Add FFC param/key validation

Embed libctx in dsa and dh objects and cleanup internal methods to not pass libctx (This makes it consistent with the rsa changes)

Reviewed-by: Matt Caswell <matt@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/10910)

7 files changed, 145 insertions, 64 deletions

diff --git a/crypto/dsa/dsa_check.c b/crypto/dsa/dsa_check.c
new file mode 100644
index 0000000000..3b86d2dc7a
--- /dev/null
+++ b/crypto/dsa/dsa_check.c
@@ -0,0 +1,85 @@
+/*
+ * Copyright 1995-2019 The OpenSSL Project Authors. All Rights Reserved.
+ *
+ * Licensed under the Apache License 2.0 (the "License").  You may not use
+ * this file except in compliance with the License.  You can obtain a copy
+ * in the file LICENSE in the source distribution or at
+ * https://www.openssl.org/source/license.html
+ */
+
+#include <stdio.h>
+#include "internal/cryptlib.h"
+#include <openssl/bn.h>
+#include "dsa_local.h"
+#include "crypto/dsa.h"
+
+int dsa_check_params(const DSA *dsa, int *ret)
+{
+    int nid;
+    /*
+     * (2b) FFC domain params conform to FIPS-186-4 explicit domain param
+     * validity tests.
+     */
+    return ffc_params_FIPS186_4_validate(&dsa->params, FFC_PARAM_TYPE_DSA, NULL,
+                                         FFC_PARAMS_VALIDATE_ALL, ret, NULL);
+}
+
+/*
+ * See SP800-56Ar3 Section 5.6.2.3.1 : FFC Full public key validation.
+ */
+int dsa_check_pub_key(const DSA *dsa, const BIGNUM *pub_key, int *ret)
+{
+    return ffc_validate_public_key(&dsa->params, pub_key, ret);
+}
+
+/*
+ * See SP800-56Ar3 Section 5.6.2.3.1 : FFC Partial public key validation.
+ * To only be used with ephemeral FFC public keys generated using the approved
+ * safe-prime groups.
+ */
+int dsa_check_pub_key_partial(const DSA *dsa, const BIGNUM *pub_key, int *ret)
+{
+    return ffc_validate_public_key_partial(&dsa->params, pub_key, ret);
+}
+
+int dsa_check_priv_key(const DSA *dsa, const BIGNUM *priv_key, int *ret)
+{
+    *ret = 0;
+
+    return (dsa->params.q != NULL
+            && ffc_validate_private_key(dsa->params.q, priv_key, ret));
+}
+
+/*
+ * FFC pairwise check from SP800-56A R3.
+ *    Section 5.6.2.1.4 Owner Assurance of Pair-wise Consistency
+ */
+int dsa_check_pairwise(const DSA *dsa)
+{
+    int ret = 0;
+    BN_CTX *ctx = NULL;
+    BIGNUM *pub_key = NULL;
+
+    if (dsa->params.p == NULL
+        || dsa->params.g == NULL
+        || dsa->priv_key == NULL
+        || dsa->pub_key == NULL)
+        return 0;
+
+    ctx = BN_CTX_new_ex(dsa->libctx);
+    if (ctx == NULL)
+        goto err;
+    pub_key = BN_new();
+    if (pub_key == NULL)
+        goto err;
+
+    /* recalculate the public key = (g ^ priv) mod p */
+    if (!dsa_generate_public_key(ctx, dsa, dsa->priv_key, pub_key))
+        goto err;
+    /* check it matches the existing pubic_key */
+    ret = BN_cmp(pub_key, dsa->pub_key) == 0;
+err:
+    BN_free(pub_key);
+    BN_CTX_free(ctx);
+    return ret;
+}
diff --git a/crypto/dsa/dsa_gen.c b/crypto/dsa/dsa_gen.c
index ac5907c4f8..2148a1a487 100644
--- a/crypto/dsa/dsa_gen.c
+++ b/crypto/dsa/dsa_gen.c
@@ -23,7 +23,7 @@
 #include "crypto/dsa.h"
 #include "dsa_local.h"
 
-int dsa_generate_ffc_parameters(OPENSSL_CTX *libctx, DSA *dsa, int type,
+int dsa_generate_ffc_parameters(DSA *dsa, int type,
                                 int pbits, int qbits, int gindex,
                                 BN_GENCB *cb)
 {
@@ -37,12 +37,12 @@ int dsa_generate_ffc_parameters(OPENSSL_CTX *libctx, DSA *dsa, int type,
     dsa->params.gindex = gindex;
 #ifndef FIPS_MODE
     if (type == DSA_PARAMGEN_TYPE_FIPS_186_2)
-        ret = ffc_params_FIPS186_2_generate(libctx, &dsa->params,
+        ret = ffc_params_FIPS186_2_generate(dsa->libctx, &dsa->params,
                                             FFC_PARAM_TYPE_DSA,
                                             pbits, qbits, NULL, &res, cb);
     else
 #endif
-        ret = ffc_params_FIPS186_4_generate(libctx, &dsa->params,
+        ret = ffc_params_FIPS186_4_generate(dsa->libctx, &dsa->params,
                                             FFC_PARAM_TYPE_DSA,
                                             pbits, qbits, NULL, &res, cb);
     if (ret > 0)
@@ -50,10 +50,10 @@ int dsa_generate_ffc_parameters(OPENSSL_CTX *libctx, DSA *dsa, int type,
     return ret;
 }
 
-int dsa_generate_parameters_ctx(OPENSSL_CTX *libctx, DSA *dsa, int bits,
-                                const unsigned char *seed_in, int seed_len,
-                                int *counter_ret, unsigned long *h_ret,
-                                BN_GENCB *cb)
+int DSA_generate_parameters_ex(DSA *dsa, int bits,
+                               const unsigned char *seed_in, int seed_len,
+                               int *counter_ret, unsigned long *h_ret,
+                               BN_GENCB *cb)
 {
 #ifndef FIPS_MODE
     if (dsa->meth->dsa_paramgen)
@@ -67,15 +67,13 @@ int dsa_generate_parameters_ctx(OPENSSL_CTX *libctx, DSA *dsa, int bits,
 #ifndef FIPS_MODE
     /* The old code used FIPS 186-2 DSA Parameter generation */
     if (bits <= 1024 && seed_len == 20) {
-        if (!dsa_generate_ffc_parameters(libctx, dsa,
-                                         DSA_PARAMGEN_TYPE_FIPS_186_2,
+        if (!dsa_generate_ffc_parameters(dsa, DSA_PARAMGEN_TYPE_FIPS_186_2,
                                          bits, 160, -1, cb))
             return 0;
     } else
 #endif
     {
-        if (!dsa_generate_ffc_parameters(libctx, dsa,
-                                         DSA_PARAMGEN_TYPE_FIPS_186_4,
+        if (!dsa_generate_ffc_parameters(dsa, DSA_PARAMGEN_TYPE_FIPS_186_4,
                                          bits, -1, -1, cb))
             return 0;
     }
@@ -86,13 +84,3 @@ int dsa_generate_parameters_ctx(OPENSSL_CTX *libctx, DSA *dsa, int bits,
         *h_ret = dsa->params.h;
     return 1;
 }
-
-int DSA_generate_parameters_ex(DSA *dsa, int bits,
-                               const unsigned char *seed_in, int seed_len,
-                               int *counter_ret, unsigned long *h_ret,
-                               BN_GENCB *cb)
-{
-    return dsa_generate_parameters_ctx(NULL, dsa, bits,
-                                       seed_in, seed_len,
-                                       counter_ret, h_ret, cb);
-}
diff --git a/crypto/dsa/dsa_key.c b/crypto/dsa/dsa_key.c
index 00e7213b97..c93ea15b76 100644
--- a/crypto/dsa/dsa_key.c
+++ b/crypto/dsa/dsa_key.c
@@ -20,31 +20,43 @@
 #include "crypto/dsa.h"
 #include "dsa_local.h"
 
-static int dsa_builtin_keygen(OPENSSL_CTX *libctx, DSA *dsa);
+static int dsa_builtin_keygen(DSA *dsa);
 
 int DSA_generate_key(DSA *dsa)
 {
+#ifndef FIPS_MODE
     if (dsa->meth->dsa_keygen != NULL)
         return dsa->meth->dsa_keygen(dsa);
-    return dsa_builtin_keygen(NULL, dsa);
+#endif
+    return dsa_builtin_keygen(dsa);
 }
 
-int dsa_generate_key_ctx(OPENSSL_CTX *libctx, DSA *dsa)
+int dsa_generate_public_key(BN_CTX *ctx, const DSA *dsa, const BIGNUM *priv_key,
+                            BIGNUM *pub_key)
 {
-#ifndef FIPS_MODE
-    if (dsa->meth->dsa_keygen != NULL)
-        return dsa->meth->dsa_keygen(dsa);
-#endif
-    return dsa_builtin_keygen(libctx, dsa);
+    int ret = 0;
+    BIGNUM *prk = BN_new();
+
+    if (prk == NULL)
+        return 0;
+    BN_with_flags(prk, priv_key, BN_FLG_CONSTTIME);
+
+    /* pub_key = g ^ priv_key mod p */
+    if (!BN_mod_exp(pub_key, dsa->params.g, prk, dsa->params.p, ctx))
+        goto err;
+    ret = 1;
+err:
+    BN_clear_free(prk);
+    return ret;
 }
 
-static int dsa_builtin_keygen(OPENSSL_CTX *libctx, DSA *dsa)
+static int dsa_builtin_keygen(DSA *dsa)
 {
     int ok = 0;
     BN_CTX *ctx = NULL;
     BIGNUM *pub_key = NULL, *priv_key = NULL;
 
-    if ((ctx = BN_CTX_new_ex(libctx)) == NULL)
+    if ((ctx = BN_CTX_new_ex(dsa->libctx)) == NULL)
         goto err;
 
     if (dsa->priv_key == NULL) {
@@ -65,21 +77,8 @@ static int dsa_builtin_keygen(OPENSSL_CTX *libctx, DSA *dsa)
         pub_key = dsa->pub_key;
     }
 
-    {
-        BIGNUM *prk = BN_new();
-
-        if (prk == NULL)
-            goto err;
-        BN_with_flags(prk, priv_key, BN_FLG_CONSTTIME);
-
-        /* pub_key = g ^ priv_key mod p */
-        if (!BN_mod_exp(pub_key, dsa->params.g, prk, dsa->params.p, ctx)) {
-            BN_free(prk);
-            goto err;
-        }
-        /* We MUST free prk before any further use of priv_key */
-        BN_free(prk);
-    }
+    if (!dsa_generate_public_key(ctx, dsa, priv_key, pub_key))
+        goto err;
 
     dsa->priv_key = priv_key;
     dsa->pub_key = pub_key;
diff --git a/crypto/dsa/dsa_lib.c b/crypto/dsa/dsa_lib.c
index 11f09891b2..4b048d48c5 100644
--- a/crypto/dsa/dsa_lib.c
+++ b/crypto/dsa/dsa_lib.c
@@ -23,6 +23,8 @@
 #include "crypto/dsa.h"
 #include "crypto/dh.h" /* required by DSA_dup_DH() */
 
+static DSA *dsa_new_intern(ENGINE *engine, OPENSSL_CTX *libctx);
+
 #ifndef FIPS_MODE
 
 int DSA_set_ex_data(DSA *d, int idx, void *arg)
@@ -128,29 +130,30 @@ const DSA_METHOD *DSA_get_method(DSA *d)
     return d->meth;
 }
 
-static DSA *dsa_new_method(OPENSSL_CTX *libctx, ENGINE *engine)
+static DSA *dsa_new_intern(ENGINE *engine, OPENSSL_CTX *libctx)
 {
     DSA *ret = OPENSSL_zalloc(sizeof(*ret));
 
     if (ret == NULL) {
-        DSAerr(DSA_F_DSA_NEW_METHOD, ERR_R_MALLOC_FAILURE);
+        DSAerr(0, ERR_R_MALLOC_FAILURE);
         return NULL;
     }
 
     ret->references = 1;
     ret->lock = CRYPTO_THREAD_lock_new();
     if (ret->lock == NULL) {
-        DSAerr(DSA_F_DSA_NEW_METHOD, ERR_R_MALLOC_FAILURE);
+        DSAerr(0, ERR_R_MALLOC_FAILURE);
         OPENSSL_free(ret);
         return NULL;
     }
 
+    ret->libctx = libctx;
     ret->meth = DSA_get_default_method();
 #if !defined(FIPS_MODE) && !defined(OPENSSL_NO_ENGINE)
     ret->flags = ret->meth->flags & ~DSA_FLAG_NON_FIPS_ALLOW; /* early default init */
     if (engine) {
         if (!ENGINE_init(engine)) {
-            DSAerr(DSA_F_DSA_NEW_METHOD, ERR_R_ENGINE_LIB);
+            DSAerr(0, ERR_R_ENGINE_LIB);
             goto err;
         }
         ret->engine = engine;
@@ -159,7 +162,7 @@ static DSA *dsa_new_method(OPENSSL_CTX *libctx, ENGINE *engine)
     if (ret->engine) {
         ret->meth = ENGINE_get_DSA(ret->engine);
         if (ret->meth == NULL) {
-            DSAerr(DSA_F_DSA_NEW_METHOD, ERR_R_ENGINE_LIB);
+            DSAerr(0, ERR_R_ENGINE_LIB);
             goto err;
         }
     }
@@ -173,7 +176,7 @@ static DSA *dsa_new_method(OPENSSL_CTX *libctx, ENGINE *engine)
 #endif
 
     if ((ret->meth->init != NULL) && !ret->meth->init(ret)) {
-        DSAerr(DSA_F_DSA_NEW_METHOD, ERR_R_INIT_FAIL);
+        DSAerr(0, ERR_R_INIT_FAIL);
         goto err;
     }
 
@@ -186,13 +189,20 @@ static DSA *dsa_new_method(OPENSSL_CTX *libctx, ENGINE *engine)
 
 DSA *DSA_new_method(ENGINE *engine)
 {
-    return dsa_new_method(NULL, engine);
+    return dsa_new_intern(engine, NULL);
+}
+
+DSA *dsa_new_with_ctx(OPENSSL_CTX *libctx)
+{
+    return dsa_new_intern(NULL, libctx);
 }
 
+#ifndef FIPS_MODE
 DSA *DSA_new(void)
 {
-    return DSA_new_method(NULL);
+    return dsa_new_intern(NULL, NULL);
 }
+#endif
 
 void DSA_free(DSA *r)
 {
diff --git a/crypto/dsa/dsa_local.h b/crypto/dsa/dsa_local.h
index f01b0aae8c..f68ae2d05b 100644
--- a/crypto/dsa/dsa_local.h
+++ b/crypto/dsa/dsa_local.h
@@ -32,6 +32,7 @@ struct dsa_st {
     /* functional reference if 'meth' is ENGINE-provided */
     ENGINE *engine;
     CRYPTO_RWLOCK *lock;
+    OPENSSL_CTX *libctx;
 
     /* Provider data */
     size_t dirty_cnt; /* If any key material changes, increment this */
@@ -68,5 +69,4 @@ struct dsa_method {
     int (*dsa_keygen) (DSA *dsa);
 };
 
-DSA_SIG *dsa_do_sign_int(OPENSSL_CTX *libctx, const unsigned char *dgst,
-                         int dlen, DSA *dsa);
+DSA_SIG *dsa_do_sign_int(const unsigned char *dgst, int dlen, DSA *dsa);
diff --git a/crypto/dsa/dsa_ossl.c b/crypto/dsa/dsa_ossl.c
index 6ff22e8c87..a87493a061 100644
--- a/crypto/dsa/dsa_ossl.c
+++ b/crypto/dsa/dsa_ossl.c
@@ -67,8 +67,7 @@ const DSA_METHOD *DSA_OpenSSL(void)
     return &openssl_dsa_meth;
 }
 
-DSA_SIG *dsa_do_sign_int(OPENSSL_CTX *libctx, const unsigned char *dgst,
-                         int dlen, DSA *dsa)
+DSA_SIG *dsa_do_sign_int(const unsigned char *dgst, int dlen, DSA *dsa)
 {
     BIGNUM *kinv = NULL;
     BIGNUM *m, *blind, *blindm, *tmp;
@@ -96,7 +95,7 @@ DSA_SIG *dsa_do_sign_int(OPENSSL_CTX *libctx, const unsigned char *dgst,
     if (ret->r == NULL || ret->s == NULL)
         goto err;
 
-    ctx = BN_CTX_new_ex(libctx);
+    ctx = BN_CTX_new_ex(dsa->libctx);
     if (ctx == NULL)
         goto err;
     m = BN_CTX_get(ctx);
@@ -186,7 +185,7 @@ DSA_SIG *dsa_do_sign_int(OPENSSL_CTX *libctx, const unsigned char *dgst,
 
 static DSA_SIG *dsa_do_sign(const unsigned char *dgst, int dlen, DSA *dsa)
 {
-    return dsa_do_sign_int(NULL, dgst, dlen, dsa);
+    return dsa_do_sign_int(dgst, dlen, dsa);
 }
 
 static int dsa_sign_setup_no_digest(DSA *dsa, BN_CTX *ctx_in,
diff --git a/crypto/dsa/dsa_sign.c b/crypto/dsa/dsa_sign.c
index 1ee9272ced..9ef8f30f1e 100644
--- a/crypto/dsa/dsa_sign.c
+++ b/crypto/dsa/dsa_sign.c
@@ -148,16 +148,16 @@ int DSA_SIG_set0(DSA_SIG *sig, BIGNUM *r, BIGNUM *s)
     return 1;
 }
 
-int dsa_sign_int(OPENSSL_CTX *libctx, int type, const unsigned char *dgst,
+int dsa_sign_int(int type, const unsigned char *dgst,
                  int dlen, unsigned char *sig, unsigned int *siglen, DSA *dsa)
 {
     DSA_SIG *s;
 
     /* legacy case uses the method table */
-    if (libctx == NULL || dsa->meth != DSA_get_default_method())
+    if (dsa->libctx == NULL || dsa->meth != DSA_get_default_method())
         s = DSA_do_sign(dgst, dlen, dsa);
     else
-        s = dsa_do_sign_int(libctx, dgst, dlen, dsa);
+        s = dsa_do_sign_int(dgst, dlen, dsa);
     if (s == NULL) {
         *siglen = 0;
         return 0;
@@ -170,7 +170,7 @@ int dsa_sign_int(OPENSSL_CTX *libctx, int type, const unsigned char *dgst,
 int DSA_sign(int type, const unsigned char *dgst, int dlen,
              unsigned char *sig, unsigned int *siglen, DSA *dsa)
 {
-    return dsa_sign_int(NULL, type, dgst, dlen, sig, siglen, dsa);
+    return dsa_sign_int(type, dgst, dlen, sig, siglen, dsa);
 }
 
 /* data has already been hashed (probably with SHA or SHA-1). */