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 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 687C5C433EF for ; Mon, 27 Sep 2021 17:27:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4748560E08 for ; Mon, 27 Sep 2021 17:27:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237826AbhI0R2U (ORCPT ); Mon, 27 Sep 2021 13:28:20 -0400 Received: from mail.kernel.org ([198.145.29.99]:43984 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236568AbhI0R0R (ORCPT ); Mon, 27 Sep 2021 13:26:17 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id A1DB861157; Mon, 27 Sep 2021 17:16:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1632762996; bh=nF4tYFCGbBcq9OnzxHtMrTvaPMOB0MOgDMZS6RCA+3I=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=1Dl8rr2y1XzEimZBIqjIa7lu4GUPME9K9egVQAOMXY7Z/7FreEMVELTjCn6YKdR9B s97ehmcdHtS6hjvHdlYtMneejeyI74N+t/XJSkCnmf5oznL8Ji8D5bOw4oo1I4LgTF ChxizN1kIHAfccfKPrGZ3XCImuWDZV6ZLiXYOZAs= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, kernel test robot , Jiashuo Liang , Borislav Petkov , Dave Hansen , Sasha Levin Subject: [PATCH 5.14 097/162] x86/fault: Fix wrong signal when vsyscall fails with pkey Date: Mon, 27 Sep 2021 19:02:23 +0200 Message-Id: <20210927170236.803732537@linuxfoundation.org> X-Mailer: git-send-email 2.33.0 In-Reply-To: <20210927170233.453060397@linuxfoundation.org> References: <20210927170233.453060397@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: stable@vger.kernel.org From: Jiashuo Liang [ Upstream commit d4ffd5df9d18031b6a53f934388726775b4452d3 ] The function __bad_area_nosemaphore() calls kernelmode_fixup_or_oops() with the parameter @signal being actually @pkey, which will send a signal numbered with the argument in @pkey. This bug can be triggered when the kernel fails to access user-given memory pages that are protected by a pkey, so it can go down the do_user_addr_fault() path and pass the !user_mode() check in __bad_area_nosemaphore(). Most cases will simply run the kernel fixup code to make an -EFAULT. But when another condition current->thread.sig_on_uaccess_err is met, which is only used to emulate vsyscall, the kernel will generate the wrong signal. Add a new parameter @pkey to kernelmode_fixup_or_oops() to fix this. [ bp: Massage commit message, fix build error as reported by the 0day bot: https://lkml.kernel.org/r/202109202245.APvuT8BX-lkp@intel.com ] Fixes: 5042d40a264c ("x86/fault: Bypass no_context() for implicit kernel faults from usermode") Reported-by: kernel test robot Signed-off-by: Jiashuo Liang Signed-off-by: Borislav Petkov Acked-by: Dave Hansen Link: https://lkml.kernel.org/r/20210730030152.249106-1-liangjs@pku.edu.cn Signed-off-by: Sasha Levin --- arch/x86/include/asm/pkeys.h | 2 -- arch/x86/mm/fault.c | 26 ++++++++++++++++++-------- include/linux/pkeys.h | 2 ++ 3 files changed, 20 insertions(+), 10 deletions(-) diff --git a/arch/x86/include/asm/pkeys.h b/arch/x86/include/asm/pkeys.h index 5c7bcaa79623..1d5f14aff5f6 100644 --- a/arch/x86/include/asm/pkeys.h +++ b/arch/x86/include/asm/pkeys.h @@ -2,8 +2,6 @@ #ifndef _ASM_X86_PKEYS_H #define _ASM_X86_PKEYS_H -#define ARCH_DEFAULT_PKEY 0 - /* * If more than 16 keys are ever supported, a thorough audit * will be necessary to ensure that the types that store key diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c index b2eefdefc108..84a2c8c4af73 100644 --- a/arch/x86/mm/fault.c +++ b/arch/x86/mm/fault.c @@ -710,7 +710,8 @@ oops: static noinline void kernelmode_fixup_or_oops(struct pt_regs *regs, unsigned long error_code, - unsigned long address, int signal, int si_code) + unsigned long address, int signal, int si_code, + u32 pkey) { WARN_ON_ONCE(user_mode(regs)); @@ -735,8 +736,12 @@ kernelmode_fixup_or_oops(struct pt_regs *regs, unsigned long error_code, set_signal_archinfo(address, error_code); - /* XXX: hwpoison faults will set the wrong code. */ - force_sig_fault(signal, si_code, (void __user *)address); + if (si_code == SEGV_PKUERR) { + force_sig_pkuerr((void __user *)address, pkey); + } else { + /* XXX: hwpoison faults will set the wrong code. */ + force_sig_fault(signal, si_code, (void __user *)address); + } } /* @@ -798,7 +803,8 @@ __bad_area_nosemaphore(struct pt_regs *regs, unsigned long error_code, struct task_struct *tsk = current; if (!user_mode(regs)) { - kernelmode_fixup_or_oops(regs, error_code, address, pkey, si_code); + kernelmode_fixup_or_oops(regs, error_code, address, + SIGSEGV, si_code, pkey); return; } @@ -930,7 +936,8 @@ do_sigbus(struct pt_regs *regs, unsigned long error_code, unsigned long address, { /* Kernel mode? Handle exceptions or die: */ if (!user_mode(regs)) { - kernelmode_fixup_or_oops(regs, error_code, address, SIGBUS, BUS_ADRERR); + kernelmode_fixup_or_oops(regs, error_code, address, + SIGBUS, BUS_ADRERR, ARCH_DEFAULT_PKEY); return; } @@ -1396,7 +1403,8 @@ good_area: */ if (!user_mode(regs)) kernelmode_fixup_or_oops(regs, error_code, address, - SIGBUS, BUS_ADRERR); + SIGBUS, BUS_ADRERR, + ARCH_DEFAULT_PKEY); return; } @@ -1416,7 +1424,8 @@ good_area: return; if (fatal_signal_pending(current) && !user_mode(regs)) { - kernelmode_fixup_or_oops(regs, error_code, address, 0, 0); + kernelmode_fixup_or_oops(regs, error_code, address, + 0, 0, ARCH_DEFAULT_PKEY); return; } @@ -1424,7 +1433,8 @@ good_area: /* Kernel mode? Handle exceptions or die: */ if (!user_mode(regs)) { kernelmode_fixup_or_oops(regs, error_code, address, - SIGSEGV, SEGV_MAPERR); + SIGSEGV, SEGV_MAPERR, + ARCH_DEFAULT_PKEY); return; } diff --git a/include/linux/pkeys.h b/include/linux/pkeys.h index 6beb26b7151d..86be8bf27b41 100644 --- a/include/linux/pkeys.h +++ b/include/linux/pkeys.h @@ -4,6 +4,8 @@ #include +#define ARCH_DEFAULT_PKEY 0 + #ifdef CONFIG_ARCH_HAS_PKEYS #include #else /* ! CONFIG_ARCH_HAS_PKEYS */ -- 2.33.0