From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 00671C32750 for ; Fri, 2 Aug 2019 09:42:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C20EA2087E for ; Fri, 2 Aug 2019 09:42:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1564738957; bh=dZpLJQa/iNeL7/6UDAIQwxGQuAixpVJtkTlR0A7g43s=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=2tPdFDcB9VeAdhEFkKyMOqH/R4wB8SqDlA84KE67GATPwEPJJsLGCH+gKIQ8gkXPz TUxG3K1qvCt7XnQBBf1+6h+IhubXzA7hm+8cZ20czp8TTEvF4k1MZeeKVu5cxXluHI 1RUbvNB0Q3uwGSy9aZ0dxwYY+O+BOmwBrJknI+es= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2391898AbfHBJmg (ORCPT ); Fri, 2 Aug 2019 05:42:36 -0400 Received: from mail.kernel.org ([198.145.29.99]:44914 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2391861AbfHBJmc (ORCPT ); Fri, 2 Aug 2019 05:42:32 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 001BE206A2; Fri, 2 Aug 2019 09:42:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1564738951; bh=dZpLJQa/iNeL7/6UDAIQwxGQuAixpVJtkTlR0A7g43s=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=f9Sogh46RIax29XB6xyGyaif6OvcgOimDvahnw5t7Zw7X7jmqmjutBZ3pLEncdPtZ qhfb9aCmauQE4VsdIfadGEJpKHUMkcYOStA1T7qGGykVF6uwhIuE2ZnTx7jaUUeQY4 exTWnntdTmICUbsW7mamP/m7FyA/Tva1Yh6ldrFw= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Ferdinand Blomqvist , Thomas Gleixner , Sasha Levin Subject: [PATCH 4.9 059/223] rslib: Fix decoding of shortened codes Date: Fri, 2 Aug 2019 11:34:44 +0200 Message-Id: <20190802092242.686267916@linuxfoundation.org> X-Mailer: git-send-email 2.22.0 In-Reply-To: <20190802092238.692035242@linuxfoundation.org> References: <20190802092238.692035242@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org [ Upstream commit 2034a42d1747fc1e1eeef2c6f1789c4d0762cb9c ] The decoding of shortenend codes is broken. It only works as expected if there are no erasures. When decoding with erasures, Lambda (the error and erasure locator polynomial) is initialized from the given erasure positions. The pad parameter is not accounted for by the initialisation code, and hence Lambda is initialized from incorrect erasure positions. The fix is to adjust the erasure positions by the supplied pad. Signed-off-by: Ferdinand Blomqvist Signed-off-by: Thomas Gleixner Link: https://lkml.kernel.org/r/20190620141039.9874-3-ferdinand.blomqvist@gmail.com Signed-off-by: Sasha Levin --- lib/reed_solomon/decode_rs.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/lib/reed_solomon/decode_rs.c b/lib/reed_solomon/decode_rs.c index 0ec3f257ffdf..8eed0f9ac495 100644 --- a/lib/reed_solomon/decode_rs.c +++ b/lib/reed_solomon/decode_rs.c @@ -99,9 +99,9 @@ if (no_eras > 0) { /* Init lambda to be the erasure locator polynomial */ lambda[1] = alpha_to[rs_modnn(rs, - prim * (nn - 1 - eras_pos[0]))]; + prim * (nn - 1 - (eras_pos[0] + pad)))]; for (i = 1; i < no_eras; i++) { - u = rs_modnn(rs, prim * (nn - 1 - eras_pos[i])); + u = rs_modnn(rs, prim * (nn - 1 - (eras_pos[i] + pad))); for (j = i + 1; j > 0; j--) { tmp = index_of[lambda[j - 1]]; if (tmp != nn) { -- 2.20.1