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=-10.1 required=3.0 tests=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 8017AC7618B for ; Fri, 26 Jul 2019 13:56:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 513C222CE5 for ; Fri, 26 Jul 2019 13:56:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1564149405; bh=nzndwPSgzd3yxlgIMwo/8KxyQSBYjo653wm/221bf28=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=gEBn/2G776zx8CN9dLePO7PYYmUBr09fCrMDCFm6f//Oi6RZ7t+EygjuPSk+1TOnN we0i1r56DOg3gfzapbTFWcrFb0F5rJejav3hmM5Dn+Z8gnp+4z4WH+vfE0nLW3fAGQ dFV6B+p14VeCckAFsVX+gLT3Fg0Z4c6vpcZDfTGo= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728504AbfGZN4o (ORCPT ); Fri, 26 Jul 2019 09:56:44 -0400 Received: from mail.kernel.org ([198.145.29.99]:48400 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387753AbfGZNlr (ORCPT ); Fri, 26 Jul 2019 09:41:47 -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 9003A22CD4; Fri, 26 Jul 2019 13:41:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1564148506; bh=nzndwPSgzd3yxlgIMwo/8KxyQSBYjo653wm/221bf28=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=HVpAbMX1NYUg2q5lNUPHRnun6wGDm5q+dxLO+PpdPmv4v7ZgxS+bU7DogomzbFJAb t3Grcezc7Tzo75QnyAUPeZoyHlzlqelDHrHDEVbphMeTELS1pYfu7AzX/vwuaMrXnf wzdo5JHw1ZKB2IAOtQYYz6ITmkbLVsEQsNb42380= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Peter Zijlstra , Vegard Nossum , Eiichi Tsukata , Thomas Gleixner , Joel Fernandes , Sasha Levin Subject: [PATCH AUTOSEL 5.2 72/85] stacktrace: Force USER_DS for stack_trace_save_user() Date: Fri, 26 Jul 2019 09:39:22 -0400 Message-Id: <20190726133936.11177-72-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190726133936.11177-1-sashal@kernel.org> References: <20190726133936.11177-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Peter Zijlstra [ Upstream commit cac9b9a4b08304f11daace03b8b48659355e44c1 ] When walking userspace stacks, USER_DS needs to be set, otherwise access_ok() will not function as expected. Reported-by: Vegard Nossum Reported-by: Eiichi Tsukata Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Thomas Gleixner Tested-by: Vegard Nossum Reviewed-by: Joel Fernandes (Google) Link: https://lkml.kernel.org/r/20190718085754.GM3402@hirez.programming.kicks-ass.net Signed-off-by: Sasha Levin --- kernel/stacktrace.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/kernel/stacktrace.c b/kernel/stacktrace.c index 36139de0a3c4..899b726c9e98 100644 --- a/kernel/stacktrace.c +++ b/kernel/stacktrace.c @@ -226,12 +226,17 @@ unsigned int stack_trace_save_user(unsigned long *store, unsigned int size) .store = store, .size = size, }; + mm_segment_t fs; /* Trace user stack if not a kernel thread */ if (!current->mm) return 0; + fs = get_fs(); + set_fs(USER_DS); arch_stack_walk_user(consume_entry, &c, task_pt_regs(current)); + set_fs(fs); + return c.len; } #endif -- 2.20.1