From patchwork Thu Apr 2 19:17:32 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Lee Jones X-Patchwork-Id: 228226 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=-9.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,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 5C2FAC43331 for ; Thu, 2 Apr 2020 19:17:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 34E94206F8 for ; Thu, 2 Apr 2020 19:17:08 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=linaro.org header.i=@linaro.org header.b="H9rIX5St" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388822AbgDBTRH (ORCPT ); Thu, 2 Apr 2020 15:17:07 -0400 Received: from mail-wr1-f65.google.com ([209.85.221.65]:40076 "EHLO mail-wr1-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388761AbgDBTRH (ORCPT ); Thu, 2 Apr 2020 15:17:07 -0400 Received: by mail-wr1-f65.google.com with SMTP id s8so3459840wrt.7 for ; Thu, 02 Apr 2020 12:17:04 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=from:to:subject:date:message-id:in-reply-to:references:mime-version :content-transfer-encoding; bh=BeyLphkFLnP4CTEflF/utnlR8G5qa5q59+49c7r8kS0=; b=H9rIX5St6Cpc0s13sla67hTjy0gu9/KMBi9l9yyxjUWgyVd+RkKIVUiQ6r6xdWTewq AHGJ9M5wOC681pQIAiewupxW6poqX5IKF+o7LQUKondRb8PmlaWzexY5vPP1VYcLix8N XsAXVOLxlD/4npfDf6ZiOLb8ds5m0DWuaGPg4HaPYZf+BTGijTGIM1OoOU/sK+K3xNTp jyUu3Ey0nBlIuKgGWSdcmiWttD7OO9GBpFjuAkemJSVjnbDKAk0dqgFwRQvHN2Yki5DX fwqRVsvPmV85lDHOIpBpPao0ZzTrkMmr5dZgVrqQNOv7yUu/4HWdVVIiebk93Nw3IZGs EaiQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=BeyLphkFLnP4CTEflF/utnlR8G5qa5q59+49c7r8kS0=; b=GJUDqXqmuH0JC5gVYq+BTK6zjcL//rk4outw5vwRu5SHQkRLMEZ7Jww/pQ0qnFOM8Z D/h9nX8RJ5Nojtr0GsjzUiUC15WWQgYuRoxKfMGsK/KWWGVdiFpxFe2DD6Wm/CPQQdf9 HESg3G/GTWHIvdNrqQsZ5CTjUjlxTJPJiCysX0CJh+EIRzx4018PB7kAljuGof++4fL9 /pna/rVhYKTh+LNAowoXvn9pE/kyz/2MXyV9pLbBINTmKRa5GU74EUFb85cqdkvies/B /QZkttD9l4GOCQsHeoSHTi9FNgxQSuVaWSKHUbmwqtkgdKWiiPOguIuf5x2c81cQw/BK yQlA== X-Gm-Message-State: AGi0PuZsEHJYOAgnfAPCh09KJ1FCe+5Vx0muH38lufWrLlyOZPsQUjq3 t6SitcKyw4ikDFvVPCiFAoaytDAHAhb51Q== X-Google-Smtp-Source: APiQypIAyytBz78o0nSdrTAMzff/UMtf/Rwh17hChZaTZhUjbZj/2N28mduUI1BbqhNyOTEE1MZ3sQ== X-Received: by 2002:adf:ff81:: with SMTP id j1mr4880611wrr.171.1585855023297; Thu, 02 Apr 2020 12:17:03 -0700 (PDT) Received: from localhost.localdomain ([95.149.164.95]) by smtp.gmail.com with ESMTPSA id y1sm879050wmd.14.2020.04.02.12.17.02 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 02 Apr 2020 12:17:02 -0700 (PDT) From: Lee Jones To: stable@vger.kernel.org Subject: [PATCH 4.9 09/24] arm64: traps: Don't print stack or raw PC/LR values in backtraces Date: Thu, 2 Apr 2020 20:17:32 +0100 Message-Id: <20200402191747.789097-9-lee.jones@linaro.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200402191747.789097-1-lee.jones@linaro.org> References: <20200402191747.789097-1-lee.jones@linaro.org> MIME-Version: 1.0 Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Will Deacon [ Upstream commit a25ffd3a6302a67814280274d8f1aa4ae2ea4b59 ] Printing raw pointer values in backtraces has potential security implications and are of questionable value anyway. This patch follows x86's lead and removes the "Exception stack:" dump from kernel backtraces, as well as converting PC/LR values to symbols such as "sysrq_handle_crash+0x20/0x30". Tested-by: Laura Abbott Signed-off-by: Will Deacon Signed-off-by: Lee Jones --- arch/arm64/kernel/process.c | 8 ++-- arch/arm64/kernel/traps.c | 74 ++----------------------------------- 2 files changed, 6 insertions(+), 76 deletions(-) diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c index e917d119490ce..6b073a31eec1c 100644 --- a/arch/arm64/kernel/process.c +++ b/arch/arm64/kernel/process.c @@ -182,11 +182,9 @@ void __show_regs(struct pt_regs *regs) } show_regs_print_info(KERN_DEFAULT); - print_symbol("PC is at %s\n", instruction_pointer(regs)); - print_symbol("LR is at %s\n", lr); - printk("pc : [<%016llx>] lr : [<%016llx>] pstate: %08llx\n", - regs->pc, lr, regs->pstate); - printk("sp : %016llx\n", sp); + print_symbol("pc : %s\n", regs->pc); + print_symbol("lr : %s\n", lr); + printk("sp : %016llx pstate : %08llx\n", sp, regs->pstate); i = top_reg; diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c index 5962badb33462..ac73d8d8cd81d 100644 --- a/arch/arm64/kernel/traps.c +++ b/arch/arm64/kernel/traps.c @@ -52,55 +52,9 @@ static const char *handler[]= { int show_unhandled_signals = 0; -/* - * Dump out the contents of some kernel memory nicely... - */ -static void dump_mem(const char *lvl, const char *str, unsigned long bottom, - unsigned long top) -{ - unsigned long first; - mm_segment_t fs; - int i; - - /* - * We need to switch to kernel mode so that we can use __get_user - * to safely read from kernel space. - */ - fs = get_fs(); - set_fs(KERNEL_DS); - - printk("%s%s(0x%016lx to 0x%016lx)\n", lvl, str, bottom, top); - - for (first = bottom & ~31; first < top; first += 32) { - unsigned long p; - char str[sizeof(" 12345678") * 8 + 1]; - - memset(str, ' ', sizeof(str)); - str[sizeof(str) - 1] = '\0'; - - for (p = first, i = 0; i < (32 / 8) - && p < top; i++, p += 8) { - if (p >= bottom && p < top) { - unsigned long val; - - if (__get_user(val, (unsigned long *)p) == 0) - sprintf(str + i * 17, " %016lx", val); - else - sprintf(str + i * 17, " ????????????????"); - } - } - printk("%s%04lx:%s\n", lvl, first & 0xffff, str); - } - - set_fs(fs); -} - static void dump_backtrace_entry(unsigned long where) { - /* - * Note that 'where' can have a physical address, but it's not handled. - */ - print_ip_sym(where); + printk(" %pS\n", (void *)where); } static void __dump_instr(const char *lvl, struct pt_regs *regs) @@ -174,10 +128,8 @@ static void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk) skip = !!regs; printk("Call trace:\n"); - while (1) { + do { unsigned long where = frame.pc; - unsigned long stack; - int ret; /* skip until specified stack frame */ if (!skip) { @@ -193,25 +145,7 @@ static void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk) */ dump_backtrace_entry(regs->pc); } - ret = unwind_frame(tsk, &frame); - if (ret < 0) - break; - stack = frame.sp; - if (in_exception_text(where)) { - /* - * If we switched to the irq_stack before calling this - * exception handler, then the pt_regs will be on the - * task stack. The easiest way to tell is if the large - * pt_regs would overlap with the end of the irq_stack. - */ - if (stack < irq_stack_ptr && - (stack + sizeof(struct pt_regs)) > irq_stack_ptr) - stack = IRQ_STACK_TO_TASK_STACK(irq_stack_ptr); - - dump_mem("", "Exception stack", stack, - stack + sizeof(struct pt_regs)); - } - } + } while (!unwind_frame(tsk, &frame)); } void show_stack(struct task_struct *tsk, unsigned long *sp) @@ -248,8 +182,6 @@ static int __die(const char *str, int err, struct thread_info *thread, TASK_COMM_LEN, tsk->comm, task_pid_nr(tsk), thread + 1); if (!user_mode(regs)) { - dump_mem(KERN_EMERG, "Stack: ", regs->sp, - THREAD_SIZE + (unsigned long)task_stack_page(tsk)); dump_backtrace(regs, tsk); dump_instr(KERN_EMERG, regs); }