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=-8.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,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 BB92FC6787C for ; Fri, 12 Oct 2018 20:05:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 61E7420835 for ; Fri, 12 Oct 2018 20:05:31 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=efficios.com header.i=@efficios.com header.b="ntlWzSce" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 61E7420835 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=efficios.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726750AbeJMDjg (ORCPT ); Fri, 12 Oct 2018 23:39:36 -0400 Received: from mail.efficios.com ([167.114.142.138]:37832 "EHLO mail.efficios.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725935AbeJMDjg (ORCPT ); Fri, 12 Oct 2018 23:39:36 -0400 Received: from localhost (ip6-localhost [IPv6:::1]) by mail.efficios.com (Postfix) with ESMTP id 331501B7462; Fri, 12 Oct 2018 16:05:28 -0400 (EDT) Received: from mail.efficios.com ([IPv6:::1]) by localhost (mail02.efficios.com [IPv6:::1]) (amavisd-new, port 10032) with ESMTP id aXYxaqWbj82k; Fri, 12 Oct 2018 16:05:27 -0400 (EDT) Received: from localhost (ip6-localhost [IPv6:::1]) by mail.efficios.com (Postfix) with ESMTP id 48F901B745F; Fri, 12 Oct 2018 16:05:27 -0400 (EDT) DKIM-Filter: OpenDKIM Filter v2.10.3 mail.efficios.com 48F901B745F DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=efficios.com; s=default; t=1539374727; bh=BUy6aEpZFCnFPPJee/L7zXeKr/QtWs4AoTmH6FKVXnU=; h=From:To:Date:Message-Id; b=ntlWzSceS5dTl7HT+gBRA4AmABM2NtUYmova6fsrzaozTmwwKxJkjeKcHrtHktZPZ c/4xuIi9wPx6T0ZtlwSaPClkV3/mciZ4Nokj2W1hbR1slzITcOTec7xX+c0+fAv1Zb XtpVBTHsIAdf5VMIeiKmHCR9Md5gC34lt1HgKvGQ9r+OEwMn42byKk0DuCYqv7NFwY AGhMm94rae55iG6WQ2G87Upf9JGax4TxWDJm7iFJ/j6vU+6YnU04ImYAfUFl0N5UPH 91nMav0Ce80BtOr78VMKqc8H+FD8FLJUWgpiR3kpTjelA0H8Ie2usL8tatlhWcSG6N iifhkAAKlLjtA== X-Virus-Scanned: amavisd-new at efficios.com Received: from mail.efficios.com ([IPv6:::1]) by localhost (mail02.efficios.com [IPv6:::1]) (amavisd-new, port 10026) with ESMTP id B1sG69jGBHdD; Fri, 12 Oct 2018 16:05:27 -0400 (EDT) Received: from localhost.localdomain (192-222-157-41.qc.cable.ebox.net [192.222.157.41]) by mail.efficios.com (Postfix) with ESMTPSA id D10661B7455; Fri, 12 Oct 2018 16:05:26 -0400 (EDT) From: Mathieu Desnoyers To: Steven Rostedt Cc: linux-kernel@vger.kernel.org, Mathieu Desnoyers , Michael Ellerman , Ingo Molnar , Ard Biesheuvel , Arnd Bergmann , Benjamin Herrenschmidt , Bjorn Helgaas , Catalin Marinas , James Morris , James Morris , Jessica Yu , Josh Poimboeuf , Kees Cook , Nicolas Pitre , Paul Mackerras , Petr Mladek , Russell King , "Serge E. Hallyn" , Sergey Senozhatsky , Thomas Garnier , Thomas Gleixner , Will Deacon , Andrew Morton , Linus Torvalds , Greg Kroah-Hartman Subject: [PATCH for 4.19] tracepoint: Fix: out-of-bound tracepoint array iteration Date: Fri, 12 Oct 2018 16:05:23 -0400 Message-Id: <20181012200523.23731-1-mathieu.desnoyers@efficios.com> X-Mailer: git-send-email 2.17.1 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org commit 46e0c9be206f ("kernel: tracepoints: add support for relative references") changes the layout of the __tracepoint_ptrs section on architectures supporting relative references. However, it does so without turning struct tracepoint * const into const int * elsewhere in the tracepoint code, which has the following side-effect: tracepoint_module_{coming,going} invoke tp_module_going_check_quiescent() with mod->tracepoints_ptrs as first argument, and computes the end address of the array for the second argument with: mod->tracepoints_ptrs + mod->num_tracepoints However, because the type of mod->tracepoint_ptrs in module.h has not been changed from pointer to int, it passes an end pointer which is twice larger than the array, causing out-of-bound array accesses. Fix this by introducing a new typedef: tracepoint_ptr_t, which is either "const int" on architectures that have PREL32 relocations, or "struct tracepoint * const" on architectures that does not have this feature. Also provide a new tracepoint_ptr_defer() static inline to encapsulate deferencing this type rather than duplicate code and ugly idefs within the for_each_tracepoint_range() implementation. This issue appears in 4.19-rc kernels, and should ideally be fixed before the end of the rc cycle. Signed-off-by: Mathieu Desnoyers Link: http://lkml.kernel.org/r/20180704083651.24360-7-ard.biesheuvel@linaro.org Cc: Michael Ellerman Cc: Ingo Molnar Cc: Steven Rostedt (VMware) Cc: Ard Biesheuvel Cc: Arnd Bergmann Cc: Benjamin Herrenschmidt Cc: Bjorn Helgaas Cc: Catalin Marinas Cc: James Morris Cc: James Morris Cc: Jessica Yu Cc: Josh Poimboeuf Cc: Kees Cook Cc: Nicolas Pitre Cc: Paul Mackerras Cc: Petr Mladek Cc: Russell King Cc: "Serge E. Hallyn" Cc: Sergey Senozhatsky Cc: Thomas Garnier Cc: Thomas Gleixner Cc: Will Deacon Cc: Andrew Morton Cc: Linus Torvalds Cc: Greg Kroah-Hartman --- include/linux/module.h | 2 +- include/linux/tracepoint-defs.h | 6 ++++++ include/linux/tracepoint.h | 36 +++++++++++++++++++++------------ kernel/tracepoint.c | 24 ++++++++-------------- 4 files changed, 38 insertions(+), 30 deletions(-) diff --git a/include/linux/module.h b/include/linux/module.h index f807f15bebbe..cdab2451d6be 100644 --- a/include/linux/module.h +++ b/include/linux/module.h @@ -430,7 +430,7 @@ struct module { #ifdef CONFIG_TRACEPOINTS unsigned int num_tracepoints; - struct tracepoint * const *tracepoints_ptrs; + tracepoint_ptr_t *tracepoints_ptrs; #endif #ifdef HAVE_JUMP_LABEL struct jump_entry *jump_entries; diff --git a/include/linux/tracepoint-defs.h b/include/linux/tracepoint-defs.h index 22c5a46e9693..49ba9cde7e4b 100644 --- a/include/linux/tracepoint-defs.h +++ b/include/linux/tracepoint-defs.h @@ -35,6 +35,12 @@ struct tracepoint { struct tracepoint_func __rcu *funcs; }; +#ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS +typedef const int tracepoint_ptr_t; +#else +typedef struct tracepoint * const tracepoint_ptr_t; +#endif + struct bpf_raw_event_map { struct tracepoint *tp; void *bpf_func; diff --git a/include/linux/tracepoint.h b/include/linux/tracepoint.h index 041f7e56a289..538ba1a58f5b 100644 --- a/include/linux/tracepoint.h +++ b/include/linux/tracepoint.h @@ -99,6 +99,29 @@ extern void syscall_unregfunc(void); #define TRACE_DEFINE_ENUM(x) #define TRACE_DEFINE_SIZEOF(x) +#ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS +static inline struct tracepoint *tracepoint_ptr_deref(tracepoint_ptr_t *p) +{ + return offset_to_ptr(p); +} + +#define __TRACEPOINT_ENTRY(name) \ + asm(" .section \"__tracepoints_ptrs\", \"a\" \n" \ + " .balign 4 \n" \ + " .long __tracepoint_" #name " - . \n" \ + " .previous \n") +#else +static inline struct tracepoint *tracepoint_ptr_deref(tracepoint_ptr_t *p) +{ + return *p; +} + +#define __TRACEPOINT_ENTRY(name) \ + static tracepoint_ptr_t __tracepoint_ptr_##name __used \ + __attribute__((section("__tracepoints_ptrs"))) = \ + &__tracepoint_##name +#endif + #endif /* _LINUX_TRACEPOINT_H */ /* @@ -253,19 +276,6 @@ extern void syscall_unregfunc(void); return static_key_false(&__tracepoint_##name.key); \ } -#ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS -#define __TRACEPOINT_ENTRY(name) \ - asm(" .section \"__tracepoints_ptrs\", \"a\" \n" \ - " .balign 4 \n" \ - " .long __tracepoint_" #name " - . \n" \ - " .previous \n") -#else -#define __TRACEPOINT_ENTRY(name) \ - static struct tracepoint * const __tracepoint_ptr_##name __used \ - __attribute__((section("__tracepoints_ptrs"))) = \ - &__tracepoint_##name -#endif - /* * We have no guarantee that gcc and the linker won't up-align the tracepoint * structures, so we create an array of pointers that will be used for iteration diff --git a/kernel/tracepoint.c b/kernel/tracepoint.c index bf2c06ef9afc..a3be42304485 100644 --- a/kernel/tracepoint.c +++ b/kernel/tracepoint.c @@ -28,8 +28,8 @@ #include #include -extern struct tracepoint * const __start___tracepoints_ptrs[]; -extern struct tracepoint * const __stop___tracepoints_ptrs[]; +extern tracepoint_ptr_t __start___tracepoints_ptrs[]; +extern tracepoint_ptr_t __stop___tracepoints_ptrs[]; DEFINE_SRCU(tracepoint_srcu); EXPORT_SYMBOL_GPL(tracepoint_srcu); @@ -371,25 +371,17 @@ int tracepoint_probe_unregister(struct tracepoint *tp, void *probe, void *data) } EXPORT_SYMBOL_GPL(tracepoint_probe_unregister); -static void for_each_tracepoint_range(struct tracepoint * const *begin, - struct tracepoint * const *end, +static void for_each_tracepoint_range( + tracepoint_ptr_t *begin, tracepoint_ptr_t *end, void (*fct)(struct tracepoint *tp, void *priv), void *priv) { + tracepoint_ptr_t *iter; + if (!begin) return; - - if (IS_ENABLED(CONFIG_HAVE_ARCH_PREL32_RELOCATIONS)) { - const int *iter; - - for (iter = (const int *)begin; iter < (const int *)end; iter++) - fct(offset_to_ptr(iter), priv); - } else { - struct tracepoint * const *iter; - - for (iter = begin; iter < end; iter++) - fct(*iter, priv); - } + for (iter = begin; iter < end; iter++) + fct(tracepoint_ptr_deref(iter), priv); } #ifdef CONFIG_MODULES -- 2.17.1