)) != 0)
if ((ret = decode_new_session_ticket(tls, &lifetime, &age_add, &nonce, ticket, max_early_data_size, src, end, properties)) != 0)
goto Exit;
src = end;
});
Expand Down Expand Up @@ -1403,7 +1452,23 @@ static int send_finished(ptls_t *tls, ptls_message_emitter_t *emitter)
return ret;
}

static int send_session_ticket(ptls_t *tls, ptls_message_emitter_t *emitter)
static int push_nst_extensions(ptls_handshake_properties_t *properties, ptls_buffer_t *sendbuf)
{
int ret;

if (properties != NULL && properties->nst_extensions != NULL) {
ptls_raw_extension_t *ext;
for (ext = properties->nst_extensions; ext->type != UINT16_MAX; ++ext) {
buffer_push_extension(sendbuf, ext->type, { ptls_buffer_pushv(sendbuf, ext->data.base, ext->data.len); });
}
}
ret = 0;
Exit:
return ret;
}


static int send_new_session_ticket(ptls_t *tls, ptls_message_emitter_t *emitter, ptls_handshake_properties_t *properties)
{
ptls_hash_context_t *msghash_backup = tls->key_schedule->hashes[0].ctx->clone_(tls->key_schedule->hashes[0].ctx);
ptls_buffer_t session_id;
Expand All @@ -1414,25 +1479,6 @@ static int send_session_ticket(ptls_t *tls, ptls_message_emitter_t *emitter)
assert(tls->ctx->ticket_lifetime != 0);
assert(tls->ctx->encrypt_ticket != NULL);

{ /* calculate verify-data that will be sent by the client */
size_t orig_off = emitter->buf->off;
if (tls->pending_handshake_secret != NULL && !tls->ctx->omit_end_of_early_data) {
assert(tls->state == PTLS_STATE_SERVER_EXPECT_END_OF_EARLY_DATA);
ptls_buffer_push_message_body(emitter->buf, tls->key_schedule, PTLS_HANDSHAKE_TYPE_END_OF_EARLY_DATA, {});
emitter->buf->off = orig_off;
}
ptls_buffer_push_message_body(emitter->buf, tls->key_schedule, PTLS_HANDSHAKE_TYPE_FINISHED, {
if ((ret = ptls_buffer_reserve(emitter->buf, tls->key_schedule->hashes[0].algo->digest_size)) != 0)
goto Exit;
if ((ret = calc_verify_data(emitter->buf->base + emitter->buf->off, tls->key_schedule,
tls->pending_handshake_secret != NULL ? tls->pending_handshake_secret
: tls->traffic_protection.dec.secret)) != 0)
goto Exit;
emitter->buf->off += tls->key_schedule->hashes[0].algo->digest_size;
});
emitter->buf->off = orig_off;
}

tls->ctx->random_bytes(&ticket_age_add, sizeof(ticket_age_add));

/* build the raw nsk */
Expand All @@ -1453,22 +1499,66 @@ static int send_session_ticket(ptls_t *tls, ptls_message_emitter_t *emitter)
goto Exit;
});
ptls_buffer_push_block(emitter->buf, 2, {
if (tls->ctx->max_early_data_size != 0)
if (tls->ctx->max_early_data_size != 0) {
buffer_push_extension(emitter->buf, PTLS_EXTENSION_TYPE_EARLY_DATA,
{ ptls_buffer_push32(emitter->buf, tls->ctx->max_early_data_size); });
push_nst_extensions(properties, emitter->buf);
}
});
});

Exit:
ptls_buffer_dispose(&session_id);
/* restore handshake state */
tls->key_schedule->hashes[0].ctx->final(tls->key_schedule->hashes[0].ctx, NULL, PTLS_HASH_FINAL_MODE_FREE);
tls->key_schedule->hashes[0].ctx = msghash_backup;


return ret;
}


static int send_session_ticket(ptls_t *tls, ptls_message_emitter_t *emitter, ptls_handshake_properties_t *properties)
{
ptls_hash_context_t *msghash_backup = tls->key_schedule->hashes[0].ctx->clone_(tls->key_schedule->hashes[0].ctx);
int ret = 0;

assert(tls->ctx->ticket_lifetime != 0);
assert(tls->ctx->encrypt_ticket != NULL);

{ /* calculate verify-data that will be sent by the client */
size_t orig_off = emitter->buf->off;
if (tls->pending_handshake_secret != NULL && !tls->ctx->omit_end_of_early_data) {
assert(tls->state == PTLS_STATE_SERVER_EXPECT_END_OF_EARLY_DATA);
ptls_buffer_push_message_body(emitter->buf, tls->key_schedule, PTLS_HANDSHAKE_TYPE_END_OF_EARLY_DATA, {});
emitter->buf->off = orig_off;
}
ptls_buffer_push_message_body(emitter->buf, tls->key_schedule, PTLS_HANDSHAKE_TYPE_FINISHED, {
if ((ret = ptls_buffer_reserve(emitter->buf, tls->key_schedule->hashes[0].algo->digest_size)) != 0)
goto Exit;
if ((ret = calc_verify_data(emitter->buf->base + emitter->buf->off, tls->key_schedule,
tls->pending_handshake_secret != NULL ? tls->pending_handshake_secret
: tls->traffic_protection.dec.secret)) != 0)
goto Exit;
emitter->buf->off += tls->key_schedule->hashes[0].algo->digest_size;
});
emitter->buf->off = orig_off;
}

{/* Send New Session Ticket */
if ((ret = send_new_session_ticket(tls, emitter, properties) != 0))
goto Exit;
}

Exit:
/* restore handshake state */
tls->key_schedule->hashes[0].ctx->final(tls->key_schedule->hashes[0].ctx, NULL, PTLS_HASH_FINAL_MODE_FREE);
tls->key_schedule->hashes[0].ctx = msghash_backup;

return ret;
}


static int push_change_cipher_spec(ptls_t *tls, ptls_message_emitter_t *emitter)
{
int ret;
Expand Down Expand Up @@ -1929,7 +2019,7 @@ static int send_client_hello(ptls_t *tls, ptls_message_emitter_t *emitter, ptls_
uint32_t max_early_data_size;
if (decode_stored_session_ticket(tls, &key_share, &cipher_suite, &resumption_secret, &obfuscated_ticket_age,
&resumption_ticket, &max_early_data_size, properties->client.session_ticket.base,
properties->client.session_ticket.base + properties->client.session_ticket.len) == 0) {
properties->client.session_ticket.base + properties->client.session_ticket.len, properties) == 0) {
tls->client.offered_psk = 1;
/* key-share selected by HRR should not be overridden */
if (tls->key_share == NULL)
Expand Down Expand Up @@ -2385,38 +2475,6 @@ static int client_handle_hello(ptls_t *tls, ptls_message_emitter_t *emitter, ptl
return ret;
}

static int should_collect_unknown_extension(ptls_t *tls, ptls_handshake_properties_t *properties, uint16_t type)
{
return properties != NULL && properties->collect_extension != NULL && properties->collect_extension(tls, properties, type);
}

static int collect_unknown_extension(ptls_t *tls, uint16_t type, const uint8_t *src, const uint8_t *const end,
ptls_raw_extension_t *slots)
{
size_t i;
for (i = 0; slots[i].type != UINT16_MAX; ++i) {
assert(i < MAX_UNKNOWN_EXTENSIONS);
if (slots[i].type == type)
return PTLS_ALERT_ILLEGAL_PARAMETER;
}
if (i < MAX_UNKNOWN_EXTENSIONS) {
slots[i].type = type;
slots[i].data = ptls_iovec_init(src, end - src);
slots[i + 1].type = UINT16_MAX;
}
return 0;
}

static int report_unknown_extensions(ptls_t *tls, ptls_handshake_properties_t *properties, ptls_raw_extension_t *slots)
{
if (properties != NULL && properties->collect_extension != NULL) {
assert(properties->collected_extensions != NULL);
return properties->collected_extensions(tls, properties, slots);
} else {
return 0;
}
}

static int client_handle_encrypted_extensions(ptls_t *tls, ptls_iovec_t message, ptls_handshake_properties_t *properties)
{
const uint8_t *src = message.base + PTLS_HANDSHAKE_HEADER_SIZE, *const end = message.base + message.len, *esni_nonce = NULL;
Expand Down Expand Up @@ -2949,7 +3007,7 @@ static int client_handle_finished(ptls_t *tls, ptls_message_emitter_t *emitter,
return ret;
}

static int client_handle_new_session_ticket(ptls_t *tls, ptls_iovec_t message)
static int client_handle_new_session_ticket(ptls_t *tls, ptls_iovec_t message, ptls_handshake_properties_t *properties)
{
const uint8_t *src = message.base + PTLS_HANDSHAKE_HEADER_SIZE, *const end = message.base + message.len;
ptls_iovec_t ticket_nonce;
Expand All @@ -2959,7 +3017,7 @@ static int client_handle_new_session_ticket(ptls_t *tls, ptls_iovec_t message)
uint32_t ticket_lifetime, ticket_age_add, max_early_data_size;
ptls_iovec_t ticket;
if ((ret = decode_new_session_ticket(tls, &ticket_lifetime, &ticket_age_add, &ticket_nonce, &ticket, &max_early_data_size,
src, end)) != 0)
src, end, properties)) != 0)
return ret;
}

Expand Down Expand Up @@ -4070,7 +4128,7 @@ static int server_handle_hello(ptls_t *tls, ptls_message_emitter_t *emitter, ptl

/* send session ticket if necessary */
if (ch->psk.ke_modes != 0 && tls->ctx->ticket_lifetime != 0) {
if ((ret = send_session_ticket(tls, emitter)) != 0)
if ((ret = send_session_ticket(tls, emitter, properties)) != 0)
goto Exit;
}

Expand Down Expand Up @@ -4478,7 +4536,7 @@ static int handle_client_handshake_message(ptls_t *tls, ptls_message_emitter_t *
case PTLS_STATE_CLIENT_POST_HANDSHAKE:
switch (type) {
case PTLS_HANDSHAKE_TYPE_NEW_SESSION_TICKET:
ret = client_handle_new_session_ticket(tls, message);
ret = client_handle_new_session_ticket(tls, message, properties);
break;
case PTLS_HANDSHAKE_TYPE_KEY_UPDATE:
ret = handle_key_update(tls, emitter, message);
Expand Down Expand Up @@ -5335,6 +5393,10 @@ int ptls_server_handle_message(ptls_t *tls, ptls_buffer_t *sendbuf, size_t epoch
{sendbuf, &tls->traffic_protection.enc, 0, begin_raw_message, commit_raw_message}, SIZE_MAX, epoch_offsets};
struct st_ptls_record_t rec = {PTLS_CONTENT_TYPE_HANDSHAKE, 0, inlen, input};

/* If necessary, can be used to send multiple session tickets during the same connection */
if (input == NULL)
return send_new_session_ticket(tls, &emitter.super, properties);

assert(input);

if (ptls_get_read_epoch(tls) != in_epoch)
Expand Down