Support key check in EVP interface

A new method is added to EVP_PKEY_METH as:

    int (*check) (EVP_PKEY_CTX *ctx);

and to EVP_PKEY_ASN1_METHOD as:

    int (*pkey_check) (EVP_PKEY_CTX *ctx);

This is used to check the validity of a specific key.

The order of calls is:
EVP_PKEY_check -> pmeth.check -> ameth.pkey_check.

Reviewed-by: Rich Salz <rsalz@openssl.org>
Reviewed-by: Richard Levitte <levitte@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/4337)

8 files changed, 71 insertions, 2 deletions

diff --git a/crypto/ec/ec_ameth.c b/crypto/ec/ec_ameth.c
index b66adf2bbc..ecf1a0207d 100644
--- a/crypto/ec/ec_ameth.c
+++ b/crypto/ec/ec_ameth.c
@@ -520,6 +520,19 @@ static int ec_pkey_ctrl(EVP_PKEY *pkey, int op, long arg1, void *arg2)
 
 }
 
+static int ec_pkey_check(const EVP_PKEY *pkey)
+{
+    EC_KEY *eckey = pkey->pkey.ec;
+
+    /* stay consistent to what EVP_PKEY_check demands */
+    if (eckey->priv_key == NULL) {
+        ECerr(EC_F_EC_KEY_CHECK_KEY, EC_R_MISSING_PRIVATE_KEY);
+        return 0;
+    }
+
+    return EC_KEY_check_key(eckey);
+}
+
 const EVP_PKEY_ASN1_METHOD eckey_asn1_meth = {
     EVP_PKEY_EC,
     EVP_PKEY_EC,
@@ -551,7 +564,11 @@ const EVP_PKEY_ASN1_METHOD eckey_asn1_meth = {
     int_ec_free,
     ec_pkey_ctrl,
     old_ec_priv_decode,
-    old_ec_priv_encode
+    old_ec_priv_encode,
+
+    0, 0, 0,
+
+    ec_pkey_check
 };
 
 int EC_KEY_print(BIO *bp, const EC_KEY *x, int off)
diff --git a/crypto/err/openssl.txt b/crypto/err/openssl.txt
index 253e0ab29c..b05d4599af 100644
--- a/crypto/err/openssl.txt
+++ b/crypto/err/openssl.txt
@@ -661,6 +661,7 @@ EVP_F_EVP_PBE_CIPHERINIT:116:EVP_PBE_CipherInit
 EVP_F_EVP_PBE_SCRYPT:181:EVP_PBE_scrypt
 EVP_F_EVP_PKCS82PKEY:111:EVP_PKCS82PKEY
 EVP_F_EVP_PKEY2PKCS8:113:EVP_PKEY2PKCS8
+EVP_F_EVP_PKEY_CHECK:186:EVP_PKEY_check
 EVP_F_EVP_PKEY_COPY_PARAMETERS:103:EVP_PKEY_copy_parameters
 EVP_F_EVP_PKEY_CTX_CTRL:137:EVP_PKEY_CTX_ctrl
 EVP_F_EVP_PKEY_CTX_CTRL_STR:150:EVP_PKEY_CTX_ctrl_str
diff --git a/crypto/evp/evp_err.c b/crypto/evp/evp_err.c
index c8161965d8..cc32a3bfde 100644
--- a/crypto/evp/evp_err.c
+++ b/crypto/evp/evp_err.c
@@ -55,6 +55,7 @@ static const ERR_STRING_DATA EVP_str_functs[] = {
     {ERR_PACK(ERR_LIB_EVP, EVP_F_EVP_PBE_SCRYPT, 0), "EVP_PBE_scrypt"},
     {ERR_PACK(ERR_LIB_EVP, EVP_F_EVP_PKCS82PKEY, 0), "EVP_PKCS82PKEY"},
     {ERR_PACK(ERR_LIB_EVP, EVP_F_EVP_PKEY2PKCS8, 0), "EVP_PKEY2PKCS8"},
+    {ERR_PACK(ERR_LIB_EVP, EVP_F_EVP_PKEY_CHECK, 0), "EVP_PKEY_check"},
     {ERR_PACK(ERR_LIB_EVP, EVP_F_EVP_PKEY_COPY_PARAMETERS, 0),
      "EVP_PKEY_copy_parameters"},
     {ERR_PACK(ERR_LIB_EVP, EVP_F_EVP_PKEY_CTX_CTRL, 0), "EVP_PKEY_CTX_ctrl"},
diff --git a/crypto/evp/pmeth_gn.c b/crypto/evp/pmeth_gn.c
index 6adc3a9c19..1a927a8320 100644
--- a/crypto/evp/pmeth_gn.c
+++ b/crypto/evp/pmeth_gn.c
@@ -13,6 +13,7 @@
 #include <openssl/objects.h>
 #include <openssl/evp.h>
 #include "internal/bn_int.h"
+#include "internal/asn1_int.h"
 #include "internal/evp_int.h"
 
 int EVP_PKEY_paramgen_init(EVP_PKEY_CTX *ctx)
@@ -167,3 +168,26 @@ EVP_PKEY *EVP_PKEY_new_mac_key(int type, ENGINE *e,
     EVP_PKEY_CTX_free(mac_ctx);
     return mac_key;
 }
+
+int EVP_PKEY_check(EVP_PKEY_CTX *ctx)
+{
+    EVP_PKEY *pkey = ctx->pkey;
+
+    if (pkey == NULL) {
+        EVPerr(EVP_F_EVP_PKEY_CHECK, EVP_R_NO_KEY_SET);
+        return 0;
+    }
+
+    /* call customized check function first */
+    if (ctx->pmeth->check != NULL)
+        return ctx->pmeth->check(pkey);
+
+    /* use default check function in ameth */
+    if (pkey->ameth == NULL || pkey->ameth->pkey_check == NULL) {
+        EVPerr(EVP_F_EVP_PKEY_CHECK,
+               EVP_R_OPERATION_NOT_SUPPORTED_FOR_THIS_KEYTYPE);
+        return -2;
+    }
+
+    return pkey->ameth->pkey_check(pkey);
+}
diff --git a/crypto/evp/pmeth_lib.c b/crypto/evp/pmeth_lib.c
index 71ec099440..c62bd81da4 100644
--- a/crypto/evp/pmeth_lib.c
+++ b/crypto/evp/pmeth_lib.c
@@ -219,6 +219,8 @@ void EVP_PKEY_meth_copy(EVP_PKEY_METHOD *dst, const EVP_PKEY_METHOD *src)
 
     dst->ctrl = src->ctrl;
     dst->ctrl_str = src->ctrl_str;
+
+    dst->check = src->check;
 }
 
 void EVP_PKEY_meth_free(EVP_PKEY_METHOD *pmeth)
@@ -603,6 +605,12 @@ void EVP_PKEY_meth_set_ctrl(EVP_PKEY_METHOD *pmeth,
     pmeth->ctrl_str = ctrl_str;
 }
 
+void EVP_PKEY_meth_set_check(EVP_PKEY_METHOD *pmeth,
+                             int (*check) (EVP_PKEY *pkey))
+{
+    pmeth->check = check;
+}
+
 void EVP_PKEY_meth_get_init(EVP_PKEY_METHOD *pmeth,
                             int (**pinit) (EVP_PKEY_CTX *ctx))
 {
@@ -769,3 +777,10 @@ void EVP_PKEY_meth_get_ctrl(EVP_PKEY_METHOD *pmeth,
     if (pctrl_str)
         *pctrl_str = pmeth->ctrl_str;
 }
+
+void EVP_PKEY_meth_get_check(EVP_PKEY_METHOD *pmeth,
+                             int (**pcheck) (EVP_PKEY *pkey))
+{
+    if (*pcheck)
+        *pcheck = pmeth->check;
+}
diff --git a/crypto/include/internal/asn1_int.h b/crypto/include/internal/asn1_int.h
index 8ff919c8fa..d8b6f45bd8 100644
--- a/crypto/include/internal/asn1_int.h
+++ b/crypto/include/internal/asn1_int.h
@@ -54,6 +54,8 @@ struct evp_pkey_asn1_method_st {
                       ASN1_BIT_STRING *sig);
     int (*siginf_set) (X509_SIG_INFO *siginf, const X509_ALGOR *alg,
                        const ASN1_STRING *sig);
+    /* Check */
+    int (*pkey_check) (const EVP_PKEY *pk);
 } /* EVP_PKEY_ASN1_METHOD */ ;
 
 DEFINE_STACK_OF_CONST(EVP_PKEY_ASN1_METHOD)
diff --git a/crypto/include/internal/evp_int.h b/crypto/include/internal/evp_int.h
index be1b9be926..b9558a60d4 100644
--- a/crypto/include/internal/evp_int.h
+++ b/crypto/include/internal/evp_int.h
@@ -75,6 +75,7 @@ struct evp_pkey_method_st {
     int (*digestverify) (EVP_MD_CTX *ctx, const unsigned char *sig,
                          size_t siglen, const unsigned char *tbs,
                          size_t tbslen);
+    int (*check) (EVP_PKEY *pkey);
 } /* EVP_PKEY_METHOD */ ;
 
 DEFINE_STACK_OF_CONST(EVP_PKEY_METHOD)
diff --git a/crypto/rsa/rsa_ameth.c b/crypto/rsa/rsa_ameth.c
index 42138ce9eb..97a37ba47d 100644
--- a/crypto/rsa/rsa_ameth.c
+++ b/crypto/rsa/rsa_ameth.c
@@ -984,6 +984,11 @@ static int rsa_cms_encrypt(CMS_RecipientInfo *ri)
 }
 #endif
 
+static int rsa_pkey_check(const EVP_PKEY *pkey)
+{
+    return RSA_check_key_ex(pkey->pkey.rsa, NULL);
+}
+
 const EVP_PKEY_ASN1_METHOD rsa_asn1_meths[2] = {
     {
      EVP_PKEY_RSA,
@@ -1015,7 +1020,8 @@ const EVP_PKEY_ASN1_METHOD rsa_asn1_meths[2] = {
      old_rsa_priv_encode,
      rsa_item_verify,
      rsa_item_sign,
-     rsa_sig_info_set
+     rsa_sig_info_set,
+     rsa_pkey_check
     },
 
     {
@@ -1053,4 +1059,6 @@ const EVP_PKEY_ASN1_METHOD rsa_pss_asn1_meth = {
      0, 0,
      rsa_item_verify,
      rsa_item_sign,
+     0,
+     rsa_pkey_check
 };