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=-24.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING, SPF_HELO_NONE,SPF_PASS,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 6ED7EC43461 for ; Thu, 20 May 2021 10:16:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4D0CC60FE5 for ; Thu, 20 May 2021 10:16:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236128AbhETKR6 (ORCPT ); Thu, 20 May 2021 06:17:58 -0400 Received: from mail.kernel.org ([198.145.29.99]:42316 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235817AbhETKJ0 (ORCPT ); Thu, 20 May 2021 06:09:26 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 1B29761956; Thu, 20 May 2021 09:42:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1621503751; bh=NbHsWF4toT2TuevvL7bKcFylbLteqHQtL3Dy47Am6cc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=w1bAG4Aqtetkdw0hy6WDmQddN1zavPx34tC0jCdQNnKqRujEg31hqkhOI5em3Mxf3 HewRO9HhtKr8h4n0lSbdm7joCcVdtgkKr1uJzZdXoE1WQRD/hfXRv8EEexNPg+VPPj aLfOu/j69lUfb7bQBf20bcLEos3KhOUxDCyC32ck= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Shahab Vahedi , Vineet Gupta Subject: [PATCH 4.19 362/425] ARC: entry: fix off-by-one error in syscall number validation Date: Thu, 20 May 2021 11:22:11 +0200 Message-Id: <20210520092143.305209944@linuxfoundation.org> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210520092131.308959589@linuxfoundation.org> References: <20210520092131.308959589@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Vineet Gupta commit 3433adc8bd09fc9f29b8baddf33b4ecd1ecd2cdc upstream. We have NR_syscall syscalls from [0 .. NR_syscall-1]. However the check for invalid syscall number is "> NR_syscall" as opposed to >=. This off-by-one error erronesously allows "NR_syscall" to be treated as valid syscall causeing out-of-bounds access into syscall-call table ensuing a crash (holes within syscall table have a invalid-entry handler but this is beyond the array implementing the table). This problem showed up on v5.6 kernel when testing glibc 2.33 (v5.10 kernel capable, includng faccessat2 syscall 439). The v5.6 kernel has NR_syscalls=439 (0 to 438). Due to the bug, 439 passed by glibc was not handled as -ENOSYS but processed leading to a crash. Link: https://github.com/foss-for-synopsys-dwc-arc-processors/linux/issues/48 Reported-by: Shahab Vahedi Cc: Signed-off-by: Vineet Gupta Signed-off-by: Greg Kroah-Hartman --- arch/arc/kernel/entry.S | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/arch/arc/kernel/entry.S +++ b/arch/arc/kernel/entry.S @@ -169,7 +169,7 @@ tracesys: ; Do the Sys Call as we normally would. ; Validate the Sys Call number - cmp r8, NR_syscalls + cmp r8, NR_syscalls - 1 mov.hi r0, -ENOSYS bhi tracesys_exit @@ -252,7 +252,7 @@ ENTRY(EV_Trap) ;============ Normal syscall case ; syscall num shd not exceed the total system calls avail - cmp r8, NR_syscalls + cmp r8, NR_syscalls - 1 mov.hi r0, -ENOSYS bhi .Lret_from_system_call