Commit 3f3504bd authored by Dr. Stephen Henson's avatar Dr. Stephen Henson
Browse files

Add ECDH/DH utility functions. 



Reviewed-by: default avatarRichard Levitte <levitte@openssl.org>
parent 44d4f8f2

ssl/s3_lib.c

+71 −0
Original line number Diff line number Diff line
@@ -4985,3 +4985,74 @@ int ssl_generate_master_secret(SSL *s, unsigned char *pms, size_t pmslen, 
        s->s3->tmp.pms = NULL;

    return s->session->master_key_length >= 0;

}



/* Generate a private key from parameters or a curve NID */

EVP_PKEY *ssl_generate_pkey(EVP_PKEY *pm, int nid)

{

    EVP_PKEY_CTX *pctx = NULL;

    EVP_PKEY *pkey = NULL;

    if (pm != NULL) {

        pctx = EVP_PKEY_CTX_new(pm, NULL);

    } else {

        /* Generate a new key for this curve */

        pctx = EVP_PKEY_CTX_new_id(EVP_PKEY_EC, NULL);

    }

    if (pctx == NULL)

        goto err;

    if (EVP_PKEY_keygen_init(pctx) <= 0)

        goto err;

    if (pm == NULL && EVP_PKEY_CTX_set_ec_paramgen_curve_nid(pctx, nid) <= 0)

        goto err;



    if (EVP_PKEY_keygen(pctx, &pkey) <= 0) {

        EVP_PKEY_free(pkey);

        pkey = NULL;

    }



    err:

    EVP_PKEY_CTX_free(pctx);

    return pkey;

}

/* Derive premaster or master secret for ECDH/DH */

int ssl_derive(SSL *s, EVP_PKEY *privkey, EVP_PKEY *pubkey)

{

    int rv = 0;

    unsigned char *pms = NULL;

    size_t pmslen = 0;

    EVP_PKEY_CTX *pctx;



    if (privkey == NULL || pubkey == NULL)

        return 0;



    pctx = EVP_PKEY_CTX_new(privkey, NULL);



    if (EVP_PKEY_derive_init(pctx) <= 0

        || EVP_PKEY_derive_set_peer(pctx, pubkey) <= 0

        || EVP_PKEY_derive(pctx, NULL, &pmslen) <= 0) {

        goto err;

    }



    pms = OPENSSL_malloc(pmslen);

    if (pms == NULL)

        goto err;



    if (EVP_PKEY_derive(pctx, pms, &pmslen) <= 0)

        goto err;



    if (s->server) {

        /* For server generate master secret and discard premaster */

        rv = ssl_generate_master_secret(s, pms, pmslen, 1);

        pms = NULL;

    } else {

        /* For client just save premaster secret */

        s->s3->tmp.pms = pms;

        s->s3->tmp.pmslen = pmslen;

        pms = NULL;

        rv = 1;

    }



    err:

    OPENSSL_clear_free(pms, pmslen);

    EVP_PKEY_CTX_free(pctx);

    return rv;

}

ssl/ssl_locl.h

+2 −0
Original line number Diff line number Diff line
@@ -1870,6 +1870,8 @@ void ssl_load_ciphers(void); 
__owur int ssl_fill_hello_random(SSL *s, int server, unsigned char *field, int len);

__owur int ssl_generate_master_secret(SSL *s, unsigned char *pms, size_t pmslen,

                                      int free_pms);

__owur EVP_PKEY *ssl_generate_pkey(EVP_PKEY *pm, int nid);

__owur int ssl_derive(SSL *s, EVP_PKEY *privkey, EVP_PKEY *pubkey);



__owur const SSL_CIPHER *ssl3_get_cipher_by_char(const unsigned char *p);

__owur int ssl3_put_cipher_by_char(const SSL_CIPHER *c, unsigned char *p);