Add a function to get the handshake digest for an SSL_CIPHER

Reviewed-by: NRich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/3670)

include/openssl/ssl.h

@@ -1418,6 +1418,7 @@ __owur const char *SSL_CIPHER_get_name(const SSL_CIPHER *c);
 __owur uint32_t SSL_CIPHER_get_id(const SSL_CIPHER *c);
 __owur int SSL_CIPHER_get_kx_nid(const SSL_CIPHER *c);
 __owur int SSL_CIPHER_get_auth_nid(const SSL_CIPHER *c);
+__owur const EVP_MD *SSL_CIPHER_get_handshake_digest(const SSL_CIPHER *c);
 __owur int SSL_CIPHER_is_aead(const SSL_CIPHER *c);
 
 __owur int SSL_get_fd(const SSL *s);

ssl/ssl_ciph.c

@@ -1931,6 +1931,16 @@ int SSL_CIPHER_get_auth_nid(const SSL_CIPHER *c)
     return ssl_cipher_table_auth[i].nid;
 }
 
+const EVP_MD *SSL_CIPHER_get_handshake_digest(const SSL_CIPHER *c)
+{
+    int idx = c->algorithm2;
+
+    idx &= SSL_HANDSHAKE_MAC_MASK;
+    if (idx < 0 || idx >= SSL_MD_NUM_IDX)
+        return NULL;
+    return ssl_digest_methods[idx];
+}
+
 int SSL_CIPHER_is_aead(const SSL_CIPHER *c)
 {
     return (c->algorithm_mac & SSL_AEAD) ? 1 : 0;

util/libssl.num

@@ -455,3 +455,4 @@ SSL_set_psk_find_session_callback       455	1_1_1	EXIST::FUNCTION:
 SSL_set_psk_use_session_callback        456	1_1_1	EXIST::FUNCTION:
 SSL_CTX_set_psk_use_session_callback    457	1_1_1	EXIST::FUNCTION:
 SSL_CTX_set_psk_find_session_callback   458	1_1_1	EXIST::FUNCTION:
+SSL_CIPHER_get_handshake_digest         459	1_1_1	EXIST::FUNCTION: