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openssl/ssl/quic/quic_record_rx.c
Hugo Landau 692a3cab11 QUIC: Minor fixups 
Reviewed-by: Tomas Mraz <tomas@openssl.org>
Reviewed-by: Matt Caswell <matt@openssl.org>
Reviewed-by: Paul Dale <pauli@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/21029)
2023-06-16 09:26:48 +10:00

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/*
* Copyright 2022 The OpenSSL Project Authors. All Rights Reserved.
*
* Licensed under the Apache License 2.0 (the "License"). You may not use
* this file except in compliance with the License. You can obtain a copy
* in the file LICENSE in the source distribution or at
* https://www.openssl.org/source/license.html
*/
#include <openssl/ssl.h>
#include "internal/quic_record_rx.h"
#include "quic_record_shared.h"
#include "internal/common.h"
#include "internal/list.h"
#include "../ssl_local.h"
/*
* Mark a packet in a bitfield.
*
* pkt_idx: index of packet within datagram.
*/
static ossl_inline void pkt_mark(uint64_t *bitf, size_t pkt_idx)
{
assert(pkt_idx < QUIC_MAX_PKT_PER_URXE);
*bitf |= ((uint64_t)1) << pkt_idx;
}
/* Returns 1 if a packet is in the bitfield. */
static ossl_inline int pkt_is_marked(const uint64_t *bitf, size_t pkt_idx)
{
assert(pkt_idx < QUIC_MAX_PKT_PER_URXE);
return (*bitf & (((uint64_t)1) << pkt_idx)) != 0;
}
/*
* RXE
* ===
*
* RX Entries (RXEs) store processed (i.e., decrypted) data received from the
* network. One RXE is used per received QUIC packet.
*/
typedef struct rxe_st RXE;
struct rxe_st {
OSSL_QRX_PKT pkt;
OSSL_LIST_MEMBER(rxe, RXE);
size_t data_len, alloc_len, refcount;
/* Extra fields for per-packet information. */
QUIC_PKT_HDR hdr; /* data/len are decrypted payload */
/* Decoded packet number. */
QUIC_PN pn;
/* Addresses copied from URXE. */
BIO_ADDR peer, local;
/* Time we received the packet (not when we processed it). */
OSSL_TIME time;
/* Total length of the datagram which contained this packet. */
size_t datagram_len;
/*
* The key epoch the packet was received with. Always 0 for non-1-RTT
* packets.
*/
uint64_t key_epoch;
/*
* alloc_len allocated bytes (of which data_len bytes are valid) follow this
* structure.
*/
};
DEFINE_LIST_OF(rxe, RXE);
typedef OSSL_LIST(rxe) RXE_LIST;
static ossl_inline unsigned char *rxe_data(const RXE *e)
{
return (unsigned char *)(e + 1);
}
/*
* QRL
* ===
*/
struct ossl_qrx_st {
OSSL_LIB_CTX *libctx;
const char *propq;
/* Demux to receive datagrams from. */
QUIC_DEMUX *demux;
/* Length of connection IDs used in short-header packets in bytes. */
size_t short_conn_id_len;
/* Maximum number of deferred datagrams buffered at any one time. */
size_t max_deferred;
/* Current count of deferred datagrams. */
size_t num_deferred;
/*
* List of URXEs which are filled with received encrypted data.
* These are returned to the DEMUX's free list as they are processed.
*/
QUIC_URXE_LIST urx_pending;
/*
* List of URXEs which we could not decrypt immediately and which are being
* kept in case they can be decrypted later.
*/
QUIC_URXE_LIST urx_deferred;
/*
* List of RXEs which are not currently in use. These are moved
* to the pending list as they are filled.
*/
RXE_LIST rx_free;
/*
* List of RXEs which are filled with decrypted packets ready to be passed
* to the user. A RXE is removed from all lists inside the QRL when passed
* to the user, then returned to the free list when the user returns it.
*/
RXE_LIST rx_pending;
/* Largest PN we have received and processed in a given PN space. */
QUIC_PN largest_pn[QUIC_PN_SPACE_NUM];
/* Per encryption-level state. */
OSSL_QRL_ENC_LEVEL_SET el_set;
/* Bytes we have received since this counter was last cleared. */
uint64_t bytes_received;
/*
* Number of forged packets we have received since the QRX was instantiated.
* Note that as per RFC 9001, this is connection-level state; it is not per
* EL and is not reset by a key update.
*/
uint64_t forged_pkt_count;
/* Validation callback. */
ossl_qrx_early_validation_cb *validation_cb;
void *validation_cb_arg;
/* Key update callback. */
ossl_qrx_key_update_cb *key_update_cb;
void *key_update_cb_arg;
/* Initial key phase. For debugging use only; always 0 in real use. */
unsigned char init_key_phase_bit;
/* Message callback related arguments */
ossl_msg_cb msg_callback;
void *msg_callback_arg;
SSL *msg_callback_ssl;
};
static void qrx_on_rx(QUIC_URXE *urxe, void *arg);
OSSL_QRX *ossl_qrx_new(const OSSL_QRX_ARGS *args)
{
OSSL_QRX *qrx;
size_t i;
if (args->demux == NULL || args->max_deferred == 0)
return 0;
qrx = OPENSSL_zalloc(sizeof(OSSL_QRX));
if (qrx == NULL)
return 0;
for (i = 0; i < OSSL_NELEM(qrx->largest_pn); ++i)
qrx->largest_pn[i] = args->init_largest_pn[i];
qrx->libctx = args->libctx;
qrx->propq = args->propq;
qrx->demux = args->demux;
qrx->short_conn_id_len = args->short_conn_id_len;
qrx->init_key_phase_bit = args->init_key_phase_bit;
qrx->max_deferred = args->max_deferred;
return qrx;
}
static void qrx_cleanup_rxl(RXE_LIST *l)
{
RXE *e, *enext;
for (e = ossl_list_rxe_head(l); e != NULL; e = enext) {
enext = ossl_list_rxe_next(e);
ossl_list_rxe_remove(l, e);
OPENSSL_free(e);
}
}
static void qrx_cleanup_urxl(OSSL_QRX *qrx, QUIC_URXE_LIST *l)
{
QUIC_URXE *e, *enext;
for (e = ossl_list_urxe_head(l); e != NULL; e = enext) {
enext = ossl_list_urxe_next(e);
ossl_list_urxe_remove(l, e);
ossl_quic_demux_release_urxe(qrx->demux, e);
}
}
void ossl_qrx_free(OSSL_QRX *qrx)
{
uint32_t i;
if (qrx == NULL)
return;
/* Unregister from the RX DEMUX. */
ossl_quic_demux_unregister_by_cb(qrx->demux, qrx_on_rx, qrx);
/* Free RXE queue data. */
qrx_cleanup_rxl(&qrx->rx_free);
qrx_cleanup_rxl(&qrx->rx_pending);
qrx_cleanup_urxl(qrx, &qrx->urx_pending);
qrx_cleanup_urxl(qrx, &qrx->urx_deferred);
/* Drop keying material and crypto resources. */
for (i = 0; i < QUIC_ENC_LEVEL_NUM; ++i)
ossl_qrl_enc_level_set_discard(&qrx->el_set, i);
OPENSSL_free(qrx);
}
void ossl_qrx_inject_urxe(OSSL_QRX *qrx, QUIC_URXE *urxe)
{
/* Initialize our own fields inside the URXE and add to the pending list. */
urxe->processed = 0;
urxe->hpr_removed = 0;
urxe->deferred = 0;
ossl_list_urxe_insert_tail(&qrx->urx_pending, urxe);
if (qrx->msg_callback != NULL)
qrx->msg_callback(0, OSSL_QUIC1_VERSION, SSL3_RT_QUIC_DATAGRAM, urxe + 1,
urxe->data_len, qrx->msg_callback_ssl,
qrx->msg_callback_arg);
}
static void qrx_on_rx(QUIC_URXE *urxe, void *arg)
{
OSSL_QRX *qrx = arg;
ossl_qrx_inject_urxe(qrx, urxe);
}
int ossl_qrx_add_dst_conn_id(OSSL_QRX *qrx,
const QUIC_CONN_ID *dst_conn_id)
{
return ossl_quic_demux_register(qrx->demux,
dst_conn_id,
qrx_on_rx,
qrx);
}
int ossl_qrx_remove_dst_conn_id(OSSL_QRX *qrx,
const QUIC_CONN_ID *dst_conn_id)
{
return ossl_quic_demux_unregister(qrx->demux, dst_conn_id);
}
static void qrx_requeue_deferred(OSSL_QRX *qrx)
{
QUIC_URXE *e;
while ((e = ossl_list_urxe_head(&qrx->urx_deferred)) != NULL) {
ossl_list_urxe_remove(&qrx->urx_deferred, e);
ossl_list_urxe_insert_head(&qrx->urx_pending, e);
}
}
int ossl_qrx_provide_secret(OSSL_QRX *qrx, uint32_t enc_level,
uint32_t suite_id, EVP_MD *md,
const unsigned char *secret, size_t secret_len)
{
if (enc_level >= QUIC_ENC_LEVEL_NUM)
return 0;
if (!ossl_qrl_enc_level_set_provide_secret(&qrx->el_set,
qrx->libctx,
qrx->propq,
enc_level,
suite_id,
md,
secret,
secret_len,
qrx->init_key_phase_bit,
/*is_tx=*/0))
return 0;
/*
* Any packets we previously could not decrypt, we may now be able to
* decrypt, so move any datagrams containing deferred packets from the
* deferred to the pending queue.
*/
qrx_requeue_deferred(qrx);
return 1;
}
int ossl_qrx_discard_enc_level(OSSL_QRX *qrx, uint32_t enc_level)
{
if (enc_level >= QUIC_ENC_LEVEL_NUM)
return 0;
ossl_qrl_enc_level_set_discard(&qrx->el_set, enc_level);
return 1;
}
/* Returns 1 if there are one or more pending RXEs. */
int ossl_qrx_processed_read_pending(OSSL_QRX *qrx)
{
return !ossl_list_rxe_is_empty(&qrx->rx_pending);
}
/* Returns 1 if there are yet-unprocessed packets. */
int ossl_qrx_unprocessed_read_pending(OSSL_QRX *qrx)
{
return !ossl_list_urxe_is_empty(&qrx->urx_pending)
|| !ossl_list_urxe_is_empty(&qrx->urx_deferred);
}
/* Pop the next pending RXE. Returns NULL if no RXE is pending. */
static RXE *qrx_pop_pending_rxe(OSSL_QRX *qrx)
{
RXE *rxe = ossl_list_rxe_head(&qrx->rx_pending);
if (rxe == NULL)
return NULL;
ossl_list_rxe_remove(&qrx->rx_pending, rxe);
return rxe;
}
/* Allocate a new RXE. */
static RXE *qrx_alloc_rxe(size_t alloc_len)
{
RXE *rxe;
if (alloc_len >= SIZE_MAX - sizeof(RXE))
return NULL;
rxe = OPENSSL_malloc(sizeof(RXE) + alloc_len);
if (rxe == NULL)
return NULL;
ossl_list_rxe_init_elem(rxe);
rxe->alloc_len = alloc_len;
rxe->data_len = 0;
rxe->refcount = 0;
return rxe;
}
/*
* Ensures there is at least one RXE in the RX free list, allocating a new entry
* if necessary. The returned RXE is in the RX free list; it is not popped.
*
* alloc_len is a hint which may be used to determine the RXE size if allocation
* is necessary. Returns NULL on allocation failure.
*/
static RXE *qrx_ensure_free_rxe(OSSL_QRX *qrx, size_t alloc_len)
{
RXE *rxe;
if (ossl_list_rxe_head(&qrx->rx_free) != NULL)
return ossl_list_rxe_head(&qrx->rx_free);
rxe = qrx_alloc_rxe(alloc_len);
if (rxe == NULL)
return NULL;
ossl_list_rxe_insert_tail(&qrx->rx_free, rxe);
return rxe;
}
/*
* Resize the data buffer attached to an RXE to be n bytes in size. The address
* of the RXE might change; the new address is returned, or NULL on failure, in
* which case the original RXE remains valid.
*/
static RXE *qrx_resize_rxe(RXE_LIST *rxl, RXE *rxe, size_t n)
{
RXE *rxe2, *p;
/* Should never happen. */
if (rxe == NULL)
return NULL;
if (n >= SIZE_MAX - sizeof(RXE))
return NULL;
/* Remove the item from the list to avoid accessing freed memory */
p = ossl_list_rxe_prev(rxe);
ossl_list_rxe_remove(rxl, rxe);
/* Should never resize an RXE which has been handed out. */
if (!ossl_assert(rxe->refcount == 0))
return NULL;
/*
* NOTE: We do not clear old memory, although it does contain decrypted
* data.
*/
rxe2 = OPENSSL_realloc(rxe, sizeof(RXE) + n);
if (rxe2 == NULL) {
/* Resize failed, restore old allocation. */
if (p == NULL)
ossl_list_rxe_insert_head(rxl, rxe);
else
ossl_list_rxe_insert_after(rxl, p, rxe);
return NULL;
}
if (p == NULL)
ossl_list_rxe_insert_head(rxl, rxe2);
else
ossl_list_rxe_insert_after(rxl, p, rxe2);
rxe2->alloc_len = n;
return rxe2;
}
/*
* Ensure the data buffer attached to an RXE is at least n bytes in size.
* Returns NULL on failure.
*/
static RXE *qrx_reserve_rxe(RXE_LIST *rxl,
RXE *rxe, size_t n)
{
if (rxe->alloc_len >= n)
return rxe;
return qrx_resize_rxe(rxl, rxe, n);
}
/* Return a RXE handed out to the user back to our freelist. */
static void qrx_recycle_rxe(OSSL_QRX *qrx, RXE *rxe)
{
/* RXE should not be in any list */
assert(ossl_list_rxe_prev(rxe) == NULL && ossl_list_rxe_next(rxe) == NULL);
rxe->pkt.hdr = NULL;
rxe->pkt.peer = NULL;
rxe->pkt.local = NULL;
ossl_list_rxe_insert_tail(&qrx->rx_free, rxe);
}
/*
* Given a pointer to a pointer pointing to a buffer and the size of that
* buffer, copy the buffer into *prxe, expanding the RXE if necessary (its
* pointer may change due to realloc). *pi is the offset in bytes to copy the
* buffer to, and on success is updated to be the offset pointing after the
* copied buffer. *pptr is updated to point to the new location of the buffer.
*/
static int qrx_relocate_buffer(OSSL_QRX *qrx, RXE **prxe, size_t *pi,
const unsigned char **pptr, size_t buf_len)
{
RXE *rxe;
unsigned char *dst;
if (!buf_len)
return 1;
if ((rxe = qrx_reserve_rxe(&qrx->rx_free, *prxe, *pi + buf_len)) == NULL)
return 0;
*prxe = rxe;
dst = (unsigned char *)rxe_data(rxe) + *pi;
memcpy(dst, *pptr, buf_len);
*pi += buf_len;
*pptr = dst;
return 1;
}
static uint32_t qrx_determine_enc_level(const QUIC_PKT_HDR *hdr)
{
switch (hdr->type) {
case QUIC_PKT_TYPE_INITIAL:
return QUIC_ENC_LEVEL_INITIAL;
case QUIC_PKT_TYPE_HANDSHAKE:
return QUIC_ENC_LEVEL_HANDSHAKE;
case QUIC_PKT_TYPE_0RTT:
return QUIC_ENC_LEVEL_0RTT;
case QUIC_PKT_TYPE_1RTT:
return QUIC_ENC_LEVEL_1RTT;
default:
assert(0);
case QUIC_PKT_TYPE_RETRY:
case QUIC_PKT_TYPE_VERSION_NEG:
return QUIC_ENC_LEVEL_INITIAL; /* not used */
}
}
static uint32_t rxe_determine_pn_space(RXE *rxe)
{
uint32_t enc_level;
enc_level = qrx_determine_enc_level(&rxe->hdr);
return ossl_quic_enc_level_to_pn_space(enc_level);
}
static int qrx_validate_hdr_early(OSSL_QRX *qrx, RXE *rxe,
const QUIC_CONN_ID *first_dcid)
{
/* Ensure version is what we want. */
if (rxe->hdr.version != QUIC_VERSION_1
&& rxe->hdr.version != QUIC_VERSION_NONE)
return 0;
/* Clients should never receive 0-RTT packets. */
if (rxe->hdr.type == QUIC_PKT_TYPE_0RTT)
return 0;
/* Version negotiation and retry packets must be the first packet. */
if (first_dcid != NULL && !ossl_quic_pkt_type_can_share_dgram(rxe->hdr.type))
return 0;
/*
* If this is not the first packet in a datagram, the destination connection
* ID must match the one in that packet.
*/
if (first_dcid != NULL) {
if (!ossl_assert(first_dcid->id_len < QUIC_MAX_CONN_ID_LEN)
|| !ossl_quic_conn_id_eq(first_dcid,
&rxe->hdr.dst_conn_id))
return 0;
}
return 1;
}
/* Validate header and decode PN. */
static int qrx_validate_hdr(OSSL_QRX *qrx, RXE *rxe)
{
int pn_space = rxe_determine_pn_space(rxe);
if (!ossl_quic_wire_decode_pkt_hdr_pn(rxe->hdr.pn, rxe->hdr.pn_len,
qrx->largest_pn[pn_space],
&rxe->pn))
return 0;
/*
* Allow our user to decide whether to discard the packet before we try and
* decrypt it.
*/
if (qrx->validation_cb != NULL
&& !qrx->validation_cb(rxe->pn, pn_space, qrx->validation_cb_arg))
return 0;
return 1;
}
/*
* Retrieves the correct cipher context for an EL and key phase. Writes the key
* epoch number actually used for packet decryption to *rx_key_epoch.
*/
static size_t qrx_get_cipher_ctx_idx(OSSL_QRX *qrx, OSSL_QRL_ENC_LEVEL *el,
uint32_t enc_level,
unsigned char key_phase_bit,
uint64_t *rx_key_epoch)
{
size_t idx;
if (enc_level != QUIC_ENC_LEVEL_1RTT) {
*rx_key_epoch = 0;
return 0;
}
if (!ossl_assert(key_phase_bit <= 1))
return SIZE_MAX;
/*
* RFC 9001 requires that we not create timing channels which could reveal
* the decrypted value of the Key Phase bit. We usually handle this by
* keeping the cipher contexts for both the current and next key epochs
* around, so that we just select a cipher context blindly using the key
* phase bit, which is time-invariant.
*
* In the COOLDOWN state, we only have one keyslot/cipher context. RFC 9001
* suggests an implementation strategy to avoid creating a timing channel in
* this case:
*
* Endpoints can use randomized packet protection keys in place of
* discarded keys when key updates are not yet permitted.
*
* Rather than use a randomised key, we simply use our existing key as it
* will fail AEAD verification anyway. This avoids the need to keep around a
* dedicated garbage key.
*
* Note: Accessing different cipher contexts is technically not
* timing-channel safe due to microarchitectural side channels, but this is
* the best we can reasonably do and appears to be directly suggested by the
* RFC.
*/
idx = (el->state == QRL_EL_STATE_PROV_COOLDOWN ? el->key_epoch & 1
: key_phase_bit);
/*
* We also need to determine the key epoch number which this index
* corresponds to. This is so we can report the key epoch number in the
* OSSL_QRX_PKT structure, which callers need to validate whether it was OK
* for a packet to be sent using a given key epoch's keys.
*/
switch (el->state) {
case QRL_EL_STATE_PROV_NORMAL:
/*
* If we are in the NORMAL state, usually the KP bit will match the LSB
* of our key epoch, meaning no new key update is being signalled. If it
* does not match, this means the packet (purports to) belong to
* the next key epoch.
*
* IMPORTANT: The AEAD tag has not been verified yet when this function
* is called, so this code must be timing-channel safe, hence use of
* XOR. Moreover, the value output below is not yet authenticated.
*/
*rx_key_epoch
= el->key_epoch + ((el->key_epoch & 1) ^ (uint64_t)key_phase_bit);
break;
case QRL_EL_STATE_PROV_UPDATING:
/*
* If we are in the UPDATING state, usually the KP bit will match the
* LSB of our key epoch. If it does not match, this means that the
* packet (purports to) belong to the previous key epoch.
*
* As above, must be timing-channel safe.
*/
*rx_key_epoch
= el->key_epoch - ((el->key_epoch & 1) ^ (uint64_t)key_phase_bit);
break;
case QRL_EL_STATE_PROV_COOLDOWN:
/*
* If we are in COOLDOWN, there is only one key epoch we can possibly
* decrypt with, so just try that. If AEAD decryption fails, the
* value we output here isn't used anyway.
*/
*rx_key_epoch = el->key_epoch;
break;
}
return idx;
}
/*
* Tries to decrypt a packet payload.
*
* Returns 1 on success or 0 on failure (which is permanent). The payload is
* decrypted from src and written to dst. The buffer dst must be of at least
* src_len bytes in length. The actual length of the output in bytes is written
* to *dec_len on success, which will always be equal to or less than (usually
* less than) src_len.
*/
static int qrx_decrypt_pkt_body(OSSL_QRX *qrx, unsigned char *dst,
const unsigned char *src,
size_t src_len, size_t *dec_len,
const unsigned char *aad, size_t aad_len,
QUIC_PN pn, uint32_t enc_level,
unsigned char key_phase_bit,
uint64_t *rx_key_epoch)
{
int l = 0, l2 = 0;
unsigned char nonce[EVP_MAX_IV_LENGTH];
size_t nonce_len, i, cctx_idx;
OSSL_QRL_ENC_LEVEL *el = ossl_qrl_enc_level_set_get(&qrx->el_set,
enc_level, 1);
EVP_CIPHER_CTX *cctx;
if (src_len > INT_MAX || aad_len > INT_MAX)
return 0;
/* We should not have been called if we do not have key material. */
if (!ossl_assert(el != NULL))
return 0;
if (el->tag_len >= src_len)
return 0;
/*
* If we have failed to authenticate a certain number of ciphertexts, refuse
* to decrypt any more ciphertexts.
*/
if (qrx->forged_pkt_count >= ossl_qrl_get_suite_max_forged_pkt(el->suite_id))
return 0;
cctx_idx = qrx_get_cipher_ctx_idx(qrx, el, enc_level, key_phase_bit,
rx_key_epoch);
if (!ossl_assert(cctx_idx < OSSL_NELEM(el->cctx)))
return 0;
cctx = el->cctx[cctx_idx];
/* Construct nonce (nonce=IV ^ PN). */
nonce_len = EVP_CIPHER_CTX_get_iv_length(cctx);
if (!ossl_assert(nonce_len >= sizeof(QUIC_PN)))
return 0;
memcpy(nonce, el->iv[cctx_idx], nonce_len);
for (i = 0; i < sizeof(QUIC_PN); ++i)
nonce[nonce_len - i - 1] ^= (unsigned char)(pn >> (i * 8));
/* type and key will already have been setup; feed the IV. */
if (EVP_CipherInit_ex(cctx, NULL,
NULL, NULL, nonce, /*enc=*/0) != 1)
return 0;
/* Feed the AEAD tag we got so the cipher can validate it. */
if (EVP_CIPHER_CTX_ctrl(cctx, EVP_CTRL_AEAD_SET_TAG,
el->tag_len,
(unsigned char *)src + src_len - el->tag_len) != 1)
return 0;
/* Feed AAD data. */
if (EVP_CipherUpdate(cctx, NULL, &l, aad, aad_len) != 1)
return 0;
/* Feed encrypted packet body. */
if (EVP_CipherUpdate(cctx, dst, &l, src, src_len - el->tag_len) != 1)
return 0;
/* Ensure authentication succeeded. */
if (EVP_CipherFinal_ex(cctx, NULL, &l2) != 1) {
/* Authentication failed, increment failed auth counter. */
++qrx->forged_pkt_count;
return 0;
}
*dec_len = l;
return 1;
}
static ossl_inline void ignore_res(int x)
{
/* No-op. */
}
static void qrx_key_update_initiated(OSSL_QRX *qrx, QUIC_PN pn)
{
if (!ossl_qrl_enc_level_set_key_update(&qrx->el_set, QUIC_ENC_LEVEL_1RTT))
/* We are already in RXKU, so we don't call the callback again. */
return;
if (qrx->key_update_cb != NULL)
qrx->key_update_cb(pn, qrx->key_update_cb_arg);
}
/* Process a single packet in a datagram. */
static int qrx_process_pkt(OSSL_QRX *qrx, QUIC_URXE *urxe,
PACKET *pkt, size_t pkt_idx,
QUIC_CONN_ID *first_dcid,
size_t datagram_len)
{
RXE *rxe;
const unsigned char *eop = NULL;
size_t i, aad_len = 0, dec_len = 0;
PACKET orig_pkt = *pkt;
const unsigned char *sop = PACKET_data(pkt);
unsigned char *dst;
char need_second_decode = 0, already_processed = 0;
QUIC_PKT_HDR_PTRS ptrs;
uint32_t pn_space, enc_level;
OSSL_QRL_ENC_LEVEL *el = NULL;
uint64_t rx_key_epoch = UINT64_MAX;
/*
* Get a free RXE. If we need to allocate a new one, use the packet length
* as a good ballpark figure.
*/
rxe = qrx_ensure_free_rxe(qrx, PACKET_remaining(pkt));
if (rxe == NULL)
return 0;
/* Have we already processed this packet? */
if (pkt_is_marked(&urxe->processed, pkt_idx))
already_processed = 1;
/*
* Decode the header into the RXE structure. We first decrypt and read the
* unprotected part of the packet header (unless we already removed header
* protection, in which case we decode all of it).
*/
need_second_decode = !pkt_is_marked(&urxe->hpr_removed, pkt_idx);
if (!ossl_quic_wire_decode_pkt_hdr(pkt,
qrx->short_conn_id_len,
need_second_decode, 0, &rxe->hdr, &ptrs))
goto malformed;
/*
* Our successful decode above included an intelligible length and the
* PACKET is now pointing to the end of the QUIC packet.
*/
eop = PACKET_data(pkt);
/*
* Make a note of the first packet's DCID so we can later ensure the
* destination connection IDs of all packets in a datagram match.
*/
if (pkt_idx == 0)
*first_dcid = rxe->hdr.dst_conn_id;
/*
* Early header validation. Since we now know the packet length, we can also
* now skip over it if we already processed it.
*/
if (already_processed
|| !qrx_validate_hdr_early(qrx, rxe, pkt_idx == 0 ? NULL : first_dcid))
/*
* Already processed packets are handled identically to malformed
* packets; i.e., they are ignored.
*/
goto malformed;
if (!ossl_quic_pkt_type_is_encrypted(rxe->hdr.type)) {
/*
* Version negotiation and retry packets are a special case. They do not
* contain a payload which needs decrypting and have no header
* protection.
*/
/* Just copy the payload from the URXE to the RXE. */
if ((rxe = qrx_reserve_rxe(&qrx->rx_free, rxe, rxe->hdr.len)) == NULL)
/*
* Allocation failure. EOP will be pointing to the end of the
* datagram so processing of this datagram will end here.
*/
goto malformed;
/* We are now committed to returning the packet. */
memcpy(rxe_data(rxe), rxe->hdr.data, rxe->hdr.len);
pkt_mark(&urxe->processed, pkt_idx);
rxe->hdr.data = rxe_data(rxe);
rxe->pn = QUIC_PN_INVALID;
/* Move RXE to pending. */
ossl_list_rxe_remove(&qrx->rx_free, rxe);
ossl_list_rxe_insert_tail(&qrx->rx_pending, rxe);
return 0; /* success, did not defer */
}
/* Determine encryption level of packet. */
enc_level = qrx_determine_enc_level(&rxe->hdr);
/* If we do not have keying material for this encryption level yet, defer. */
switch (ossl_qrl_enc_level_set_have_el(&qrx->el_set, enc_level)) {
case 1:
/* We have keys. */
break;
case 0:
/* No keys yet. */
goto cannot_decrypt;
default:
/* We already discarded keys for this EL, we will never process this.*/
goto malformed;
}
/*
* We will copy any token included in the packet to the start of our RXE
* data buffer (so that we don't reference the URXE buffer any more and can
* recycle it). Track our position in the RXE buffer by index instead of
* pointer as the pointer may change as reallocs occur.
*/
i = 0;
/*
* rxe->hdr.data is now pointing at the (encrypted) packet payload. rxe->hdr
* also has fields pointing into the PACKET buffer which will be going away
* soon (the URXE will be reused for another incoming packet).
*
* Firstly, relocate some of these fields into the RXE as needed.
*
* Relocate token buffer and fix pointer.
*/
if (rxe->hdr.type == QUIC_PKT_TYPE_INITIAL
&& !qrx_relocate_buffer(qrx, &rxe, &i, &rxe->hdr.token,
rxe->hdr.token_len))
goto malformed;
/* Now remove header protection. */
*pkt = orig_pkt;
el = ossl_qrl_enc_level_set_get(&qrx->el_set, enc_level, 1);
assert(el != NULL); /* Already checked above */
if (need_second_decode) {
if (!ossl_quic_hdr_protector_decrypt(&el->hpr, &ptrs))
goto malformed;
/*
* We have removed header protection, so don't attempt to do it again if
* the packet gets deferred and processed again.
*/
pkt_mark(&urxe->hpr_removed, pkt_idx);
/* Decode the now unprotected header. */
if (ossl_quic_wire_decode_pkt_hdr(pkt, qrx->short_conn_id_len,
0, 0, &rxe->hdr, NULL) != 1)
goto malformed;
}
/* Validate header and decode PN. */
if (!qrx_validate_hdr(qrx, rxe))
goto malformed;
if (qrx->msg_callback != NULL)
qrx->msg_callback(0, OSSL_QUIC1_VERSION, SSL3_RT_QUIC_PACKET, sop,
eop - sop - rxe->hdr.len, qrx->msg_callback_ssl,
qrx->msg_callback_arg);
/*
* The AAD data is the entire (unprotected) packet header including the PN.
* The packet header has been unprotected in place, so we can just reuse the
* PACKET buffer. The header ends where the payload begins.
*/
aad_len = rxe->hdr.data - sop;
/* Ensure the RXE buffer size is adequate for our payload. */
if ((rxe = qrx_reserve_rxe(&qrx->rx_free, rxe, rxe->hdr.len + i)) == NULL) {
/*
* Allocation failure, treat as malformed and do not bother processing
* any further packets in the datagram as they are likely to also
* encounter allocation failures.
*/
eop = NULL;
goto malformed;
}
/*
* We decrypt the packet body to immediately after the token at the start of
* the RXE buffer (where present).
*
* Do the decryption from the PACKET (which points into URXE memory) to our
* RXE payload (single-copy decryption), then fixup the pointers in the
* header to point to our new buffer.
*
* If decryption fails this is considered a permanent error; we defer
* packets we don't yet have decryption keys for above, so if this fails,
* something has gone wrong with the handshake process or a packet has been
* corrupted.
*/
dst = (unsigned char *)rxe_data(rxe) + i;
if (!qrx_decrypt_pkt_body(qrx, dst, rxe->hdr.data, rxe->hdr.len,
&dec_len, sop, aad_len, rxe->pn, enc_level,
rxe->hdr.key_phase, &rx_key_epoch))
goto malformed;
/*
* -----------------------------------------------------
* IMPORTANT: ANYTHING ABOVE THIS LINE IS UNVERIFIED
* AND MUST BE TIMING-CHANNEL SAFE.
* -----------------------------------------------------
*
* At this point, we have successfully authenticated the AEAD tag and no
* longer need to worry about exposing the Key Phase bit in timing channels.
* Check for a Key Phase bit differing from our expectation.
*/
if (rxe->hdr.type == QUIC_PKT_TYPE_1RTT
&& rxe->hdr.key_phase != (el->key_epoch & 1))
qrx_key_update_initiated(qrx, rxe->pn);
/*
* We have now successfully decrypted the packet payload. If there are
* additional packets in the datagram, it is possible we will fail to
* decrypt them and need to defer them until we have some key material we
* don't currently possess. If this happens, the URXE will be moved to the
* deferred queue. Since a URXE corresponds to one datagram, which may
* contain multiple packets, we must ensure any packets we have already
* processed in the URXE are not processed again (this is an RFC
* requirement). We do this by marking the nth packet in the datagram as
* processed.
*
* We are now committed to returning this decrypted packet to the user,
* meaning we now consider the packet processed and must mark it
* accordingly.
*/
pkt_mark(&urxe->processed, pkt_idx);
/*
* Update header to point to the decrypted buffer, which may be shorter
* due to AEAD tags, block padding, etc.
*/
rxe->hdr.data = dst;
rxe->hdr.len = dec_len;
rxe->data_len = dec_len;
rxe->datagram_len = datagram_len;
rxe->key_epoch = rx_key_epoch;
/* We processed the PN successfully, so update largest processed PN. */
pn_space = rxe_determine_pn_space(rxe);
if (rxe->pn > qrx->largest_pn[pn_space])
qrx->largest_pn[pn_space] = rxe->pn;
/* Copy across network addresses and RX time from URXE to RXE. */
rxe->peer = urxe->peer;
rxe->local = urxe->local;
rxe->time = urxe->time;
/* Move RXE to pending. */
ossl_list_rxe_remove(&qrx->rx_free, rxe);
ossl_list_rxe_insert_tail(&qrx->rx_pending, rxe);
return 0; /* success, did not defer; not distinguished from failure */
cannot_decrypt:
/*
* We cannot process this packet right now (but might be able to later). We
* MUST attempt to process any other packets in the datagram, so defer it
* and skip over it.
*/
assert(eop != NULL && eop >= PACKET_data(pkt));
/*
* We don't care if this fails as it will just result in the packet being at
* the end of the datagram buffer.
*/
ignore_res(PACKET_forward(pkt, eop - PACKET_data(pkt)));
return 1; /* deferred */
malformed:
if (eop != NULL) {
/*
* This packet cannot be processed and will never be processable. We
* were at least able to decode its header and determine its length, so
* we can skip over it and try to process any subsequent packets in the
* datagram.
*
* Mark as processed as an optimization.
*/
assert(eop >= PACKET_data(pkt));
pkt_mark(&urxe->processed, pkt_idx);
/* We don't care if this fails (see above) */
ignore_res(PACKET_forward(pkt, eop - PACKET_data(pkt)));
} else {
/*
* This packet cannot be processed and will never be processable.
* Because even its header is not intelligible, we cannot examine any
* further packets in the datagram because its length cannot be
* discerned.
*
* Advance over the entire remainder of the datagram, and mark it as
* processed gap as an optimization.
*/
pkt_mark(&urxe->processed, pkt_idx);
/* We don't care if this fails (see above) */
ignore_res(PACKET_forward(pkt, PACKET_remaining(pkt)));
}
return 0; /* failure, did not defer; not distinguished from success */
}
/* Process a datagram which was received. */
static int qrx_process_datagram(OSSL_QRX *qrx, QUIC_URXE *e,
const unsigned char *data,
size_t data_len)
{
int have_deferred = 0;
PACKET pkt;
size_t pkt_idx = 0;
QUIC_CONN_ID first_dcid = { 255 };
qrx->bytes_received += data_len;
if (!PACKET_buf_init(&pkt, data, data_len))
return 0;
for (; PACKET_remaining(&pkt) > 0; ++pkt_idx) {
/*
* A packet smaller than the minimum possible QUIC packet size is not
* considered valid. We also ignore more than a certain number of
* packets within the same datagram.
*/
if (PACKET_remaining(&pkt) < QUIC_MIN_VALID_PKT_LEN
|| pkt_idx >= QUIC_MAX_PKT_PER_URXE)
break;
/*
* We note whether packet processing resulted in a deferral since
* this means we need to move the URXE to the deferred list rather
* than the free list after we're finished dealing with it for now.
*
* However, we don't otherwise care here whether processing succeeded or
* failed, as the RFC says even if a packet in a datagram is malformed,
* we should still try to process any packets following it.
*
* In the case where the packet is so malformed we can't determine its
* length, qrx_process_pkt will take care of advancing to the end of
* the packet, so we will exit the loop automatically in this case.
*/
if (qrx_process_pkt(qrx, e, &pkt, pkt_idx, &first_dcid, data_len))
have_deferred = 1;
}
/* Only report whether there were any deferrals. */
return have_deferred;
}
/* Process a single pending URXE. */
static int qrx_process_one_urxe(OSSL_QRX *qrx, QUIC_URXE *e)
{
int was_deferred;
/* The next URXE we process should be at the head of the pending list. */
if (!ossl_assert(e == ossl_list_urxe_head(&qrx->urx_pending)))
return 0;
/*
* Attempt to process the datagram. The return value indicates only if
* processing of the datagram was deferred. If we failed to process the
* datagram, we do not attempt to process it again and silently eat the
* error.
*/
was_deferred = qrx_process_datagram(qrx, e, ossl_quic_urxe_data(e),
e->data_len);
/*
* Remove the URXE from the pending list and return it to
* either the free or deferred list.
*/
ossl_list_urxe_remove(&qrx->urx_pending, e);
if (was_deferred > 0 &&
(e->deferred || qrx->num_deferred < qrx->max_deferred)) {
ossl_list_urxe_insert_tail(&qrx->urx_deferred, e);
if (!e->deferred) {
e->deferred = 1;
++qrx->num_deferred;
}
} else {
if (e->deferred) {
e->deferred = 0;
--qrx->num_deferred;
}
ossl_quic_demux_release_urxe(qrx->demux, e);
}
return 1;
}
/* Process any pending URXEs to generate pending RXEs. */
static int qrx_process_pending_urxl(OSSL_QRX *qrx)
{
QUIC_URXE *e;
while ((e = ossl_list_urxe_head(&qrx->urx_pending)) != NULL)
if (!qrx_process_one_urxe(qrx, e))
return 0;
return 1;
}
int ossl_qrx_read_pkt(OSSL_QRX *qrx, OSSL_QRX_PKT **ppkt)
{
RXE *rxe;
if (!ossl_qrx_processed_read_pending(qrx)) {
if (!qrx_process_pending_urxl(qrx))
return 0;
if (!ossl_qrx_processed_read_pending(qrx))
return 0;
}
rxe = qrx_pop_pending_rxe(qrx);
if (!ossl_assert(rxe != NULL))
return 0;
assert(rxe->refcount == 0);
rxe->refcount = 1;
rxe->pkt.hdr = &rxe->hdr;
rxe->pkt.pn = rxe->pn;
rxe->pkt.time = rxe->time;
rxe->pkt.datagram_len = rxe->datagram_len;
rxe->pkt.peer
= BIO_ADDR_family(&rxe->peer) != AF_UNSPEC ? &rxe->peer : NULL;
rxe->pkt.local
= BIO_ADDR_family(&rxe->local) != AF_UNSPEC ? &rxe->local : NULL;
rxe->pkt.key_epoch = rxe->key_epoch;
rxe->pkt.qrx = qrx;
*ppkt = &rxe->pkt;
return 1;
}
void ossl_qrx_pkt_release(OSSL_QRX_PKT *pkt)
{
RXE *rxe;
if (pkt == NULL)
return;
rxe = (RXE *)pkt;
assert(rxe->refcount > 0);
if (--rxe->refcount == 0)
qrx_recycle_rxe(pkt->qrx, rxe);
}
void ossl_qrx_pkt_up_ref(OSSL_QRX_PKT *pkt)
{
RXE *rxe = (RXE *)pkt;
assert(rxe->refcount > 0);
++rxe->refcount;
}
uint64_t ossl_qrx_get_bytes_received(OSSL_QRX *qrx, int clear)
{
uint64_t v = qrx->bytes_received;
if (clear)
qrx->bytes_received = 0;
return v;
}
int ossl_qrx_set_early_validation_cb(OSSL_QRX *qrx,
ossl_qrx_early_validation_cb *cb,
void *cb_arg)
{
qrx->validation_cb = cb;
qrx->validation_cb_arg = cb_arg;
return 1;
}
int ossl_qrx_set_key_update_cb(OSSL_QRX *qrx,
ossl_qrx_key_update_cb *cb,
void *cb_arg)
{
qrx->key_update_cb = cb;
qrx->key_update_cb_arg = cb_arg;
return 1;
}
uint64_t ossl_qrx_get_key_epoch(OSSL_QRX *qrx)
{
OSSL_QRL_ENC_LEVEL *el = ossl_qrl_enc_level_set_get(&qrx->el_set,
QUIC_ENC_LEVEL_1RTT, 1);
return el == NULL ? UINT64_MAX : el->key_epoch;
}
int ossl_qrx_key_update_timeout(OSSL_QRX *qrx, int normal)
{
OSSL_QRL_ENC_LEVEL *el = ossl_qrl_enc_level_set_get(&qrx->el_set,
QUIC_ENC_LEVEL_1RTT, 1);
if (el == NULL)
return 0;
if (el->state == QRL_EL_STATE_PROV_UPDATING
&& !ossl_qrl_enc_level_set_key_update_done(&qrx->el_set,
QUIC_ENC_LEVEL_1RTT))
return 0;
if (normal && el->state == QRL_EL_STATE_PROV_COOLDOWN
&& !ossl_qrl_enc_level_set_key_cooldown_done(&qrx->el_set,
QUIC_ENC_LEVEL_1RTT))
return 0;
return 1;
}
uint64_t ossl_qrx_get_cur_forged_pkt_count(OSSL_QRX *qrx)
{
return qrx->forged_pkt_count;
}
uint64_t ossl_qrx_get_max_forged_pkt_count(OSSL_QRX *qrx,
uint32_t enc_level)
{
OSSL_QRL_ENC_LEVEL *el = ossl_qrl_enc_level_set_get(&qrx->el_set,
enc_level, 1);
return el == NULL ? UINT64_MAX
: ossl_qrl_get_suite_max_forged_pkt(el->suite_id);
}
void ossl_qrx_set_msg_callback(OSSL_QRX *qrx, ossl_msg_cb msg_callback,
SSL *msg_callback_ssl)
{
qrx->msg_callback = msg_callback;
qrx->msg_callback_ssl = msg_callback_ssl;
}
void ossl_qrx_set_msg_callback_arg(OSSL_QRX *qrx, void *msg_callback_arg)
{
qrx->msg_callback_arg = msg_callback_arg;
}
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