From 8c185e0ae5e42bf5f3d76a1a0898946671116fa3 Mon Sep 17 00:00:00 2001
From: Kazuki Yamaguchi <k@rhe.jp>
Date: Wed, 3 Nov 2021 23:31:29 +0900
Subject: [PATCH 1/2] pkey: test parsing concatenated PEM string

PEM-encoded private keys are sometimes stored together with irrelevant
PEM blocks, such as the corresponding X.509 certificate.

PEM_read_bio_*() family automatically skips unknown PEM blocks, but on
OpenSSL 3.0 we will be using the new OSSL_DECODER API instead due to
some breaking changes around the password callback.

Let's add a test case so that we won't break the current behavior.
---
 test/openssl/test_pkey_rsa.rb | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/test/openssl/test_pkey_rsa.rb b/test/openssl/test_pkey_rsa.rb
index dbe87ba4..7510658d 100644
--- a/test/openssl/test_pkey_rsa.rb
+++ b/test/openssl/test_pkey_rsa.rb
@@ -306,6 +306,12 @@ def test_RSAPrivateKey
 
     assert_equal asn1.to_der, rsa1024.to_der
     assert_equal pem, rsa1024.export
+
+    # Unknown PEM prepended
+    cert = issue_cert(OpenSSL::X509::Name.new([["CN", "nobody"]]), rsa1024, 1, [], nil, nil)
+    str = cert.to_text + cert.to_pem + rsa1024.to_pem
+    key = OpenSSL::PKey::RSA.new(str)
+    assert_same_rsa rsa1024, key
   end
 
   def test_RSAPrivateKey_encrypted

From a84ea531bbd080c3f58fe8d3dc9ffb1af2251f35 Mon Sep 17 00:00:00 2001
From: Kazuki Yamaguchi <k@rhe.jp>
Date: Sat, 20 Mar 2021 23:16:16 +0900
Subject: [PATCH 2/2] pkey: use OSSL_DECODER to load encrypted PEM on OpenSSL
 3.0

OpenSSL 3.0 has rewritten routines to load pkeys (PEM_read_bio_* and
d2i_* functions) around the newly introduced OSSL_DECODER API.

This comes with a slight behavior change. They now decrypt and parse
each encountered PEM block, then check the kind of the block. This used
to be the reverse: they checked the PEM header to see the kind, and then
decrypted the content. This means that the password callback may now be
called repeatedly.

Let's use the OSSL_DECODER API directly on OpenSSL 3.0 so that the
return value from the password callback will be reused automatically.
---
 ext/openssl/ossl_pkey.c | 40 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 40 insertions(+)

diff --git a/ext/openssl/ossl_pkey.c b/ext/openssl/ossl_pkey.c
index f9f5162e..b08168a5 100644
--- a/ext/openssl/ossl_pkey.c
+++ b/ext/openssl/ossl_pkey.c
@@ -78,6 +78,45 @@ ossl_pkey_new(EVP_PKEY *pkey)
     return obj;
 }
 
+#if OSSL_OPENSSL_PREREQ(3, 0, 0)
+# include <openssl/decoder.h>
+
+EVP_PKEY *
+ossl_pkey_read_generic(BIO *bio, VALUE pass)
+{
+    void *ppass = (void *)pass;
+    OSSL_DECODER_CTX *dctx;
+    EVP_PKEY *pkey = NULL;
+    int pos = 0, pos2;
+
+    dctx = OSSL_DECODER_CTX_new_for_pkey(&pkey, "DER", NULL, NULL, 0, NULL, NULL);
+    if (!dctx)
+        goto out;
+    if (OSSL_DECODER_CTX_set_pem_password_cb(dctx, ossl_pem_passwd_cb, ppass) != 1)
+        goto out;
+
+    /* First check DER */
+    if (OSSL_DECODER_from_bio(dctx, bio) == 1)
+        goto out;
+
+    /* Then check PEM; multiple OSSL_DECODER_from_bio() calls may be needed */
+    OSSL_BIO_reset(bio);
+    if (OSSL_DECODER_CTX_set_input_type(dctx, "PEM") != 1)
+        goto out;
+    while (OSSL_DECODER_from_bio(dctx, bio) != 1) {
+        if (BIO_eof(bio))
+            goto out;
+        pos2 = BIO_tell(bio);
+        if (pos2 < 0 || pos2 <= pos)
+            goto out;
+        pos = pos2;
+    }
+
+  out:
+    OSSL_DECODER_CTX_free(dctx);
+    return pkey;
+}
+#else
 EVP_PKEY *
 ossl_pkey_read_generic(BIO *bio, VALUE pass)
 {
@@ -106,6 +145,7 @@ ossl_pkey_read_generic(BIO *bio, VALUE pass)
   out:
     return pkey;
 }
+#endif
 
 /*
  *  call-seq: