# HG changeset patch
# User Vladimir Homutov <vl@nginx.com>
# Date 1645524401 -10800
# Tue Feb 22 13:06:41 2022 +0300
# Branch quic
# Node ID a881ff28070262f3810517d5d3cb4ff67a4b7121
# Parent 5b1011b5702b5c5db2ba3d392a4da25596183cc2
QUIC: fixed-length buffers for secrets.

diff --git a/src/event/quic/ngx_event_quic_protection.c b/src/event/quic/ngx_event_quic_protection.c
--- a/src/event/quic/ngx_event_quic_protection.c
+++ b/src/event/quic/ngx_event_quic_protection.c
@@ -17,6 +17,9 @@

#define NGX_QUIC_AES_128_KEY_LEN 16

+/* largest hash used in TLS is SHA-384 */
+#define NGX_QUIC_MAX_MD_SIZE 48
+
#define NGX_AES_128_GCM_SHA256 0x1301
#define NGX_AES_256_GCM_SHA384 0x1302
#define NGX_CHACHA20_POLY1305_SHA256 0x1303
@@ -30,6 +33,18 @@


typedef struct {
+ size_t len;
+ u_char data[NGX_QUIC_MAX_MD_SIZE];
+} ngx_quic_md_t;
+
+
+typedef struct {
+ size_t len;
+ u_char data[NGX_QUIC_IV_LEN];
+} ngx_quic_iv_t;
+
+
+typedef struct {
const ngx_quic_cipher_t *c;
const EVP_CIPHER *hp;
const EVP_MD *d;
@@ -37,10 +52,10 @@ typedef struct {


typedef struct ngx_quic_secret_s {
- ngx_str_t secret;
- ngx_str_t key;
- ngx_str_t iv;
- ngx_str_t hp;
+ ngx_quic_md_t secret;
+ ngx_quic_md_t key;
+ ngx_quic_iv_t iv;
+ ngx_quic_md_t hp;
} ngx_quic_secret_t;


@@ -57,6 +72,25 @@ struct ngx_quic_keys_s {
};


+typedef struct {
+ size_t out_len;
+ u_char *out;
+
+ size_t prk_len;
+ const uint8_t *prk;
+
+ size_t label_len;
+ const u_char *label;
+} ngx_quic_hkdf_t;
+
+#define ngx_quic_hkdf_set(label, out, prk) \
+ { \
+ (out)->len, (out)->data, \
+ (prk)->len, (prk)->data, \
+ (sizeof(label) - 1), (u_char *)(label), \
+ }
+
+
static ngx_int_t ngx_hkdf_expand(u_char *out_key, size_t out_len,
const EVP_MD *digest, const u_char *prk, size_t prk_len,
const u_char *info, size_t info_len);
@@ -78,8 +112,8 @@ static ngx_int_t ngx_quic_tls_seal(const
ngx_str_t *ad, ngx_log_t *log);
static ngx_int_t ngx_quic_tls_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_hkdf_expand(ngx_pool_t *pool, const EVP_MD *digest,
- ngx_str_t *out, ngx_str_t *label, const uint8_t *prk, size_t prk_len);
+static ngx_int_t ngx_quic_hkdf_expand(ngx_quic_hkdf_t *hkdf,
+ const EVP_MD *digest, ngx_pool_t *pool);

static ngx_int_t ngx_quic_create_packet(ngx_quic_header_t *pkt,
ngx_str_t *res);
@@ -204,28 +238,20 @@ ngx_quic_keys_set_initial_secret(ngx_poo
client->iv.len = NGX_QUIC_IV_LEN;
server->iv.len = NGX_QUIC_IV_LEN;

- struct {
- ngx_str_t label;
- ngx_str_t *key;
- ngx_str_t *prk;
- } seq[] = {
+ ngx_quic_hkdf_t seq[] = {
/* labels per RFC 9001, 5.1. Packet Protection Keys */
- { ngx_string("tls13 client in"), &client->secret, &iss },
- { ngx_string("tls13 quic key"), &client->key, &client->secret },
- { ngx_string("tls13 quic iv"), &client->iv, &client->secret },
- { ngx_string("tls13 quic hp"), &client->hp, &client->secret },
- { ngx_string("tls13 server in"), &server->secret, &iss },
- { ngx_string("tls13 quic key"), &server->key, &server->secret },
- { ngx_string("tls13 quic iv"), &server->iv, &server->secret },
- { ngx_string("tls13 quic hp"), &server->hp, &server->secret },
+ ngx_quic_hkdf_set("tls13 client in", &client->secret, &iss),
+ ngx_quic_hkdf_set("tls13 quic key", &client->key, &client->secret),
+ ngx_quic_hkdf_set("tls13 quic iv", &client->iv, &client->secret),
+ ngx_quic_hkdf_set("tls13 quic hp", &client->hp, &client->secret),
+ ngx_quic_hkdf_set("tls13 server in", &server->secret, &iss),
+ ngx_quic_hkdf_set("tls13 quic key", &server->key, &server->secret),
+ ngx_quic_hkdf_set("tls13 quic iv", &server->iv, &server->secret),
+ ngx_quic_hkdf_set("tls13 quic hp", &server->hp, &server->secret),
};

for (i = 0; i < (sizeof(seq) / sizeof(seq[0])); i++) {
-
- if (ngx_quic_hkdf_expand(pool, digest, seq[i].key, &seq[i].label,
- seq[i].prk->data, seq[i].prk->len)
- != NGX_OK)
- {
+ if (ngx_quic_hkdf_expand(&seq[i], digest, pool) != NGX_OK) {
return NGX_ERROR;
}
}
@@ -235,40 +261,41 @@ ngx_quic_keys_set_initial_secret(ngx_poo


static ngx_int_t
-ngx_quic_hkdf_expand(ngx_pool_t *pool, const EVP_MD *digest, ngx_str_t *out,
- ngx_str_t *label, const uint8_t *prk, size_t prk_len)
+ngx_quic_hkdf_expand(ngx_quic_hkdf_t *h, const EVP_MD *digest, ngx_pool_t *pool)
{
size_t info_len;
uint8_t *p;
uint8_t info[20];

- if (out->data == NULL) {
- out->data = ngx_pnalloc(pool, out->len);
- if (out->data == NULL) {
+ if (h->out == NULL) {
+ h->out = ngx_pnalloc(pool, h->out_len);
+ if (h->out == NULL) {
return NGX_ERROR;
}
}

- info_len = 2 + 1 + label->len + 1;
+ info_len = 2 + 1 + h->label_len + 1;

info[0] = 0;
- info[1] = out->len;
- info[2] = label->len;
- p = ngx_cpymem(&info[3], label->data, label->len);
+ info[1] = h->out_len;
+ info[2] = h->label_len;
+
+ p = ngx_cpymem(&info[3], h->label, h->label_len);
*p = '\0';

- if (ngx_hkdf_expand(out->data, out->len, digest,
- prk, prk_len, info, info_len)
+ if (ngx_hkdf_expand(h->out, h->out_len, digest,
+ h->prk, h->prk_len, info, info_len)
!= NGX_OK)
{
ngx_ssl_error(NGX_LOG_INFO, pool->log, 0,
- "ngx_hkdf_expand(%V) failed", label);
+ "ngx_hkdf_expand(%*s) failed", h->label_len, h->label);
return NGX_ERROR;
}

#ifdef NGX_QUIC_DEBUG_CRYPTO
- ngx_log_debug3(NGX_LOG_DEBUG_EVENT, pool->log, 0,
- "quic expand %V key len:%uz %xV", label, out->len, out);
+ ngx_log_debug5(NGX_LOG_DEBUG_EVENT, pool->log, 0,
+ "quic expand \"%*s\" key len:%uz %*xs",
+ h->label_len, h->label, h->out_len, h->out_len, h->out);
#endif

return NGX_OK;
@@ -652,6 +679,7 @@ ngx_quic_keys_set_encryption_secret(ngx_
const SSL_CIPHER *cipher, const uint8_t *secret, size_t secret_len)
{
ngx_int_t key_len;
+ ngx_str_t secret_str;
ngx_uint_t i;
ngx_quic_secret_t *peer_secret;
ngx_quic_ciphers_t ciphers;
@@ -668,8 +696,9 @@ ngx_quic_keys_set_encryption_secret(ngx_
return NGX_ERROR;
}

- peer_secret->secret.data = ngx_pnalloc(pool, secret_len);
- if (peer_secret->secret.data == NULL) {
+ if (sizeof(peer_secret->secret.data) < secret_len) {
+ ngx_log_error(NGX_LOG_ALERT, pool->log, 0,
+ "unexpected secret len: %uz", secret_len);
return NGX_ERROR;
}

@@ -680,22 +709,17 @@ ngx_quic_keys_set_encryption_secret(ngx_
peer_secret->iv.len = NGX_QUIC_IV_LEN;
peer_secret->hp.len = key_len;

- struct {
- ngx_str_t label;
- ngx_str_t *key;
- const uint8_t *secret;
- } seq[] = {
- { ngx_string("tls13 quic key"), &peer_secret->key, secret },
- { ngx_string("tls13 quic iv"), &peer_secret->iv, secret },
- { ngx_string("tls13 quic hp"), &peer_secret->hp, secret },
+ secret_str.len = secret_len;
+ secret_str.data = (u_char *) secret;
+
+ ngx_quic_hkdf_t seq[] = {
+ ngx_quic_hkdf_set("tls13 quic key", &peer_secret->key, &secret_str),
+ ngx_quic_hkdf_set("tls13 quic iv", &peer_secret->iv, &secret_str),
+ ngx_quic_hkdf_set("tls13 quic hp", &peer_secret->hp, &secret_str),
};

for (i = 0; i < (sizeof(seq) / sizeof(seq[0])); i++) {
-
- if (ngx_quic_hkdf_expand(pool, ciphers.d, seq[i].key, &seq[i].label,
- seq[i].secret, secret_len)
- != NGX_OK)
- {
+ if (ngx_quic_hkdf_expand(&seq[i], ciphers.d, pool) != NGX_OK) {
return NGX_ERROR;
}
}
@@ -769,49 +793,23 @@ ngx_quic_keys_update(ngx_connection_t *c
next->server.iv.len = NGX_QUIC_IV_LEN;
next->server.hp = current->server.hp;

- struct {
- ngx_str_t label;
- ngx_str_t *key;
- ngx_str_t *secret;
- } seq[] = {
- {
- ngx_string("tls13 quic ku"),
- &next->client.secret,
- &current->client.secret,
- },
- {
- ngx_string("tls13 quic key"),
- &next->client.key,
- &next->client.secret,
- },
- {
- ngx_string("tls13 quic iv"),
- &next->client.iv,
- &next->client.secret,
- },
- {
- ngx_string("tls13 quic ku"),
- &next->server.secret,
- &current->server.secret,
- },
- {
- ngx_string("tls13 quic key"),
- &next->server.key,
- &next->server.secret,
- },
- {
- ngx_string("tls13 quic iv"),
- &next->server.iv,
- &next->server.secret,
- },
+ ngx_quic_hkdf_t seq[] = {
+ ngx_quic_hkdf_set("tls13 quic ku",
+ &next->client.secret, &current->client.secret),
+ ngx_quic_hkdf_set("tls13 quic key",
+ &next->client.key, &next->client.secret),
+ ngx_quic_hkdf_set("tls13 quic iv",
+ &next->client.iv, &next->client.secret),
+ ngx_quic_hkdf_set("tls13 quic ku",
+ &next->server.secret, &current->server.secret),
+ ngx_quic_hkdf_set("tls13 quic key",
+ &next->server.key, &next->server.secret),
+ ngx_quic_hkdf_set("tls13 quic iv",
+ &next->server.iv, &next->server.secret),
};

for (i = 0; i < (sizeof(seq) / sizeof(seq[0])); i++) {
-
- if (ngx_quic_hkdf_expand(c->pool, ciphers.d, seq[i].key, &seq[i].label,
- seq[i].secret->data, seq[i].secret->len)
- != NGX_OK)
- {
+ if (ngx_quic_hkdf_expand(&seq[i], ciphers.d, c->pool) != NGX_OK) {
return NGX_ERROR;
}
}
@@ -909,7 +907,7 @@ ngx_quic_create_retry_packet(ngx_quic_he
}

secret.key.len = sizeof(key);
- secret.key.data = key;
+ ngx_memcpy(secret.key.data, key, sizeof(key));
secret.iv.len = NGX_QUIC_IV_LEN;

if (ngx_quic_tls_seal(ciphers.c, &secret, &itag, nonce, &in, &ad, pkt->log)

_______________________________________________
nginx-devel mailing list -- nginx-devel@nginx.org
To unsubscribe send an email to nginx-devel-leave@nginx.org