From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756520AbaFYLNE (ORCPT ); Wed, 25 Jun 2014 07:13:04 -0400 Received: from ip4-83-240-18-248.cust.nbox.cz ([83.240.18.248]:41090 "EHLO ip4-83-240-18-248.cust.nbox.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754115AbaFYLHQ (ORCPT ); Wed, 25 Jun 2014 07:07:16 -0400 From: Jiri Slaby To: linux-kernel@vger.kernel.org Cc: tj@kernel.org, rostedt@goodmis.org, mingo@redhat.com, akpm@linux-foundation.org, andi@firstfloor.org, paulmck@linux.vnet.ibm.com, pavel@ucw.cz, jirislaby@gmail.com, Vojtech Pavlik , Michael Matz , Jiri Kosina , Jiri Slaby , Frederic Weisbecker Subject: [PATCH -repost 04/21] kgr: add testing kgraft patch Date: Wed, 25 Jun 2014 13:06:58 +0200 Message-Id: <1403694435-3180-4-git-send-email-jslaby@suse.cz> X-Mailer: git-send-email 2.0.0 In-Reply-To: <1403694435-3180-1-git-send-email-jslaby@suse.cz> References: <1403694435-3180-1-git-send-email-jslaby@suse.cz> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This is intended to be a presentation of the kGraft engine, so it is placed into samples/ directory. It patches two chosen functions sys_iopl() and sys_capable() to print a message in addition to the original functionality. js: fix filename in Makefile (thanks mmarek) Signed-off-by: Jiri Kosina Signed-off-by: Jiri Slaby Cc: Steven Rostedt Cc: Frederic Weisbecker Cc: Ingo Molnar --- samples/Kconfig | 4 ++ samples/Makefile | 3 +- samples/kgraft/Makefile | 1 + samples/kgraft/kgraft_patcher.c | 92 +++++++++++++++++++++++++++++++++++++++++ 4 files changed, 99 insertions(+), 1 deletion(-) create mode 100644 samples/kgraft/Makefile create mode 100644 samples/kgraft/kgraft_patcher.c diff --git a/samples/Kconfig b/samples/Kconfig index 6181c2cc9ca0..b33a397dfc58 100644 --- a/samples/Kconfig +++ b/samples/Kconfig @@ -55,6 +55,10 @@ config SAMPLE_KDB Build an example of how to dynamically add the hello command to the kdb shell. +config SAMPLE_KGRAFT_PATCHER + tristate "Build kGraft patcher example -- loadable modules only" + depends on KGRAFT && m + config SAMPLE_RPMSG_CLIENT tristate "Build rpmsg client sample -- loadable modules only" depends on RPMSG && m diff --git a/samples/Makefile b/samples/Makefile index 1a60c62e2045..a0d1626bd5bb 100644 --- a/samples/Makefile +++ b/samples/Makefile @@ -1,4 +1,5 @@ # Makefile for Linux samples code obj-$(CONFIG_SAMPLES) += kobject/ kprobes/ trace_events/ \ - hw_breakpoint/ kfifo/ kdb/ hidraw/ rpmsg/ seccomp/ + hw_breakpoint/ kfifo/ kdb/ kgraft/ \ + hidraw/ rpmsg/ seccomp/ diff --git a/samples/kgraft/Makefile b/samples/kgraft/Makefile new file mode 100644 index 000000000000..888a332c3148 --- /dev/null +++ b/samples/kgraft/Makefile @@ -0,0 +1 @@ +obj-$(CONFIG_SAMPLE_KGRAFT_PATCHER) += kgraft_patcher.o diff --git a/samples/kgraft/kgraft_patcher.c b/samples/kgraft/kgraft_patcher.c new file mode 100644 index 000000000000..abb0c05bf739 --- /dev/null +++ b/samples/kgraft/kgraft_patcher.c @@ -0,0 +1,92 @@ +/* + * kgraft_patcher -- just kick the kGraft infrastructure for test + * + * We patch two (arbitrarily chosen) functions at once... + * + * Copyright (c) 2013-2014 SUSE + * Authors: Jiri Kosina + * Vojtech Pavlik + * Jiri Slaby + */ + +/* + * This program is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License as published by the Free + * Software Foundation; either version 2 of the License, or (at your option) + * any later version. + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include + +/* + * This all should be autogenerated from the patched sources + */ + +asmlinkage long kgr_new_sys_iopl(unsigned int level) +{ + struct pt_regs *regs = current_pt_regs(); + unsigned int old = (regs->flags >> 12) & 3; + struct thread_struct *t = ¤t->thread; + + printk(KERN_DEBUG "kgr-patcher: this is a new sys_iopl()\n"); + + if (level > 3) + return -EINVAL; + /* Trying to gain more privileges? */ + if (level > old) { + if (!capable(CAP_SYS_RAWIO)) + return -EPERM; + } + regs->flags = (regs->flags & ~X86_EFLAGS_IOPL) | (level << 12); + t->iopl = level << 12; + set_iopl_mask(t->iopl); + + return 0; +} +KGR_PATCHED_FUNCTION(SyS_iopl, kgr_new_sys_iopl); + +static bool new_capable(int cap) +{ + printk(KERN_DEBUG "kgr-patcher: this is a new capable()\n"); + + return ns_capable(&init_user_ns, cap); +} +KGR_PATCHED_FUNCTION(capable, new_capable); + +static const struct kgr_patch patch = { + .patches = { + KGR_PATCH(SyS_iopl), + KGR_PATCH(capable), + KGR_PATCH_END + } +}; + +static int __init kgr_patcher_init(void) +{ + /* removing not supported */ + __module_get(THIS_MODULE); + kgr_start_patching(&patch); + return 0; +} + +static void __exit kgr_patcher_cleanup(void) +{ + /* extra care needs to be taken when freeing ftrace_ops->private */ + pr_err("removing now buggy!\n"); +} + +module_init(kgr_patcher_init); +module_exit(kgr_patcher_cleanup); + +MODULE_LICENSE("GPL"); + -- 2.0.0