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Clean up signature algorithm logic.

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With public keys reliably extractable from SSL_PRIVATE_KEY_METHOD keys,
we can share the pkey/sigalg check between signing and verifying.

BUG=188

Change-Id: Ieb9382807781e48ffed720b27f450847d3fca788
Reviewed-on: https://boringssl-review.googlesource.com/14566
Reviewed-by: Adam Langley <agl@google.com>
This commit is contained in:
David Benjamin 2017-03-30 16:37:54 -05:00 committed by Adam Langley
parent a232a7159c
commit 6114c3c5d4
2 changed files with 94 additions and 139 deletions
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4
ssl/internal.h
View File

@ -565,9 +565,9 @@ enum ssl_private_key_result_t ssl_private_key_complete(SSL *ssl, uint8_t *out,
size_t max_out);
/* ssl_private_key_supports_signature_algorithm returns one if |hs|'s private
* key supports |signature_algorithm| and zero otherwise. */
* key supports |sigalg| and zero otherwise. */
int ssl_private_key_supports_signature_algorithm(SSL_HANDSHAKE *hs,
uint16_t signature_algorithm);
uint16_t sigalg);
/* ssl_public_key_verify verifies that the |signature| is valid for the public
* key |pkey| and input |in|, using the |signature_algorithm| specified. */

229
ssl/ssl_privkey.c
View File

@ -66,6 +66,7 @@
#include <openssl/type_check.h>
#include "internal.h"
#include "../crypto/internal.h"
int ssl_is_key_type_supported(int key_type) {
@ -294,139 +295,115 @@ int SSL_set_private_key_digest_prefs(SSL *ssl, const int *digest_nids,
return 1;
}
typedef struct {
uint16_t sigalg;
int pkey_type;
int curve;
const EVP_MD *(*digest_func)(void);
char is_rsa_pss;
} SSL_SIGNATURE_ALGORITHM;
static const SSL_SIGNATURE_ALGORITHM kSignatureAlgorithms[] = {
{SSL_SIGN_RSA_PKCS1_MD5_SHA1, EVP_PKEY_RSA, NID_undef, &EVP_md5_sha1, 0},
{SSL_SIGN_RSA_PKCS1_SHA1, EVP_PKEY_RSA, NID_undef, &EVP_sha1, 0},
{SSL_SIGN_RSA_PKCS1_SHA256, EVP_PKEY_RSA, NID_undef, &EVP_sha256, 0},
{SSL_SIGN_RSA_PKCS1_SHA384, EVP_PKEY_RSA, NID_undef, &EVP_sha384, 0},
{SSL_SIGN_RSA_PKCS1_SHA512, EVP_PKEY_RSA, NID_undef, &EVP_sha512, 0},
{SSL_SIGN_RSA_PSS_SHA256, EVP_PKEY_RSA, NID_undef, &EVP_sha256, 1},
{SSL_SIGN_RSA_PSS_SHA384, EVP_PKEY_RSA, NID_undef, &EVP_sha384, 1},
{SSL_SIGN_RSA_PSS_SHA512, EVP_PKEY_RSA, NID_undef, &EVP_sha512, 1},
{SSL_SIGN_ECDSA_SHA1, EVP_PKEY_EC, NID_undef, &EVP_sha1, 0},
{SSL_SIGN_ECDSA_SECP256R1_SHA256, EVP_PKEY_EC, NID_X9_62_prime256v1,
&EVP_sha256, 0},
{SSL_SIGN_ECDSA_SECP384R1_SHA384, EVP_PKEY_EC, NID_secp384r1, &EVP_sha384,
0},
{SSL_SIGN_ECDSA_SECP521R1_SHA512, EVP_PKEY_EC, NID_secp521r1, &EVP_sha512,
0},
};
static const SSL_SIGNATURE_ALGORITHM *get_signature_algorithm(uint16_t sigalg) {
for (size_t i = 0; i < OPENSSL_ARRAY_SIZE(kSignatureAlgorithms); i++) {
if (kSignatureAlgorithms[i].sigalg == sigalg) {
return &kSignatureAlgorithms[i];
}
}
return NULL;
}
int ssl_has_private_key(const SSL *ssl) {
return ssl->cert->privatekey != NULL || ssl->cert->key_method != NULL;
}
static int is_rsa_pkcs1(const EVP_MD **out_md, uint16_t sigalg) {
switch (sigalg) {
case SSL_SIGN_RSA_PKCS1_MD5_SHA1:
*out_md = EVP_md5_sha1();
return 1;
case SSL_SIGN_RSA_PKCS1_SHA1:
*out_md = EVP_sha1();
return 1;
case SSL_SIGN_RSA_PKCS1_SHA256:
*out_md = EVP_sha256();
return 1;
case SSL_SIGN_RSA_PKCS1_SHA384:
*out_md = EVP_sha384();
return 1;
case SSL_SIGN_RSA_PKCS1_SHA512:
*out_md = EVP_sha512();
return 1;
default:
return 0;
static int pkey_supports_algorithm(const SSL *ssl, EVP_PKEY *pkey,
uint16_t sigalg) {
const SSL_SIGNATURE_ALGORITHM *alg = get_signature_algorithm(sigalg);
if (alg == NULL ||
EVP_PKEY_id(pkey) != alg->pkey_type) {
return 0;
}
if (ssl3_protocol_version(ssl) >= TLS1_3_VERSION) {
/* RSA keys may only be used with RSA-PSS. */
if (alg->pkey_type == EVP_PKEY_RSA && !alg->is_rsa_pss) {
return 0;
}
/* EC keys have a curve requirement. */
if (alg->pkey_type == EVP_PKEY_EC &&
(alg->curve == NID_undef ||
EC_GROUP_get_curve_name(
EC_KEY_get0_group(EVP_PKEY_get0_EC_KEY(pkey))) != alg->curve)) {
return 0;
}
}
return 1;
}
static int is_rsa_pss(const EVP_MD **out_md, uint16_t sigalg) {
switch (sigalg) {
case SSL_SIGN_RSA_PSS_SHA256:
*out_md = EVP_sha256();
return 1;
case SSL_SIGN_RSA_PSS_SHA384:
*out_md = EVP_sha384();
return 1;
case SSL_SIGN_RSA_PSS_SHA512:
*out_md = EVP_sha512();
return 1;
default:
return 0;
static int setup_ctx(SSL *ssl, EVP_PKEY_CTX *ctx, uint16_t sigalg) {
if (!pkey_supports_algorithm(ssl, EVP_PKEY_CTX_get0_pkey(ctx), sigalg)) {
OPENSSL_PUT_ERROR(SSL, SSL_R_WRONG_SIGNATURE_TYPE);
return 0;
}
}
static int is_ecdsa(int *out_curve, const EVP_MD **out_md, uint16_t sigalg) {
switch (sigalg) {
case SSL_SIGN_ECDSA_SHA1:
*out_curve = NID_undef;
*out_md = EVP_sha1();
return 1;
case SSL_SIGN_ECDSA_SECP256R1_SHA256:
*out_curve = NID_X9_62_prime256v1;
*out_md = EVP_sha256();
return 1;
case SSL_SIGN_ECDSA_SECP384R1_SHA384:
*out_curve = NID_secp384r1;
*out_md = EVP_sha384();
return 1;
case SSL_SIGN_ECDSA_SECP521R1_SHA512:
*out_curve = NID_secp521r1;
*out_md = EVP_sha512();
return 1;
default:
return 0;
const SSL_SIGNATURE_ALGORITHM *alg = get_signature_algorithm(sigalg);
if (alg->digest_func != NULL &&
!EVP_PKEY_CTX_set_signature_md(ctx, alg->digest_func())) {
return 0;
}
}
static int setup_ctx(SSL *ssl, EVP_PKEY_CTX *ctx,
uint16_t signature_algorithm) {
EVP_PKEY *pkey = EVP_PKEY_CTX_get0_pkey(ctx);
const EVP_MD *md;
if (is_rsa_pkcs1(&md, signature_algorithm) &&
ssl3_protocol_version(ssl) < TLS1_3_VERSION) {
if (pkey->type != EVP_PKEY_RSA) {
OPENSSL_PUT_ERROR(SSL, SSL_R_WRONG_SIGNATURE_TYPE);
if (alg->is_rsa_pss) {
if (!EVP_PKEY_CTX_set_rsa_padding(ctx, RSA_PKCS1_PSS_PADDING) ||
!EVP_PKEY_CTX_set_rsa_pss_saltlen(ctx, -1 /* salt len = hash len */)) {
return 0;
}
return EVP_PKEY_CTX_set_signature_md(ctx, md);
}
if (is_rsa_pss(&md, signature_algorithm)) {
if (pkey->type != EVP_PKEY_RSA) {
OPENSSL_PUT_ERROR(SSL, SSL_R_WRONG_SIGNATURE_TYPE);
return 0;
}
return EVP_PKEY_CTX_set_signature_md(ctx, md) &&
EVP_PKEY_CTX_set_rsa_padding(ctx, RSA_PKCS1_PSS_PADDING) &&
EVP_PKEY_CTX_set_rsa_pss_saltlen(ctx, -1 /* salt len = hash len */);
}
int curve;
if (is_ecdsa(&curve, &md, signature_algorithm)) {
EC_KEY *ec_key = EVP_PKEY_get0_EC_KEY(pkey);
if (ec_key == NULL) {
OPENSSL_PUT_ERROR(SSL, SSL_R_WRONG_SIGNATURE_TYPE);
return 0;
}
/* In TLS 1.3, the curve is also specified by the signature algorithm. */
if (ssl3_protocol_version(ssl) >= TLS1_3_VERSION &&
(curve == NID_undef ||
EC_GROUP_get_curve_name(EC_KEY_get0_group(ec_key)) != curve)) {
OPENSSL_PUT_ERROR(SSL, SSL_R_WRONG_SIGNATURE_TYPE);
return 0;
}
return EVP_PKEY_CTX_set_signature_md(ctx, md);
}
OPENSSL_PUT_ERROR(SSL, SSL_R_WRONG_SIGNATURE_TYPE);
return 0;
return 1;
}
enum ssl_private_key_result_t ssl_private_key_sign(
SSL *ssl, uint8_t *out, size_t *out_len, size_t max_out,
uint16_t signature_algorithm, const uint8_t *in, size_t in_len) {
uint16_t sigalg, const uint8_t *in, size_t in_len) {
if (ssl->cert->key_method != NULL) {
if (ssl->cert->key_method->sign != NULL) {
return ssl->cert->key_method->sign(ssl, out, out_len, max_out,
signature_algorithm, in, in_len);
return ssl->cert->key_method->sign(ssl, out, out_len, max_out, sigalg, in,
in_len);
}
/* TODO(davidben): Remove support for |sign_digest|-only
* |SSL_PRIVATE_KEY_METHOD|s. */
const EVP_MD *md;
int curve;
if (!is_rsa_pkcs1(&md, signature_algorithm) &&
!is_ecdsa(&curve, &md, signature_algorithm)) {
const SSL_SIGNATURE_ALGORITHM *alg = get_signature_algorithm(sigalg);
if (alg == NULL ||
(alg->pkey_type != EVP_PKEY_EC && alg->pkey_type != EVP_PKEY_RSA) ||
alg->is_rsa_pss) {
OPENSSL_PUT_ERROR(SSL, SSL_R_UNSUPPORTED_PROTOCOL_FOR_CUSTOM_KEY);
return ssl_private_key_failure;
}
const EVP_MD *md = alg->digest_func();
uint8_t hash[EVP_MAX_MD_SIZE];
unsigned hash_len;
if (!EVP_Digest(in, in_len, hash, &hash_len, md, NULL)) {
@ -441,7 +418,7 @@ enum ssl_private_key_result_t ssl_private_key_sign(
EVP_PKEY_CTX *ctx = EVP_PKEY_CTX_new(ssl->cert->privatekey, NULL);
int ret = ctx != NULL &&
EVP_PKEY_sign_init(ctx) &&
setup_ctx(ssl, ctx, signature_algorithm) &&
setup_ctx(ssl, ctx, sigalg) &&
EVP_PKEY_sign_message(ctx, out, out_len, in, in_len);
EVP_PKEY_CTX_free(ctx);
return ret ? ssl_private_key_success : ssl_private_key_failure;
@ -490,53 +467,31 @@ enum ssl_private_key_result_t ssl_private_key_complete(SSL *ssl, uint8_t *out,
}
int ssl_private_key_supports_signature_algorithm(SSL_HANDSHAKE *hs,
uint16_t signature_algorithm) {
uint16_t sigalg) {
SSL *const ssl = hs->ssl;
int type = EVP_PKEY_id(hs->local_pubkey);
const EVP_MD *md;
if (is_rsa_pkcs1(&md, signature_algorithm) &&
ssl3_protocol_version(ssl) < TLS1_3_VERSION) {
return type == EVP_PKEY_RSA;
if (!pkey_supports_algorithm(ssl, hs->local_pubkey, sigalg)) {
return 0;
}
int curve;
if (is_ecdsa(&curve, &md, signature_algorithm)) {
if (type != EVP_PKEY_EC) {
return 0;
}
/* Prior to TLS 1.3, ECDSA curves did not match the signature algorithm. */
if (ssl3_protocol_version(ssl) < TLS1_3_VERSION) {
return 1;
}
return curve != NID_undef &&
EC_GROUP_get_curve_name(EC_KEY_get0_group(
EVP_PKEY_get0_EC_KEY(hs->local_pubkey))) == curve;
}
if (is_rsa_pss(&md, signature_algorithm)) {
if (type != EVP_PKEY_RSA) {
return 0;
}
const SSL_SIGNATURE_ALGORITHM *alg = get_signature_algorithm(sigalg);
if (alg->is_rsa_pss) {
/* Ensure the RSA key is large enough for the hash. RSASSA-PSS requires that
* emLen be at least hLen + sLen + 2. Both hLen and sLen are the size of the
* hash in TLS. Reasonable RSA key sizes are large enough for the largest
* defined RSASSA-PSS algorithm, but 1024-bit RSA is slightly too large for
* SHA-512. 1024-bit RSA is sometimes used for test credentials, so check
* the size to fall back to another algorithm. */
if ((size_t)EVP_PKEY_size(hs->local_pubkey) < 2 * EVP_MD_size(md) + 2) {
if ((size_t)EVP_PKEY_size(hs->local_pubkey) <
2 * EVP_MD_size(alg->digest_func()) + 2) {
return 0;
}
/* RSA-PSS is only supported by message-based private keys. */
/* RSA-PSS is only supported by message-based private keys.
* TODO(davidben): Remove this check when sign_digest is gone. */
if (ssl->cert->key_method != NULL && ssl->cert->key_method->sign == NULL) {
return 0;
}
return 1;
}
return 0;
return 1;
}