Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751739AbbKIFnZ (ORCPT ); Mon, 9 Nov 2015 00:43:25 -0500 Received: from aserp1040.oracle.com ([141.146.126.69]:18104 "EHLO aserp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750798AbbKIFnV (ORCPT ); Mon, 9 Nov 2015 00:43:21 -0500 Date: Mon, 9 Nov 2015 08:42:53 +0300 From: Dan Carpenter To: Julia Lawall , Joe Perches Cc: kernel-janitors@vger.kernel.org, linux-kernel@vger.kernel.org, Kees Cook , kernel-hardening@lists.openwall.com Subject: Re: [PATCH] video: constify geode ops structures Message-ID: <20151109054253.GQ18797@mwanda> References: <1447018493-20631-1-git-send-email-Julia.Lawall@lip6.fr> <20151108221624.GP18797@mwanda> MIME-Version: 1.0 Content-Type: multipart/mixed; boundary="17pEHd4RhPHOinZp" Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) X-Source-IP: userv0022.oracle.com [156.151.31.74] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4138 Lines: 165 --17pEHd4RhPHOinZp Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Sun, Nov 08, 2015 at 10:24:49PM +0000, Julia Lawall wrote: > On Mon, 9 Nov 2015, Dan Carpenter wrote: > > > Cool. So, in grsec they use a GCC plugin to make these const > > automatically since they only contain function pointers. There about > > 100 struct types marked as __no_const. Kees would like to adopt the > > grsec pluggin approach I expect. Do you have an idea how many structs > > only contain function pointers or how many consts we would have to add > > to get the same effect without the plugin? > > My list has 373 type names. In the list there are counts for good > (already const) and bad (not const). The sum of the bad values is 2467. > The list is below. > > julia Fantastic! Thanks. We could autogenerate the list of type names and make checkpatch.pl complain if we declared those types as non const. I ran this command to find which functions grsec marks as __no_const. egrep '(^ struct |^@@|__no_const;)' grsecurity-3.1-4.2.5-201511021814.patch | grep __no_const -B1 | grep -v __no_const | grep -v '^--' | cut -d @ -f 5- | cut -b 9- | cut -d ' ' -f 1 There are 60 structs declared as __no_const. For some structs they declare a no_const version and use it as needed. Like this: typedef struct net_device_ops __no_const net_device_ops_no_const; grep __no_const grsecurity-3.1-4.2.5-201511021814.patch | grep typedef | cut -d ' ' -f 3 There are 32 of those. Then I compared to see if their structs were on your list. For some reason there quite a few one their list which are not on yours. Out of the first 10 about half weren't on your list. cpu_cache_fns, outer_cache_fns, psci_operations, smp_operations, omap_hwmod_soc_ops, smp_ops_t. These are mostly different arches? Also bit_table has in int has well as a function pointers but it is on their list. I'm not sure why. Maybe they are marking structs const that I don't know about. The other trick that they do is they define structs as __do_const if they want them to be const by default, which is pretty neat. This feels like it should be a standard GCC feature. In the meantime we could mark things as __do_const and print a sparse warning if it was declared as not const. I have attached the list of __no_const structs. regards, dan carpenter --17pEHd4RhPHOinZp Content-Type: text/plain; charset=us-ascii Content-Disposition: attachment; filename=no_const cpu_cache_fns cpuidle_ops outer_cache_fns cpu_user_fns psci_operations smp_operations cpu_pm_ops omap_hwmod_soc_ops smp_ops_t machine_ops smp_ops x86_init_ops x86_cpuinit_ops x86_platform_ops x86_msi_ops x86_io_apic_ops cryptd_blkcipher_request_ctx cryptd_aead_request_ctx od_ops amd_decoder_ops kernel_queue_ops bit_table af9033_ops dib_fe_xfer_ops dib7000p_ops dib8000_ops xpc_interface l2t_skb_cb ath10k_htc_ops ath10k_htc_ep_ops ath_hw_private_ops ath_hw_ops bfa_itn_s bfa_ioc_cbfn_s bfa_ioc_hwif_s fbtft_ops ldlm_callback_suite md_ops hal_ops _io_ops visorchipset_busdev_notifiers visorchipset_busdev_responders via_clock drm_encoder_helper_funcs ttm_mem_shrink cleancache_ops cipher_tfm compress_tfm softirq_action gpd_dev_ops rchan_callbacks rio_ops renesas_usbhs_driver_callback cfctrl_rsp iw_cm_verbs snd_compr_ops lane2_ops rtnl_link tipc_nl_compat_cmd_dump tipc_nl_compat_cmd_doit Sometimes not const: fw_card_driver dm_space_map v4l2_ioctl_info xpc_arch_operations drm_info_list clk_ops global_attr cpuidle_state device_attribute efivar_operations fb_ops file_operations sensor_device_attribute sensor_device_attribute_2 i2c_algorithm irq_chip irq_chip kobj_attribute vm_operations_struct module_attribute net_device_ops notifier_block hotplug_slot_ops dev_pm_domain user_regset seq_operations ctl_table attribute attribute_group bin_attribute libfc_function_template fc_function_template --17pEHd4RhPHOinZp-- -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/