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=-6.8 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 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 E2F79C28CF8 for ; Sat, 13 Oct 2018 18:34:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 81F252064E for ; Sat, 13 Oct 2018 18:34:29 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=efficios.com header.i=@efficios.com header.b="CoNXh91f" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 81F252064E 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 S1726795AbeJNCMi (ORCPT ); Sat, 13 Oct 2018 22:12:38 -0400 Received: from mail.efficios.com ([167.114.142.138]:33632 "EHLO mail.efficios.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726668AbeJNCMh (ORCPT ); Sat, 13 Oct 2018 22:12:37 -0400 Received: from localhost (ip6-localhost [IPv6:::1]) by mail.efficios.com (Postfix) with ESMTP id CA9CE1BEE7D; Sat, 13 Oct 2018 14:34:25 -0400 (EDT) Received: from mail.efficios.com ([IPv6:::1]) by localhost (mail02.efficios.com [IPv6:::1]) (amavisd-new, port 10032) with ESMTP id rMHF1f2sC1qU; Sat, 13 Oct 2018 14:34:24 -0400 (EDT) Received: from localhost (ip6-localhost [IPv6:::1]) by mail.efficios.com (Postfix) with ESMTP id 62E2E1BEE76; Sat, 13 Oct 2018 14:34:24 -0400 (EDT) DKIM-Filter: OpenDKIM Filter v2.10.3 mail.efficios.com 62E2E1BEE76 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=efficios.com; s=default; t=1539455664; bh=M7WXEKQBVui8qLxtCZU89aRC3T/BSayQWb0i3X3F6nk=; h=Date:From:To:Message-ID:MIME-Version; b=CoNXh91fAZFPJ0qJpgNmgl3dOCAteBTPrMAMckLHjU3og63dKvXRHVnxae5cKawzx G0/HokIobm2fiHTEnL+0StZNtbWlgEZlQb5bTFS56UkWdFnqoq0BL2+oQAh9n7rzRo MlP2guWBEq6dVsX7fz0gfk+c1YrWPRotBi/hjDXcStz7LlL7zAT2v8JM+oYojaAJPF a1tGSpFI6rfJy0V1lo4aGLD+CmderqHP21VQdQv3iY0KmoPMJgmC3rDflzkGJnNnEa GRfAjcHL8AI8JBO/YhfLCu5DseWOFtln/XeEc15BahW2xeFJBWgLsGVE4n5E8G3Rb4 7j3gCZVpo6ybQ== 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 qfKFpgxLDUEL; Sat, 13 Oct 2018 14:34:24 -0400 (EDT) Received: from mail02.efficios.com (mail02.efficios.com [167.114.142.138]) by mail.efficios.com (Postfix) with ESMTP id 3B2E91BEE70; Sat, 13 Oct 2018 14:34:24 -0400 (EDT) Date: Sat, 13 Oct 2018 14:34:23 -0400 (EDT) From: Mathieu Desnoyers To: Ard Biesheuvel Cc: rostedt , linux-kernel , Michael Ellerman , Ingo Molnar , 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, ARM Linux" , "Serge E. Hallyn" , Sergey Senozhatsky , Thomas Garnier , Thomas Gleixner , Will Deacon , Andrew Morton , Linus Torvalds , Greg Kroah-Hartman Message-ID: <1921357606.3547.1539455663932.JavaMail.zimbra@efficios.com> In-Reply-To: References: <20181012200523.23731-1-mathieu.desnoyers@efficios.com> Subject: Re: [PATCH for 4.19] tracepoint: Fix: out-of-bound tracepoint array iteration MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit X-Originating-IP: [167.114.142.138] X-Mailer: Zimbra 8.8.10_GA_3039 (ZimbraWebClient - FF52 (Linux)/8.8.10_GA_3039) Thread-Topic: tracepoint: Fix: out-of-bound tracepoint array iteration Thread-Index: Yq0g2RTNffX73sk0E+n4pHd0vAah/g== Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org ----- On Oct 13, 2018, at 11:24 AM, Ard Biesheuvel ard.biesheuvel@linaro.org wrote: > On 12 October 2018 at 23:07, Ard Biesheuvel wrote: >> Hi Mathieu, >> >> On 12 October 2018 at 22:05, Mathieu Desnoyers >> wrote: >>> 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. >>> >> >> Apologies for the breakage. FWIW, this looks like the correct approach >> to me (and mirrors what I did for initcalls in the same series) >> >>> This issue appears in 4.19-rc kernels, and should ideally be fixed >>> before the end of the rc cycle. >>> >> >> +1 >> >>> 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 >> >> Acked-by: Ard Biesheuvel >> > > This fixes the build breakage for me that kbuild test robot reports. > > diff --git a/include/linux/module.h b/include/linux/module.h > index cdab2451d6be..e19ae08c7fb8 100644 > --- a/include/linux/module.h > +++ b/include/linux/module.h > @@ -20,6 +20,7 @@ > #include > #include > #include > +#include You've beat me to it :) I'll fold this change in a v2 of the patch, Thanks! Mathieu > > #include > #include > > > > > >>> --- >>> 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 -- Mathieu Desnoyers EfficiOS Inc. http://www.efficios.com