From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965709AbcIZIcZ (ORCPT ); Mon, 26 Sep 2016 04:32:25 -0400 Received: from mail.skyhub.de ([78.46.96.112]:34073 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S935526AbcIZIbz (ORCPT ); Mon, 26 Sep 2016 04:31:55 -0400 From: Borislav Petkov To: X86 ML Cc: LKML Subject: [PATCH 1/2] x86/RAS/mce_amd_inj: Fix signed wrap around when decrementing index i Date: Mon, 26 Sep 2016 10:31:51 +0200 Message-Id: <20160926083152.30848-2-bp@alien8.de> X-Mailer: git-send-email 2.10.0 In-Reply-To: <20160926083152.30848-1-bp@alien8.de> References: <20160926083152.30848-1-bp@alien8.de> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Colin Ian King Change predecrement compare to post decrement compare to avoid an unsigned integer wrap-around comparisomn when decrementing in the while loop. For example, if the debugfs_create_file() fails when i is zero, the current situation will predecrement i in the while loop, wrapping i to the maximum signed integer and cause multiple out of bounds reads on dfs_fls[i].d as the loop interates to zero. Also, as Borislav Petkov suggested, return -ENODEV rather than -ENOMEM on the error condition. Signed-off-by: Colin Ian King Cc: Yazen Ghannam Cc: x86-ml Link: http://lkml.kernel.org/r/20160917101750.6436-1-colin.king@canonical.com Signed-off-by: Borislav Petkov --- arch/x86/ras/mce_amd_inj.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/x86/ras/mce_amd_inj.c b/arch/x86/ras/mce_amd_inj.c index cd318d93099e..20b227f63407 100644 --- a/arch/x86/ras/mce_amd_inj.c +++ b/arch/x86/ras/mce_amd_inj.c @@ -464,13 +464,13 @@ static int __init init_mce_inject(void) return 0; err_dfs_add: - while (--i >= 0) + while (i-- > 0) debugfs_remove(dfs_fls[i].d); debugfs_remove(dfs_inj); dfs_inj = NULL; - return -ENOMEM; + return -ENODEV; } static void __exit exit_mce_inject(void) -- 2.10.0