/* Copyright (c) 2017 - 2022 LiteSpeed Technologies Inc. See LICENSE. */ /* * Parsing routines shared by all IETF QUIC versions. */ #include #include #include #include #include #include #include #include #include "lsquic_types.h" #include "lsquic_int_types.h" #include "lsquic_packet_common.h" #include "lsquic_packet_in.h" #include "lsquic_parse_common.h" #include "lsquic_parse.h" #include "lsquic_version.h" #include "lsquic.h" #include "lsquic_logger.h" #include "lsquic_byteswap.h" #include "lsquic_varint.h" #include "lsquic_enc_sess.h" #include "lsquic_tokgen.h" #include "lsquic_mm.h" #include "lsquic_engine_public.h" #include "lsquic_ietf.h" /* [draft-ietf-quic-transport-17] Section-17.2 */ static const enum header_type bits2ht[4] = { [0] = HETY_INITIAL, [1] = HETY_0RTT, [2] = HETY_HANDSHAKE, [3] = HETY_RETRY, }; int lsquic_Q046_parse_packet_in_long_begin (struct lsquic_packet_in *packet_in, size_t length, int is_server, unsigned cid_len, struct packin_parse_state *state) { const unsigned char *p = packet_in->pi_data; const unsigned char *const end = p + length; lsquic_ver_tag_t tag; enum header_type header_type; unsigned dcil, scil, packet_len; int verneg; unsigned char first_byte; lsquic_packno_t packno; if (length < 6) return -1; first_byte = *p++; memcpy(&tag, p, 4); p += 4; verneg = 0 == tag; if (!verneg) header_type = bits2ht[ (first_byte >> 4) & 3 ]; else header_type = HETY_VERNEG; packet_in->pi_header_type = header_type; dcil = p[0] >> 4; if (dcil) dcil += 3; scil = p[0] & 0xF; if (scil) scil += 3; ++p; /* Chromium comments state that the client sends packets with destination * CID of 8 bytes and source CID of 0 bytes and the server does it the * other way around. */ if (is_server) { if (!(dcil == cid_len && scil == 0)) return -1; } else if (!(dcil == 0 && scil == cid_len)) return -1; if (!verneg) { packet_in->pi_flags |= (first_byte & 3) << PIBIT_BITS_SHIFT; packet_len = 1 + (first_byte & 3); if (end - p < (ptrdiff_t) (dcil + scil + packet_len)) return -1; } else { /* Need at least one version in the version array: add 4 */ if (end - p < (ptrdiff_t) (dcil + scil + 4)) return -1; #ifdef WIN32 /* Useless initialization: */ packet_len = 0; #endif } memcpy(&packet_in->pi_dcid.idbuf, p, cid_len); packet_in->pi_dcid.len = cid_len; p += cid_len; packet_in->pi_flags |= PI_CONN_ID; if (!verneg) { READ_UINT(packno, 64, p, packet_len); packet_in->pi_packno = packno; p += packet_len; packet_in->pi_quic_ver = 1; if (is_server || HETY_0RTT != header_type) packet_in->pi_nonce = 0; else { packet_in->pi_nonce = p - packet_in->pi_data; p += 32; } } else { if (p >= end || (3 & (uintptr_t) (end - p))) return -1; packet_in->pi_quic_ver = p - packet_in->pi_data; p = end; } packet_in->pi_header_sz = p - packet_in->pi_data; packet_in->pi_frame_types = 0; packet_in->pi_data_sz = length; packet_in->pi_refcnt = 0; packet_in->pi_received = 0; return 0; } int lsquic_Q046_parse_packet_in_short_begin (lsquic_packet_in_t *packet_in, size_t length, int is_server, unsigned cid_len, struct packin_parse_state *state) { const unsigned char *p = packet_in->pi_data; const unsigned char *const pend = packet_in->pi_data + length; unsigned packet_len, header_len; lsquic_packno_t packno; if (*p & 0x40) /* Q046 and higher */ packet_len = 1 + (*p & 3); else return -1; if (is_server) header_len = 1 + cid_len + packet_len; else header_len = 1 + packet_len; if (pend - p < (ptrdiff_t) header_len) return -1; packet_in->pi_flags |= (*p & 3) << PIBIT_BITS_SHIFT; ++p; if (is_server) { memcpy(packet_in->pi_dcid.idbuf, packet_in->pi_data + 1, cid_len); packet_in->pi_dcid.len = cid_len; packet_in->pi_flags |= PI_CONN_ID; p += cid_len; } READ_UINT(packno, 64, p, packet_len); packet_in->pi_packno = packno; p += packet_len; packet_in->pi_header_type = HETY_SHORT; packet_in->pi_quic_ver = 0; packet_in->pi_nonce = 0; packet_in->pi_header_sz = p - packet_in->pi_data; packet_in->pi_frame_types = 0; packet_in->pi_data_sz = length; packet_in->pi_refcnt = 0; packet_in->pi_received = 0; return 0; } /* This is a bare-bones version of lsquic_Q046_parse_packet_in_long_begin() */ int lsquic_is_valid_iquic_hs_packet (const unsigned char *buf, size_t length, lsquic_ver_tag_t *tagp) { const unsigned char *p = buf; const unsigned char *const end = p + length; lsquic_ver_tag_t tag; unsigned dcil, scil, packet_len; unsigned char first_byte; const unsigned cid_len = 8; if (length < 6) return 0; first_byte = *p++; memcpy(&tag, p, 4); p += 4; if (0 == tag) return 0; /* Client never sends version negotiation */ dcil = p[0] >> 4; if (dcil) dcil += 3; scil = p[0] & 0xF; if (scil) scil += 3; ++p; if (!(dcil == cid_len && scil == 0)) return 0; packet_len = first_byte & 3; if (end - p >= (ptrdiff_t) (dcil + scil + packet_len)) { *tagp = tag; return 1; } else return 0; } const enum quic_frame_type lsquic_iquic_byte2type[0x40] = { [0x00] = QUIC_FRAME_PADDING, [0x01] = QUIC_FRAME_PING, [0x02] = QUIC_FRAME_ACK, [0x03] = QUIC_FRAME_ACK, [0x04] = QUIC_FRAME_RST_STREAM, [0x05] = QUIC_FRAME_STOP_SENDING, [0x06] = QUIC_FRAME_CRYPTO, [0x07] = QUIC_FRAME_NEW_TOKEN, [0x08] = QUIC_FRAME_STREAM, [0x09] = QUIC_FRAME_STREAM, [0x0A] = QUIC_FRAME_STREAM, [0x0B] = QUIC_FRAME_STREAM, [0x0C] = QUIC_FRAME_STREAM, [0x0D] = QUIC_FRAME_STREAM, [0x0E] = QUIC_FRAME_STREAM, [0x0F] = QUIC_FRAME_STREAM, [0x10] = QUIC_FRAME_MAX_DATA, [0x11] = QUIC_FRAME_MAX_STREAM_DATA, [0x12] = QUIC_FRAME_MAX_STREAMS, [0x13] = QUIC_FRAME_MAX_STREAMS, [0x14] = QUIC_FRAME_BLOCKED, [0x15] = QUIC_FRAME_STREAM_BLOCKED, [0x16] = QUIC_FRAME_STREAMS_BLOCKED, [0x17] = QUIC_FRAME_STREAMS_BLOCKED, [0x18] = QUIC_FRAME_NEW_CONNECTION_ID, [0x19] = QUIC_FRAME_RETIRE_CONNECTION_ID, [0x1A] = QUIC_FRAME_PATH_CHALLENGE, [0x1B] = QUIC_FRAME_PATH_RESPONSE, [0x1C] = QUIC_FRAME_CONNECTION_CLOSE, [0x1D] = QUIC_FRAME_CONNECTION_CLOSE, [0x1E] = QUIC_FRAME_HANDSHAKE_DONE, [0x1F] = QUIC_FRAME_INVALID, [0x20] = QUIC_FRAME_INVALID, [0x21] = QUIC_FRAME_INVALID, [0x22] = QUIC_FRAME_INVALID, [0x23] = QUIC_FRAME_INVALID, [0x24] = QUIC_FRAME_INVALID, [0x25] = QUIC_FRAME_INVALID, [0x26] = QUIC_FRAME_INVALID, [0x27] = QUIC_FRAME_INVALID, [0x28] = QUIC_FRAME_INVALID, [0x29] = QUIC_FRAME_INVALID, [0x2A] = QUIC_FRAME_INVALID, [0x2B] = QUIC_FRAME_INVALID, [0x2C] = QUIC_FRAME_INVALID, [0x2D] = QUIC_FRAME_INVALID, [0x2E] = QUIC_FRAME_INVALID, [0x2F] = QUIC_FRAME_INVALID, [0x30] = QUIC_FRAME_DATAGRAM, [0x31] = QUIC_FRAME_DATAGRAM, [0x32] = QUIC_FRAME_INVALID, [0x33] = QUIC_FRAME_INVALID, [0x34] = QUIC_FRAME_INVALID, [0x35] = QUIC_FRAME_INVALID, [0x36] = QUIC_FRAME_INVALID, [0x37] = QUIC_FRAME_INVALID, [0x38] = QUIC_FRAME_INVALID, [0x39] = QUIC_FRAME_INVALID, [0x3A] = QUIC_FRAME_INVALID, [0x3B] = QUIC_FRAME_INVALID, [0x3C] = QUIC_FRAME_INVALID, [0x3D] = QUIC_FRAME_INVALID, [0x3E] = QUIC_FRAME_INVALID, [0x3F] = QUIC_FRAME_INVALID, }; #if __GNUC__ # define popcount __builtin_popcount #else static int popcount (unsigned v) { int count, i; for (i = 0, count = 0; i < sizeof(v) * 8; ++i) if (v & (1 << i)) ++count; return count; } #endif int lsquic_Q046_gen_ver_nego_pkt (unsigned char *buf, size_t bufsz, const lsquic_cid_t *scid, const lsquic_cid_t *dcid, unsigned versions, uint8_t rand) { unsigned slen, dlen; size_t need; int r; need = 1 /* Type */ + 4 /* Packet number */ + 1 /* SCIL */ + scid->len + dcid->len + popcount(versions) * 4; if (need > bufsz) return -1; *buf++ = 0x80 | 0x40 | rand; memset(buf, 0, 4); buf += 4; /* From [draft-ietf-quic-transport-11], Section 4.3: * * The server MUST include the value from the Source Connection ID field * of the packet it receives in the Destination Connection ID field. * The value for Source Connection ID MUST be copied from the * Destination Connection ID of the received packet, which is initially * randomly selected by a client. Echoing both connection IDs gives * clients some assurance that the server received the packet and that * the Version Negotiation packet was not generated by an off-path * attacker. */ dlen = dcid->len; if (dlen) dlen -= 3; slen = scid->len; if (slen) slen -= 3; *buf++ = (dlen << 4) | slen; memcpy(buf, dcid->idbuf, dcid->len); buf += dcid->len; memcpy(buf, scid->idbuf, scid->len); buf += scid->len; r = lsquic_gen_ver_tags(buf, bufsz - 1 - 4 - 1 - dcid->len - scid->len, versions); if (r < 0) return -1; assert((unsigned) r == popcount(versions) * 4u); return need; } int lsquic_iquic_gen_retry_pkt (unsigned char *buf, size_t bufsz, const struct lsquic_engine_public *enpub, const lsquic_cid_t *scid, const lsquic_cid_t *dcid, enum lsquic_version version, const struct sockaddr *sockaddr, uint8_t random_nybble) { struct token_generator *const tokgen = enpub->enp_tokgen; const unsigned our_scid_len = enpub->enp_settings.es_scid_len; unsigned char *const end = buf + bufsz; unsigned char *p = buf; lsquic_ver_tag_t ver_tag; size_t ad_len, out_len; unsigned ret_ver; ssize_t sz; #define INTEGRITY_TAG_LEN 16 /* [draft-ietf-quic-tls-25] Section 5.8 specifies the layout of the * Retry Pseudo-Packet: */ unsigned char ad_buf[ 1 + MAX_CID_LEN /* ODCID */ + 1 + 4 /* Type and version */ + 1 + MAX_CID_LEN /* DCID */ + 1 + MAX_CID_LEN /* SCID */ + MAX_RETRY_TOKEN_LEN /* Retry token */ ]; unsigned char tag[INTEGRITY_TAG_LEN]; /* See [draft-ietf-quic-transport-25], Section 17.2.5 */ if (bufsz < 1 + sizeof(ver_tag) + 1 + our_scid_len + 1 + dcid->len + MAX_RETRY_TOKEN_LEN + INTEGRITY_TAG_LEN) return -1; p = ad_buf; *p++ = dcid->len; memcpy(p, dcid->idbuf, dcid->len); p += dcid->len; *p++ = 0xC0 | (3 << 4) | random_nybble ; ver_tag = lsquic_ver2tag(version); memcpy(p, &ver_tag, sizeof(ver_tag)); p += sizeof(ver_tag); *p++ = scid->len; memcpy(p, scid->idbuf, scid->len); p += scid->len; *p++ = our_scid_len; RAND_bytes(p, our_scid_len); p += our_scid_len; sz = lsquic_tg_generate_retry(tokgen, p, end - p, p - our_scid_len, our_scid_len, sockaddr, dcid); if (sz < 0) return -1; p += sz; ad_len = p - ad_buf; ret_ver = lsquic_version_2_retryver(version); out_len = sizeof(tag); if (!(1 == EVP_AEAD_CTX_seal(&enpub->enp_retry_aead_ctx[ret_ver], tag, &out_len, out_len, lsquic_retry_nonce_buf[ret_ver], IETF_RETRY_NONCE_SZ, NULL, 0, ad_buf, ad_len) && out_len == sizeof(tag))) return -1; memcpy(buf, ad_buf + 1 + dcid->len, ad_len - 1 - dcid->len); memcpy(buf + ad_len - 1 - dcid->len, tag, sizeof(tag)); return ad_len - 1 - dcid->len + sizeof(tag); }