From da76459dc21b5af2449af2d36eb95226cb186ce2 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sun, 28 Apr 2024 11:35:11 +0200 Subject: Adding upstream version 2.6.12. Signed-off-by: Daniel Baumann --- src/quic_tls.c | 672 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 672 insertions(+) create mode 100644 src/quic_tls.c (limited to 'src/quic_tls.c') diff --git a/src/quic_tls.c b/src/quic_tls.c new file mode 100644 index 0000000..7d2d2c1 --- /dev/null +++ b/src/quic_tls.c @@ -0,0 +1,672 @@ +#include + +#include + +#include +#include +#include + +#include +#include +#include +#include + + +DECLARE_POOL(pool_head_quic_tls_secret, "quic_tls_secret", QUIC_TLS_SECRET_LEN); +DECLARE_POOL(pool_head_quic_tls_iv, "quic_tls_iv", QUIC_TLS_IV_LEN); +DECLARE_POOL(pool_head_quic_tls_key, "quic_tls_key", QUIC_TLS_KEY_LEN); + +/* Initial salt depending on QUIC version to derive client/server initial secrets. + * This one is for draft-29 QUIC version. + */ +const unsigned char initial_salt_draft_29[20] = { + 0xaf, 0xbf, 0xec, 0x28, 0x99, 0x93, 0xd2, 0x4c, + 0x9e, 0x97, 0x86, 0xf1, 0x9c, 0x61, 0x11, 0xe0, + 0x43, 0x90, 0xa8, 0x99 +}; + +const unsigned char initial_salt_v1[20] = { + 0x38, 0x76, 0x2c, 0xf7, 0xf5, 0x59, 0x34, 0xb3, + 0x4d, 0x17, 0x9a, 0xe6, 0xa4, 0xc8, 0x0c, 0xad, + 0xcc, 0xbb, 0x7f, 0x0a +}; + +const unsigned char initial_salt_v2_draft[20] = { + 0xa7, 0x07, 0xc2, 0x03, 0xa5, 0x9b, 0x47, 0x18, + 0x4a, 0x1d, 0x62, 0xca, 0x57, 0x04, 0x06, 0xea, + 0x7a, 0xe3, 0xe5, 0xd3 +}; + +/* Dump the RX/TX secrets of QUIC TLS secrets. */ +void quic_tls_keys_hexdump(struct buffer *buf, + const struct quic_tls_secrets *secs) +{ + int i; + size_t aead_keylen = (size_t)EVP_CIPHER_key_length(secs->aead); + size_t aead_ivlen = (size_t)EVP_CIPHER_iv_length(secs->aead); + size_t hp_len = (size_t)EVP_CIPHER_key_length(secs->hp); + + chunk_appendf(buf, "\n key="); + for (i = 0; i < aead_keylen; i++) + chunk_appendf(buf, "%02x", secs->key[i]); + chunk_appendf(buf, "\n iv="); + for (i = 0; i < aead_ivlen; i++) + chunk_appendf(buf, "%02x", secs->iv[i]); + chunk_appendf(buf, "\n hp="); + for (i = 0; i < hp_len; i++) + chunk_appendf(buf, "%02x", secs->hp_key[i]); +} + +/* Dump TLS secret. */ +void quic_tls_secret_hexdump(struct buffer *buf, + const unsigned char *secret, size_t secret_len) +{ + int i; + + chunk_appendf(buf, " secret="); + for (i = 0; i < secret_len; i++) + chunk_appendf(buf, "%02x", secret[i]); +} + +int quic_hkdf_extract(const EVP_MD *md, + unsigned char *buf, size_t buflen, + const unsigned char *key, size_t keylen, + const unsigned char *salt, size_t saltlen) +{ + EVP_PKEY_CTX *ctx; + + ctx = EVP_PKEY_CTX_new_id(EVP_PKEY_HKDF, NULL); + if (!ctx) + return 0; + + if (EVP_PKEY_derive_init(ctx) <= 0 || + EVP_PKEY_CTX_hkdf_mode(ctx, EVP_PKEY_HKDEF_MODE_EXTRACT_ONLY) <= 0 || + EVP_PKEY_CTX_set_hkdf_md(ctx, md) <= 0 || + EVP_PKEY_CTX_set1_hkdf_salt(ctx, salt, saltlen) <= 0 || + EVP_PKEY_CTX_set1_hkdf_key(ctx, key, keylen) <= 0 || + EVP_PKEY_derive(ctx, buf, &buflen) <= 0) + goto err; + + EVP_PKEY_CTX_free(ctx); + return 1; + + err: + EVP_PKEY_CTX_free(ctx); + return 0; +} + +int quic_hkdf_expand(const EVP_MD *md, + unsigned char *buf, size_t buflen, + const unsigned char *key, size_t keylen, + const unsigned char *label, size_t labellen) +{ + EVP_PKEY_CTX *ctx; + + ctx = EVP_PKEY_CTX_new_id(EVP_PKEY_HKDF, NULL); + if (!ctx) + return 0; + + if (EVP_PKEY_derive_init(ctx) <= 0 || + EVP_PKEY_CTX_hkdf_mode(ctx, EVP_PKEY_HKDEF_MODE_EXPAND_ONLY) <= 0 || + EVP_PKEY_CTX_set_hkdf_md(ctx, md) <= 0 || + EVP_PKEY_CTX_set1_hkdf_key(ctx, key, keylen) <= 0 || + EVP_PKEY_CTX_add1_hkdf_info(ctx, label, labellen) <= 0 || + EVP_PKEY_derive(ctx, buf, &buflen) <= 0) + goto err; + + EVP_PKEY_CTX_free(ctx); + return 1; + + err: + EVP_PKEY_CTX_free(ctx); + return 0; +} + +/* Extracts a peudo-random secret key from which is eventually not + * pseudo-random and expand it to a new pseudo-random key into + * with as key length according to HKDF specifications + * (https://datatracker.ietf.org/doc/html/rfc5869). + * According to this specifications it is highly recommended to use + * a salt, even if optional (NULL value). + * Return 1 if succeeded, 0 if not. + */ +int quic_hkdf_extract_and_expand(const EVP_MD *md, + unsigned char *buf, size_t buflen, + const unsigned char *key, size_t keylen, + const unsigned char *salt, size_t saltlen, + const unsigned char *label, size_t labellen) +{ + EVP_PKEY_CTX *ctx; + + ctx = EVP_PKEY_CTX_new_id(EVP_PKEY_HKDF, NULL); + if (!ctx) + return 0; + + if (EVP_PKEY_derive_init(ctx) <= 0 || + EVP_PKEY_CTX_hkdf_mode(ctx, EVP_PKEY_HKDEF_MODE_EXTRACT_AND_EXPAND) <= 0 || + EVP_PKEY_CTX_set_hkdf_md(ctx, md) <= 0 || + EVP_PKEY_CTX_set1_hkdf_salt(ctx, salt, saltlen) <= 0 || + EVP_PKEY_CTX_set1_hkdf_key(ctx, key, keylen) <= 0 || + EVP_PKEY_CTX_add1_hkdf_info(ctx, label, labellen) <= 0 || + EVP_PKEY_derive(ctx, buf, &buflen) <= 0) + goto err; + + EVP_PKEY_CTX_free(ctx); + return 1; + + err: + EVP_PKEY_CTX_free(ctx); + return 0; +} + +/* https://quicwg.org/base-drafts/draft-ietf-quic-tls.html#protection-keys + * refers to: + * + * https://tools.ietf.org/html/rfc8446#section-7.1: + * 7.1. Key Schedule + * + * The key derivation process makes use of the HKDF-Extract and + * HKDF-Expand functions as defined for HKDF [RFC5869], as well as the + * functions defined below: + * + * HKDF-Expand-Label(Secret, Label, Context, Length) = + * HKDF-Expand(Secret, HkdfLabel, Length) + * + * Where HkdfLabel is specified as: + * + * struct { + * uint16 length = Length; + * opaque label<7..255> = "tls13 " + Label; + * opaque context<0..255> = Context; + * } HkdfLabel; + * + * Derive-Secret(Secret, Label, Messages) = + * HKDF-Expand-Label(Secret, Label, + * Transcript-Hash(Messages), Hash.length) + * + */ +int quic_hkdf_expand_label(const EVP_MD *md, + unsigned char *buf, size_t buflen, + const unsigned char *key, size_t keylen, + const unsigned char *label, size_t labellen) +{ + unsigned char hdkf_label[256], *pos; + const unsigned char hdkf_label_label[] = "tls13 "; + size_t hdkf_label_label_sz = sizeof hdkf_label_label - 1; + + pos = hdkf_label; + *pos++ = buflen >> 8; + *pos++ = buflen & 0xff; + *pos++ = hdkf_label_label_sz + labellen; + memcpy(pos, hdkf_label_label, hdkf_label_label_sz); + pos += hdkf_label_label_sz; + memcpy(pos, label, labellen); + pos += labellen; + *pos++ = '\0'; + + return quic_hkdf_expand(md, buf, buflen, + key, keylen, hdkf_label, pos - hdkf_label); +} + +/* + * This function derives two keys from is as TLS cryptographic context. + * ->key is the TLS key to be derived to encrypt/decrypt data at TLS level. + * ->iv is the initialization vector to be used with ->key. + * ->hp_key is the key to be derived for header protection. + * Obviouly these keys have the same size becaused derived with the same TLS cryptographic context. + */ +int quic_tls_derive_keys(const EVP_CIPHER *aead, const EVP_CIPHER *hp, + const EVP_MD *md, const struct quic_version *qv, + unsigned char *key, size_t keylen, + unsigned char *iv, size_t ivlen, + unsigned char *hp_key, size_t hp_keylen, + const unsigned char *secret, size_t secretlen) +{ + size_t aead_keylen = (size_t)EVP_CIPHER_key_length(aead); + size_t aead_ivlen = (size_t)EVP_CIPHER_iv_length(aead); + size_t hp_len = hp ? (size_t)EVP_CIPHER_key_length(hp) : 0; + + if (aead_keylen > keylen || aead_ivlen > ivlen || hp_len > hp_keylen) + return 0; + + if (!quic_hkdf_expand_label(md, key, aead_keylen, secret, secretlen, + qv->key_label,qv->key_label_len) || + !quic_hkdf_expand_label(md, iv, aead_ivlen, secret, secretlen, + qv->iv_label, qv->iv_label_len) || + (hp_key && !quic_hkdf_expand_label(md, hp_key, hp_len, secret, secretlen, + qv->hp_label, qv->hp_label_len))) + return 0; + + return 1; +} + +/* + * Derive the initial secret from and QUIC version dependent salt. + * Returns the size of the derived secret if succeeded, 0 if not. + */ +int quic_derive_initial_secret(const EVP_MD *md, + const unsigned char *initial_salt, size_t initial_salt_sz, + unsigned char *initial_secret, size_t initial_secret_sz, + const unsigned char *secret, size_t secret_sz) +{ + if (!quic_hkdf_extract(md, initial_secret, initial_secret_sz, secret, secret_sz, + initial_salt, initial_salt_sz)) + return 0; + + return 1; +} + +/* + * Derive the client initial secret from the initial secret. + * Returns the size of the derived secret if succeeded, 0 if not. + */ +int quic_tls_derive_initial_secrets(const EVP_MD *md, + unsigned char *rx, size_t rx_sz, + unsigned char *tx, size_t tx_sz, + const unsigned char *secret, size_t secret_sz, + int server) +{ + const unsigned char client_label[] = "client in"; + const unsigned char server_label[] = "server in"; + const unsigned char *tx_label, *rx_label; + size_t rx_label_sz, tx_label_sz; + + if (server) { + rx_label = client_label; + rx_label_sz = sizeof client_label; + tx_label = server_label; + tx_label_sz = sizeof server_label; + } + else { + rx_label = server_label; + rx_label_sz = sizeof server_label; + tx_label = client_label; + tx_label_sz = sizeof client_label; + } + + if (!quic_hkdf_expand_label(md, rx, rx_sz, secret, secret_sz, + rx_label, rx_label_sz - 1) || + !quic_hkdf_expand_label(md, tx, tx_sz, secret, secret_sz, + tx_label, tx_label_sz - 1)) + return 0; + + return 1; +} + +/* Update secret key into according to RFC 9001 6.1. + * Always succeeds. + */ +int quic_tls_sec_update(const EVP_MD *md, const struct quic_version *qv, + unsigned char *new_sec, size_t new_seclen, + const unsigned char *sec, size_t seclen) +{ + return quic_hkdf_expand_label(md, new_sec, new_seclen, sec, seclen, + qv->ku_label, qv->ku_label_len); +} + +/* + * Build an IV into buffer with as size from with + * as size depending on packet number. + * This is the function which must be called to build an AEAD IV for the AEAD cryptographic algorithm + * used to encrypt/decrypt the QUIC packet payloads depending on the packet number . + * This function fails and return 0 only if the two buffer lengths are different, 1 if not. + */ +int quic_aead_iv_build(unsigned char *iv, size_t ivlen, + unsigned char *aead_iv, size_t aead_ivlen, uint64_t pn) +{ + int i; + unsigned int shift; + unsigned char *pos = iv; + + if (ivlen != aead_ivlen) + return 0; + + for (i = 0; i < ivlen - sizeof pn; i++) + *pos++ = *aead_iv++; + + /* Only the remaining (sizeof pn) bytes are XOR'ed. */ + shift = 56; + for (i = aead_ivlen - sizeof pn; i < aead_ivlen ; i++, shift -= 8) + *pos++ = *aead_iv++ ^ (pn >> shift); + + return 1; +} + +/* Initialize the cipher context for RX part of QUIC TLS context. + * Return 1 if succeeded, 0 if not. + */ +int quic_tls_rx_ctx_init(EVP_CIPHER_CTX **rx_ctx, + const EVP_CIPHER *aead, unsigned char *key) +{ + EVP_CIPHER_CTX *ctx; + int aead_nid = EVP_CIPHER_nid(aead); + + ctx = EVP_CIPHER_CTX_new(); + if (!ctx) + return 0; + + if (!EVP_DecryptInit_ex(ctx, aead, NULL, NULL, NULL) || + !EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_AEAD_SET_IVLEN, QUIC_TLS_IV_LEN, NULL) || + (aead_nid == NID_aes_128_ccm && + !EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_AEAD_SET_TAG, QUIC_TLS_TAG_LEN, NULL)) || + !EVP_DecryptInit_ex(ctx, NULL, NULL, key, NULL)) + goto err; + + *rx_ctx = ctx; + + return 1; + + err: + EVP_CIPHER_CTX_free(ctx); + return 0; +} + +/* Initialize <*aes_ctx> AES cipher context with as key for encryption */ +int quic_tls_enc_aes_ctx_init(EVP_CIPHER_CTX **aes_ctx, + const EVP_CIPHER *aes, unsigned char *key) +{ + EVP_CIPHER_CTX *ctx; + + ctx = EVP_CIPHER_CTX_new(); + if (!ctx) + return 0; + + if (!EVP_EncryptInit_ex(ctx, aes, NULL, key, NULL)) + goto err; + + *aes_ctx = ctx; + return 1; + + err: + EVP_CIPHER_CTX_free(ctx); + return 0; +} + +/* Encrypt bytes from buffer into with as AES + * cipher context. This is the responsibility of the caller to check there + * is at least bytes of available space in buffer. + * Return 1 if succeeded, 0 if not. + */ +int quic_tls_aes_encrypt(unsigned char *out, + const unsigned char *in, size_t inlen, + EVP_CIPHER_CTX *ctx) +{ + int ret = 0; + + if (!EVP_EncryptInit_ex(ctx, NULL, NULL, NULL, in) || + !EVP_EncryptUpdate(ctx, out, &ret, out, inlen) || + !EVP_EncryptFinal_ex(ctx, out, &ret)) + return 0; + + return 1; +} + +/* Initialize <*aes_ctx> AES cipher context with as key for decryption */ +int quic_tls_dec_aes_ctx_init(EVP_CIPHER_CTX **aes_ctx, + const EVP_CIPHER *aes, unsigned char *key) +{ + EVP_CIPHER_CTX *ctx; + + ctx = EVP_CIPHER_CTX_new(); + if (!ctx) + return 0; + + if (!EVP_DecryptInit_ex(ctx, aes, NULL, key, NULL)) + goto err; + + *aes_ctx = ctx; + return 1; + + err: + EVP_CIPHER_CTX_free(ctx); + return 0; +} + +/* Decrypt data into with as AES cipher context. + * This is the responsibility of the caller to check there is at least + * bytes into buffer. + * Return 1 if succeeded, 0 if not. + */ +int quic_tls_aes_decrypt(unsigned char *out, + const unsigned char *in, size_t inlen, + EVP_CIPHER_CTX *ctx) +{ + int ret = 0; + + if (!EVP_DecryptInit_ex(ctx, NULL, NULL, NULL, in) || + !EVP_DecryptUpdate(ctx, out, &ret, out, inlen) || + !EVP_DecryptFinal_ex(ctx, out, &ret)) + return 0; + + return 1; +} + +/* Initialize the cipher context for TX part of QUIC TLS context. + * Return 1 if succeeded, 0 if not. + */ +int quic_tls_tx_ctx_init(EVP_CIPHER_CTX **tx_ctx, + const EVP_CIPHER *aead, unsigned char *key) +{ + EVP_CIPHER_CTX *ctx; + int aead_nid = EVP_CIPHER_nid(aead); + + ctx = EVP_CIPHER_CTX_new(); + if (!ctx) + return 0; + + if (!EVP_EncryptInit_ex(ctx, aead, NULL, NULL, NULL) || + !EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_AEAD_SET_IVLEN, QUIC_TLS_IV_LEN, NULL) || + (aead_nid == NID_aes_128_ccm && + !EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_AEAD_SET_TAG, QUIC_TLS_TAG_LEN, NULL)) || + !EVP_EncryptInit_ex(ctx, NULL, NULL, key, NULL)) + goto err; + + *tx_ctx = ctx; + + return 1; + + err: + EVP_CIPHER_CTX_free(ctx); + return 0; +} + +/* + * https://quicwg.org/base-drafts/draft-ietf-quic-tls.html#aead + * + * 5.3. AEAD Usage + * + * Packets are protected prior to applying header protection (Section 5.4). + * The unprotected packet header is part of the associated data (A). When removing + * packet protection, an endpoint first removes the header protection. + * (...) + * These ciphersuites have a 16-byte authentication tag and produce an output 16 + * bytes larger than their input. + * The key and IV for the packet are computed as described in Section 5.1. The nonce, + * N, is formed by combining the packet protection IV with the packet number. The 62 + * bits of the reconstructed QUIC packet number in network byte order are left-padded + * with zeros to the size of the IV. The exclusive OR of the padded packet number and + * the IV forms the AEAD nonce. + * + * The associated data, A, for the AEAD is the contents of the QUIC header, starting + * from the flags byte in either the short or long header, up to and including the + * unprotected packet number. + * + * The input plaintext, P, for the AEAD is the payload of the QUIC packet, as described + * in [QUIC-TRANSPORT]. + * + * The output ciphertext, C, of the AEAD is transmitted in place of P. + * + * Some AEAD functions have limits for how many packets can be encrypted under the same + * key and IV (see for example [AEBounds]). This might be lower than the packet number limit. + * An endpoint MUST initiate a key update (Section 6) prior to exceeding any limit set for + * the AEAD that is in use. + */ + +/* Encrypt in place plaintext with as length with QUIC_TLS_TAG_LEN + * included tailing bytes for the tag. + * Note that for CCM mode, we must set the the ciphertext length if AAD data + * are provided from buffer with as length. This is always the + * case here. So the caller of this function must provide . + * + * https://wiki.openssl.org/index.php/EVP_Authenticated_Encryption_and_Decryption + */ +int quic_tls_encrypt(unsigned char *buf, size_t len, + const unsigned char *aad, size_t aad_len, + EVP_CIPHER_CTX *ctx, const EVP_CIPHER *aead, + const unsigned char *key, const unsigned char *iv) +{ + int outlen; + int aead_nid = EVP_CIPHER_nid(aead); + + if (!EVP_EncryptInit_ex(ctx, NULL, NULL, NULL, iv) || + (aead_nid == NID_aes_128_ccm && + !EVP_EncryptUpdate(ctx, NULL, &outlen, NULL, len)) || + !EVP_EncryptUpdate(ctx, NULL, &outlen, aad, aad_len) || + !EVP_EncryptUpdate(ctx, buf, &outlen, buf, len) || + !EVP_EncryptFinal_ex(ctx, buf + outlen, &outlen) || + !EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_AEAD_GET_TAG, QUIC_TLS_TAG_LEN, buf + len)) + return 0; + + return 1; +} + +/* Decrypt in place ciphertext with as length with QUIC_TLS_TAG_LEN + * included tailing bytes for the tag. + * Note that for CCM mode, we must set the the ciphertext length if AAD data + * are provided from buffer with as length. This is always the + * case here. So the caller of this function must provide . Also not the + * there is no need to call EVP_DecryptFinal_ex for CCM mode. + * + * https://wiki.openssl.org/index.php/EVP_Authenticated_Encryption_and_Decryption + */ +int quic_tls_decrypt(unsigned char *buf, size_t len, + unsigned char *aad, size_t aad_len, + EVP_CIPHER_CTX *ctx, const EVP_CIPHER *aead, + const unsigned char *key, const unsigned char *iv) +{ + int outlen; + int aead_nid = EVP_CIPHER_nid(aead); + + if (!EVP_DecryptInit_ex(ctx, NULL, NULL, NULL, iv) || + !EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_AEAD_SET_TAG, QUIC_TLS_TAG_LEN, + buf + len - QUIC_TLS_TAG_LEN) || + (aead_nid == NID_aes_128_ccm && + !EVP_DecryptUpdate(ctx, NULL, &outlen, NULL, len - QUIC_TLS_TAG_LEN)) || + !EVP_DecryptUpdate(ctx, NULL, &outlen, aad, aad_len) || + !EVP_DecryptUpdate(ctx, buf, &outlen, buf, len - QUIC_TLS_TAG_LEN) || + (aead_nid != NID_aes_128_ccm && + !EVP_DecryptFinal_ex(ctx, buf + outlen, &outlen))) + return 0; + + return 1; +} + +/* Similar to quic_tls_decrypt(), except that this function does not decrypt + * in place its ciphertest if output buffer ciphertest with as length + * is different from input buffer. This is the responbality of the caller + * to check that the output buffer has at least the same size as the input buffer. + * Note that for CCM mode, we must set the the ciphertext length if AAD data + * are provided from buffer with as length. This is always the + * case here. So the caller of this function must provide . Also note that + * there is no need to call EVP_DecryptFinal_ex for CCM mode. + * + * https://wiki.openssl.org/index.php/EVP_Authenticated_Encryption_and_Decryption + * + * Return 1 if succeeded, 0 if not. + */ +int quic_tls_decrypt2(unsigned char *out, + unsigned char *in, size_t len, + unsigned char *aad, size_t aad_len, + EVP_CIPHER_CTX *ctx, const EVP_CIPHER *aead, + const unsigned char *key, const unsigned char *iv) +{ + int outlen; + int aead_nid = EVP_CIPHER_nid(aead); + + len -= QUIC_TLS_TAG_LEN; + if (!EVP_DecryptInit_ex(ctx, NULL, NULL, NULL, iv) || + !EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_AEAD_SET_TAG, QUIC_TLS_TAG_LEN, in + len) || + (aead_nid == NID_aes_128_ccm && + !EVP_DecryptUpdate(ctx, NULL, &outlen, NULL, len)) || + !EVP_DecryptUpdate(ctx, NULL, &outlen, aad, aad_len) || + !EVP_DecryptUpdate(ctx, out, &outlen, in, len) || + (aead_nid != NID_aes_128_ccm && + !EVP_DecryptFinal_ex(ctx, out + outlen, &outlen))) + return 0; + + return 1; +} + +/* Derive and key and IV to be used to encrypt a retry token + * with which is not pseudo-random. + * Return 1 if succeeded, 0 if not. + */ +int quic_tls_derive_retry_token_secret(const EVP_MD *md, + unsigned char *key, size_t keylen, + unsigned char *iv, size_t ivlen, + const unsigned char *salt, size_t saltlen, + const unsigned char *secret, size_t secretlen) +{ + unsigned char tmpkey[QUIC_TLS_KEY_LEN]; + const unsigned char tmpkey_label[] = "retry token"; + const unsigned char key_label[] = "retry token key"; + const unsigned char iv_label[] = "retry token iv"; + + if (!quic_hkdf_extract_and_expand(md, tmpkey, sizeof tmpkey, + secret, secretlen, salt, saltlen, + tmpkey_label, sizeof tmpkey_label - 1) || + !quic_hkdf_expand(md, key, keylen, tmpkey, sizeof tmpkey, + key_label, sizeof key_label - 1) || + !quic_hkdf_expand(md, iv, ivlen, secret, secretlen, + iv_label, sizeof iv_label - 1)) + return 0; + + return 1; +} + +/* Generate the AEAD tag for the Retry packet of bytes and + * write it to . The tag is written just after the area. It should + * be at least 16 bytes longs. is the CID of the Initial packet + * received which triggers the Retry. + * + * Returns non-zero on success else zero. + */ +int quic_tls_generate_retry_integrity_tag(unsigned char *odcid, unsigned char odcid_len, + unsigned char *pkt, size_t pkt_len, + const struct quic_version *qv) +{ + const EVP_CIPHER *evp = EVP_aes_128_gcm(); + EVP_CIPHER_CTX *ctx; + + /* encryption buffer - not used as only AEAD tag generation is proceed */ + unsigned char *out = NULL; + /* address to store the AEAD tag */ + unsigned char *tag = pkt + pkt_len; + int outlen, ret = 0; + + ctx = EVP_CIPHER_CTX_new(); + if (!ctx) + return 0; + + /* rfc9001 5.8. Retry Packet Integrity + * + * AEAD is proceed over a pseudo-Retry packet used as AAD. It contains + * the ODCID len + data and the Retry packet itself. + */ + if (!EVP_EncryptInit_ex(ctx, evp, NULL, qv->retry_tag_key, qv->retry_tag_nonce) || + /* specify pseudo-Retry as AAD */ + !EVP_EncryptUpdate(ctx, NULL, &outlen, &odcid_len, sizeof(odcid_len)) || + !EVP_EncryptUpdate(ctx, NULL, &outlen, odcid, odcid_len) || + !EVP_EncryptUpdate(ctx, NULL, &outlen, pkt, pkt_len) || + /* finalize */ + !EVP_EncryptFinal_ex(ctx, out, &outlen) || + /* store the tag */ + !EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_AEAD_GET_TAG, QUIC_TLS_TAG_LEN, tag)) { + goto out; + } + ret = 1; + + out: + EVP_CIPHER_CTX_free(ctx); + return ret; +} -- cgit v1.2.3