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=-3.0 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS, T_DKIMWL_WL_HIGH,UNWANTED_LANGUAGE_BODY,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham 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 C1579C32789 for ; Fri, 2 Nov 2018 18:46:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8A3D220847 for ; Fri, 2 Nov 2018 18:46:00 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="AQDjwEiY" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8A3D220847 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linuxfoundation.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730302AbeKCDyL (ORCPT ); Fri, 2 Nov 2018 23:54:11 -0400 Received: from mail.kernel.org ([198.145.29.99]:50040 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729136AbeKCDyL (ORCPT ); Fri, 2 Nov 2018 23:54:11 -0400 Received: from localhost (5356596B.cm-6-7b.dynamic.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 AB4582084A; Fri, 2 Nov 2018 18:45:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1541184357; bh=VNSbBlSGdwHJgPvZ+XJdYJvSFpvdqNq5Odqko+duQgw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=AQDjwEiYcRPvZiFW3czPu12vCVYHZazpYjCY70wUozUgTqIgI4wCmEAXLWQush1v4 qc1Ge3AP2vbffhJnj5vI8Zfc02Z5oQ+U6PTYGHnuivdGhtpJAQJJBmoA2AJrbgolD5 L7TcTLjtNxObPdYJ8tCTM+NxsT8gbMW3nEso4EvE= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, "David S. Miller" Subject: [PATCH 4.18 143/150] sparc64: Make corrupted user stacks more debuggable. Date: Fri, 2 Nov 2018 19:35:05 +0100 Message-Id: <20181102182912.436326786@linuxfoundation.org> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20181102182902.250560510@linuxfoundation.org> References: <20181102182902.250560510@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: David Miller [ 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: Greg Kroah-Hartman --- 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(-) --- 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 */ --- a/arch/sparc/kernel/process_64.c +++ b/arch/sparc/kernel/process_64.c @@ -36,6 +36,7 @@ #include #include #include +#include #include #include @@ -521,7 +522,12 @@ static void stack_unaligned(unsigned lon force_sig_fault(SIGBUS, BUS_ADRALN, (void __user *) sp, 0, 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; @@ -534,9 +540,9 @@ 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; @@ -547,8 +553,16 @@ 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); @@ -556,8 +570,7 @@ 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, --- a/arch/sparc/kernel/rtrap_64.S +++ b/arch/sparc/kernel/rtrap_64.S @@ -39,6 +39,7 @@ __handle_preemption: wrpr %g0, RTRAP_PSTATE_IRQOFF, %pstate __handle_user_windows: + add %sp, PTREGS_OFF, %o0 call fault_in_user_windows 661: wrpr %g0, RTRAP_PSTATE, %pstate /* If userspace is using ADI, it could potentially pass --- a/arch/sparc/kernel/signal32.c +++ b/arch/sparc/kernel/signal32.c @@ -371,7 +371,11 @@ static int setup_frame32(struct ksignal 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; } @@ -501,7 +505,11 @@ static int setup_rt_frame32(struct ksign 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; } --- a/arch/sparc/kernel/signal_64.c +++ b/arch/sparc/kernel/signal_64.c @@ -370,7 +370,11 @@ setup_rt_frame(struct ksignal *ksig, str 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; }