Convert EC curves extension to the new system
Change-Id: Ia8be431bf279e0e895076609ee147bc935f46cee
Reviewed-on: https://boringssl-review.googlesource.com/5465
Reviewed-by: Adam Langley <agl@google.com>
diff --git a/ssl/t1_lib.c b/ssl/t1_lib.c
index f5a28d9..70743df 100644
--- a/ssl/t1_lib.c
+++ b/ssl/t1_lib.c
@@ -2010,6 +2010,98 @@
return ext_ec_point_add_extension(ssl, out);
}
+
+/* EC supported curves.
+ *
+ * https://tools.ietf.org/html/rfc4492#section-5.1.2 */
+
+static void ext_ec_curves_init(SSL *ssl) {
+ OPENSSL_free(ssl->s3->tmp.peer_ellipticcurvelist);
+ ssl->s3->tmp.peer_ellipticcurvelist = NULL;
+ ssl->s3->tmp.peer_ellipticcurvelist_length = 0;
+}
+
+static int ext_ec_curves_add_clienthello(SSL *ssl, CBB *out) {
+ if (!ssl_any_ec_cipher_suites_enabled(ssl)) {
+ return 1;
+ }
+
+ CBB contents, curves_bytes;
+ if (!CBB_add_u16(out, TLSEXT_TYPE_elliptic_curves) ||
+ !CBB_add_u16_length_prefixed(out, &contents) ||
+ !CBB_add_u16_length_prefixed(&contents, &curves_bytes)) {
+ return 0;
+ }
+
+ const uint16_t *curves;
+ size_t curves_len;
+ tls1_get_curvelist(ssl, 0, &curves, &curves_len);
+
+ size_t i;
+ for (i = 0; i < curves_len; i++) {
+ if (!CBB_add_u16(&curves_bytes, curves[i])) {
+ return 0;
+ }
+ }
+
+ return CBB_flush(out);
+}
+
+static int ext_ec_curves_parse_serverhello(SSL *ssl, uint8_t *out_alert,
+ CBS *contents) {
+ /* This extension is not expected to be echoed by servers and is ignored. */
+ return 1;
+}
+
+static int ext_ec_curves_parse_clienthello(SSL *ssl, uint8_t *out_alert,
+ CBS *contents) {
+ if (contents == NULL) {
+ return 1;
+ }
+
+ CBS elliptic_curve_list;
+ if (!CBS_get_u16_length_prefixed(contents, &elliptic_curve_list) ||
+ CBS_len(&elliptic_curve_list) == 0 ||
+ (CBS_len(&elliptic_curve_list) & 1) != 0 ||
+ CBS_len(contents) != 0) {
+ return 0;
+ }
+
+ ssl->s3->tmp.peer_ellipticcurvelist =
+ (uint16_t *)OPENSSL_malloc(CBS_len(&elliptic_curve_list));
+
+ if (ssl->s3->tmp.peer_ellipticcurvelist == NULL) {
+ *out_alert = SSL_AD_INTERNAL_ERROR;
+ return 0;
+ }
+
+ const size_t num_curves = CBS_len(&elliptic_curve_list) / 2;
+ size_t i;
+ for (i = 0; i < num_curves; i++) {
+ if (!CBS_get_u16(&elliptic_curve_list,
+ &ssl->s3->tmp.peer_ellipticcurvelist[i])) {
+ goto err;
+ }
+ }
+
+ assert(CBS_len(&elliptic_curve_list) == 0);
+ ssl->s3->tmp.peer_ellipticcurvelist_length = num_curves;
+
+ return 1;
+
+err:
+ OPENSSL_free(ssl->s3->tmp.peer_ellipticcurvelist);
+ ssl->s3->tmp.peer_ellipticcurvelist = NULL;
+ *out_alert = SSL_AD_INTERNAL_ERROR;
+ return 0;
+}
+
+static int ext_ec_curves_add_serverhello(SSL *ssl, CBB *out) {
+ /* Servers don't echo this extension. */
+ return 1;
+}
+
+
/* kExtensions contains all the supported extensions. */
static const struct tls_extension kExtensions[] = {
{
@@ -2111,6 +2203,14 @@
ext_ec_point_parse_clienthello,
ext_ec_point_add_serverhello,
},
+ {
+ TLSEXT_TYPE_elliptic_curves,
+ ext_ec_curves_init,
+ ext_ec_curves_add_clienthello,
+ ext_ec_curves_parse_serverhello,
+ ext_ec_curves_parse_clienthello,
+ ext_ec_curves_add_serverhello,
+ },
};
#define kNumExtensions (sizeof(kExtensions) / sizeof(struct tls_extension))
@@ -2144,25 +2244,6 @@
int extdatalen = 0;
uint8_t *ret = buf;
uint8_t *orig = buf;
- /* See if we support any ECC ciphersuites */
- int using_ecc = 0;
-
- if (s->version >= TLS1_VERSION || SSL_IS_DTLS(s)) {
- size_t i;
- uint32_t alg_k, alg_a;
- STACK_OF(SSL_CIPHER) *cipher_stack = SSL_get_ciphers(s);
-
- for (i = 0; i < sk_SSL_CIPHER_num(cipher_stack); i++) {
- const SSL_CIPHER *c = sk_SSL_CIPHER_value(cipher_stack, i);
-
- alg_k = c->algorithm_mkey;
- alg_a = c->algorithm_auth;
- if ((alg_k & SSL_kECDHE) || (alg_a & SSL_aECDSA)) {
- using_ecc = 1;
- break;
- }
- }
- }
/* don't add extensions for SSLv3 unless doing secure renegotiation */
if (s->client_version == SSL3_VERSION && !s->s3->send_connection_binding) {
@@ -2207,35 +2288,6 @@
ret += CBB_len(&cbb);
CBB_cleanup(&cbb);
- if (using_ecc) {
- long lenmax;
- const uint16_t *curves;
- size_t curves_len;
-
- /* Add TLS extension EllipticCurves to the ClientHello message */
- tls1_get_curvelist(s, 0, &curves, &curves_len);
-
- lenmax = limit - ret - 6;
- if (lenmax < 0) {
- return NULL;
- }
- if (curves_len * 2 > (size_t)lenmax) {
- return NULL;
- }
- if (curves_len * 2 > 65532) {
- OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
- return NULL;
- }
-
- s2n(TLSEXT_TYPE_elliptic_curves, ret);
- s2n((curves_len * 2) + 2, ret);
-
- s2n(curves_len * 2, ret);
- for (i = 0; i < curves_len; i++) {
- s2n(curves[i], ret);
- }
- }
-
if (header_len > 0) {
size_t clienthello_minsize = 0;
header_len += ret - orig;
@@ -2338,11 +2390,6 @@
static int ssl_scan_clienthello_tlsext(SSL *s, CBS *cbs, int *out_alert) {
CBS extensions;
- /* Clear ECC extensions */
- OPENSSL_free(s->s3->tmp.peer_ellipticcurvelist);
- s->s3->tmp.peer_ellipticcurvelist = NULL;
- s->s3->tmp.peer_ellipticcurvelist_length = 0;
-
size_t i;
for (i = 0; i < kNumExtensions; i++) {
if (kExtensions[i].init != NULL) {
@@ -2393,46 +2440,6 @@
continue;
}
-
- if (type == TLSEXT_TYPE_elliptic_curves) {
- CBS elliptic_curve_list;
- size_t num_curves;
-
- if (!CBS_get_u16_length_prefixed(&extension, &elliptic_curve_list) ||
- CBS_len(&elliptic_curve_list) == 0 ||
- (CBS_len(&elliptic_curve_list) & 1) != 0 ||
- CBS_len(&extension) != 0) {
- *out_alert = SSL_AD_DECODE_ERROR;
- return 0;
- }
-
- OPENSSL_free(s->s3->tmp.peer_ellipticcurvelist);
- s->s3->tmp.peer_ellipticcurvelist_length = 0;
-
- s->s3->tmp.peer_ellipticcurvelist =
- (uint16_t *)OPENSSL_malloc(CBS_len(&elliptic_curve_list));
-
- if (s->s3->tmp.peer_ellipticcurvelist == NULL) {
- *out_alert = SSL_AD_INTERNAL_ERROR;
- return 0;
- }
-
- num_curves = CBS_len(&elliptic_curve_list) / 2;
- for (i = 0; i < num_curves; i++) {
- if (!CBS_get_u16(&elliptic_curve_list,
- &s->s3->tmp.peer_ellipticcurvelist[i])) {
- *out_alert = SSL_AD_INTERNAL_ERROR;
- return 0;
- }
- }
-
- if (CBS_len(&elliptic_curve_list) != 0) {
- *out_alert = SSL_AD_INTERNAL_ERROR;
- return 0;
- }
-
- s->s3->tmp.peer_ellipticcurvelist_length = num_curves;
- }
}
no_extensions:
