From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753474AbcGVBJV (ORCPT ); Thu, 21 Jul 2016 21:09:21 -0400 Received: from mail-it0-f50.google.com ([209.85.214.50]:37717 "EHLO mail-it0-f50.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752814AbcGVBJT (ORCPT ); Thu, 21 Jul 2016 21:09:19 -0400 Date: Thu, 21 Jul 2016 18:08:59 -0700 From: Sargun Dhillon To: linux-kernel@vger.kernel.org, netdev@vger.kernel.org Cc: alexei.starovoitov@gmail.com, daniel@iogearbox.net Subject: [PATCH v4 0/2] bpf: add bpf_probe_write helper & example Message-ID: <20160722010856.GA22966@ircssh.c.rugged-nimbus-611.internal> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This patch series contains two patches that add support for a probe_write helper to BPF programs. This allows them to manipulate user memory during the course of tracing. The second patch in the series has an example that uses it, in one the intended ways to divert execution. Thanks to Alexei Starovoitov, and Daniel Borkmann for review, I've made changes based on their recommendations. This helper should be considered experimental, so we print a warning to dmesg when it is first invoked. Subsequent invocations print the command and pid --- v1->v2: restrict writing to user space, as opposed to globally v2->v3: Fixed formatting issues v3->v4: Rename copy_to_user -> bpf_probe_write Simplify checking of whether or not it's safe to write Add warnings to dmesg Sargun Dhillon (2): bpf: Add bpf_probe_write BPF helper to be called in tracers (kprobes) samples/bpf: Add example of using bpf_probe_write in bpf kprobes include/uapi/linux/bpf.h | 12 ++++++++ kernel/bpf/verifier.c | 9 ++++++ kernel/trace/bpf_trace.c | 37 +++++++++++++++++++++++ samples/bpf/Makefile | 4 +++ samples/bpf/bpf_helpers.h | 2 ++ samples/bpf/tracex7_kern.c | 51 +++++++++++++++++++++++++++++++ samples/bpf/tracex7_user.c | 75 ++++++++++++++++++++++++++++++++++++++++++++++ 7 files changed, 190 insertions(+) create mode 100644 samples/bpf/tracex7_kern.c create mode 100644 samples/bpf/tracex7_user.c -- 2.7.4