PROV: Add type specific PKCS#8 decoding to the DER->key decoders

This required refactoring a number of functions from the diverse
EVP_PKEY_ASN1_METHOD implementations to become shared backend
functions.  It also meant modifying a few of them to return pointers
to our internal RSA / DSA/ DH / EC_KEY, ... structures instead of
manipulating an EVP_PKEY pointer directly, letting the caller do the
latter.

Reviewed-by: Tomas Mraz <tomas@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/14314)

2 files changed, 77 insertions, 59 deletions

diff --git a/crypto/dsa/dsa_ameth.c b/crypto/dsa/dsa_ameth.c
index 50ecd3ed3b..e4c739daf9 100644
--- a/crypto/dsa/dsa_ameth.c
+++ b/crypto/dsa/dsa_ameth.c
@@ -149,69 +149,14 @@ static int dsa_pub_encode(X509_PUBKEY *pk, const EVP_PKEY *pkey)
 
 static int dsa_priv_decode(EVP_PKEY *pkey, const PKCS8_PRIV_KEY_INFO *p8)
 {
-    const unsigned char *p, *pm;
-    int pklen, pmlen;
-    int ptype;
-    const void *pval;
-    const ASN1_STRING *pstr;
-    const X509_ALGOR *palg;
-    ASN1_INTEGER *privkey = NULL;
-    BN_CTX *ctx = NULL;
-
-    DSA *dsa = NULL;
-
     int ret = 0;
+    DSA *dsa = ossl_dsa_key_from_pkcs8(p8, NULL, NULL);
 
-    if (!PKCS8_pkey_get0(NULL, &p, &pklen, &palg, p8))
-        return 0;
-    X509_ALGOR_get0(NULL, &ptype, &pval, palg);
-
-    if ((privkey = d2i_ASN1_INTEGER(NULL, &p, pklen)) == NULL)
-        goto decerr;
-    if (privkey->type == V_ASN1_NEG_INTEGER || ptype != V_ASN1_SEQUENCE)
-        goto decerr;
-
-    pstr = pval;
-    pm = pstr->data;
-    pmlen = pstr->length;
-    if ((dsa = d2i_DSAparams(NULL, &pm, pmlen)) == NULL)
-        goto decerr;
-    /* We have parameters now set private key */
-    if ((dsa->priv_key = BN_secure_new()) == NULL
-        || !ASN1_INTEGER_to_BN(privkey, dsa->priv_key)) {
-        ERR_raise(ERR_LIB_DSA, DSA_R_BN_ERROR);
-        goto dsaerr;
-    }
-    /* Calculate public key */
-    if ((dsa->pub_key = BN_new()) == NULL) {
-        ERR_raise(ERR_LIB_DSA, ERR_R_MALLOC_FAILURE);
-        goto dsaerr;
-    }
-    if ((ctx = BN_CTX_new()) == NULL) {
-        ERR_raise(ERR_LIB_DSA, ERR_R_MALLOC_FAILURE);
-        goto dsaerr;
-    }
-
-    BN_set_flags(dsa->priv_key, BN_FLG_CONSTTIME);
-    if (!BN_mod_exp(dsa->pub_key, dsa->params.g, dsa->priv_key, dsa->params.p,
-                    ctx)) {
-        ERR_raise(ERR_LIB_DSA, DSA_R_BN_ERROR);
-        goto dsaerr;
+    if (dsa != NULL) {
+        ret = 1;
+        EVP_PKEY_assign_DSA(pkey, dsa);
     }
 
-    dsa->dirty_cnt++;
-    EVP_PKEY_assign_DSA(pkey, dsa);
-
-    ret = 1;
-    goto done;
-
- decerr:
-    ERR_raise(ERR_LIB_DSA, DSA_R_DECODE_ERROR);
- dsaerr:
-    DSA_free(dsa);
- done:
-    BN_CTX_free(ctx);
-    ASN1_STRING_clear_free(privkey);
     return ret;
 }
 
diff --git a/crypto/dsa/dsa_backend.c b/crypto/dsa/dsa_backend.c
index e6f8f3645e..f3e54aeb13 100644
--- a/crypto/dsa/dsa_backend.c
+++ b/crypto/dsa/dsa_backend.c
@@ -14,6 +14,7 @@
 #include "internal/deprecated.h"
 
 #include <openssl/core_names.h>
+#include <openssl/err.h>
 #include "crypto/dsa.h"
 
 /*
@@ -54,3 +55,75 @@ int ossl_dsa_key_fromdata(DSA *dsa, const OSSL_PARAM params[])
     BN_free(pub_key);
     return 0;
 }
+
+#ifndef FIPS_MODULE
+DSA *ossl_dsa_key_from_pkcs8(const PKCS8_PRIV_KEY_INFO *p8inf,
+                             OSSL_LIB_CTX *libctx, const char *propq)
+{
+    const unsigned char *p, *pm;
+    int pklen, pmlen;
+    int ptype;
+    const void *pval;
+    const ASN1_STRING *pstr;
+    const X509_ALGOR *palg;
+    ASN1_INTEGER *privkey = NULL;
+    const BIGNUM *dsa_p, *dsa_g;
+    BIGNUM *dsa_pubkey = NULL, *dsa_privkey = NULL;
+    BN_CTX *ctx = NULL;
+
+    DSA *dsa = NULL;
+
+    if (!PKCS8_pkey_get0(NULL, &p, &pklen, &palg, p8inf))
+        return 0;
+    X509_ALGOR_get0(NULL, &ptype, &pval, palg);
+
+    if ((privkey = d2i_ASN1_INTEGER(NULL, &p, pklen)) == NULL)
+        goto decerr;
+    if (privkey->type == V_ASN1_NEG_INTEGER || ptype != V_ASN1_SEQUENCE)
+        goto decerr;
+
+    pstr = pval;
+    pm = pstr->data;
+    pmlen = pstr->length;
+    if ((dsa = d2i_DSAparams(NULL, &pm, pmlen)) == NULL)
+        goto decerr;
+    /* We have parameters now set private key */
+    if ((dsa_privkey = BN_secure_new()) == NULL
+        || !ASN1_INTEGER_to_BN(privkey, dsa_privkey)) {
+        ERR_raise(ERR_LIB_DSA, DSA_R_BN_ERROR);
+        goto dsaerr;
+    }
+    /* Calculate public key */
+    if ((dsa_pubkey = BN_new()) == NULL) {
+        ERR_raise(ERR_LIB_DSA, ERR_R_MALLOC_FAILURE);
+        goto dsaerr;
+    }
+    if ((ctx = BN_CTX_new()) == NULL) {
+        ERR_raise(ERR_LIB_DSA, ERR_R_MALLOC_FAILURE);
+        goto dsaerr;
+    }
+
+    dsa_p = DSA_get0_p(dsa);
+    dsa_g = DSA_get0_g(dsa);
+    BN_set_flags(dsa_privkey, BN_FLG_CONSTTIME);
+    if (!BN_mod_exp(dsa_pubkey, dsa_g, dsa_privkey, dsa_p, ctx)) {
+        ERR_raise(ERR_LIB_DSA, DSA_R_BN_ERROR);
+        goto dsaerr;
+    }
+    DSA_set0_key(dsa, dsa_pubkey, dsa_privkey);
+
+    goto done;
+
+ decerr:
+    ERR_raise(ERR_LIB_DSA, DSA_R_DECODE_ERROR);
+ dsaerr:
+    BN_free(dsa_privkey);
+    BN_free(dsa_pubkey);
+    DSA_free(dsa);
+    dsa = NULL;
+ done:
+    BN_CTX_free(ctx);
+    ASN1_STRING_clear_free(privkey);
+    return dsa;
+}
+#endif