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[nginx] QUIC: reusing crypto contexts for header protection.

Sergey Kandaurov
October 20, 2023 10:44AM
details: https://hg.nginx.org/nginx/rev/31702c53d2db
branches:
changeset: 9174:31702c53d2db
user: Sergey Kandaurov <pluknet@nginx.com>
date: Fri Oct 20 18:05:07 2023 +0400
description:
QUIC: reusing crypto contexts for header protection.

diffstat:

src/event/quic/ngx_event_quic_protection.c | 102 +++++++++++++++++++++-------
src/event/quic/ngx_event_quic_protection.h | 1 +
2 files changed, 75 insertions(+), 28 deletions(-)

diffs (204 lines):

diff -r 904a54092d5b -r 31702c53d2db src/event/quic/ngx_event_quic_protection.c
--- a/src/event/quic/ngx_event_quic_protection.c Fri Oct 20 18:05:07 2023 +0400
+++ b/src/event/quic/ngx_event_quic_protection.c Fri Oct 20 18:05:07 2023 +0400
@@ -32,8 +32,12 @@ static ngx_int_t ngx_quic_crypto_open(ng
static ngx_int_t ngx_quic_crypto_common(ngx_quic_secret_t *s, ngx_str_t *out,
u_char *nonce, ngx_str_t *in, ngx_str_t *ad, ngx_log_t *log);
#endif
-static ngx_int_t ngx_quic_crypto_hp(ngx_log_t *log, const EVP_CIPHER *cipher,
- ngx_quic_secret_t *s, u_char *out, u_char *in);
+
+static ngx_int_t ngx_quic_crypto_hp_init(const EVP_CIPHER *cipher,
+ ngx_quic_secret_t *s, ngx_log_t *log);
+static ngx_int_t ngx_quic_crypto_hp(ngx_quic_secret_t *s,
+ u_char *out, u_char *in, ngx_log_t *log);
+static void ngx_quic_crypto_hp_cleanup(ngx_quic_secret_t *s);

static ngx_int_t ngx_quic_create_packet(ngx_quic_header_t *pkt,
ngx_str_t *res);
@@ -196,6 +200,14 @@ ngx_quic_keys_set_initial_secret(ngx_qui
goto failed;
}

+ if (ngx_quic_crypto_hp_init(ciphers.hp, client, log) == NGX_ERROR) {
+ goto failed;
+ }
+
+ if (ngx_quic_crypto_hp_init(ciphers.hp, server, log) == NGX_ERROR) {
+ goto failed;
+ }
+
return NGX_OK;

failed:
@@ -556,53 +568,82 @@ ngx_quic_crypto_cleanup(ngx_quic_secret_


static ngx_int_t
-ngx_quic_crypto_hp(ngx_log_t *log, const EVP_CIPHER *cipher,
- ngx_quic_secret_t *s, u_char *out, u_char *in)
+ngx_quic_crypto_hp_init(const EVP_CIPHER *cipher, ngx_quic_secret_t *s,
+ ngx_log_t *log)
{
- int outlen;
EVP_CIPHER_CTX *ctx;
- u_char zero[NGX_QUIC_HP_LEN] = {0};

#ifdef OPENSSL_IS_BORINGSSL
- uint32_t cnt;
-
- ngx_memcpy(&cnt, in, sizeof(uint32_t));
-
- if (cipher == (const EVP_CIPHER *) EVP_aead_chacha20_poly1305()) {
- CRYPTO_chacha_20(out, zero, NGX_QUIC_HP_LEN, s->hp.data, &in[4], cnt);
+ if (cipher == (EVP_CIPHER *) EVP_aead_chacha20_poly1305()) {
+ /* no EVP interface */
+ s->hp_ctx = NULL;
return NGX_OK;
}
#endif

ctx = EVP_CIPHER_CTX_new();
if (ctx == NULL) {
+ ngx_ssl_error(NGX_LOG_INFO, log, 0, "EVP_CIPHER_CTX_new() failed");
+ return NGX_ERROR;
+ }
+
+ if (EVP_EncryptInit_ex(ctx, cipher, NULL, s->hp.data, NULL) != 1) {
+ EVP_CIPHER_CTX_free(ctx);
+ ngx_ssl_error(NGX_LOG_INFO, log, 0, "EVP_EncryptInit_ex() failed");
return NGX_ERROR;
}

- if (EVP_EncryptInit_ex(ctx, cipher, NULL, s->hp.data, in) != 1) {
+ s->hp_ctx = ctx;
+ return NGX_OK;
+}
+
+
+static ngx_int_t
+ngx_quic_crypto_hp(ngx_quic_secret_t *s, u_char *out, u_char *in,
+ ngx_log_t *log)
+{
+ int outlen;
+ EVP_CIPHER_CTX *ctx;
+ u_char zero[NGX_QUIC_HP_LEN] = {0};
+
+ ctx = s->hp_ctx;
+
+#ifdef OPENSSL_IS_BORINGSSL
+ uint32_t cnt;
+
+ if (ctx == NULL) {
+ ngx_memcpy(&cnt, in, sizeof(uint32_t));
+ CRYPTO_chacha_20(out, zero, NGX_QUIC_HP_LEN, s->hp.data, &in[4], cnt);
+ return NGX_OK;
+ }
+#endif
+
+ if (EVP_EncryptInit_ex(ctx, NULL, NULL, NULL, in) != 1) {
ngx_ssl_error(NGX_LOG_INFO, log, 0, "EVP_EncryptInit_ex() failed");
- goto failed;
+ return NGX_ERROR;
}

if (!EVP_EncryptUpdate(ctx, out, &outlen, zero, NGX_QUIC_HP_LEN)) {
ngx_ssl_error(NGX_LOG_INFO, log, 0, "EVP_EncryptUpdate() failed");
- goto failed;
+ return NGX_ERROR;
}

if (!EVP_EncryptFinal_ex(ctx, out + NGX_QUIC_HP_LEN, &outlen)) {
ngx_ssl_error(NGX_LOG_INFO, log, 0, "EVP_EncryptFinal_Ex() failed");
- goto failed;
+ return NGX_ERROR;
}

- EVP_CIPHER_CTX_free(ctx);
-
return NGX_OK;
+}

-failed:

- EVP_CIPHER_CTX_free(ctx);
-
- return NGX_ERROR;
+static void
+ngx_quic_crypto_hp_cleanup(ngx_quic_secret_t *s)
+{
+ if (s->hp_ctx) {
+ EVP_CIPHER_CTX_free(s->hp_ctx);
+ s->hp_ctx = NULL;
+ }
}


@@ -663,6 +704,10 @@ ngx_quic_keys_set_encryption_secret(ngx_
return NGX_ERROR;
}

+ if (ngx_quic_crypto_hp_init(ciphers.hp, peer_secret, log) == NGX_ERROR) {
+ return NGX_ERROR;
+ }
+
return NGX_OK;
}

@@ -690,6 +735,9 @@ ngx_quic_keys_discard(ngx_quic_keys_t *k

ngx_quic_crypto_cleanup(client);
ngx_quic_crypto_cleanup(server);
+
+ ngx_quic_crypto_hp_cleanup(client);
+ ngx_quic_crypto_hp_cleanup(server);
}


@@ -742,11 +790,13 @@ ngx_quic_keys_update(ngx_event_t *ev)
next->client.key.len = current->client.key.len;
next->client.iv.len = NGX_QUIC_IV_LEN;
next->client.hp = current->client.hp;
+ next->client.hp_ctx = current->client.hp_ctx;

next->server.secret.len = current->server.secret.len;
next->server.key.len = current->server.key.len;
next->server.iv.len = NGX_QUIC_IV_LEN;
next->server.hp = current->server.hp;
+ next->server.hp_ctx = current->server.hp_ctx;

ngx_quic_hkdf_set(&seq[0], "tls13 quic ku",
&next->client.secret, &current->client.secret);
@@ -840,9 +890,7 @@ ngx_quic_create_packet(ngx_quic_header_t
}

sample = &out.data[4 - pkt->num_len];
- if (ngx_quic_crypto_hp(pkt->log, ciphers.hp, secret, mask, sample)
- != NGX_OK)
- {
+ if (ngx_quic_crypto_hp(secret, mask, sample, pkt->log) != NGX_OK) {
return NGX_ERROR;
}

@@ -1070,9 +1118,7 @@ ngx_quic_decrypt(ngx_quic_header_t *pkt,

/* header protection */

- if (ngx_quic_crypto_hp(pkt->log, ciphers.hp, secret, mask, sample)
- != NGX_OK)
- {
+ if (ngx_quic_crypto_hp(secret, mask, sample, pkt->log) != NGX_OK) {
return NGX_DECLINED;
}

diff -r 904a54092d5b -r 31702c53d2db src/event/quic/ngx_event_quic_protection.h
--- a/src/event/quic/ngx_event_quic_protection.h Fri Oct 20 18:05:07 2023 +0400
+++ b/src/event/quic/ngx_event_quic_protection.h Fri Oct 20 18:05:07 2023 +0400
@@ -51,6 +51,7 @@ typedef struct {
ngx_quic_iv_t iv;
ngx_quic_md_t hp;
ngx_quic_crypto_ctx_t *ctx;
+ EVP_CIPHER_CTX *hp_ctx;
} ngx_quic_secret_t;


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[nginx] QUIC: reusing crypto contexts for header protection.

Sergey Kandaurov 272 October 20, 2023 10:44AM



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