Various fixes in {dh,dsa}_priv_encode()

Avoid creating an ASN1_STRING with negative length, set type, data
and length via ASN1_STRING_type_new() and ASN1_STRING_set0() instead
of doing this manually. Check return value for i2d_ASN1_INTEGER()
and use an intermediate ASN1_OBJECT instead of nested function calls.
Finally, clear sensitive data with freezero().

ok jsing

diff --git a/lib/libcrypto/dh/dh_ameth.c b/lib/libcrypto/dh/dh_ameth.c
index cc594cf..12f2db7 100644 (file)
--- a/lib/libcrypto/dh/dh_ameth.c
+++ b/lib/libcrypto/dh/dh_ameth.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: dh_ameth.c,v 1.30 2023/07/08 15:29:03 beck Exp $ */
+/* $OpenBSD: dh_ameth.c,v 1.31 2023/08/10 09:43:51 tb Exp $ */
 /* Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL
  * project 2006.
  */
@@ -236,48 +236,51 @@ dherr:
 static int
 dh_priv_encode(PKCS8_PRIV_KEY_INFO *p8, const EVP_PKEY *pkey)
 {
+       const DH *dh = pkey->pkey.dh;
        ASN1_STRING *params = NULL;
        ASN1_INTEGER *prkey = NULL;
-       unsigned char *dp = NULL;
-       int dplen;
+       ASN1_OBJECT *aobj;
+       unsigned char *data = NULL, *dp = NULL;
+       int datalen = 0, dplen = 0;
 
-       params = ASN1_STRING_new();
-
-       if (!params) {
+       if ((datalen = i2d_DHparams(dh, &data)) <= 0) {
                DHerror(ERR_R_MALLOC_FAILURE);
+               datalen = 0;
                goto err;
        }
-
-       params->length = i2d_DHparams(pkey->pkey.dh, &params->data);
-       if (params->length <= 0) {
+       if ((params = ASN1_STRING_type_new(V_ASN1_SEQUENCE)) == NULL) {
                DHerror(ERR_R_MALLOC_FAILURE);
                goto err;
        }
-       params->type = V_ASN1_SEQUENCE;
-
-       /* Get private key into integer */
-       prkey = BN_to_ASN1_INTEGER(pkey->pkey.dh->priv_key, NULL);
+       ASN1_STRING_set0(params, data, datalen);
+       data = NULL;
+       datalen = 0;
 
-       if (!prkey) {
+       if ((prkey = BN_to_ASN1_INTEGER(dh->priv_key, NULL)) == NULL) {
                DHerror(DH_R_BN_ERROR);
                goto err;
        }
-
-       dplen = i2d_ASN1_INTEGER(prkey, &dp);
-
+       if ((dplen = i2d_ASN1_INTEGER(prkey, &dp)) <= 0) {
+               DHerror(ERR_R_MALLOC_FAILURE);
+               dplen = 0;
+               goto err;
+       }
        ASN1_INTEGER_free(prkey);
        prkey = NULL;
 
-       if (!PKCS8_pkey_set0(p8, OBJ_nid2obj(NID_dhKeyAgreement), 0,
-           V_ASN1_SEQUENCE, params, dp, dplen))
+       if ((aobj = OBJ_nid2obj(NID_dhKeyAgreement)) == NULL)
+               goto err;
+       if (!PKCS8_pkey_set0(p8, aobj, 0, V_ASN1_SEQUENCE, params, dp, dplen))
                goto err;
 
        return 1;
 
-err:
-       free(dp);
+ err:
        ASN1_STRING_free(params);
        ASN1_INTEGER_free(prkey);
+       freezero(data, datalen);
+       freezero(dp, dplen);
+
        return 0;
 }
 

diff --git a/lib/libcrypto/dsa/dsa_ameth.c b/lib/libcrypto/dsa/dsa_ameth.c
index 5a0c311..ad5aa09 100644 (file)
--- a/lib/libcrypto/dsa/dsa_ameth.c
+++ b/lib/libcrypto/dsa/dsa_ameth.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: dsa_ameth.c,v 1.43 2023/07/07 06:59:18 tb Exp $ */
+/* $OpenBSD: dsa_ameth.c,v 1.44 2023/08/10 09:43:51 tb Exp $ */
 /* Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL
  * project 2006.
  */
@@ -265,46 +265,51 @@ done:
 static int
 dsa_priv_encode(PKCS8_PRIV_KEY_INFO *p8, const EVP_PKEY *pkey)
 {
+       const DSA *dsa = pkey->pkey.dsa;
        ASN1_STRING *params = NULL;
        ASN1_INTEGER *prkey = NULL;
-       unsigned char *dp = NULL;
-       int dplen;
+       ASN1_OBJECT *aobj;
+       unsigned char *data = NULL, *dp = NULL;
+       int datalen = 0, dplen = 0;
 
-       params = ASN1_STRING_new();
-       if (!params) {
+       if ((datalen = i2d_DSAparams(dsa, &data)) <= 0) {
                DSAerror(ERR_R_MALLOC_FAILURE);
+               datalen = 0;
                goto err;
        }
-
-       params->length = i2d_DSAparams(pkey->pkey.dsa, &params->data);
-       if (params->length <= 0) {
+       if ((params = ASN1_STRING_type_new(V_ASN1_SEQUENCE)) == NULL) {
                DSAerror(ERR_R_MALLOC_FAILURE);
                goto err;
        }
-       params->type = V_ASN1_SEQUENCE;
+       ASN1_STRING_set0(params, data, datalen);
+       data = NULL;
+       datalen = 0;
 
-       /* Get private key into integer */
-       prkey = BN_to_ASN1_INTEGER(pkey->pkey.dsa->priv_key, NULL);
-       if (!prkey) {
+       if ((prkey = BN_to_ASN1_INTEGER(dsa->priv_key, NULL)) == NULL) {
                DSAerror(DSA_R_BN_ERROR);
                goto err;
        }
-
-       dplen = i2d_ASN1_INTEGER(prkey, &dp);
-
+       if ((dplen = i2d_ASN1_INTEGER(prkey, &dp)) <= 0) {
+               DSAerror(ERR_R_MALLOC_FAILURE);
+               dplen = 0;
+               goto err;
+       }
        ASN1_INTEGER_free(prkey);
        prkey = NULL;
 
-       if (!PKCS8_pkey_set0(p8, OBJ_nid2obj(NID_dsa), 0, V_ASN1_SEQUENCE,
-           params, dp, dplen))
+       if ((aobj = OBJ_nid2obj(NID_dsa)) == NULL)
+               goto err;
+       if (!PKCS8_pkey_set0(p8, aobj, 0, V_ASN1_SEQUENCE, params, dp, dplen))
                goto err;
 
        return 1;
 
-err:
-       free(dp);
+ err:
        ASN1_STRING_free(params);
        ASN1_INTEGER_free(prkey);
+       freezero(data, datalen);
+       freezero(dp, dplen);
+
        return 0;
 }