PEM_write_bio_PrivateKey is always PKCS#8.

Every key type which has a legacy PEM encoding also has a PKCS#8
encoding. The fallback codepath is never reached.

This removes the only consumer of pem_str, so that may be removed from
EVP_PKEY_ASN1_METHOD.

Change-Id: Ic680bfc162e1dc76db8b8016f6c10f669b24f5aa
Reviewed-on: https://boringssl-review.googlesource.com/6870
Reviewed-by: Adam Langley <agl@google.com>
diff --git a/crypto/evp/internal.h b/crypto/evp/internal.h
index 1cbf28b..3347cd4 100644
--- a/crypto/evp/internal.h
+++ b/crypto/evp/internal.h
@@ -69,8 +69,6 @@
 struct evp_pkey_asn1_method_st {
   int pkey_id;
 
-  const char *pem_str;
-
   /* pub_decode decodes |params| and |key| as a SubjectPublicKeyInfo
    * and writes the result into |out|. It returns one on success and zero on
    * error. |params| is the AlgorithmIdentifier after the OBJECT IDENTIFIER
diff --git a/crypto/evp/p_dsa_asn1.c b/crypto/evp/p_dsa_asn1.c
index 755d5de..c3dbe50 100644
--- a/crypto/evp/p_dsa_asn1.c
+++ b/crypto/evp/p_dsa_asn1.c
@@ -255,7 +255,6 @@
 
 const EVP_PKEY_ASN1_METHOD dsa_asn1_meth = {
   EVP_PKEY_DSA,
-  "DSA",
 
   dsa_pub_decode,
   dsa_pub_encode,
diff --git a/crypto/evp/p_ec_asn1.c b/crypto/evp/p_ec_asn1.c
index 9a84bb6..738b7fb 100644
--- a/crypto/evp/p_ec_asn1.c
+++ b/crypto/evp/p_ec_asn1.c
@@ -251,7 +251,6 @@
 
 const EVP_PKEY_ASN1_METHOD ec_asn1_meth = {
   EVP_PKEY_EC,
-  "EC",
 
   eckey_pub_decode,
   eckey_pub_encode,
diff --git a/crypto/evp/p_rsa_asn1.c b/crypto/evp/p_rsa_asn1.c
index 480ef22..7138ad7 100644
--- a/crypto/evp/p_rsa_asn1.c
+++ b/crypto/evp/p_rsa_asn1.c
@@ -188,7 +188,6 @@
 
 const EVP_PKEY_ASN1_METHOD rsa_asn1_meth = {
   EVP_PKEY_RSA,
-  "RSA",
 
   rsa_pub_decode,
   rsa_pub_encode,
diff --git a/crypto/pem/pem_pkey.c b/crypto/pem/pem_pkey.c
index 4cac7c2..c1467f7 100644
--- a/crypto/pem/pem_pkey.c
+++ b/crypto/pem/pem_pkey.c
@@ -150,14 +150,7 @@
                              unsigned char *kstr, int klen,
                              pem_password_cb *cb, void *u)
 {
-    char pem_str[80];
-    if (!x->ameth || x->ameth->priv_encode)
-        return PEM_write_bio_PKCS8PrivateKey(bp, x, enc,
-                                             (char *)kstr, klen, cb, u);
-
-    BIO_snprintf(pem_str, 80, "%s PRIVATE KEY", x->ameth->pem_str);
-    return PEM_ASN1_write_bio((i2d_of_void *)i2d_PrivateKey,
-                              pem_str, bp, x, enc, kstr, klen, cb, u);
+    return PEM_write_bio_PKCS8PrivateKey(bp, x, enc, (char *)kstr, klen, cb, u);
 }
 
 #ifndef OPENSSL_NO_FP_API