From patchwork Mon Sep 19 15:33:53 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: =?utf-8?q?Daniel_P=2E_Berrang=C3=A9?= X-Patchwork-Id: 671804 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 3sd92h6Sw1z9ryv for ; Tue, 20 Sep 2016 01:35:56 +1000 (AEST) Received: from localhost ([::1]:56212 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bm0bq-0007lN-Ei for incoming@patchwork.ozlabs.org; Mon, 19 Sep 2016 11:35:54 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:47991) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bm0aE-0006S7-R5 for qemu-devel@nongnu.org; Mon, 19 Sep 2016 11:34:16 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1bm0a9-00074P-JD for qemu-devel@nongnu.org; Mon, 19 Sep 2016 11:34:13 -0400 Received: from mx1.redhat.com ([209.132.183.28]:54740) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bm0a9-00074E-9c for qemu-devel@nongnu.org; Mon, 19 Sep 2016 11:34:09 -0400 Received: from int-mx10.intmail.prod.int.phx2.redhat.com (int-mx10.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id C95949C0D7; Mon, 19 Sep 2016 15:34:08 +0000 (UTC) Received: from t530wlan.home.berrange.com.com (vpn1-5-73.ams2.redhat.com [10.36.5.73]) by int-mx10.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id u8JFY1ps015443; Mon, 19 Sep 2016 11:34:07 -0400 From: "Daniel P. Berrange" To: qemu-devel@nongnu.org Date: Mon, 19 Sep 2016 16:33:53 +0100 Message-Id: <1474299237-1054-5-git-send-email-berrange@redhat.com> In-Reply-To: <1474299237-1054-1-git-send-email-berrange@redhat.com> References: <1474299237-1054-1-git-send-email-berrange@redhat.com> X-Scanned-By: MIMEDefang 2.68 on 10.5.11.23 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.26]); Mon, 19 Sep 2016 15:34:08 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: [Qemu-devel] [PULL v2 4/8] crypto: use correct derived key size when timing pbkdf X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Peter Maydell Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: "Qemu-devel" Currently when timing the pbkdf algorithm a fixed key size of 32 bytes is used. This results in inaccurate timings for certain hashes depending on their digest size. For example when using sha1 with aes-256, this causes us to measure time for the master key digest doing 2 sha1 operations per iteration, instead of 1. Instead we should pass in the desired key size to the timing routine that matches the key size that will be used for real later. Reviewed-by: Eric Blake Signed-off-by: Daniel P. Berrange --- crypto/block-luks.c | 2 ++ crypto/pbkdf.c | 10 +++++++--- include/crypto/pbkdf.h | 6 +++++- tests/test-crypto-pbkdf.c | 1 + 4 files changed, 15 insertions(+), 4 deletions(-) diff --git a/crypto/block-luks.c b/crypto/block-luks.c index 91a4172..9269aaf 100644 --- a/crypto/block-luks.c +++ b/crypto/block-luks.c @@ -1072,6 +1072,7 @@ qcrypto_block_luks_create(QCryptoBlock *block, masterkey, luks->header.key_bytes, luks->header.master_key_salt, QCRYPTO_BLOCK_LUKS_SALT_LEN, + QCRYPTO_BLOCK_LUKS_DIGEST_LEN, &local_err); if (local_err) { error_propagate(errp, local_err); @@ -1152,6 +1153,7 @@ qcrypto_block_luks_create(QCryptoBlock *block, (uint8_t *)password, strlen(password), luks->header.key_slots[0].salt, QCRYPTO_BLOCK_LUKS_SALT_LEN, + luks->header.key_bytes, &local_err); if (local_err) { error_propagate(errp, local_err); diff --git a/crypto/pbkdf.c b/crypto/pbkdf.c index e391505..f22e71d 100644 --- a/crypto/pbkdf.c +++ b/crypto/pbkdf.c @@ -65,13 +65,16 @@ static int qcrypto_pbkdf2_get_thread_cpu(unsigned long long *val_ms, uint64_t qcrypto_pbkdf2_count_iters(QCryptoHashAlgorithm hash, const uint8_t *key, size_t nkey, const uint8_t *salt, size_t nsalt, + size_t nout, Error **errp) { uint64_t ret = -1; - uint8_t out[32]; + uint8_t *out; uint64_t iterations = (1 << 15); unsigned long long delta_ms, start_ms, end_ms; + out = g_new(uint8_t, nout); + while (1) { if (qcrypto_pbkdf2_get_thread_cpu(&start_ms, errp) < 0) { goto cleanup; @@ -80,7 +83,7 @@ uint64_t qcrypto_pbkdf2_count_iters(QCryptoHashAlgorithm hash, key, nkey, salt, nsalt, iterations, - out, sizeof(out), + out, nout, errp) < 0) { goto cleanup; } @@ -104,6 +107,7 @@ uint64_t qcrypto_pbkdf2_count_iters(QCryptoHashAlgorithm hash, ret = iterations; cleanup: - memset(out, 0, sizeof(out)); + memset(out, 0, nout); + g_free(out); return ret; } diff --git a/include/crypto/pbkdf.h b/include/crypto/pbkdf.h index 6f4ac85..ef209b3 100644 --- a/include/crypto/pbkdf.h +++ b/include/crypto/pbkdf.h @@ -133,6 +133,7 @@ int qcrypto_pbkdf2(QCryptoHashAlgorithm hash, * @nkey: the length of @key in bytes * @salt: a random salt * @nsalt: length of @salt in bytes + * @nout: size of desired derived key * @errp: pointer to a NULL-initialized error object * * Time the PBKDF2 algorithm to determine how many @@ -140,13 +141,16 @@ int qcrypto_pbkdf2(QCryptoHashAlgorithm hash, * key from a user password provided in @key in 1 * second of compute time. The result of this can * be used as a the @iterations parameter of a later - * call to qcrypto_pbkdf2(). + * call to qcrypto_pbkdf2(). The value of @nout should + * match that value that will later be provided with + * a call to qcrypto_pbkdf2(). * * Returns: number of iterations in 1 second, -1 on error */ uint64_t qcrypto_pbkdf2_count_iters(QCryptoHashAlgorithm hash, const uint8_t *key, size_t nkey, const uint8_t *salt, size_t nsalt, + size_t nout, Error **errp); #endif /* QCRYPTO_PBKDF_H */ diff --git a/tests/test-crypto-pbkdf.c b/tests/test-crypto-pbkdf.c index 8ceceb1..a651dc5 100644 --- a/tests/test-crypto-pbkdf.c +++ b/tests/test-crypto-pbkdf.c @@ -358,6 +358,7 @@ static void test_pbkdf_timing(void) iters = qcrypto_pbkdf2_count_iters(QCRYPTO_HASH_ALG_SHA256, key, sizeof(key), salt, sizeof(salt), + 32, &error_abort); g_assert(iters >= (1 << 15));