Reimplement d2i_PrivateKey.

Functions which lose object reuse and need auditing:
- d2i_PrivateKey

This removes evp_asn1.c's dependency on the old stack. (Aside from
obj/.) It also takes old_priv_decode out of EVP_ASN1_METHOD in favor of
calling out to the new-style function. EVP_ASN1_METHOD no longer has any
old-style type-specific serialization hooks, only the PKCS#8 and SPKI
ones.

BUG=499653

Change-Id: Ic142dc05a5505b50e4717c260d3893b20e680194
Reviewed-on: https://boringssl-review.googlesource.com/7027
Reviewed-by: Adam Langley <agl@google.com>

1 files changed, 4 insertions, 5 deletions

diff --git a/include/openssl/evp.h b/include/openssl/evp.h
index f9b9496a..595672c7 100644
--- a/include/openssl/evp.h
+++ b/include/openssl/evp.h
@@ -698,11 +698,10 @@ OPENSSL_EXPORT int i2d_PublicKey(EVP_PKEY *key, uint8_t **outp);
 
 /* d2i_PrivateKey parses an ASN.1, DER-encoded, private key from |len| bytes at
  * |*inp|. If |out| is not NULL then, on exit, a pointer to the result is in
- * |*out|. If |*out| is already non-NULL on entry then the result is written
- * directly into |*out|, otherwise a fresh |EVP_PKEY| is allocated. However,
- * one should not depend on writing into |*out| because this behaviour is
- * likely to change in the future. On successful exit, |*inp| is advanced past
- * the DER structure. It returns the result or NULL on error.
+ * |*out|. Note that, even if |*out| is already non-NULL on entry, it will not
+ * be written to. Rather, a fresh |EVP_PKEY| is allocated and the previous one
+ * is freed. On successful exit, |*inp| is advanced past the DER structure. It
+ * returns the result or NULL on error.
  *
  * This function tries to detect one of several formats. Instead, use
  * |EVP_parse_private_key| for a PrivateKeyInfo, |RSA_parse_private_key| for an