pkey: unify error classes into PKeyError

Remove the following subclasses of OpenSSL::PKey::PKeyError and make
them aliases of it.

 - OpenSSL::PKey::DHError
 - OpenSSL::PKey::DSAError
 - OpenSSL::PKey::ECError
 - OpenSSL::PKey::RSAError

Historically, methods defined on OpenSSL::PKey and OpenSSL::PKey::PKey
raise OpenSSL::PKey::PKeyError, while methods on the subclasses raise
their respective exception classes. However, this distinction is not
particularly useful since all those exception classes represent the
same kind of errors from the underlying EVP_PKEY API.

I think this convention comes from the fact that OpenSSL::PKey::{DH,
DSA,RSA} originally wrapped the corresponding OpenSSL structs DH, DSA,
and RSA, before they were unified to wrap EVP_PKEY, way back in 2002.

OpenSSL::PKey::EC::Group::Error and OpenSSL::PKey::EC::Point::Error
are out of scope of this change, as they are not subclasses of
OpenSSL::PKey::PKeyError and do not represent errors from the EVP_PKEY
API.

Author: rhenium

ext/openssl/ossl_pkey.c

@@ -1717,7 +1717,16 @@ Init_ossl_pkey(void)
 
     /* Document-class: OpenSSL::PKey::PKeyError
      *
-     *Raised when errors occur during PKey#sign or PKey#verify.
+     * Raised when errors occur during PKey#sign or PKey#verify.
+     *
+     * Before version 4.0.0, OpenSSL::PKey::PKeyError had the following
+     * subclasses. These subclasses have been removed and the constants are
+     * now defined as aliases of OpenSSL::PKey::PKeyError.
+     *
+     * * OpenSSL::PKey::DHError
+     * * OpenSSL::PKey::DSAError
+     * * OpenSSL::PKey::ECError
+     * * OpenSSL::PKey::RSAError
      */
     ePKeyError = rb_define_class_under(mPKey, "PKeyError", eOSSLError);
 

ext/openssl/ossl_pkey_dh.c

@@ -27,7 +27,6 @@
  * Classes
  */
 VALUE cDH;
-static VALUE eDHError;
 
 /*
  * Private
@@ -86,7 +85,7 @@ ossl_dh_initialize(int argc, VALUE *argv, VALUE self)
     if (rb_scan_args(argc, argv, "01", &arg) == 0) {
         dh = DH_new();
         if (!dh)
-            ossl_raise(eDHError, "DH_new");
+            ossl_raise(ePKeyError, "DH_new");
         goto legacy;
     }
 
@@ -105,12 +104,12 @@ ossl_dh_initialize(int argc, VALUE *argv, VALUE self)
     pkey = ossl_pkey_read_generic(in, Qnil);
     BIO_free(in);
     if (!pkey)
-        ossl_raise(eDHError, "could not parse pkey");
+        ossl_raise(ePKeyError, "could not parse pkey");
 
     type = EVP_PKEY_base_id(pkey);
     if (type != EVP_PKEY_DH) {
         EVP_PKEY_free(pkey);
-        rb_raise(eDHError, "incorrect pkey type: %s", OBJ_nid2sn(type));
+        rb_raise(ePKeyError, "incorrect pkey type: %s", OBJ_nid2sn(type));
     }
     RTYPEDDATA_DATA(self) = pkey;
     return self;
@@ -121,7 +120,7 @@ ossl_dh_initialize(int argc, VALUE *argv, VALUE self)
     if (!pkey || EVP_PKEY_assign_DH(pkey, dh) != 1) {
         EVP_PKEY_free(pkey);
         DH_free(dh);
-        ossl_raise(eDHError, "EVP_PKEY_assign_DH");
+        ossl_raise(ePKeyError, "EVP_PKEY_assign_DH");
     }
     RTYPEDDATA_DATA(self) = pkey;
     return self;
@@ -143,7 +142,7 @@ ossl_dh_initialize_copy(VALUE self, VALUE other)
 
     dh = DHparams_dup(dh_other);
     if (!dh)
-	ossl_raise(eDHError, "DHparams_dup");
+	ossl_raise(ePKeyError, "DHparams_dup");
 
     DH_get0_key(dh_other, &pub, &priv);
     if (pub) {
@@ -153,7 +152,7 @@ ossl_dh_initialize_copy(VALUE self, VALUE other)
         if (!pub2 || (priv && !priv2)) {
 	    BN_clear_free(pub2);
 	    BN_clear_free(priv2);
-	    ossl_raise(eDHError, "BN_dup");
+	    ossl_raise(ePKeyError, "BN_dup");
 	}
 	DH_set0_key(dh, pub2, priv2);
     }
@@ -162,7 +161,7 @@ ossl_dh_initialize_copy(VALUE self, VALUE other)
     if (!pkey || EVP_PKEY_assign_DH(pkey, dh) != 1) {
         EVP_PKEY_free(pkey);
         DH_free(dh);
-        ossl_raise(eDHError, "EVP_PKEY_assign_DH");
+        ossl_raise(ePKeyError, "EVP_PKEY_assign_DH");
     }
     RTYPEDDATA_DATA(self) = pkey;
     return self;
@@ -241,11 +240,11 @@ ossl_dh_export(VALUE self)
 
     GetDH(self, dh);
     if (!(out = BIO_new(BIO_s_mem()))) {
-	ossl_raise(eDHError, NULL);
+	ossl_raise(ePKeyError, NULL);
     }
     if (!PEM_write_bio_DHparams(out, dh)) {
 	BIO_free(out);
-	ossl_raise(eDHError, NULL);
+	ossl_raise(ePKeyError, NULL);
     }
     str = ossl_membio2str(out);
 
@@ -275,11 +274,11 @@ ossl_dh_to_der(VALUE self)
 
     GetDH(self, dh);
     if((len = i2d_DHparams(dh, NULL)) <= 0)
-	ossl_raise(eDHError, NULL);
+	ossl_raise(ePKeyError, NULL);
     str = rb_str_new(0, len);
     p = (unsigned char *)RSTRING_PTR(str);
     if(i2d_DHparams(dh, &p) < 0)
-	ossl_raise(eDHError, NULL);
+	ossl_raise(ePKeyError, NULL);
     ossl_str_adjust(str, p);
 
     return str;
@@ -306,7 +305,7 @@ ossl_dh_check_params(VALUE self)
     GetPKey(self, pkey);
     pctx = EVP_PKEY_CTX_new(pkey, /* engine */NULL);
     if (!pctx)
-        ossl_raise(eDHError, "EVP_PKEY_CTX_new");
+        ossl_raise(ePKeyError, "EVP_PKEY_CTX_new");
     ret = EVP_PKEY_param_check(pctx);
     EVP_PKEY_CTX_free(pctx);
 #else
@@ -355,13 +354,6 @@ Init_ossl_dh(void)
     ePKeyError = rb_define_class_under(mPKey, "PKeyError", eOSSLError);
 #endif
 
-    /* Document-class: OpenSSL::PKey::DHError
-     *
-     * Generic exception that is raised if an operation on a DH PKey
-     * fails unexpectedly or in case an instantiation of an instance of DH
-     * fails due to non-conformant input data.
-     */
-    eDHError = rb_define_class_under(mPKey, "DHError", ePKeyError);
     /* Document-class: OpenSSL::PKey::DH
      *
      * An implementation of the Diffie-Hellman key exchange protocol based on

ext/openssl/ossl_pkey_dsa.c

@@ -41,7 +41,6 @@ DSA_PRIVATE(VALUE obj, OSSL_3_const DSA *dsa)
  * Classes
  */
 VALUE cDSA;
-static VALUE eDSAError;
 
 /*
  * Private
@@ -98,7 +97,7 @@ ossl_dsa_initialize(int argc, VALUE *argv, VALUE self)
     if (argc == 0) {
         dsa = DSA_new();
         if (!dsa)
-            ossl_raise(eDSAError, "DSA_new");
+            ossl_raise(ePKeyError, "DSA_new");
         goto legacy;
     }
 
@@ -117,12 +116,12 @@ ossl_dsa_initialize(int argc, VALUE *argv, VALUE self)
     pkey = ossl_pkey_read_generic(in, pass);
     BIO_free(in);
     if (!pkey)
-        ossl_raise(eDSAError, "Neither PUB key nor PRIV key");
+        ossl_raise(ePKeyError, "Neither PUB key nor PRIV key");
 
     type = EVP_PKEY_base_id(pkey);
     if (type != EVP_PKEY_DSA) {
         EVP_PKEY_free(pkey);
-        rb_raise(eDSAError, "incorrect pkey type: %s", OBJ_nid2sn(type));
+        rb_raise(ePKeyError, "incorrect pkey type: %s", OBJ_nid2sn(type));
     }
     RTYPEDDATA_DATA(self) = pkey;
     return self;
@@ -133,7 +132,7 @@ ossl_dsa_initialize(int argc, VALUE *argv, VALUE self)
     if (!pkey || EVP_PKEY_assign_DSA(pkey, dsa) != 1) {
         EVP_PKEY_free(pkey);
         DSA_free(dsa);
-        ossl_raise(eDSAError, "EVP_PKEY_assign_DSA");
+        ossl_raise(ePKeyError, "EVP_PKEY_assign_DSA");
     }
     RTYPEDDATA_DATA(self) = pkey;
     return self;
@@ -156,13 +155,13 @@ ossl_dsa_initialize_copy(VALUE self, VALUE other)
                               (d2i_of_void *)d2i_DSAPrivateKey,
                               (char *)dsa);
     if (!dsa_new)
-	ossl_raise(eDSAError, "ASN1_dup");
+	ossl_raise(ePKeyError, "ASN1_dup");
 
     pkey = EVP_PKEY_new();
     if (!pkey || EVP_PKEY_assign_DSA(pkey, dsa_new) != 1) {
         EVP_PKEY_free(pkey);
         DSA_free(dsa_new);
-        ossl_raise(eDSAError, "EVP_PKEY_assign_DSA");
+        ossl_raise(ePKeyError, "EVP_PKEY_assign_DSA");
     }
     RTYPEDDATA_DATA(self) = pkey;
 
@@ -333,14 +332,6 @@ Init_ossl_dsa(void)
     ePKeyError = rb_define_class_under(mPKey, "PKeyError", eOSSLError);
 #endif
 
-    /* Document-class: OpenSSL::PKey::DSAError
-     *
-     * Generic exception that is raised if an operation on a DSA PKey
-     * fails unexpectedly or in case an instantiation of an instance of DSA
-     * fails due to non-conformant input data.
-     */
-    eDSAError = rb_define_class_under(mPKey, "DSAError", ePKeyError);
-
     /* Document-class: OpenSSL::PKey::DSA
      *
      * DSA, the Digital Signature Algorithm, is specified in NIST's