Adapt DH to use with KEYMGMT

The biggest part in this was to move the key->param builder from EVP
to the DH ASN.1 method, and to implement the KEYMGMT support in the
provider DH.

Reviewed-by: Matt Caswell <matt@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/9394)

7 files changed, 65 insertions, 2 deletions

diff --git a/crypto/dh/dh_ameth.c b/crypto/dh/dh_ameth.c
index 524cac5bd8..6da4878200 100644
--- a/crypto/dh/dh_ameth.c
+++ b/crypto/dh/dh_ameth.c
@@ -16,6 +16,8 @@
 #include "internal/asn1_int.h"
 #include "internal/evp_int.h"
 #include <openssl/cms.h>
+#include <openssl/core_names.h>
+#include "internal/param_build.h"
 
 /*
  * i2d/d2i like DH parameter functions which use the appropriate routine for
@@ -181,7 +183,7 @@ static int dh_priv_decode(EVP_PKEY *pkey, const PKCS8_PRIV_KEY_INFO *p8)
         DHerr(DH_F_DH_PRIV_DECODE, DH_R_BN_ERROR);
         goto dherr;
     }
-    /* Calculate public key */
+    /* Calculate public key, increments dirty_cnt */
     if (!DH_generate_key(dh))
         goto dherr;
 
@@ -255,6 +257,7 @@ static int dh_param_decode(EVP_PKEY *pkey,
         DHerr(DH_F_DH_PARAM_DECODE, ERR_R_DH_LIB);
         return 0;
     }
+    dh->dirty_cnt++;
     EVP_PKEY_assign(pkey, pkey->ameth->pkey_id, dh);
     return 1;
 }
@@ -415,6 +418,7 @@ static int int_dh_param_copy(DH *to, const DH *from, int is_x942)
         }
     } else
         to->length = from->length;
+    to->dirty_cnt++;
     return 1;
 }
 
@@ -540,6 +544,50 @@ static int dh_pkey_param_check(const EVP_PKEY *pkey)
     return DH_check_ex(dh);
 }
 
+static size_t dh_pkey_dirty_cnt(const EVP_PKEY *pkey)
+{
+    return pkey->pkey.dh->dirty_cnt;
+}
+
+static void *dh_pkey_export_to(const EVP_PKEY *pk, EVP_KEYMGMT *keymgmt)
+{
+    DH *dh = pk->pkey.dh;
+    OSSL_PARAM_BLD tmpl;
+    const BIGNUM *p = DH_get0_p(dh), *g = DH_get0_g(dh), *q = DH_get0_q(dh);
+    const BIGNUM *pub_key = DH_get0_pub_key(dh);
+    const BIGNUM *priv_key = DH_get0_priv_key(dh);
+    OSSL_PARAM *params;
+    void *provkey = NULL;
+
+    if (p == NULL || g == NULL || pub_key == NULL)
+        return NULL;
+
+    ossl_param_bld_init(&tmpl);
+    if (!ossl_param_bld_push_BN(&tmpl, OSSL_PKEY_PARAM_DH_P, p)
+        || !ossl_param_bld_push_BN(&tmpl, OSSL_PKEY_PARAM_DH_G, g)
+        || !ossl_param_bld_push_BN(&tmpl, OSSL_PKEY_PARAM_DH_PUB_KEY, pub_key))
+        return NULL;
+
+    if (q != NULL) {
+        if (!ossl_param_bld_push_BN(&tmpl, OSSL_PKEY_PARAM_DH_Q, q))
+            return NULL;
+    }
+
+    if (priv_key != NULL) {
+        if (!ossl_param_bld_push_BN(&tmpl, OSSL_PKEY_PARAM_DH_PRIV_KEY,
+                                    priv_key))
+            return NULL;
+    }
+
+    params = ossl_param_bld_to_param(&tmpl);
+
+    /* We export, the provider imports */
+    provkey = evp_keymgmt_importkey(keymgmt, params);
+
+    ossl_param_bld_free(params);
+    return provkey;
+}
+
 const EVP_PKEY_ASN1_METHOD dh_asn1_meth = {
     EVP_PKEY_DH,
     EVP_PKEY_DH,
@@ -576,7 +624,12 @@ const EVP_PKEY_ASN1_METHOD dh_asn1_meth = {
 
     0,
     dh_pkey_public_check,
-    dh_pkey_param_check
+    dh_pkey_param_check,
+
+    0, 0, 0, 0,
+
+    dh_pkey_dirty_cnt,
+    dh_pkey_export_to,
 };
 
 const EVP_PKEY_ASN1_METHOD dhx_asn1_meth = {
diff --git a/crypto/dh/dh_asn1.c b/crypto/dh/dh_asn1.c
index aabdfa8360..71379d73bb 100644
--- a/crypto/dh/dh_asn1.c
+++ b/crypto/dh/dh_asn1.c
@@ -27,6 +27,8 @@ static int dh_cb(int operation, ASN1_VALUE **pval, const ASN1_ITEM *it,
         DH_free((DH *)*pval);
         *pval = NULL;
         return 2;
+    } else if (operation == ASN1_OP_D2I_POST) {
+        ((DH *)*pval)->dirty_cnt++;
     }
     return 1;
 }
diff --git a/crypto/dh/dh_gen.c b/crypto/dh/dh_gen.c
index bbf774f138..6e98b59d85 100644
--- a/crypto/dh/dh_gen.c
+++ b/crypto/dh/dh_gen.c
@@ -111,6 +111,7 @@ static int dh_builtin_genparams(DH *ret, int prime_len, int generator,
         goto err;
     if (!BN_set_word(ret->g, g))
         goto err;
+    ret->dirty_cnt++;
     ok = 1;
  err:
     if (ok == -1) {
diff --git a/crypto/dh/dh_key.c b/crypto/dh/dh_key.c
index 4df993e345..0d6b04de20 100644
--- a/crypto/dh/dh_key.c
+++ b/crypto/dh/dh_key.c
@@ -154,6 +154,7 @@ static int generate_key(DH *dh)
 
     dh->pub_key = pub_key;
     dh->priv_key = priv_key;
+    dh->dirty_cnt++;
     ok = 1;
  err:
     if (ok != 1)
diff --git a/crypto/dh/dh_lib.c b/crypto/dh/dh_lib.c
index 70298edd08..df3166279e 100644
--- a/crypto/dh/dh_lib.c
+++ b/crypto/dh/dh_lib.c
@@ -209,6 +209,7 @@ int DH_set0_pqg(DH *dh, BIGNUM *p, BIGNUM *q, BIGNUM *g)
         dh->length = BN_num_bits(q);
     }
 
+    dh->dirty_cnt++;
     return 1;
 }
 
@@ -242,6 +243,7 @@ int DH_set0_key(DH *dh, BIGNUM *pub_key, BIGNUM *priv_key)
         dh->priv_key = priv_key;
     }
 
+    dh->dirty_cnt++;
     return 1;
 }
 
diff --git a/crypto/dh/dh_locl.h b/crypto/dh/dh_locl.h
index bb64cde9f7..f0247b8d7d 100644
--- a/crypto/dh/dh_locl.h
+++ b/crypto/dh/dh_locl.h
@@ -35,6 +35,9 @@ struct dh_st {
     const DH_METHOD *meth;
     ENGINE *engine;
     CRYPTO_RWLOCK *lock;
+
+    /* Provider data */
+    size_t dirty_cnt; /* If any key material changes, increment this */
 };
 
 struct dh_method {
diff --git a/crypto/dh/dh_rfc7919.c b/crypto/dh/dh_rfc7919.c
index e9f3eafb0e..4e676fd3d1 100644
--- a/crypto/dh/dh_rfc7919.c
+++ b/crypto/dh/dh_rfc7919.c
@@ -22,6 +22,7 @@ static DH *dh_param_init(const BIGNUM *p, int32_t nbits)
     dh->p = (BIGNUM *)p;
     dh->g = (BIGNUM *)&_bignum_const_2;
     dh->length = nbits;
+    dh->dirty_cnt++;
     return dh;
 }