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 C9E0FC433EF for ; Wed, 20 Oct 2021 17:45:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id AC6C26128E for ; Wed, 20 Oct 2021 17:45:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231153AbhJTRrT (ORCPT ); Wed, 20 Oct 2021 13:47:19 -0400 Received: from out03.mta.xmission.com ([166.70.13.233]:57072 "EHLO out03.mta.xmission.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230456AbhJTRrN (ORCPT ); Wed, 20 Oct 2021 13:47:13 -0400 Received: from in02.mta.xmission.com ([166.70.13.52]:52780) by out03.mta.xmission.com with esmtps (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.93) (envelope-from ) id 1mdFe6-002tLR-A8; Wed, 20 Oct 2021 11:44:58 -0600 Received: from ip68-227-160-95.om.om.cox.net ([68.227.160.95]:47894 helo=localhost.localdomain) by in02.mta.xmission.com with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.93) (envelope-from ) id 1mdFe3-001NdN-Te; Wed, 20 Oct 2021 11:44:57 -0600 From: "Eric W. Biederman" To: linux-kernel@vger.kernel.org Cc: linux-arch@vger.kernel.org, Linus Torvalds , Oleg Nesterov , Al Viro , Kees Cook , "Eric W. Biederman" , Michael Ellerman , Benjamin Herrenschmidt , Paul Mackerras , linuxppc-dev@lists.ozlabs.org Date: Wed, 20 Oct 2021 12:43:53 -0500 Message-Id: <20211020174406.17889-7-ebiederm@xmission.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <87y26nmwkb.fsf@disp2133> References: <87y26nmwkb.fsf@disp2133> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-XM-SPF: eid=1mdFe3-001NdN-Te;;;mid=<20211020174406.17889-7-ebiederm@xmission.com>;;;hst=in02.mta.xmission.com;;;ip=68.227.160.95;;;frm=ebiederm@xmission.com;;;spf=neutral X-XM-AID: U2FsdGVkX19Emo7IPRF0mj2xClpddKvdhPaEtu2o4MA= X-SA-Exim-Connect-IP: 68.227.160.95 X-SA-Exim-Mail-From: ebiederm@xmission.com Subject: [PATCH 07/20] signal/powerpc: On swapcontext failure force SIGSEGV X-SA-Exim-Version: 4.2.1 (built Sat, 08 Feb 2020 21:53:50 +0000) X-SA-Exim-Scanned: Yes (on in02.mta.xmission.com) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org If the register state may be partial and corrupted instead of calling do_exit, call force_sigsegv(SIGSEGV). Which properly kills the process with SIGSEGV and does not let any more userspace code execute, instead of just killing one thread of the process and potentially confusing everything. Cc: Michael Ellerman Cc: Benjamin Herrenschmidt Cc: Paul Mackerras Cc: linuxppc-dev@lists.ozlabs.org History-tree: git://git.kernel.org/pub/scm/linux/kernel/git/tglx/history.git Fixes: 756f1ae8a44e ("PPC32: Rework signal code and add a swapcontext system call.") Fixes: 04879b04bf50 ("[PATCH] ppc64: VMX (Altivec) support & signal32 rework, from Ben Herrenschmidt") Signed-off-by: "Eric W. Biederman" --- arch/powerpc/kernel/signal_32.c | 6 ++++-- arch/powerpc/kernel/signal_64.c | 9 ++++++--- 2 files changed, 10 insertions(+), 5 deletions(-) diff --git a/arch/powerpc/kernel/signal_32.c b/arch/powerpc/kernel/signal_32.c index 0608581967f0..666f3da41232 100644 --- a/arch/powerpc/kernel/signal_32.c +++ b/arch/powerpc/kernel/signal_32.c @@ -1062,8 +1062,10 @@ SYSCALL_DEFINE3(swapcontext, struct ucontext __user *, old_ctx, * or if another thread unmaps the region containing the context. * We kill the task with a SIGSEGV in this situation. */ - if (do_setcontext(new_ctx, regs, 0)) - do_exit(SIGSEGV); + if (do_setcontext(new_ctx, regs, 0)) { + force_sigsegv(SIGSEGV); + return -EFAULT; + } set_thread_flag(TIF_RESTOREALL); return 0; diff --git a/arch/powerpc/kernel/signal_64.c b/arch/powerpc/kernel/signal_64.c index 1831bba0582e..d8de622c9e4a 100644 --- a/arch/powerpc/kernel/signal_64.c +++ b/arch/powerpc/kernel/signal_64.c @@ -703,15 +703,18 @@ SYSCALL_DEFINE3(swapcontext, struct ucontext __user *, old_ctx, * We kill the task with a SIGSEGV in this situation. */ - if (__get_user_sigset(&set, &new_ctx->uc_sigmask)) - do_exit(SIGSEGV); + if (__get_user_sigset(&set, &new_ctx->uc_sigmask)) { + force_sigsegv(SIGSEGV); + return -EFAULT; + } set_current_blocked(&set); if (!user_read_access_begin(new_ctx, ctx_size)) return -EFAULT; if (__unsafe_restore_sigcontext(current, NULL, 0, &new_ctx->uc_mcontext)) { user_read_access_end(); - do_exit(SIGSEGV); + force_sigsegv(SIGSEGV); + return -EFAULT; } user_read_access_end(); -- 2.20.1