From patchwork Fri May 27 14:51:54 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Peter Maydell X-Patchwork-Id: 9138619 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 721DA6075A for ; Fri, 27 May 2016 15:00:28 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 650AA27F17 for ; Fri, 27 May 2016 15:00:28 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 58E5027B90; Fri, 27 May 2016 15:00:28 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 0B47027B90 for ; Fri, 27 May 2016 15:00:28 +0000 (UTC) Received: from localhost ([::1]:46472 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1b6JFT-0007dC-4b for patchwork-qemu-devel@patchwork.kernel.org; Fri, 27 May 2016 11:00:27 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:49548) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1b6J9X-0002Pg-BB for qemu-devel@nongnu.org; Fri, 27 May 2016 10:54:20 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1b6J9V-0005nc-As for qemu-devel@nongnu.org; Fri, 27 May 2016 10:54:18 -0400 Received: from orth.archaic.org.uk ([2001:8b0:1d0::2]:57388) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1b6J9V-0005mS-47 for qemu-devel@nongnu.org; Fri, 27 May 2016 10:54:17 -0400 Received: from pm215 by orth.archaic.org.uk with local (Exim 4.84_2) (envelope-from ) id 1b6J7Q-0004l7-1p; Fri, 27 May 2016 15:52:08 +0100 From: Peter Maydell To: qemu-devel@nongnu.org Date: Fri, 27 May 2016 15:51:54 +0100 Message-Id: <1464360721-14359-13-git-send-email-peter.maydell@linaro.org> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1464360721-14359-1-git-send-email-peter.maydell@linaro.org> References: <1464360721-14359-1-git-send-email-peter.maydell@linaro.org> X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 2001:8b0:1d0::2 Subject: [Qemu-devel] [PATCH v2 12/19] linux-user: Block signals during sigaction() handling X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Riku Voipio , Timothy Edward Baldwin , patches@linaro.org Errors-To: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" X-Virus-Scanned: ClamAV using ClamSMTP From: Timothy E Baldwin Block signals while emulating sigaction. This is a non-interruptible syscall, and using block_signals() avoids races where the host signal handler is invoked and tries to examine the signal handler data structures while we are updating them. Signed-off-by: Timothy Edward Baldwin Message-id: 1441497448-32489-29-git-send-email-T.E.Baldwin99@members.leeds.ac.uk [PMM: expanded commit message] Reviewed-by: Peter Maydell Signed-off-by: Peter Maydell --- linux-user/signal.c | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) diff --git a/linux-user/signal.c b/linux-user/signal.c index f489028..b21d6bf 100644 --- a/linux-user/signal.c +++ b/linux-user/signal.c @@ -640,7 +640,7 @@ out: return ret; } -/* do_sigaction() return host values and errnos */ +/* do_sigaction() return target values and host errnos */ int do_sigaction(int sig, const struct target_sigaction *act, struct target_sigaction *oact) { @@ -649,8 +649,14 @@ int do_sigaction(int sig, const struct target_sigaction *act, int host_sig; int ret = 0; - if (sig < 1 || sig > TARGET_NSIG || sig == TARGET_SIGKILL || sig == TARGET_SIGSTOP) - return -EINVAL; + if (sig < 1 || sig > TARGET_NSIG || sig == TARGET_SIGKILL || sig == TARGET_SIGSTOP) { + return -TARGET_EINVAL; + } + + if (block_signals()) { + return -TARGET_ERESTARTSYS; + } + k = &sigact_table[sig - 1]; if (oact) { __put_user(k->_sa_handler, &oact->_sa_handler);