digest: remove OpenSSL engine

The OpenSSL engine of Digest uses the low-level API of OpenSSL, whose
use has been discouraged for years for multiple reasons.

A long-standing issue on a FIPS-enabled system is that using ::Digest
results in crashing the Ruby process, because the low-level API lacks
the mechanism to report an error (the policy violation) and thus kills
the process as a last resort[1][2]. Also, the upcoming OpenSSL 3.0 will
deprecate it for future removal[3]. Compiling with
-Wdeprecated-declarations will start to emit warnings.

A proper fix for this is to make it use the EVP API instead. This is a
non-trivial work as it requires backwards-incompatible changes to the
framework interface of Digest::Base and rb_digest_metadata_t.

It is more than 15 years ago that the openssl library became part of the
standard library. It has implemented the exactly same functionality as
OpenSSL::Digest, in fact, as a subclass of Digest::Class. There is not
much point in having an identical code in the digest library. Let's
just get rid of OpenSSL within digest. This leaves the C implementations
and the CommonCrypto engine for Apple systems.

A patch is being prepared for the openssl library to provide ::Digest
constants for better performance[4].

[1] https://bugs.ruby-lang.org/issues/6946
[2] https://bugs.ruby-lang.org/issues/13681
[3] https://www.openssl.org/docs/OpenSSL300Design.html
[4] https://github.com/ruby/openssl/pull/377

1 files changed, 0 insertions, 22 deletions

diff --git a/ext/digest/sha1/sha1ossl.h b/ext/digest/sha1/sha1ossl.h
deleted file mode 100644
index 599efe9a2f..0000000000
--- a/ext/digest/sha1/sha1ossl.h
+++ /dev/null
@@ -1,22 +0,0 @@
-/* $Id$ */
-
-#ifndef SHA1OSSL_H_INCLUDED
-#define SHA1OSSL_H_INCLUDED
-
-#include <stddef.h>
-#include <openssl/sha.h>
-
-#define SHA1_CTX	SHA_CTX
-
-#ifdef SHA_BLOCK_LENGTH
-#define SHA1_BLOCK_LENGTH	SHA_BLOCK_LENGTH
-#else
-#define SHA1_BLOCK_LENGTH	SHA_CBLOCK
-#endif
-#define SHA1_DIGEST_LENGTH	SHA_DIGEST_LENGTH
-
-static DEFINE_FINISH_FUNC_FROM_FINAL(SHA1)
-#undef SHA1_Finish
-#define SHA1_Finish rb_digest_SHA1_finish
-
-#endif