Mercurial > hg > nginx
view src/event/quic/ngx_event_quic_tokens.c @ 9189:fcec773dd249
QUIC: avoid partial expansion of PATH_CHALLENGE/PATH_RESPONSE.
By default packets with these frames are expanded to 1200 bytes. Previously,
if anti-amplification limit did not allow this expansion, it was limited to
whatever size was allowed. However RFC 9000 clearly states no partial
expansion should happen in both cases.
Section 8.2.1. Initiating Path Validation:
An endpoint MUST expand datagrams that contain a PATH_CHALLENGE frame
to at least the smallest allowed maximum datagram size of 1200 bytes,
unless the anti-amplification limit for the path does not permit
sending a datagram of this size.
Section 8.2.2. Path Validation Responses:
An endpoint MUST expand datagrams that contain a PATH_RESPONSE frame
to at least the smallest allowed maximum datagram size of 1200 bytes.
...
However, an endpoint MUST NOT expand the datagram containing the
PATH_RESPONSE if the resulting data exceeds the anti-amplification limit.
author | Roman Arutyunyan <arut@nginx.com> |
---|---|
date | Wed, 29 Nov 2023 18:13:25 +0400 |
parents | 77c1418916f7 |
children |
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/* * 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; }