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=-9.2 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,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 5869BC43387 for ; Mon, 17 Dec 2018 08:21:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2720D217F4 for ; Mon, 17 Dec 2018 08:21:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1545034882; bh=nOufy+5Q97ErJCPdA6sg5bXp2yPze6GK6jeSkjaimg0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=D0lrdiESV7e4TpwG2HQs5nMuvEVZEVNRefTtg5xZujhVxngGq0jgR99X9I7Ea+UlZ P+0EmEcdcumn01q1BJz0MXaaqr6eK8dR+xWia6T9YszACfnNp+1f4+xbVbr4CBRCuq nM8zU4a9G5d5dj8EnmAXPXfKQKX+asJ8xgvwvWwI= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731720AbeLQIVU (ORCPT ); Mon, 17 Dec 2018 03:21:20 -0500 Received: from mail.kernel.org ([198.145.29.99]:56204 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726496AbeLQIVU (ORCPT ); Mon, 17 Dec 2018 03:21:20 -0500 Received: from localhost.localdomain (NE2965lan1.rev.em-net.ne.jp [210.141.244.193]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 1E6E520672; Mon, 17 Dec 2018 08:21:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1545034879; bh=nOufy+5Q97ErJCPdA6sg5bXp2yPze6GK6jeSkjaimg0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=zJgMibpKlHIZHaJuc1GkmFmqOVKPTGOikGRAJyFjdaHSN1slFXlk44O71dbHwerC9 YtQ7DdY8xXOY2gVD0py1hkQ6v2J/7V9l5Yr6ZU7i5fLJ3xT+iBLqjU9pv8k01rZyM+ e93ao3PeQgkIkWZooiArNuvuONGomEYfD5EYSdPc= From: Masami Hiramatsu To: Ingo Molnar , Andrea Righi Cc: "Naveen N . Rao" , Anil S Keshavamurthy , "David S . Miller" , Masami Hiramatsu , Yonghong Song , Andy Lutomirski , Thomas Gleixner , Borislav Petkov , "H . Peter Anvin" , x86@kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v2 1/3] kprobes: Blacklist symbols in arch-defined prohibited area Date: Mon, 17 Dec 2018 17:20:55 +0900 Message-Id: <154503485491.26176.15823229545155174796.stgit@devbox> X-Mailer: git-send-email 2.13.6 In-Reply-To: <154503482486.26176.6224515860220847638.stgit@devbox> References: <154503482486.26176.6224515860220847638.stgit@devbox> User-Agent: StGit/0.17.1-dirty MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Blacklist symbols in arch-defined probe-prohibited areas. With this change, user can see all symbols which are prohibited to probe in debugfs. All archtectures which have custom prohibit areas should define its own arch_populate_kprobe_blacklist() function, but unless that, all symbols marked __kprobes are blacklisted. Reported-by: Andrea Righi Signed-off-by: Masami Hiramatsu --- Changes in v2: - Add area based blacklist adding helper function - Blacklist __kprobes_text symbols by default - Add __init to default function --- include/linux/kprobes.h | 3 ++ kernel/kprobes.c | 67 +++++++++++++++++++++++++++++++++++++---------- 2 files changed, 56 insertions(+), 14 deletions(-) diff --git a/include/linux/kprobes.h b/include/linux/kprobes.h index e64b26c81c2f..e07e91daaacc 100644 --- a/include/linux/kprobes.h +++ b/include/linux/kprobes.h @@ -242,10 +242,13 @@ extern int arch_init_kprobes(void); extern void show_registers(struct pt_regs *regs); extern void kprobes_inc_nmissed_count(struct kprobe *p); extern bool arch_within_kprobe_blacklist(unsigned long addr); +extern int arch_populate_kprobe_blacklist(void); extern bool arch_kprobe_on_func_entry(unsigned long offset); extern bool kprobe_on_func_entry(kprobe_opcode_t *addr, const char *sym, unsigned long offset); extern bool within_kprobe_blacklist(unsigned long addr); +extern int kprobe_add_ksym_blacklist(unsigned long entry); +extern int kprobe_add_area_blacklist(unsigned long start, unsigned long end); struct kprobe_insn_cache { struct mutex mutex; diff --git a/kernel/kprobes.c b/kernel/kprobes.c index 08e31d863191..f4ddfdd2d07e 100644 --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -2093,6 +2093,47 @@ void dump_kprobe(struct kprobe *kp) } NOKPROBE_SYMBOL(dump_kprobe); +int kprobe_add_ksym_blacklist(unsigned long entry) +{ + struct kprobe_blacklist_entry *ent; + unsigned long offset = 0, size = 0; + + if (!kernel_text_address(entry) || + !kallsyms_lookup_size_offset(entry, &size, &offset)) + return -EINVAL; + + ent = kmalloc(sizeof(*ent), GFP_KERNEL); + if (!ent) + return -ENOMEM; + ent->start_addr = entry; + ent->end_addr = entry + size; + INIT_LIST_HEAD(&ent->list); + list_add_tail(&ent->list, &kprobe_blacklist); + + return (int)size; +} + +/* Add all symbols in given area into kprobe blacklist */ +int kprobe_add_area_blacklist(unsigned long start, unsigned long end) +{ + unsigned long entry; + int ret = 0; + + for (entry = start; entry < end; entry += ret) { + ret = kprobe_add_ksym_blacklist(entry); + if (ret < 0) + return ret; + if (ret == 0) /* In case of alias symbol */ + ret = 1; + } + return 0; +} + +int __init __weak arch_populate_kprobe_blacklist(void) +{ + return 0; +} + /* * Lookup and populate the kprobe_blacklist. * @@ -2104,26 +2145,24 @@ NOKPROBE_SYMBOL(dump_kprobe); static int __init populate_kprobe_blacklist(unsigned long *start, unsigned long *end) { + unsigned long entry; unsigned long *iter; - struct kprobe_blacklist_entry *ent; - unsigned long entry, offset = 0, size = 0; + int ret; for (iter = start; iter < end; iter++) { entry = arch_deref_entry_point((void *)*iter); - - if (!kernel_text_address(entry) || - !kallsyms_lookup_size_offset(entry, &size, &offset)) + ret = kprobe_add_ksym_blacklist(entry); + if (ret == -EINVAL) continue; - - ent = kmalloc(sizeof(*ent), GFP_KERNEL); - if (!ent) - return -ENOMEM; - ent->start_addr = entry; - ent->end_addr = entry + size; - INIT_LIST_HEAD(&ent->list); - list_add_tail(&ent->list, &kprobe_blacklist); + if (ret < 0) + return ret; } - return 0; + + /* Symbols in __kprobes_text are blacklisted */ + ret = kprobe_add_area_blacklist((unsigned long)__kprobes_text_start, + (unsigned long)__kprobes_text_end); + + return ret ? : arch_populate_kprobe_blacklist(); } /* Module notifier call back, checking kprobes on the module */