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=-9.0 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,T_DKIMWL_WL_HIGH,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 58AE0C43219 for ; Thu, 2 May 2019 15:42:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 24380204EC for ; Thu, 2 May 2019 15:42:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1556811737; bh=qDtKRsWuIMmZcc4ZwSMKLWL+HFxXnroOuOmeguBr7aE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=wIWPIgadUcvjD4RIZduMfqIitwvx9HjsZzfBuaiobJMOwPowWlUusBICeM/c+lFXP e0cwRFuRTXwkS0vC047MDZ//o9xmSo1EVQH7PjB4Wc5WrmY+qkXQ8tpxZqC023lemf sQZKOUUmFgytXNkruYTB37aFHUTteqArFWUHzsqc= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728175AbfEBP2S (ORCPT ); Thu, 2 May 2019 11:28:18 -0400 Received: from mail.kernel.org ([198.145.29.99]:45416 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727254AbfEBP2Q (ORCPT ); Thu, 2 May 2019 11:28:16 -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 46A2920449; Thu, 2 May 2019 15:28:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1556810895; bh=qDtKRsWuIMmZcc4ZwSMKLWL+HFxXnroOuOmeguBr7aE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=oNvN78cQqA3uJHGYXedWeVpB7WV3MutYMsdJzW6V2ZITURHuJqJ7UEiOBMt1W5w5k miKA9JVTvwMLjnWfpOG4xisTaHurxJV9W/rUHSDeiK795F971mJEqDhXUFGLn7EX3o JnL9Bi0f2ZVP0/s/XvIxPadLS2yQhr/016Qj83YU= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Andrei Vagin , Oleg Nesterov , "Eric W. Biederman" , Andrew Morton , Linus Torvalds , "Sasha Levin (Microsoft)" Subject: [PATCH 4.19 70/72] ptrace: take into account saved_sigmask in PTRACE{GET,SET}SIGMASK Date: Thu, 2 May 2019 17:21:32 +0200 Message-Id: <20190502143338.821505814@linuxfoundation.org> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190502143333.437607839@linuxfoundation.org> References: <20190502143333.437607839@linuxfoundation.org> User-Agent: quilt/0.66 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 [ Upstream commit fcfc2aa0185f4a731d05a21e9f359968fdfd02e7 ] There are a few system calls (pselect, ppoll, etc) which replace a task sigmask while they are running in a kernel-space When a task calls one of these syscalls, the kernel saves a current sigmask in task->saved_sigmask and sets a syscall sigmask. On syscall-exit-stop, ptrace traps a task before restoring the saved_sigmask, so PTRACE_GETSIGMASK returns the syscall sigmask and PTRACE_SETSIGMASK does nothing, because its sigmask is replaced by saved_sigmask, when the task returns to user-space. This patch fixes this problem. PTRACE_GETSIGMASK returns saved_sigmask if it's set. PTRACE_SETSIGMASK drops the TIF_RESTORE_SIGMASK flag. Link: http://lkml.kernel.org/r/20181120060616.6043-1-avagin@gmail.com Fixes: 29000caecbe8 ("ptrace: add ability to get/set signal-blocked mask") Signed-off-by: Andrei Vagin Acked-by: Oleg Nesterov Cc: "Eric W. Biederman" Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin (Microsoft) --- include/linux/sched/signal.h | 18 ++++++++++++++++++ kernel/ptrace.c | 15 +++++++++++++-- 2 files changed, 31 insertions(+), 2 deletions(-) diff --git a/include/linux/sched/signal.h b/include/linux/sched/signal.h index 1be35729c2c5..660d78c9af6c 100644 --- a/include/linux/sched/signal.h +++ b/include/linux/sched/signal.h @@ -417,10 +417,20 @@ static inline void set_restore_sigmask(void) set_thread_flag(TIF_RESTORE_SIGMASK); WARN_ON(!test_thread_flag(TIF_SIGPENDING)); } + +static inline void clear_tsk_restore_sigmask(struct task_struct *tsk) +{ + clear_tsk_thread_flag(tsk, TIF_RESTORE_SIGMASK); +} + static inline void clear_restore_sigmask(void) { clear_thread_flag(TIF_RESTORE_SIGMASK); } +static inline bool test_tsk_restore_sigmask(struct task_struct *tsk) +{ + return test_tsk_thread_flag(tsk, TIF_RESTORE_SIGMASK); +} static inline bool test_restore_sigmask(void) { return test_thread_flag(TIF_RESTORE_SIGMASK); @@ -438,6 +448,10 @@ static inline void set_restore_sigmask(void) current->restore_sigmask = true; WARN_ON(!test_thread_flag(TIF_SIGPENDING)); } +static inline void clear_tsk_restore_sigmask(struct task_struct *tsk) +{ + tsk->restore_sigmask = false; +} static inline void clear_restore_sigmask(void) { current->restore_sigmask = false; @@ -446,6 +460,10 @@ static inline bool test_restore_sigmask(void) { return current->restore_sigmask; } +static inline bool test_tsk_restore_sigmask(struct task_struct *tsk) +{ + return tsk->restore_sigmask; +} static inline bool test_and_clear_restore_sigmask(void) { if (!current->restore_sigmask) diff --git a/kernel/ptrace.c b/kernel/ptrace.c index 21fec73d45d4..fc0d667f5792 100644 --- a/kernel/ptrace.c +++ b/kernel/ptrace.c @@ -29,6 +29,7 @@ #include #include #include +#include /* * Access another process' address space via ptrace. @@ -925,18 +926,26 @@ int ptrace_request(struct task_struct *child, long request, ret = ptrace_setsiginfo(child, &siginfo); break; - case PTRACE_GETSIGMASK: + case PTRACE_GETSIGMASK: { + sigset_t *mask; + if (addr != sizeof(sigset_t)) { ret = -EINVAL; break; } - if (copy_to_user(datavp, &child->blocked, sizeof(sigset_t))) + if (test_tsk_restore_sigmask(child)) + mask = &child->saved_sigmask; + else + mask = &child->blocked; + + if (copy_to_user(datavp, mask, sizeof(sigset_t))) ret = -EFAULT; else ret = 0; break; + } case PTRACE_SETSIGMASK: { sigset_t new_set; @@ -962,6 +971,8 @@ int ptrace_request(struct task_struct *child, long request, child->blocked = new_set; spin_unlock_irq(&child->sighand->siglock); + clear_tsk_restore_sigmask(child); + ret = 0; break; } -- 2.19.1