From patchwork Tue Apr 30 11:26:53 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: tip-bot for Kobe Wu X-Patchwork-Id: 10923319 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 57F7414B6 for ; Tue, 30 Apr 2019 11:31:47 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 418F728AA8 for ; Tue, 30 Apr 2019 11:31:47 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 32B2028AAC; Tue, 30 Apr 2019 11:31:47 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.0 required=2.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,MAILING_LIST_MULTI,RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from mother.openwall.net (mother.openwall.net [195.42.179.200]) by mail.wl.linuxfoundation.org (Postfix) with SMTP id AFF8928AA8 for ; Tue, 30 Apr 2019 11:31:45 +0000 (UTC) Received: (qmail 23906 invoked by uid 550); 30 Apr 2019 11:30:30 -0000 Mailing-List: contact kernel-hardening-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-ID: Delivered-To: mailing list kernel-hardening@lists.openwall.com Delivered-To: moderator for kernel-hardening@lists.openwall.com Received: (qmail 1742 invoked from network); 30 Apr 2019 11:27:51 -0000 DKIM-Filter: OpenDKIM Filter v2.11.0 terminus.zytor.com x3UBQrkD1350079 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=zytor.com; s=2019041745; t=1556623615; bh=xXyYrf0EgteWkvzKH3RVYTzxUw64JdnW8DeW9VS7Eag=; h=Date:From:Cc:Reply-To:In-Reply-To:References:To:Subject:From; b=Rgl7WnTFdskDNyv+HGJ4Ut7YMo4tfN4PZ5h5dIxnOP3HPo4TZzZED/RLjM7wpJGYp qcACMjZoMmnZ6WOkrCSVBJ/dP4exMt+ua7/gy7vtLPJzDxzvwzIBs5AdX8VKdwDV3n IZ9YB8j6yEsaQB78oVWXWWZHQdxulBCBg8fkY2RXdk+ECmtqCU91f6LPyEA3KPgqTX urGwmuz8Mj7PeEuFNv8DGG70n9I9P3L2OxCofFtDs74N9y+j+xfZQ+VP9F4MpiZxwz LoM1bt/gyz32PC6EweXVhWB5GMNWi/QvuuFmd8UyUKhXyO3eAzGx17IC9R59QPgIj/ 4l5/BhuOnh8Mg== Date: Tue, 30 Apr 2019 04:26:53 -0700 X-Authentication-Warning: terminus.zytor.com: tipbot set sender to tipbot@zytor.com using -f Sender: tip tree robot From: tip-bot for Rick Edgecombe Message-ID: Cc: tglx@linutronix.de, bp@alien8.de, mingo@kernel.org, deneen.t.dock@intel.com, peterz@infradead.org, will.deacon@arm.com, linux_dti@icloud.com, linux-kernel@vger.kernel.org, kernel-hardening@lists.openwall.com, kristen@linux.intel.com, rostedt@goodmis.org, akpm@linux-foundation.org, dave.hansen@linux.intel.com, rick.p.edgecombe@intel.com, nadav.amit@gmail.com, ard.biesheuvel@linaro.org, luto@kernel.org, hpa@zytor.com, jeyu@kernel.org, torvalds@linux-foundation.org, riel@surriel.com In-Reply-To: <20190426001143.4983-18-namit@vmware.com> References: <20190426001143.4983-18-namit@vmware.com> To: linux-tip-commits@vger.kernel.org Subject: [tip:x86/mm] modules: Use vmalloc special flag Git-Commit-ID: 1a7b7d9220819afe79d1ec5d759fe4349bd2453e X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Disposition: inline X-Virus-Scanned: ClamAV using ClamSMTP Commit-ID: 1a7b7d9220819afe79d1ec5d759fe4349bd2453e Gitweb: https://git.kernel.org/tip/1a7b7d9220819afe79d1ec5d759fe4349bd2453e Author: Rick Edgecombe AuthorDate: Thu, 25 Apr 2019 17:11:37 -0700 Committer: Ingo Molnar CommitDate: Tue, 30 Apr 2019 12:37:58 +0200 modules: Use vmalloc special flag Use new flag for handling freeing of special permissioned memory in vmalloc and remove places where memory was set RW before freeing which is no longer needed. Since freeing of VM_FLUSH_RESET_PERMS memory is not supported in an interrupt by vmalloc, the freeing of init sections is moved to a work queue. Instead of call_rcu it now uses synchronize_rcu() in the work queue. Lastly, there is now a WARN_ON in module_memfree since it should not be called in an interrupt with special memory as is required for VM_FLUSH_RESET_PERMS. Signed-off-by: Rick Edgecombe Signed-off-by: Peter Zijlstra (Intel) Cc: Cc: Cc: Cc: Cc: Cc: Cc: Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Dave Hansen Cc: H. Peter Anvin Cc: Jessica Yu Cc: Linus Torvalds Cc: Nadav Amit Cc: Rik van Riel Cc: Steven Rostedt Cc: Thomas Gleixner Link: https://lkml.kernel.org/r/20190426001143.4983-18-namit@vmware.com Signed-off-by: Ingo Molnar --- kernel/module.c | 77 +++++++++++++++++++++++++++++---------------------------- 1 file changed, 39 insertions(+), 38 deletions(-) diff --git a/kernel/module.c b/kernel/module.c index 2b2845ae983e..a9020bdd4cf6 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -98,6 +98,10 @@ DEFINE_MUTEX(module_mutex); EXPORT_SYMBOL_GPL(module_mutex); static LIST_HEAD(modules); +/* Work queue for freeing init sections in success case */ +static struct work_struct init_free_wq; +static struct llist_head init_free_list; + #ifdef CONFIG_MODULES_TREE_LOOKUP /* @@ -1949,6 +1953,8 @@ void module_enable_ro(const struct module *mod, bool after_init) if (!rodata_enabled) return; + set_vm_flush_reset_perms(mod->core_layout.base); + set_vm_flush_reset_perms(mod->init_layout.base); frob_text(&mod->core_layout, set_memory_ro); frob_text(&mod->core_layout, set_memory_x); @@ -1972,15 +1978,6 @@ static void module_enable_nx(const struct module *mod) frob_writable_data(&mod->init_layout, set_memory_nx); } -static void module_disable_nx(const struct module *mod) -{ - frob_rodata(&mod->core_layout, set_memory_x); - frob_ro_after_init(&mod->core_layout, set_memory_x); - frob_writable_data(&mod->core_layout, set_memory_x); - frob_rodata(&mod->init_layout, set_memory_x); - frob_writable_data(&mod->init_layout, set_memory_x); -} - /* Iterate through all modules and set each module's text as RW */ void set_all_modules_text_rw(void) { @@ -2024,23 +2021,8 @@ void set_all_modules_text_ro(void) } mutex_unlock(&module_mutex); } - -static void disable_ro_nx(const struct module_layout *layout) -{ - if (rodata_enabled) { - frob_text(layout, set_memory_rw); - frob_rodata(layout, set_memory_rw); - frob_ro_after_init(layout, set_memory_rw); - } - frob_rodata(layout, set_memory_x); - frob_ro_after_init(layout, set_memory_x); - frob_writable_data(layout, set_memory_x); -} - #else -static void disable_ro_nx(const struct module_layout *layout) { } static void module_enable_nx(const struct module *mod) { } -static void module_disable_nx(const struct module *mod) { } #endif #ifdef CONFIG_LIVEPATCH @@ -2120,6 +2102,11 @@ static void free_module_elf(struct module *mod) void __weak module_memfree(void *module_region) { + /* + * This memory may be RO, and freeing RO memory in an interrupt is not + * supported by vmalloc. + */ + WARN_ON(in_interrupt()); vfree(module_region); } @@ -2171,7 +2158,6 @@ static void free_module(struct module *mod) mutex_unlock(&module_mutex); /* This may be empty, but that's OK */ - disable_ro_nx(&mod->init_layout); module_arch_freeing_init(mod); module_memfree(mod->init_layout.base); kfree(mod->args); @@ -2181,7 +2167,6 @@ static void free_module(struct module *mod) lockdep_free_key_range(mod->core_layout.base, mod->core_layout.size); /* Finally, free the core (containing the module structure) */ - disable_ro_nx(&mod->core_layout); module_memfree(mod->core_layout.base); } @@ -3420,17 +3405,34 @@ static void do_mod_ctors(struct module *mod) /* For freeing module_init on success, in case kallsyms traversing */ struct mod_initfree { - struct rcu_head rcu; + struct llist_node node; void *module_init; }; -static void do_free_init(struct rcu_head *head) +static void do_free_init(struct work_struct *w) { - struct mod_initfree *m = container_of(head, struct mod_initfree, rcu); - module_memfree(m->module_init); - kfree(m); + struct llist_node *pos, *n, *list; + struct mod_initfree *initfree; + + list = llist_del_all(&init_free_list); + + synchronize_rcu(); + + llist_for_each_safe(pos, n, list) { + initfree = container_of(pos, struct mod_initfree, node); + module_memfree(initfree->module_init); + kfree(initfree); + } } +static int __init modules_wq_init(void) +{ + INIT_WORK(&init_free_wq, do_free_init); + init_llist_head(&init_free_list); + return 0; +} +module_init(modules_wq_init); + /* * This is where the real work happens. * @@ -3507,7 +3509,6 @@ static noinline int do_init_module(struct module *mod) #endif module_enable_ro(mod, true); mod_tree_remove_init(mod); - disable_ro_nx(&mod->init_layout); module_arch_freeing_init(mod); mod->init_layout.base = NULL; mod->init_layout.size = 0; @@ -3518,14 +3519,18 @@ static noinline int do_init_module(struct module *mod) * We want to free module_init, but be aware that kallsyms may be * walking this with preempt disabled. In all the failure paths, we * call synchronize_rcu(), but we don't want to slow down the success - * path, so use actual RCU here. + * path. module_memfree() cannot be called in an interrupt, so do the + * work and call synchronize_rcu() in a work queue. + * * Note that module_alloc() on most architectures creates W+X page * mappings which won't be cleaned up until do_free_init() runs. Any * code such as mark_rodata_ro() which depends on those mappings to * be cleaned up needs to sync with the queued work - ie * rcu_barrier() */ - call_rcu(&freeinit->rcu, do_free_init); + if (llist_add(&freeinit->node, &init_free_list)) + schedule_work(&init_free_wq); + mutex_unlock(&module_mutex); wake_up_all(&module_wq); @@ -3822,10 +3827,6 @@ static int load_module(struct load_info *info, const char __user *uargs, module_bug_cleanup(mod); mutex_unlock(&module_mutex); - /* we can't deallocate the module until we clear memory protection */ - module_disable_ro(mod); - module_disable_nx(mod); - ddebug_cleanup: ftrace_release_mod(mod); dynamic_debug_remove(mod, info->debug);