From patchwork Sat Mar 3 20:00:31 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alexander Popov X-Patchwork-Id: 10256165 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id ACB916037E for ; Sat, 3 Mar 2018 20:02:16 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 97DB028787 for ; Sat, 3 Mar 2018 20:02:16 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 8B8C6287A1; Sat, 3 Mar 2018 20:02:16 +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=-4.2 required=2.0 tests=BAYES_00, 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 2C79628787 for ; Sat, 3 Mar 2018 20:02:14 +0000 (UTC) Received: (qmail 15942 invoked by uid 550); 3 Mar 2018 20:01:16 -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 Received: (qmail 15856 invoked from network); 3 Mar 2018 20:01:12 -0000 X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:subject:date:message-id:in-reply-to :references; bh=9EurYOra3Ue2MJQCiNPXthWw/UoRvl7zB3QouAgHt3M=; b=ncXx0zr1QLMOehmXKtcZujUaBDGDkj6hJT9Xd7N6DDd1201IMIZpt1XUSYbA2XNqlJ jFyU4OSkuaoEepGvAVPEcg5f7VORpNlPhG9WpB6ZyJBlcVw4SnvSapZrJLJ51bqPxjMo 2Z7PFgm7TSWOIaiZzdvySh+phlGoY22Idl88tjX5Uk/BbxaX8RQ2LZfFX3ekca9b94x7 q0mjcqkjbKReNViJFim+F6HayA7krL/gCJTgnRJsE+CfB924ow9YfIs8tg2GodYEma5g 5jLIO43coRj9Gq7STWwf+lhb2lyL+FdkYwrJnQSQLUwAoQqWV7kQlOTc5jG1kimNhK+5 4dyw== X-Gm-Message-State: AElRT7FEU6wIz4hSivXPNmw2SMwKcacUhcoCO3K8Pp+UDOaysYXy0UGG I0cao3gvDcPSkola1Rlx0qOX9KjHvFw= X-Google-Smtp-Source: AG47ELvHjj75FAJ2UDhbZ7ahbUHcIcjmLBZ41pzU1KLqt/M3MDVoQHwb9Y8vCLD3uhkApUJAxPeVZw== X-Received: by 10.25.225.84 with SMTP id y81mr6280382lfg.102.1520107260599; Sat, 03 Mar 2018 12:01:00 -0800 (PST) From: Alexander Popov To: kernel-hardening@lists.openwall.com, Kees Cook , PaX Team , Brad Spengler , Ingo Molnar , Andy Lutomirski , Tycho Andersen , Laura Abbott , Mark Rutland , Ard Biesheuvel , Borislav Petkov , Richard Sandiford , Thomas Gleixner , "H . Peter Anvin" , Peter Zijlstra , "Dmitry V . Levin" , Emese Revfy , Jonathan Corbet , Andrey Ryabinin , "Kirill A . Shutemov" , Thomas Garnier , Andrew Morton , Alexei Starovoitov , Josef Bacik , Masami Hiramatsu , Nicholas Piggin , Al Viro , "David S . Miller" , Ding Tianhong , David Woodhouse , Josh Poimboeuf , Steven Rostedt , Dominik Brodowski , Juergen Gross , Greg Kroah-Hartman , Dan Williams , Dave Hansen , Mathias Krause , Vikas Shivappa , Kyle Huey , Dmitry Safonov , Will Deacon , Arnd Bergmann , x86@kernel.org, linux-kernel@vger.kernel.org, alex.popov@linux.com Subject: [PATCH RFC v9 6/7] fs/proc: Show STACKLEAK metrics in the /proc file system Date: Sat, 3 Mar 2018 23:00:31 +0300 Message-Id: <1520107232-14111-7-git-send-email-alex.popov@linux.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1520107232-14111-1-git-send-email-alex.popov@linux.com> References: <1520107232-14111-1-git-send-email-alex.popov@linux.com> X-Virus-Scanned: ClamAV using ClamSMTP Introduce CONFIG_STACKLEAK_METRICS providing STACKLEAK information about tasks via the /proc file system. In particular, /proc//stack_depth shows the maximum kernel stack consumption for the current and previous syscalls. Although this information is not precise, it can be useful for estimating the STACKLEAK performance impact for your workloads. Signed-off-by: Alexander Popov --- arch/Kconfig | 12 ++++++++++++ arch/x86/entry/entry_32.S | 4 ++++ arch/x86/entry/entry_64.S | 4 ++++ arch/x86/include/asm/processor.h | 3 +++ arch/x86/kernel/asm-offsets.c | 3 +++ arch/x86/kernel/process_32.c | 3 +++ arch/x86/kernel/process_64.c | 3 +++ fs/proc/base.c | 18 ++++++++++++++++++ 8 files changed, 50 insertions(+) diff --git a/arch/Kconfig b/arch/Kconfig index a4a8fba..42ebfb9 100644 --- a/arch/Kconfig +++ b/arch/Kconfig @@ -572,6 +572,18 @@ config STACKLEAK_TRACK_MIN_SIZE frame size greater than or equal to this parameter. If unsure, leave the default value 100. +config STACKLEAK_METRICS + bool "Show STACKLEAK metrics in the /proc file system" + depends on GCC_PLUGIN_STACKLEAK + depends on PROC_FS + help + If this is set, STACKLEAK metrics for every task are available in + the /proc file system. In particular, /proc//stack_depth + shows the maximum kernel stack consumption for the current and + previous syscalls. Although this information is not precise, it + can be useful for estimating the STACKLEAK performance impact for + your workloads. + config HAVE_CC_STACKPROTECTOR bool help diff --git a/arch/x86/entry/entry_32.S b/arch/x86/entry/entry_32.S index 068dde6..f5236b3 100644 --- a/arch/x86/entry/entry_32.S +++ b/arch/x86/entry/entry_32.S @@ -134,6 +134,10 @@ ENTRY(erase_kstack) mov %esp, %ecx sub %edi, %ecx +#ifdef CONFIG_STACKLEAK_METRICS + mov %edi, TASK_prev_lowest_stack(%ebp) +#endif + cmp $THREAD_SIZE_asm, %ecx jb .Lgood_counter ud2 diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S index 9b360f8..c82cdbd 100644 --- a/arch/x86/entry/entry_64.S +++ b/arch/x86/entry/entry_64.S @@ -119,6 +119,10 @@ ENTRY(erase_kstack) */ or $2 * 8, %rdi +#ifdef CONFIG_STACKLEAK_METRICS + mov %rdi, TASK_prev_lowest_stack(%r11) +#endif + /* * Check whether we are on the thread stack to prepare the counter * for stack poisoning. diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h index 0c87813..bca1074 100644 --- a/arch/x86/include/asm/processor.h +++ b/arch/x86/include/asm/processor.h @@ -496,6 +496,9 @@ struct thread_struct { #ifdef CONFIG_GCC_PLUGIN_STACKLEAK unsigned long lowest_stack; +# ifdef CONFIG_STACKLEAK_METRICS + unsigned long prev_lowest_stack; +# endif #endif unsigned int sig_on_uaccess_err:1; diff --git a/arch/x86/kernel/asm-offsets.c b/arch/x86/kernel/asm-offsets.c index ef5d260..f48197a 100644 --- a/arch/x86/kernel/asm-offsets.c +++ b/arch/x86/kernel/asm-offsets.c @@ -41,6 +41,9 @@ void common(void) { OFFSET(TASK_addr_limit, task_struct, thread.addr_limit); #ifdef CONFIG_GCC_PLUGIN_STACKLEAK OFFSET(TASK_lowest_stack, task_struct, thread.lowest_stack); +# ifdef CONFIG_STACKLEAK_METRICS + OFFSET(TASK_prev_lowest_stack, task_struct, thread.prev_lowest_stack); +# endif #endif BLANK(); diff --git a/arch/x86/kernel/process_32.c b/arch/x86/kernel/process_32.c index 6d256ab..48993fe 100644 --- a/arch/x86/kernel/process_32.c +++ b/arch/x86/kernel/process_32.c @@ -139,6 +139,9 @@ int copy_thread_tls(unsigned long clone_flags, unsigned long sp, #ifdef CONFIG_GCC_PLUGIN_STACKLEAK p->thread.lowest_stack = (unsigned long)task_stack_page(p) + 2 * sizeof(unsigned long); +# ifdef CONFIG_STACKLEAK_METRICS + p->thread.prev_lowest_stack = p->thread.lowest_stack; +# endif #endif if (unlikely(p->flags & PF_KTHREAD)) { diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c index 6dc55f6..0355fba 100644 --- a/arch/x86/kernel/process_64.c +++ b/arch/x86/kernel/process_64.c @@ -284,6 +284,9 @@ int copy_thread_tls(unsigned long clone_flags, unsigned long sp, #ifdef CONFIG_GCC_PLUGIN_STACKLEAK p->thread.lowest_stack = (unsigned long)task_stack_page(p) + 2 * sizeof(unsigned long); +# ifdef CONFIG_STACKLEAK_METRICS + p->thread.prev_lowest_stack = p->thread.lowest_stack; +# endif #endif savesegment(gs, p->thread.gsindex); diff --git a/fs/proc/base.c b/fs/proc/base.c index 9298324..6a7f9bd 100644 --- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -2914,6 +2914,21 @@ static int proc_pid_patch_state(struct seq_file *m, struct pid_namespace *ns, } #endif /* CONFIG_LIVEPATCH */ +#ifdef CONFIG_STACKLEAK_METRICS +static int proc_stack_depth(struct seq_file *m, struct pid_namespace *ns, + struct pid *pid, struct task_struct *task) +{ + unsigned long prev_depth = THREAD_SIZE - + (task->thread.prev_lowest_stack & (THREAD_SIZE - 1)); + unsigned long depth = THREAD_SIZE - + (task->thread.lowest_stack & (THREAD_SIZE - 1)); + + seq_printf(m, "previous stack depth: %lu\nstack depth: %lu\n", + prev_depth, depth); + return 0; +} +#endif /* CONFIG_STACKLEAK_METRICS */ + /* * Thread groups */ @@ -3018,6 +3033,9 @@ static const struct pid_entry tgid_base_stuff[] = { #ifdef CONFIG_LIVEPATCH ONE("patch_state", S_IRUSR, proc_pid_patch_state), #endif +#ifdef CONFIG_STACKLEAK_METRICS + ONE("stack_depth", S_IRUGO, proc_stack_depth), +#endif }; static int proc_tgid_base_readdir(struct file *file, struct dir_context *ctx)