From: Juergen Christ <jchrist@linux.ibm.com>
Date: Wed, 7 Sep 2022 13:01:17 +0000 (+0200)
Subject: s390x: fix ecx derive
X-Git-Tag: openssl-3.2.0-alpha1~2112
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=3cca05cc194c0528865deea57d9e60ca3fb0e5d3;p=thirdparty%2Fopenssl.git

s390x: fix ecx derive

Derivation via ecx-methods did not properly set the length.  Make the code
more similar to common code and set the length property.

Signed-off-by: Juergen Christ <jchrist@linux.ibm.com>

Reviewed-by: Tomas Mraz <tomas@openssl.org>
Reviewed-by: Paul Dale <pauli@openssl.org>
Reviewed-by: Hugo Landau <hlandau@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/19158)
---

diff --git a/crypto/ec/ecx_meth.c b/crypto/ec/ecx_meth.c
index 6e6e55e085d..c70e0461c05 100644
--- a/crypto/ec/ecx_meth.c
+++ b/crypto/ec/ecx_meth.c
@@ -1161,12 +1161,10 @@ static int s390x_pkey_ecx_derive25519(EVP_PKEY_CTX *ctx, unsigned char *key,
 {
     const unsigned char *privkey, *pubkey;
 
-    if (!validate_ecx_derive(ctx, key, keylen, &privkey, &pubkey))
+    if (!validate_ecx_derive(ctx, key, keylen, &privkey, &pubkey)
+        || (key != NULL
+            && s390x_x25519_mul(key, privkey, pubkey) == 0))
         return 0;
-
-    if (key != NULL)
-        return s390x_x25519_mul(key, pubkey, privkey);
-
     *keylen = X25519_KEYLEN;
     return 1;
 }
@@ -1176,12 +1174,10 @@ static int s390x_pkey_ecx_derive448(EVP_PKEY_CTX *ctx, unsigned char *key,
 {
     const unsigned char *privkey, *pubkey;
 
-    if (!validate_ecx_derive(ctx, key, keylen, &privkey, &pubkey))
+    if (!validate_ecx_derive(ctx, key, keylen, &privkey, &pubkey)
+        || (key != NULL
+            && s390x_x448_mul(key, pubkey, privkey) == 0))
         return 0;
-
-    if (key != NULL)
-        return s390x_x448_mul(key, pubkey, privkey);
-
     *keylen = X448_KEYLEN;
     return 1;
 }