From patchwork Tue Jul 22 09:14:57 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: AKASHI Takahiro X-Patchwork-Id: 34024 Return-Path: X-Original-To: linaro@patches.linaro.org Delivered-To: linaro@patches.linaro.org Received: from mail-ie0-f198.google.com (mail-ie0-f198.google.com [209.85.223.198]) by ip-10-151-82-157.ec2.internal (Postfix) with ESMTPS id 9743520672 for ; Tue, 22 Jul 2014 09:15:53 +0000 (UTC) Received: by mail-ie0-f198.google.com with SMTP id rl12sf68324794iec.1 for ; Tue, 22 Jul 2014 02:15:52 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:mime-version:delivered-to:from:to:cc:subject :date:message-id:in-reply-to:references:sender:precedence:list-id :x-original-sender:x-original-authentication-results:mailing-list :list-post:list-help:list-archive:list-unsubscribe; bh=VNEt7BD5t+WY4GZT7GTYMQg8UYjhjzGiOK6jiMleklI=; b=dXowcivda49xtlU2kM2k7KXZOXrxgFaDFKCCtT8sZKMbjxwhFIGNuKUIKFA3PCFYu8 Bt35AFLOak6NHhMsadnJ3FPeNHvwvT2idOYHsmCNtnbFvT3SEfUVKrC//PiFmRssl7WN FjF4EWUlKo8SyaFmNxlWySjsxmimOGw55OgjSf0JmhzwmQW1N3KeqH4FC+Y3JWytCK8q yADKUWdHfBxFm139iiL2dTqqW821zgDQn97S0gzX41AMRa/t0rtch1up3Q8KQEd85ukP fH42OTtCn6/8CetUO32P/N9u8uOawJSSezhZFKWUhUdbkVnd30DmCmtzskLaORUbDzm/ I9iQ== X-Gm-Message-State: ALoCoQkf2Zbvr3h57/DvqBnLX8UE5WejjPIorEE5j9a3Kbr3SW4+PWCQvHUiuq9LdjpPSL8MbIm3 X-Received: by 10.182.28.5 with SMTP id x5mr16625224obg.44.1406020552658; Tue, 22 Jul 2014 02:15:52 -0700 (PDT) MIME-Version: 1.0 X-BeenThere: patchwork-forward@linaro.org Received: by 10.140.19.16 with SMTP id 16ls2420182qgg.57.gmail; Tue, 22 Jul 2014 02:15:52 -0700 (PDT) X-Received: by 10.52.0.177 with SMTP id 17mr32103132vdf.12.1406020552544; Tue, 22 Jul 2014 02:15:52 -0700 (PDT) Received: from mail-vc0-f182.google.com (mail-vc0-f182.google.com [209.85.220.182]) by mx.google.com with ESMTPS id zt9si13498616vdc.31.2014.07.22.02.15.52 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Tue, 22 Jul 2014 02:15:52 -0700 (PDT) Received-SPF: pass (google.com: domain of patch+caf_=patchwork-forward=linaro.org@linaro.org designates 209.85.220.182 as permitted sender) client-ip=209.85.220.182; Received: by mail-vc0-f182.google.com with SMTP id hy4so14749780vcb.27 for ; Tue, 22 Jul 2014 02:15:52 -0700 (PDT) X-Received: by 10.221.26.10 with SMTP id rk10mr38051202vcb.0.1406020552403; Tue, 22 Jul 2014 02:15:52 -0700 (PDT) X-Forwarded-To: patchwork-forward@linaro.org X-Forwarded-For: patch@linaro.org patchwork-forward@linaro.org Delivered-To: patch@linaro.org Received: by 10.221.37.5 with SMTP id tc5csp179988vcb; Tue, 22 Jul 2014 02:15:51 -0700 (PDT) X-Received: by 10.66.161.38 with SMTP id xp6mr15159017pab.15.1406020551510; Tue, 22 Jul 2014 02:15:51 -0700 (PDT) Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id uh4si5443588pac.46.2014.07.22.02.15.50 for ; Tue, 22 Jul 2014 02:15:50 -0700 (PDT) Received-SPF: none (google.com: linux-kernel-owner@vger.kernel.org does not designate permitted sender hosts) client-ip=209.132.180.67; Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754115AbaGVJPr (ORCPT + 12 others); Tue, 22 Jul 2014 05:15:47 -0400 Received: from mail-pd0-f170.google.com ([209.85.192.170]:63274 "EHLO mail-pd0-f170.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753869AbaGVJPp (ORCPT ); Tue, 22 Jul 2014 05:15:45 -0400 Received: by mail-pd0-f170.google.com with SMTP id g10so10914511pdj.1 for ; Tue, 22 Jul 2014 02:15:44 -0700 (PDT) X-Received: by 10.70.102.102 with SMTP id fn6mr31764634pdb.100.1406020544810; Tue, 22 Jul 2014 02:15:44 -0700 (PDT) Received: from localhost.localdomain (KD182249094163.au-net.ne.jp. [182.249.94.163]) by mx.google.com with ESMTPSA id v1sm12071461pbs.1.2014.07.22.02.15.39 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Tue, 22 Jul 2014 02:15:43 -0700 (PDT) From: AKASHI Takahiro To: wad@chromium.org, catalin.marinas@arm.com, will.deacon@arm.com, keescook@chromium.org Cc: dsaxena@linaro.org, linux-arm-kernel@lists.infradead.org, linaro-kernel@lists.linaro.org, linux-kernel@vger.kernel.org, AKASHI Takahiro Subject: [PATCH v5 1/3] arm64: ptrace: reload a syscall number after ptrace operations Date: Tue, 22 Jul 2014 18:14:57 +0900 Message-Id: <1406020499-5537-2-git-send-email-takahiro.akashi@linaro.org> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1406020499-5537-1-git-send-email-takahiro.akashi@linaro.org> References: <1406020499-5537-1-git-send-email-takahiro.akashi@linaro.org> Sender: linux-kernel-owner@vger.kernel.org Precedence: list List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-Removed-Original-Auth: Dkim didn't pass. X-Original-Sender: takahiro.akashi@linaro.org X-Original-Authentication-Results: mx.google.com; spf=pass (google.com: domain of patch+caf_=patchwork-forward=linaro.org@linaro.org designates 209.85.220.182 as permitted sender) smtp.mail=patch+caf_=patchwork-forward=linaro.org@linaro.org Mailing-list: list patchwork-forward@linaro.org; contact patchwork-forward+owners@linaro.org X-Google-Group-Id: 836684582541 List-Post: , List-Help: , List-Archive: List-Unsubscribe: , Arm64 holds a syscall number in w8(x8) register. Ptrace tracer may change its value either to: * any valid syscall number to alter a system call, or * -1 to skip a system call This patch implements this behavior by reloading that value into syscallno in struct pt_regs after tracehook_report_syscall_entry() or secure_computing(). In case of '-1', a return value of system call can also be changed by the tracer setting the value to x0 register, and so sys_ni_nosyscall() should not be called. See also: 42309ab4, ARM: 8087/1: ptrace: reload syscall number after secure_computing() check Signed-off-by: AKASHI Takahiro --- arch/arm64/kernel/entry.S | 2 ++ arch/arm64/kernel/ptrace.c | 13 +++++++++++++ 2 files changed, 15 insertions(+) diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S index 5141e79..de8bdbc 100644 --- a/arch/arm64/kernel/entry.S +++ b/arch/arm64/kernel/entry.S @@ -628,6 +628,8 @@ ENDPROC(el0_svc) __sys_trace: mov x0, sp bl syscall_trace_enter + cmp w0, #-1 // skip syscall? + b.eq ret_to_user adr lr, __sys_trace_return // return address uxtw scno, w0 // syscall number (possibly new) mov x1, sp // pointer to regs diff --git a/arch/arm64/kernel/ptrace.c b/arch/arm64/kernel/ptrace.c index 70526cf..100d7d1 100644 --- a/arch/arm64/kernel/ptrace.c +++ b/arch/arm64/kernel/ptrace.c @@ -21,6 +21,7 @@ #include #include +#include #include #include #include @@ -1109,9 +1110,21 @@ static void tracehook_report_syscall(struct pt_regs *regs, asmlinkage int syscall_trace_enter(struct pt_regs *regs) { + unsigned long saved_x0, saved_x8; + + saved_x0 = regs->regs[0]; + saved_x8 = regs->regs[8]; + if (test_thread_flag(TIF_SYSCALL_TRACE)) tracehook_report_syscall(regs, PTRACE_SYSCALL_ENTER); + regs->syscallno = regs->regs[8]; + if ((long)regs->syscallno == ~0UL) { /* skip this syscall */ + regs->regs[8] = saved_x8; + if (regs->regs[0] == saved_x0) /* not changed by user */ + regs->regs[0] = -ENOSYS; + } + if (test_thread_flag(TIF_SYSCALL_TRACEPOINT)) trace_sys_enter(regs, regs->syscallno);