pkcs7: raise OpenSSL::PKCS7::PKCS7Error in #initialize

When d2i_PKCS7_bio() and PEM_read_bio_PKCS7() fail to decode the input,
OpenSSL::PKCS7.new currently raises ArgumentError. The usual practice
in ruby/openssl where an error originates from the underlying OpenSSL
library is to raise OpenSSL::OpenSSLError.

Raise OpenSSL::PKCS7::PKCS7Error instead for consistency with
OpenSSL::PKCS7.read_smime and all other existing #initialize methods
that handle DER/PEM-encoded inputs.

Author: rhenium

ext/openssl/ossl_pkcs7.c

@@ -390,10 +390,10 @@ ossl_pkcs7_initialize(int argc, VALUE *argv, VALUE self)
     }
     BIO_free(in);
     if (!p7)
-        ossl_raise(rb_eArgError, "Could not parse the PKCS7");
+        ossl_raise(ePKCS7Error, "Could not parse the PKCS7");
     if (!p7->d.ptr) {
         PKCS7_free(p7);
-        ossl_raise(rb_eArgError, "No content in PKCS7");
+        ossl_raise(ePKCS7Error, "No content in PKCS7");
     }
 
     RTYPEDDATA_DATA(self) = p7;

test/openssl/test_pkcs7.rb

@@ -304,7 +304,7 @@ def test_data
 
   def test_empty_signed_data_ruby_bug_19974
     data = "-----BEGIN PKCS7-----\nMAsGCSqGSIb3DQEHAg==\n-----END PKCS7-----\n"
-    assert_raise(ArgumentError) { OpenSSL::PKCS7.new(data) }
+    assert_raise(OpenSSL::PKCS7::PKCS7Error) { OpenSSL::PKCS7.new(data) }
 
     data = <<END
 MIME-Version: 1.0
@@ -319,7 +319,7 @@ def test_empty_signed_data_ruby_bug_19974
 
   def test_graceful_parsing_failure #[ruby-core:43250]
     contents = "not a valid PKCS #7 PEM block"
-    assert_raise(ArgumentError) { OpenSSL::PKCS7.new(contents) }
+    assert_raise(OpenSSL::PKCS7::PKCS7Error) { OpenSSL::PKCS7.new(contents) }
   end
 
   def test_set_type_signed