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=-6.2 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_PASS,UNWANTED_LANGUAGE_BODY,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 16D68C04E87 for ; Wed, 15 May 2019 11:57:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D897620657 for ; Wed, 15 May 2019 11:57:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1557921437; bh=xFiCKmtsOvgoT4wK1Uqxsoxvd2pdKj+Zjdqq4SnKHgk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=EFBBbWq89pHdEuFV7GsJ7Q7zAyN43m81+RX22Aps1+LfAKje53/yeyHo0avYNCXXB YcYNibhQLJ91GipTYIHjA4vSK7KqP5HIewaTz7kOgInCEFdiqUwUdmIcy5K10c2pXS OWpgMrlsiJXrGWyhmOLOMXvV4uDOkNkGgShy1jnE= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727656AbfEOLRS (ORCPT ); Wed, 15 May 2019 07:17:18 -0400 Received: from mail.kernel.org ([198.145.29.99]:54436 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730641AbfEOLRP (ORCPT ); Wed, 15 May 2019 07:17:15 -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 7445920644; Wed, 15 May 2019 11:17:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1557919034; bh=xFiCKmtsOvgoT4wK1Uqxsoxvd2pdKj+Zjdqq4SnKHgk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=LO/beIkktyGom5i/y9W4mkJMx+PgeSCqk9+r3VeE5bIjqhWHr0cOPSSi1tRFmLwac KoEPW9okYpvYP6xjotdSRcfuUq2rNhXe1y7eFh5y8LClwdFYYMiPezf4XUCr4VLPwz vT7vdrp7VijHkGEaIOG6ibBNMgvZ79EUWQGShd8k= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, "David S. Miller" , Sasha Levin Subject: [PATCH 4.14 041/115] sparc64: Make corrupted user stacks more debuggable. Date: Wed, 15 May 2019 12:55:21 +0200 Message-Id: <20190515090702.483620383@linuxfoundation.org> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190515090659.123121100@linuxfoundation.org> References: <20190515090659.123121100@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org [ Upstream commit 5b4fc3882a649c9411dd0dcad2ddb78e911d340e ] Right now if we get a corrupted user stack frame we do a do_exit(SIGILL) which is not helpful. If under a debugger, this behavior causes the inferior process to exit. So the register and other state cannot be examined at the time of the event. Instead, conditionally log a rate limited kernel log message and then force a SIGSEGV. With bits and ideas borrowed (as usual) from powerpc. Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- arch/sparc/include/asm/switch_to_64.h | 3 ++- arch/sparc/kernel/process_64.c | 25 +++++++++++++++++++------ arch/sparc/kernel/rtrap_64.S | 1 + arch/sparc/kernel/signal32.c | 12 ++++++++++-- arch/sparc/kernel/signal_64.c | 6 +++++- 5 files changed, 37 insertions(+), 10 deletions(-) diff --git a/arch/sparc/include/asm/switch_to_64.h b/arch/sparc/include/asm/switch_to_64.h index 4ff29b1406a9b..b1d4e2e3210fb 100644 --- a/arch/sparc/include/asm/switch_to_64.h +++ b/arch/sparc/include/asm/switch_to_64.h @@ -67,6 +67,7 @@ do { save_and_clear_fpu(); \ } while(0) void synchronize_user_stack(void); -void fault_in_user_windows(void); +struct pt_regs; +void fault_in_user_windows(struct pt_regs *); #endif /* __SPARC64_SWITCH_TO_64_H */ diff --git a/arch/sparc/kernel/process_64.c b/arch/sparc/kernel/process_64.c index 318efd784a0b3..5640131e2abf3 100644 --- a/arch/sparc/kernel/process_64.c +++ b/arch/sparc/kernel/process_64.c @@ -36,6 +36,7 @@ #include #include #include +#include #include #include @@ -528,7 +529,12 @@ static void stack_unaligned(unsigned long sp) force_sig_info(SIGBUS, &info, current); } -void fault_in_user_windows(void) +static const char uwfault32[] = KERN_INFO \ + "%s[%d]: bad register window fault: SP %08lx (orig_sp %08lx) TPC %08lx O7 %08lx\n"; +static const char uwfault64[] = KERN_INFO \ + "%s[%d]: bad register window fault: SP %016lx (orig_sp %016lx) TPC %08lx O7 %016lx\n"; + +void fault_in_user_windows(struct pt_regs *regs) { struct thread_info *t = current_thread_info(); unsigned long window; @@ -541,9 +547,9 @@ void fault_in_user_windows(void) do { struct reg_window *rwin = &t->reg_window[window]; int winsize = sizeof(struct reg_window); - unsigned long sp; + unsigned long sp, orig_sp; - sp = t->rwbuf_stkptrs[window]; + orig_sp = sp = t->rwbuf_stkptrs[window]; if (test_thread_64bit_stack(sp)) sp += STACK_BIAS; @@ -554,8 +560,16 @@ void fault_in_user_windows(void) stack_unaligned(sp); if (unlikely(copy_to_user((char __user *)sp, - rwin, winsize))) + rwin, winsize))) { + if (show_unhandled_signals) + printk_ratelimited(is_compat_task() ? + uwfault32 : uwfault64, + current->comm, current->pid, + sp, orig_sp, + regs->tpc, + regs->u_regs[UREG_I7]); goto barf; + } } while (window--); } set_thread_wsaved(0); @@ -563,8 +577,7 @@ void fault_in_user_windows(void) barf: set_thread_wsaved(window + 1); - user_exit(); - do_exit(SIGILL); + force_sig(SIGSEGV, current); } asmlinkage long sparc_do_fork(unsigned long clone_flags, diff --git a/arch/sparc/kernel/rtrap_64.S b/arch/sparc/kernel/rtrap_64.S index 0b21042ab181b..ad88d60bb740c 100644 --- a/arch/sparc/kernel/rtrap_64.S +++ b/arch/sparc/kernel/rtrap_64.S @@ -30,6 +30,7 @@ __handle_preemption: wrpr %g0, RTRAP_PSTATE_IRQOFF, %pstate __handle_user_windows: + add %sp, PTREGS_OFF, %o0 call fault_in_user_windows wrpr %g0, RTRAP_PSTATE, %pstate ba,pt %xcc, __handle_preemption_continue diff --git a/arch/sparc/kernel/signal32.c b/arch/sparc/kernel/signal32.c index 5c572de64c748..879f8d86bc21c 100644 --- a/arch/sparc/kernel/signal32.c +++ b/arch/sparc/kernel/signal32.c @@ -442,7 +442,11 @@ static int setup_frame32(struct ksignal *ksig, struct pt_regs *regs, get_sigframe(ksig, regs, sigframe_size); if (invalid_frame_pointer(sf, sigframe_size)) { - do_exit(SIGILL); + if (show_unhandled_signals) + pr_info("%s[%d] bad frame in setup_frame32: %08lx TPC %08lx O7 %08lx\n", + current->comm, current->pid, (unsigned long)sf, + regs->tpc, regs->u_regs[UREG_I7]); + force_sigsegv(ksig->sig, current); return -EINVAL; } @@ -573,7 +577,11 @@ static int setup_rt_frame32(struct ksignal *ksig, struct pt_regs *regs, get_sigframe(ksig, regs, sigframe_size); if (invalid_frame_pointer(sf, sigframe_size)) { - do_exit(SIGILL); + if (show_unhandled_signals) + pr_info("%s[%d] bad frame in setup_rt_frame32: %08lx TPC %08lx O7 %08lx\n", + current->comm, current->pid, (unsigned long)sf, + regs->tpc, regs->u_regs[UREG_I7]); + force_sigsegv(ksig->sig, current); return -EINVAL; } diff --git a/arch/sparc/kernel/signal_64.c b/arch/sparc/kernel/signal_64.c index 20426a1c28f29..2d0a50bde3f96 100644 --- a/arch/sparc/kernel/signal_64.c +++ b/arch/sparc/kernel/signal_64.c @@ -373,7 +373,11 @@ setup_rt_frame(struct ksignal *ksig, struct pt_regs *regs) get_sigframe(ksig, regs, sf_size); if (invalid_frame_pointer (sf)) { - do_exit(SIGILL); /* won't return, actually */ + if (show_unhandled_signals) + pr_info("%s[%d] bad frame in setup_rt_frame: %016lx TPC %016lx O7 %016lx\n", + current->comm, current->pid, (unsigned long)sf, + regs->tpc, regs->u_regs[UREG_I7]); + force_sigsegv(ksig->sig, current); return -EINVAL; } -- 2.20.1