From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephan Mueller Subject: [PATCH v3 0/3] crypto: drbg - revamp locking Date: Sat, 18 Apr 2015 19:35:11 +0200 Message-ID: <1702481.h2hMdNkdaF@myon.chronox.de> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7Bit Cc: linux-crypto@vger.kernel.org To: herbert@gondor.apana.org.au Return-path: Received: from mail.eperm.de ([89.247.134.16]:34200 "EHLO mail.eperm.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932153AbbDRRiq (ORCPT ); Sat, 18 Apr 2015 13:38:46 -0400 Sender: linux-crypto-owner@vger.kernel.org List-ID: Hi, the current implementation of the DRBG generates a shadow copy of its DRBG state for each incoming request. The idea is that only a short term lock is needed to spawn the shadow copy. The drawback is that if multiple parallel requests come in, the generated DRBG shadow states only differ by a high-resolution timer that was mixed in during the shadow state generation. This patch now removes this shadow state and introduces a mutex to serialize all requests to one DRBG instance. The patch was fully CAVS tested and demonstrates that the DRBG still complies with the standard. Changes v2: * fix return code check of drbg_generate in drbg_generate_long * move mutex_init to drbg_kcapi_init to ensure the mutex is initialized only during the instantiation of a DRBG and during a reset * merge the patch for replacing the spinlock with a mutex and the removal of the shadow copy generation as both patches cannot stand alone and would therefore break bisection * drop patch that fixes the memory release (Herbert: you mentioned the patch is applied but it is not yet in the repo -- this patch is vital as otherwise AES192 now breaks without the shadow copy operation) Changes v3: * patch for fixing the return code handling in drbg_generate_long did not cover all code paths -- now the issue should be truly fixed Stephan Mueller (3): crypto: drbg - fix drbg_generate return val check crypto: drbg - replace spinlock with mutex crypto: drbg - leave cipher handles operational crypto/drbg.c | 166 +++++++++++--------------------------------------- include/crypto/drbg.h | 4 +- 2 files changed, 36 insertions(+), 134 deletions(-) -- 2.1.0