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Simplify ssl3_send_cert_verify's async logic.

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The only thing we've written before the signature is the hash. We can just
choose it anew. This is along the way to getting init_buf out of the handshake
output side. (init_buf is kind of a mess since it doesn't integrate nicely with
a top-level CBB. Some of the logic hasn't been converted to CBB because they're
interspersed with a BUF_MEM_grow.)

Change-Id: I693e834b5a03849bebb04f3f6b81f81fb04e2530
Reviewed-on: https://boringssl-review.googlesource.com/8431
Reviewed-by: Adam Langley <agl@google.com>
This commit is contained in:
David Benjamin 2016-06-17 17:33:30 -04:00 committed by Adam Langley
parent f0ee907942
commit 429fdc0d3d
1 changed files with 18 additions and 26 deletions
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34
ssl/handshake_client.c
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@ -1822,18 +1822,14 @@ static int ssl3_send_cert_verify(SSL *ssl) {
return ssl_do_write(ssl);
}
assert(ssl_has_private_key(ssl));
CBB cbb, child;
if (!CBB_init_fixed(&cbb, ssl_handshake_start(ssl),
ssl->init_buf->max - SSL_HM_HEADER_LENGTH(ssl))) {
goto err;
}
assert(ssl_has_private_key(ssl));
const size_t max_sig_len = ssl_private_key_max_signature_len(ssl);
size_t sig_len;
enum ssl_private_key_result_t sign_result;
if (ssl->state == SSL3_ST_CW_CERT_VRFY_A) {
/* Select and write out the digest type in TLS 1.2. */
const EVP_MD *md = NULL;
if (ssl3_protocol_version(ssl) >= TLS1_2_VERSION) {
@ -1844,6 +1840,17 @@ static int ssl3_send_cert_verify(SSL *ssl) {
}
}
/* Set aside space for the signature. */
const size_t max_sig_len = ssl_private_key_max_signature_len(ssl);
uint8_t *ptr;
if (!CBB_add_u16_length_prefixed(&cbb, &child) ||
!CBB_reserve(&child, &ptr, max_sig_len)) {
goto err;
}
size_t sig_len;
enum ssl_private_key_result_t sign_result;
if (ssl->state == SSL3_ST_CW_CERT_VRFY_A) {
/* Compute the digest. In TLS 1.1 and below, the digest type is also
* selected here. */
uint8_t digest[EVP_MAX_MD_SIZE];
@ -1857,25 +1864,10 @@ static int ssl3_send_cert_verify(SSL *ssl) {
ssl3_free_handshake_buffer(ssl);
/* Sign the digest. */
uint8_t *ptr;
if (!CBB_add_u16_length_prefixed(&cbb, &child) ||
!CBB_reserve(&child, &ptr, max_sig_len)) {
goto err;
}
sign_result = ssl_private_key_sign(ssl, ptr, &sig_len, max_sig_len, md,
digest, digest_len);
} else {
assert(ssl->state == SSL3_ST_CW_CERT_VRFY_B);
/* Skip over the already written signature algorithm and retry the
* signature. */
uint8_t *ptr;
if ((ssl3_protocol_version(ssl) >= TLS1_2_VERSION &&
!CBB_did_write(&cbb, 2)) ||
!CBB_add_u16_length_prefixed(&cbb, &child) ||
!CBB_reserve(&child, &ptr, max_sig_len)) {
goto err;
}
sign_result =
ssl_private_key_sign_complete(ssl, ptr, &sig_len, max_sig_len);
}