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=-19.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,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 1CC63C433E9 for ; Mon, 8 Mar 2021 12:32:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C4A51651C3 for ; Mon, 8 Mar 2021 12:32:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230078AbhCHMbd (ORCPT ); Mon, 8 Mar 2021 07:31:33 -0500 Received: from mail.kernel.org ([198.145.29.99]:40472 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229757AbhCHMbI (ORCPT ); Mon, 8 Mar 2021 07:31:08 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 2BDC364EBC; Mon, 8 Mar 2021 12:31:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1615206667; bh=aaZGSCPB3/0imlRKgvnEmmG7FWVeoTA9PuWRxWqkgNo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=BZvSyYIcv7tNx+3PJMOFGODbrjVAbSFwfA8QjkJZ+OJVGgfMgo55Tz41D7NVSvhIs UyqwQFfGJpukTGll0leE2jOUU43MoOA6mZOsTe6uX6L7ciPBdSy6/WV6lhpf654lqb 7Zx62OKWZLXn7eTyuNeZhiciW6doTPbSbA6dc6YY= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Oleg Nesterov , Catalin Marinas , Kees Cook , Sudeep Holla , Timothy E Baldwin , Will Deacon Subject: [PATCH 5.4 13/22] arm64: ptrace: Fix seccomp of traced syscall -1 (NO_SYSCALL) Date: Mon, 8 Mar 2021 13:30:30 +0100 Message-Id: <20210308122715.036978550@linuxfoundation.org> X-Mailer: git-send-email 2.30.1 In-Reply-To: <20210308122714.391917404@linuxfoundation.org> References: <20210308122714.391917404@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Timothy E Baldwin commit df84fe94708985cdfb78a83148322bcd0a699472 upstream. Since commit f086f67485c5 ("arm64: ptrace: add support for syscall emulation"), if system call number -1 is called and the process is being traced with PTRACE_SYSCALL, for example by strace, the seccomp check is skipped and -ENOSYS is returned unconditionally (unless altered by the tracer) rather than carrying out action specified in the seccomp filter. The consequence of this is that it is not possible to reliably strace a seccomp based implementation of a foreign system call interface in which r7/x8 is permitted to be -1 on entry to a system call. Also trace_sys_enter and audit_syscall_entry are skipped if a system call is skipped. Fix by removing the in_syscall(regs) check restoring the previous behaviour which is like AArch32, x86 (which uses generic code) and everything else. Cc: Oleg Nesterov Cc: Catalin Marinas Cc: Fixes: f086f67485c5 ("arm64: ptrace: add support for syscall emulation") Reviewed-by: Kees Cook Reviewed-by: Sudeep Holla Tested-by: Sudeep Holla Signed-off-by: Timothy E Baldwin Link: https://lore.kernel.org/r/90edd33b-6353-1228-791f-0336d94d5f8c@majoroak.me.uk Signed-off-by: Will Deacon Signed-off-by: Greg Kroah-Hartman --- arch/arm64/kernel/ptrace.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/arch/arm64/kernel/ptrace.c +++ b/arch/arm64/kernel/ptrace.c @@ -1844,7 +1844,7 @@ int syscall_trace_enter(struct pt_regs * if (flags & (_TIF_SYSCALL_EMU | _TIF_SYSCALL_TRACE)) { tracehook_report_syscall(regs, PTRACE_SYSCALL_ENTER); - if (!in_syscall(regs) || (flags & _TIF_SYSCALL_EMU)) + if (flags & _TIF_SYSCALL_EMU) return -1; }