Tidy up keyblock and CCS logic slightly.
Move the actual SSL_AEAD_CTX swap into the record layer. Also revise the
intermediate state we store between setup_key_block and
change_cipher_state. With SSL_AEAD_CTX_new abstracted out, keeping the
EVP_AEAD around doesn't make much sense. Just store enough to partition
the key block.
Change-Id: I773fb46a2cb78fa570f00c0a89339c15bbb1d719
Reviewed-on: https://boringssl-review.googlesource.com/6832
Reviewed-by: Adam Langley <alangley@gmail.com>
diff --git a/ssl/t1_enc.c b/ssl/t1_enc.c
index 0f1d683..7dd6f0e 100644
--- a/ssl/t1_enc.c
+++ b/ssl/t1_enc.c
@@ -277,63 +277,28 @@
* or a server reading a client's ChangeCipherSpec. */
const char use_client_keys = which == SSL3_CHANGE_CIPHER_CLIENT_WRITE ||
which == SSL3_CHANGE_CIPHER_SERVER_READ;
- const uint8_t *client_write_mac_secret, *server_write_mac_secret, *mac_secret;
- const uint8_t *client_write_key, *server_write_key, *key;
- const uint8_t *client_write_iv, *server_write_iv, *iv;
- const EVP_AEAD *aead = ssl->s3->tmp.new_aead;
- size_t key_len, iv_len, mac_secret_len;
- const uint8_t *key_data;
- /* Reset sequence number to zero. */
- if (is_read) {
- if (SSL_IS_DTLS(ssl)) {
- ssl->d1->r_epoch++;
- memset(&ssl->d1->bitmap, 0, sizeof(ssl->d1->bitmap));
- }
- memset(ssl->s3->read_sequence, 0, sizeof(ssl->s3->read_sequence));
- } else {
- if (SSL_IS_DTLS(ssl)) {
- ssl->d1->w_epoch++;
- memcpy(ssl->d1->last_write_sequence, ssl->s3->write_sequence,
- sizeof(ssl->s3->write_sequence));
- }
- memset(ssl->s3->write_sequence, 0, sizeof(ssl->s3->write_sequence));
- }
+ size_t mac_secret_len = ssl->s3->tmp.new_mac_secret_len;
+ size_t key_len = ssl->s3->tmp.new_key_len;
+ size_t iv_len = ssl->s3->tmp.new_fixed_iv_len;
+ assert((mac_secret_len + key_len + iv_len) * 2 ==
+ ssl->s3->tmp.key_block_length);
- mac_secret_len = ssl->s3->tmp.new_mac_secret_len;
- iv_len = ssl->s3->tmp.new_fixed_iv_len;
-
- if (aead == NULL) {
- OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
- return 0;
- }
-
- key_len = EVP_AEAD_key_length(aead);
- if (mac_secret_len > 0) {
- /* For "stateful" AEADs (i.e. compatibility with pre-AEAD cipher
- * suites) the key length reported by |EVP_AEAD_key_length| will
- * include the MAC and IV key bytes. */
- if (key_len < mac_secret_len + iv_len) {
- OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
- return 0;
- }
- key_len -= mac_secret_len + iv_len;
- }
-
- key_data = ssl->s3->tmp.key_block;
- client_write_mac_secret = key_data;
+ const uint8_t *key_data = ssl->s3->tmp.key_block;
+ const uint8_t *client_write_mac_secret = key_data;
key_data += mac_secret_len;
- server_write_mac_secret = key_data;
+ const uint8_t *server_write_mac_secret = key_data;
key_data += mac_secret_len;
- client_write_key = key_data;
+ const uint8_t *client_write_key = key_data;
key_data += key_len;
- server_write_key = key_data;
+ const uint8_t *server_write_key = key_data;
key_data += key_len;
- client_write_iv = key_data;
+ const uint8_t *client_write_iv = key_data;
key_data += iv_len;
- server_write_iv = key_data;
+ const uint8_t *server_write_iv = key_data;
key_data += iv_len;
+ const uint8_t *mac_secret, *key, *iv;
if (use_client_keys) {
mac_secret = client_write_mac_secret;
key = client_write_key;
@@ -344,50 +309,37 @@
iv = server_write_iv;
}
- if (key_data - ssl->s3->tmp.key_block != ssl->s3->tmp.key_block_length) {
- OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
+ SSL_AEAD_CTX *aead_ctx = SSL_AEAD_CTX_new(
+ is_read ? evp_aead_open : evp_aead_seal,
+ ssl3_version_from_wire(ssl, ssl->version), ssl->s3->tmp.new_cipher, key,
+ key_len, mac_secret, mac_secret_len, iv, iv_len);
+ if (aead_ctx == NULL) {
return 0;
}
if (is_read) {
- SSL_AEAD_CTX_free(ssl->aead_read_ctx);
- ssl->aead_read_ctx = SSL_AEAD_CTX_new(
- evp_aead_open, ssl3_version_from_wire(ssl, ssl->version),
- ssl->s3->tmp.new_cipher, key, key_len, mac_secret, mac_secret_len, iv,
- iv_len);
- return ssl->aead_read_ctx != NULL;
+ ssl_set_read_state(ssl, aead_ctx);
+ } else {
+ ssl_set_write_state(ssl, aead_ctx);
}
-
- SSL_AEAD_CTX_free(ssl->aead_write_ctx);
- ssl->aead_write_ctx = SSL_AEAD_CTX_new(
- evp_aead_seal, ssl3_version_from_wire(ssl, ssl->version),
- ssl->s3->tmp.new_cipher, key, key_len, mac_secret, mac_secret_len, iv,
- iv_len);
- return ssl->aead_write_ctx != NULL;
+ return 1;
}
int tls1_setup_key_block(SSL *ssl) {
- uint8_t *p;
- const EVP_AEAD *aead = NULL;
- int ret = 0;
- size_t mac_secret_len, fixed_iv_len, variable_iv_len, key_len;
- size_t key_block_len;
-
if (ssl->s3->tmp.key_block_length != 0) {
return 1;
}
- if (ssl->session->cipher == NULL) {
- goto cipher_unavailable_err;
- }
-
- if (!ssl_cipher_get_evp_aead(&aead, &mac_secret_len, &fixed_iv_len,
+ const EVP_AEAD *aead = NULL;
+ size_t mac_secret_len, fixed_iv_len;
+ if (ssl->session->cipher == NULL ||
+ !ssl_cipher_get_evp_aead(&aead, &mac_secret_len, &fixed_iv_len,
ssl->session->cipher,
ssl3_version_from_wire(ssl, ssl->version))) {
- goto cipher_unavailable_err;
+ OPENSSL_PUT_ERROR(SSL, SSL_R_CIPHER_OR_HASH_UNAVAILABLE);
+ return 0;
}
- key_len = EVP_AEAD_key_length(aead);
- variable_iv_len = EVP_AEAD_nonce_length(aead);
+ size_t key_len = EVP_AEAD_key_length(aead);
if (mac_secret_len > 0) {
/* For "stateful" AEADs (i.e. compatibility with pre-AEAD cipher suites) the
* key length reported by |EVP_AEAD_key_length| will include the MAC key
@@ -397,50 +349,36 @@
return 0;
}
key_len -= mac_secret_len + fixed_iv_len;
- } else {
- /* The nonce is split into a fixed portion and a variable portion. */
- if (variable_iv_len < fixed_iv_len) {
- OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
- return 0;
- }
- variable_iv_len -= fixed_iv_len;
}
assert(mac_secret_len < 256);
+ assert(key_len < 256);
assert(fixed_iv_len < 256);
- assert(variable_iv_len < 256);
- ssl->s3->tmp.new_aead = aead;
ssl->s3->tmp.new_mac_secret_len = (uint8_t)mac_secret_len;
+ ssl->s3->tmp.new_key_len = (uint8_t)key_len;
ssl->s3->tmp.new_fixed_iv_len = (uint8_t)fixed_iv_len;
- ssl->s3->tmp.new_variable_iv_len = (uint8_t)variable_iv_len;
- key_block_len = key_len + mac_secret_len + fixed_iv_len;
+ size_t key_block_len = mac_secret_len + key_len + fixed_iv_len;
key_block_len *= 2;
ssl3_cleanup_key_block(ssl);
- p = (uint8_t *)OPENSSL_malloc(key_block_len);
- if (p == NULL) {
+ uint8_t *keyblock = (uint8_t *)OPENSSL_malloc(key_block_len);
+ if (keyblock == NULL) {
OPENSSL_PUT_ERROR(SSL, ERR_R_MALLOC_FAILURE);
- goto err;
+ return 0;
}
- ssl->s3->tmp.key_block_length = key_block_len;
- ssl->s3->tmp.key_block = p;
-
- if (!tls1_generate_key_block(ssl, p, key_block_len)) {
- goto err;
+ if (!tls1_generate_key_block(ssl, keyblock, key_block_len)) {
+ OPENSSL_free(keyblock);
+ return 0;
}
- ret = 1;
-
-err:
- return ret;
-
-cipher_unavailable_err:
- OPENSSL_PUT_ERROR(SSL, SSL_R_CIPHER_OR_HASH_UNAVAILABLE);
- return 0;
+ assert(key_block_len < 256);
+ ssl->s3->tmp.key_block_length = (uint8_t)key_block_len;
+ ssl->s3->tmp.key_block = keyblock;
+ return 1;
}
int tls1_cert_verify_mac(SSL *ssl, int md_nid, uint8_t *out) {
