Implement PEM_read_bio_DHparams with the macro.

Upstream used the macro originally, but later added a bespoke
implementation to transparently support X9.42 DH parameter serialization
(DHXPARAMS in OpenSSL) in 2ca873e8d898e8a232ea707227400213980059a4.

We don't support DHXPARAMS, so revert to the macro.

Change-Id: Ib17902c6c640bb88ee55881945ce57a032f7061b
Reviewed-on: https://boringssl-review.googlesource.com/c/boringssl/+/51105
Reviewed-by: Adam Langley <agl@google.com>

crypto/pem/pem_all.c

@@ -200,7 +200,7 @@ DSA *PEM_read_bio_DSAPrivateKey(BIO *bp, DSA **dsa, pem_password_cb *cb,
 IMPLEMENT_PEM_write_cb_const(DSAPrivateKey, DSA, PEM_STRING_DSA,
                              DSAPrivateKey)
 
-    IMPLEMENT_PEM_rw(DSA_PUBKEY, DSA, PEM_STRING_PUBLIC, DSA_PUBKEY)
+IMPLEMENT_PEM_rw(DSA_PUBKEY, DSA, PEM_STRING_PUBLIC, DSA_PUBKEY)
 DSA *PEM_read_DSAPrivateKey(FILE *fp, DSA **dsa, pem_password_cb *cb, void *u)
 {
     EVP_PKEY *pktmp;
@@ -237,7 +237,7 @@ EC_KEY *PEM_read_bio_ECPrivateKey(BIO *bp, EC_KEY **key, pem_password_cb *cb,
 IMPLEMENT_PEM_write_cb(ECPrivateKey, EC_KEY, PEM_STRING_ECPRIVATEKEY,
                        ECPrivateKey)
 
-    IMPLEMENT_PEM_rw(EC_PUBKEY, EC_KEY, PEM_STRING_PUBLIC, EC_PUBKEY)
+IMPLEMENT_PEM_rw(EC_PUBKEY, EC_KEY, PEM_STRING_PUBLIC, EC_PUBKEY)
 EC_KEY *PEM_read_ECPrivateKey(FILE *fp, EC_KEY **eckey, pem_password_cb *cb,
                               void *u)
 {
@@ -247,6 +247,6 @@ EC_KEY *PEM_read_ECPrivateKey(FILE *fp, EC_KEY **eckey, pem_password_cb *cb,
 }
 
 
-IMPLEMENT_PEM_write_const(DHparams, DH, PEM_STRING_DHPARAMS, DHparams)
+IMPLEMENT_PEM_rw_const(DHparams, DH, PEM_STRING_DHPARAMS, DHparams)
 
-    IMPLEMENT_PEM_rw(PUBKEY, EVP_PKEY, PEM_STRING_PUBLIC, PUBKEY)
+IMPLEMENT_PEM_rw(PUBKEY, EVP_PKEY, PEM_STRING_PUBLIC, PUBKEY)

crypto/pem/pem_pkey.c

@@ -176,39 +176,3 @@ int PEM_write_PrivateKey(FILE *fp, EVP_PKEY *x, const EVP_CIPHER *enc,
     BIO_free(b);
     return ret;
 }
-
-
-/* Transparently read in PKCS#3 or X9.42 DH parameters */
-
-DH *PEM_read_bio_DHparams(BIO *bp, DH **x, pem_password_cb *cb, void *u)
-{
-    char *nm = NULL;
-    const unsigned char *p = NULL;
-    unsigned char *data = NULL;
-    long len;
-    DH *ret = NULL;
-
-    if (!PEM_bytes_read_bio(&data, &len, &nm, PEM_STRING_DHPARAMS, bp, cb, u))
-        return NULL;
-    p = data;
-
-    ret = d2i_DHparams(x, &p, len);
-
-    if (ret == NULL)
-        OPENSSL_PUT_ERROR(PEM, ERR_R_ASN1_LIB);
-    OPENSSL_free(nm);
-    OPENSSL_free(data);
-    return ret;
-}
-
-DH *PEM_read_DHparams(FILE *fp, DH **x, pem_password_cb *cb, void *u)
-{
-    BIO *b = BIO_new_fp(fp, BIO_NOCLOSE);
-    if (b == NULL) {
-        OPENSSL_PUT_ERROR(PEM, ERR_R_BUF_LIB);
-        return NULL;
-    }
-    DH *ret = PEM_read_bio_DHparams(b, x, cb, u);
-    BIO_free(b);
-    return ret;
-}