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=-16.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,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 0E53AC43464 for ; Fri, 18 Sep 2020 03:08:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id AEA29206DB for ; Fri, 18 Sep 2020 03:08:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600398519; bh=3UzKPJpQ37RhRn+1oYQIhbxWLpk7fMNkZoK9Ve7/WU8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=moF2MZQy0P3/nFvbjhJmdAWGatWJmUb00doa5pp96T1O5wRsfaAPshKR8y5PsIImu yVTpYLJJPrnZO6fhFQIW5BHq/3pzwdek8glzUJ1E4Ro3Y+QNmTk+f6MwSSKAheNJT/ AmwfRuwnO6s5Xo2XfLnQXqg+MzIYsjtvmxqP6WsI= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730439AbgIRDIi (ORCPT ); Thu, 17 Sep 2020 23:08:38 -0400 Received: from mail.kernel.org ([198.145.29.99]:49398 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727033AbgIRCDT (ORCPT ); Thu, 17 Sep 2020 22:03:19 -0400 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 263F421734; Fri, 18 Sep 2020 02:03:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600394598; bh=3UzKPJpQ37RhRn+1oYQIhbxWLpk7fMNkZoK9Ve7/WU8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=PF0vUiatpdYfODYD7Ow8pkjgOqHD+ojKe/FHLOYOtmdRIgayCb2rG55BS4Q1yDKMj 8rhr/eqtO38MU1hMLbMZRtkb92854TMqiiSuYY91oC51KdYai2tYv4/CjDk26Tc+jq FDl1+8ypEUt2UE1DIS7YdYvarKjW52KyuFgBPf5w= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Vincent Whitchurch , Russell King , Sasha Levin , linux-arm-kernel@lists.infradead.org Subject: [PATCH AUTOSEL 5.4 106/330] ARM: 8948/1: Prevent OOB access in stacktrace Date: Thu, 17 Sep 2020 21:57:26 -0400 Message-Id: <20200918020110.2063155-106-sashal@kernel.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200918020110.2063155-1-sashal@kernel.org> References: <20200918020110.2063155-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Vincent Whitchurch [ Upstream commit 40ff1ddb5570284e039e0ff14d7a859a73dc3673 ] The stacktrace code can read beyond the stack size, when it attempts to read pt_regs from exception frames. This can happen on normal, non-corrupt stacks. Since the unwind information in the extable is not correct for function prologues, the unwinding code can return data from the stack which is not actually the caller function address, and if in_entry_text() happens to succeed on this value, we can end up reading data from outside the task's stack when attempting to read pt_regs, since there is no bounds check. Example: [<8010e729>] (unwind_backtrace) from [<8010a9c9>] (show_stack+0x11/0x14) [<8010a9c9>] (show_stack) from [<8057d8d7>] (dump_stack+0x87/0xac) [<8057d8d7>] (dump_stack) from [<8012271d>] (tasklet_action_common.constprop.4+0xa5/0xa8) [<8012271d>] (tasklet_action_common.constprop.4) from [<80102333>] (__do_softirq+0x11b/0x31c) [<80102333>] (__do_softirq) from [<80122485>] (irq_exit+0xad/0xd8) [<80122485>] (irq_exit) from [<8015f3d7>] (__handle_domain_irq+0x47/0x84) [<8015f3d7>] (__handle_domain_irq) from [<8036a523>] (gic_handle_irq+0x43/0x78) [<8036a523>] (gic_handle_irq) from [<80101a49>] (__irq_svc+0x69/0xb4) Exception stack(0xeb491f58 to 0xeb491fa0) 1f40: 7eb14794 00000000 1f60: ffffffff 008dd32c 008dd324 ffffffff 008dd314 0000002a 801011e4 eb490000 1f80: 0000002a 7eb1478c 50c5387d eb491fa8 80101001 8023d09c 40080033 ffffffff [<80101a49>] (__irq_svc) from [<8023d09c>] (do_pipe2+0x0/0xac) [<8023d09c>] (do_pipe2) from [] (0xffffffff) Exception stack(0xeb491fc8 to 0xeb492010) 1fc0: 008dd314 0000002a 00511ad8 008de4c8 7eb14790 7eb1478c 1fe0: 00511e34 7eb14774 004c8557 76f44098 60080030 7eb14794 00000000 00000000 2000: 00000001 00000000 ea846c00 ea847cc0 In this example, the stack limit is 0xeb492000, but 16 bytes outside the stack have been read. Fix it by adding bounds checks. Signed-off-by: Vincent Whitchurch Signed-off-by: Russell King Signed-off-by: Sasha Levin --- arch/arm/kernel/stacktrace.c | 2 ++ arch/arm/kernel/traps.c | 6 ++++-- 2 files changed, 6 insertions(+), 2 deletions(-) diff --git a/arch/arm/kernel/stacktrace.c b/arch/arm/kernel/stacktrace.c index a082f6e4f0f4a..76ea4178a55cb 100644 --- a/arch/arm/kernel/stacktrace.c +++ b/arch/arm/kernel/stacktrace.c @@ -116,6 +116,8 @@ static int save_trace(struct stackframe *frame, void *d) return 0; regs = (struct pt_regs *)frame->sp; + if ((unsigned long)®s[1] > ALIGN(frame->sp, THREAD_SIZE)) + return 0; trace->entries[trace->nr_entries++] = regs->ARM_pc; diff --git a/arch/arm/kernel/traps.c b/arch/arm/kernel/traps.c index c053abd1fb539..97a512551b217 100644 --- a/arch/arm/kernel/traps.c +++ b/arch/arm/kernel/traps.c @@ -64,14 +64,16 @@ static void dump_mem(const char *, const char *, unsigned long, unsigned long); void dump_backtrace_entry(unsigned long where, unsigned long from, unsigned long frame) { + unsigned long end = frame + 4 + sizeof(struct pt_regs); + #ifdef CONFIG_KALLSYMS printk("[<%08lx>] (%ps) from [<%08lx>] (%pS)\n", where, (void *)where, from, (void *)from); #else printk("Function entered at [<%08lx>] from [<%08lx>]\n", where, from); #endif - if (in_entry_text(from)) - dump_mem("", "Exception stack", frame + 4, frame + 4 + sizeof(struct pt_regs)); + if (in_entry_text(from) && end <= ALIGN(frame, THREAD_SIZE)) + dump_mem("", "Exception stack", frame + 4, end); } void dump_backtrace_stm(u32 *stack, u32 instruction) -- 2.25.1