From patchwork Sat May 26 20:10:29 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alexander Popov X-Patchwork-Id: 10429223 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 BF27760249 for ; Sat, 26 May 2018 20:11:52 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id B00F22919A for ; Sat, 26 May 2018 20:11:52 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id A42C52940A; Sat, 26 May 2018 20:11:52 +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=-5.2 required=2.0 tests=BAYES_00, 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 807052919A for ; Sat, 26 May 2018 20:11:51 +0000 (UTC) Received: (qmail 26245 invoked by uid 550); 26 May 2018 20:11:12 -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 26097 invoked from network); 26 May 2018 20:11:07 -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=DpAO981J4IviWrj2blstnQqbVNxsFTnFpMrlDDtHng0=; b=T/6Ie1t7Qo1OIUx0X+ctjJuQTfi2mP+vn8UyTIcP+uPNDhcUvSVMcNUBbTnmKqUsp3 rRgeGAOhAUUjMT57Xmq7Xzo9U55vV5SoWfy3TmfSsxrk4AdrzabpbuhxX7JO3b0IAMuZ 3oFysPf1AIMPH1t0JANcyuo71vWvximkOqlqrjCdU/chVDfGSHuUTDdqDgcKY4+iXRBh CMvyUUFkkxjaGqvjUnQzDVsm1epxFgTHneSMcdIbNlvyukQP/j/skOe6aEVF3OErmBRz j2eWsvr6FjBHoBc90egNS+rMUMFNyIex8FQelMEafQsBK501jWeDsMFt1sQ+x/DHlWr5 k/5Q== X-Gm-Message-State: ALKqPwdfwmH7cm8V7x7gbCrZhe++QcZ92EbwPZ6swpprSHR0OhzmD7mf 09B4fqZAvdjiakyk6PVLJ/KYPLzx X-Google-Smtp-Source: ADUXVKL6yRkEHbVkTBz8VAnrC59MSP5Xtzs/UYm3kr4pucf9x3yXm0wJT0JM74h2dfqNc0NZUBFogA== X-Received: by 2002:a19:2092:: with SMTP id g140-v6mr4068277lfg.38.1527365456279; Sat, 26 May 2018 13:10:56 -0700 (PDT) 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 , Linus Torvalds , Greg Kroah-Hartman , Dan Williams , Dave Hansen , Mathias Krause , Vikas Shivappa , Kyle Huey , Dmitry Safonov , Will Deacon , Arnd Bergmann , Florian Weimer , Boris Lukashev , Andrey Konovalov , x86@kernel.org, linux-kernel@vger.kernel.org, alex.popov@linux.com Subject: [PATCH v13 5/6] fs/proc: Show STACKLEAK metrics in the /proc file system Date: Sat, 26 May 2018 23:10:29 +0300 Message-Id: <1527365430-8303-6-git-send-email-alex.popov@linux.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1527365430-8303-1-git-send-email-alex.popov@linux.com> References: <1527365430-8303-1-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 ++++++++++++ fs/proc/base.c | 18 ++++++++++++++++++ include/linux/sched.h | 1 + include/linux/stackleak.h | 3 +++ kernel/stackleak.c | 4 ++++ 5 files changed, 38 insertions(+) diff --git a/arch/Kconfig b/arch/Kconfig index 46fe6c8..ee213f2 100644 --- a/arch/Kconfig +++ b/arch/Kconfig @@ -576,6 +576,18 @@ config STACKLEAK_TRACK_MIN_SIZE a stack 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/fs/proc/base.c b/fs/proc/base.c index 1a76d75..5a97edf 100644 --- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -2924,6 +2924,21 @@ 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->prev_lowest_stack & (THREAD_SIZE - 1)); + unsigned long depth = THREAD_SIZE - + (task->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 */ @@ -3025,6 +3040,9 @@ 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) diff --git a/include/linux/sched.h b/include/linux/sched.h index 050906f..3456d7c 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1170,6 +1170,7 @@ struct task_struct { #ifdef CONFIG_GCC_PLUGIN_STACKLEAK unsigned long lowest_stack; + unsigned long prev_lowest_stack; #endif /* diff --git a/include/linux/stackleak.h b/include/linux/stackleak.h index 743c911..e2da99b 100644 --- a/include/linux/stackleak.h +++ b/include/linux/stackleak.h @@ -18,6 +18,9 @@ static inline void stackleak_task_init(struct task_struct *task) #ifdef CONFIG_GCC_PLUGIN_STACKLEAK task->lowest_stack = (unsigned long)end_of_stack(task) + sizeof(unsigned long); +# ifdef CONFIG_STACKLEAK_METRICS + task->prev_lowest_stack = task->lowest_stack; +# endif #endif } diff --git a/kernel/stackleak.c b/kernel/stackleak.c index 7343f41..8cb29fb 100644 --- a/kernel/stackleak.c +++ b/kernel/stackleak.c @@ -40,6 +40,10 @@ asmlinkage void stackleak_erase_kstack(void) if (kstack_ptr == boundary) kstack_ptr += sizeof(unsigned long); +#ifdef CONFIG_STACKLEAK_METRICS + current->prev_lowest_stack = kstack_ptr; +#endif + /* * Now write the poison value to the kernel stack. Start from * 'kstack_ptr' and move up till the new 'boundary'. We assume that