Mercurial > hg > nginx
view src/event/quic/ngx_event_quic_tokens.c @ 9153:8f7e6d8c061e
QUIC: use last client dcid to receive initial packets.
Previously, original dcid was used to receive initial client packets in case
server initial response was lost. However, last dcid should be used instead.
These two are the same unless retry is used. In case of retry, client resends
initial packet with a new dcid, that is different from the original dcid. If
server response is lost, the client resends this packet again with the same
dcid. This is shown in RFC 9000, 7.3. Authenticating Connection IDs, Figure 8.
The issue manifested itself with creating multiple server sessions in response
to each post-retry client initial packet, if server response is lost.
author | Roman Arutyunyan <arut@nginx.com> |
---|---|
date | Wed, 30 Aug 2023 11:09:21 +0400 |
parents | 77c1418916f7 |
children |
line wrap: on
line source
/* * Copyright (C) Nginx, Inc. */ #include <ngx_config.h> #include <ngx_core.h> #include <ngx_event.h> #include <ngx_sha1.h> #include <ngx_event_quic_connection.h> static void ngx_quic_address_hash(struct sockaddr *sockaddr, socklen_t socklen, ngx_uint_t no_port, u_char buf[20]); ngx_int_t ngx_quic_new_sr_token(ngx_connection_t *c, ngx_str_t *cid, u_char *secret, u_char *token) { ngx_str_t tmp; tmp.data = secret; tmp.len = NGX_QUIC_SR_KEY_LEN; if (ngx_quic_derive_key(c->log, "sr_token_key", &tmp, cid, token, NGX_QUIC_SR_TOKEN_LEN) != NGX_OK) { return NGX_ERROR; } ngx_log_debug2(NGX_LOG_DEBUG_EVENT, c->log, 0, "quic stateless reset token %*xs", (size_t) NGX_QUIC_SR_TOKEN_LEN, token); return NGX_OK; } ngx_int_t ngx_quic_new_token(ngx_log_t *log, struct sockaddr *sockaddr, socklen_t socklen, u_char *key, ngx_str_t *token, ngx_str_t *odcid, time_t exp, ngx_uint_t is_retry) { int len, iv_len; u_char *p, *iv; EVP_CIPHER_CTX *ctx; const EVP_CIPHER *cipher; u_char in[NGX_QUIC_MAX_TOKEN_SIZE]; ngx_quic_address_hash(sockaddr, socklen, !is_retry, in); p = in + 20; p = ngx_cpymem(p, &exp, sizeof(time_t)); *p++ = is_retry ? 1 : 0; if (odcid) { *p++ = odcid->len; p = ngx_cpymem(p, odcid->data, odcid->len); } else { *p++ = 0; } len = p - in; cipher = EVP_aes_256_gcm(); iv_len = NGX_QUIC_AES_256_GCM_IV_LEN; if ((size_t) (iv_len + len + NGX_QUIC_AES_256_GCM_TAG_LEN) > token->len) { ngx_log_error(NGX_LOG_ALERT, log, 0, "quic token buffer is too small"); return NGX_ERROR; } ctx = EVP_CIPHER_CTX_new(); if (ctx == NULL) { return NGX_ERROR; } iv = token->data; if (RAND_bytes(iv, iv_len) <= 0 || !EVP_EncryptInit_ex(ctx, cipher, NULL, key, iv)) { EVP_CIPHER_CTX_free(ctx); return NGX_ERROR; } token->len = iv_len; if (EVP_EncryptUpdate(ctx, token->data + token->len, &len, in, len) != 1) { EVP_CIPHER_CTX_free(ctx); return NGX_ERROR; } token->len += len; if (EVP_EncryptFinal_ex(ctx, token->data + token->len, &len) <= 0) { EVP_CIPHER_CTX_free(ctx); return NGX_ERROR; } token->len += len; if (EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_AEAD_GET_TAG, NGX_QUIC_AES_256_GCM_TAG_LEN, token->data + token->len) == 0) { EVP_CIPHER_CTX_free(ctx); return NGX_ERROR; } token->len += NGX_QUIC_AES_256_GCM_TAG_LEN; EVP_CIPHER_CTX_free(ctx); #ifdef NGX_QUIC_DEBUG_PACKETS ngx_log_debug2(NGX_LOG_DEBUG_EVENT, log, 0, "quic new token len:%uz %xV", token->len, token); #endif return NGX_OK; } static void ngx_quic_address_hash(struct sockaddr *sockaddr, socklen_t socklen, ngx_uint_t no_port, u_char buf[20]) { size_t len; u_char *data; ngx_sha1_t sha1; struct sockaddr_in *sin; #if (NGX_HAVE_INET6) struct sockaddr_in6 *sin6; #endif len = (size_t) socklen; data = (u_char *) sockaddr; if (no_port) { switch (sockaddr->sa_family) { #if (NGX_HAVE_INET6) case AF_INET6: sin6 = (struct sockaddr_in6 *) sockaddr; len = sizeof(struct in6_addr); data = sin6->sin6_addr.s6_addr; break; #endif case AF_INET: sin = (struct sockaddr_in *) sockaddr; len = sizeof(in_addr_t); data = (u_char *) &sin->sin_addr; break; } } ngx_sha1_init(&sha1); ngx_sha1_update(&sha1, data, len); ngx_sha1_final(buf, &sha1); } ngx_int_t ngx_quic_validate_token(ngx_connection_t *c, u_char *key, ngx_quic_header_t *pkt) { int len, tlen, iv_len; u_char *iv, *p; time_t now, exp; size_t total; ngx_str_t odcid; EVP_CIPHER_CTX *ctx; const EVP_CIPHER *cipher; u_char addr_hash[20]; u_char tdec[NGX_QUIC_MAX_TOKEN_SIZE]; #if NGX_SUPPRESS_WARN ngx_str_null(&odcid); #endif /* Retry token or NEW_TOKEN in a previous connection */ cipher = EVP_aes_256_gcm(); iv = pkt->token.data; iv_len = NGX_QUIC_AES_256_GCM_IV_LEN; /* sanity checks */ if (pkt->token.len < (size_t) iv_len + NGX_QUIC_AES_256_GCM_TAG_LEN) { goto garbage; } if (pkt->token.len > (size_t) iv_len + NGX_QUIC_MAX_TOKEN_SIZE + NGX_QUIC_AES_256_GCM_TAG_LEN) { goto garbage; } ctx = EVP_CIPHER_CTX_new(); if (ctx == NULL) { return NGX_ERROR; } if (!EVP_DecryptInit_ex(ctx, cipher, NULL, key, iv)) { EVP_CIPHER_CTX_free(ctx); return NGX_ERROR; } p = pkt->token.data + iv_len; len = pkt->token.len - iv_len - NGX_QUIC_AES_256_GCM_TAG_LEN; if (EVP_DecryptUpdate(ctx, tdec, &tlen, p, len) != 1) { EVP_CIPHER_CTX_free(ctx); goto garbage; } total = tlen; if (EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_AEAD_SET_TAG, NGX_QUIC_AES_256_GCM_TAG_LEN, p + len) == 0) { EVP_CIPHER_CTX_free(ctx); goto garbage; } if (EVP_DecryptFinal_ex(ctx, tdec + tlen, &tlen) <= 0) { EVP_CIPHER_CTX_free(ctx); goto garbage; } total += tlen; EVP_CIPHER_CTX_free(ctx); if (total < (20 + sizeof(time_t) + 2)) { goto garbage; } p = tdec + 20; ngx_memcpy(&exp, p, sizeof(time_t)); p += sizeof(time_t); pkt->retried = (*p++ == 1); ngx_quic_address_hash(c->sockaddr, c->socklen, !pkt->retried, addr_hash); if (ngx_memcmp(tdec, addr_hash, 20) != 0) { goto bad_token; } odcid.len = *p++; if (odcid.len) { if (odcid.len > NGX_QUIC_MAX_CID_LEN) { goto bad_token; } if ((size_t)(tdec + total - p) < odcid.len) { goto bad_token; } odcid.data = p; } now = ngx_time(); if (now > exp) { ngx_log_error(NGX_LOG_INFO, c->log, 0, "quic expired token"); return NGX_DECLINED; } if (odcid.len) { pkt->odcid.len = odcid.len; pkt->odcid.data = pkt->odcid_buf; ngx_memcpy(pkt->odcid.data, odcid.data, odcid.len); } else { pkt->odcid = pkt->dcid; } pkt->validated = 1; return NGX_OK; garbage: ngx_log_error(NGX_LOG_INFO, c->log, 0, "quic garbage token"); return NGX_ABORT; bad_token: ngx_log_error(NGX_LOG_INFO, c->log, 0, "quic invalid token"); return NGX_DECLINED; }