Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756589AbaBEVMC (ORCPT ); Wed, 5 Feb 2014 16:12:02 -0500 Received: from mail1.windriver.com ([147.11.146.13]:47946 "EHLO mail1.windriver.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754002AbaBEUDz (ORCPT ); Wed, 5 Feb 2014 15:03:55 -0500 From: Paul Gortmaker To: , CC: Neil Horman , Stephan Mueller , Petr Matousek , Herbert Xu , "David S. Miller" , Paul Gortmaker Subject: [v2.6.34-stable 016/213] crypto: ansi_cprng - Fix off by one error in non-block size request Date: Wed, 5 Feb 2014 14:59:31 -0500 Message-ID: <1391630568-49251-17-git-send-email-paul.gortmaker@windriver.com> X-Mailer: git-send-email 1.8.5.2 In-Reply-To: <1391630568-49251-1-git-send-email-paul.gortmaker@windriver.com> References: <1391630568-49251-1-git-send-email-paul.gortmaker@windriver.com> MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Neil Horman ------------------- This is a commit scheduled for the next v2.6.34 longterm release. http://git.kernel.org/?p=linux/kernel/git/paulg/longterm-queue-2.6.34.git If you see a problem with using this for longterm, please comment. ------------------- commit 714b33d15130cbb5ab426456d4e3de842d6c5b8a upstream. Stephan Mueller reported to me recently a error in random number generation in the ansi cprng. If several small requests are made that are less than the instances block size, the remainder for loop code doesn't increment rand_data_valid in the last iteration, meaning that the last bytes in the rand_data buffer gets reused on the subsequent smaller-than-a-block request for random data. The fix is pretty easy, just re-code the for loop to make sure that rand_data_valid gets incremented appropriately Signed-off-by: Neil Horman Reported-by: Stephan Mueller CC: Stephan Mueller CC: Petr Matousek CC: Herbert Xu CC: "David S. Miller" Signed-off-by: Herbert Xu Signed-off-by: Paul Gortmaker --- crypto/ansi_cprng.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/crypto/ansi_cprng.c b/crypto/ansi_cprng.c index 2bc332142849..5c565d72d1cc 100644 --- a/crypto/ansi_cprng.c +++ b/crypto/ansi_cprng.c @@ -230,11 +230,11 @@ remainder: */ if (byte_count < DEFAULT_BLK_SZ) { empty_rbuf: - for (; ctx->rand_data_valid < DEFAULT_BLK_SZ; - ctx->rand_data_valid++) { + while (ctx->rand_data_valid < DEFAULT_BLK_SZ) { *ptr = ctx->rand_data[ctx->rand_data_valid]; ptr++; byte_count--; + ctx->rand_data_valid++; if (byte_count == 0) goto done; } -- 1.8.5.2 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/