From patchwork Tue Jan 24 18:51:07 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Eric Biggers X-Patchwork-Id: 13114574 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id D449AC54EAA for ; Tue, 24 Jan 2023 18:52:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234391AbjAXSwp (ORCPT ); Tue, 24 Jan 2023 13:52:45 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56560 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234295AbjAXSwh (ORCPT ); Tue, 24 Jan 2023 13:52:37 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 45327485B3; Tue, 24 Jan 2023 10:52:13 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id A174E61336; Tue, 24 Jan 2023 18:52:12 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 60217C4339E; Tue, 24 Jan 2023 18:52:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1674586332; bh=oM/na0j6KDMeNxgMkCt7OnT1CUcFT9V+mDvHYbo5v4g=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=jEo/hJUabqEsYEfWYqvuU37DZczDnvT7Tl71Gv1+qOevulSwjqqwBW+t2EuNiOSVp Grft20xPVgVdqjmMuKrn3CnvZMNzmD9c1ErpeVvd3ZIBBQBIWxqeCh81npymd9onz7 4HNgGVElba0Lbu+t1LVroZn+N4+dm9NWFSIZsf55bJxKSWMuM7dgEkfjhNsIY3GRE6 M0+XvQiWSpvFtim5VCXnBmc2szm1TzAsQQ8+WcFGAprA5NsPG2VbZpMRvUTyKZvYt1 LU8Afue6V6Kt19dOLDVhKzeaUcUOaDI+H79SEOz/udNTX5wQNeAR5GW7ovkaKBcrid 6q0IE3zyKjnJA== From: Eric Biggers To: stable@vger.kernel.org, Greg Kroah-Hartman Cc: Kees Cook , SeongJae Park , Seth Jenkins , Jann Horn , "Eric W . Biederman" , linux-hardening@vger.kernel.org, linux-kernel@vger.kernel.org, Jonathan Corbet , Andrew Morton , Baolin Wang , "Jason A. Donenfeld" , Eric Biggers , Huang Ying , Petr Mladek , tangmeng , "Guilherme G. Piccoli" , Tiezhu Yang , Sebastian Andrzej Siewior , linux-doc@vger.kernel.org, Luis Chamberlain Subject: [PATCH 5.15 17/20] panic: Introduce warn_limit Date: Tue, 24 Jan 2023 10:51:07 -0800 Message-Id: <20230124185110.143857-18-ebiggers@kernel.org> X-Mailer: git-send-email 2.39.1 In-Reply-To: <20230124185110.143857-1-ebiggers@kernel.org> References: <20230124185110.143857-1-ebiggers@kernel.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-hardening@vger.kernel.org From: Kees Cook commit 9fc9e278a5c0b708eeffaf47d6eb0c82aa74ed78 upstream. Like oops_limit, add warn_limit for limiting the number of warnings when panic_on_warn is not set. Cc: Jonathan Corbet Cc: Andrew Morton Cc: Baolin Wang Cc: "Jason A. Donenfeld" Cc: Eric Biggers Cc: Huang Ying Cc: Petr Mladek Cc: tangmeng Cc: "Guilherme G. Piccoli" Cc: Tiezhu Yang Cc: Sebastian Andrzej Siewior Cc: linux-doc@vger.kernel.org Reviewed-by: Luis Chamberlain Signed-off-by: Kees Cook Link: https://lore.kernel.org/r/20221117234328.594699-5-keescook@chromium.org Signed-off-by: Eric Biggers --- Documentation/admin-guide/sysctl/kernel.rst | 10 ++++++++++ kernel/panic.c | 14 ++++++++++++++ 2 files changed, 24 insertions(+) diff --git a/Documentation/admin-guide/sysctl/kernel.rst b/Documentation/admin-guide/sysctl/kernel.rst index d6f1d3892e71e..48b91c485c993 100644 --- a/Documentation/admin-guide/sysctl/kernel.rst +++ b/Documentation/admin-guide/sysctl/kernel.rst @@ -1494,6 +1494,16 @@ entry will default to 2 instead of 0. 2 Unprivileged calls to ``bpf()`` are disabled = ============================================================= + +warn_limit +========== + +Number of kernel warnings after which the kernel should panic when +``panic_on_warn`` is not set. Setting this to 0 disables checking +the warning count. Setting this to 1 has the same effect as setting +``panic_on_warn=1``. The default value is 0. + + watchdog ======== diff --git a/kernel/panic.c b/kernel/panic.c index bf0324941e433..604d7ad77042e 100644 --- a/kernel/panic.c +++ b/kernel/panic.c @@ -57,6 +57,7 @@ bool crash_kexec_post_notifiers; int panic_on_warn __read_mostly; unsigned long panic_on_taint; bool panic_on_taint_nousertaint = false; +static unsigned int warn_limit __read_mostly; int panic_timeout = CONFIG_PANIC_TIMEOUT; EXPORT_SYMBOL_GPL(panic_timeout); @@ -86,6 +87,13 @@ static struct ctl_table kern_panic_table[] = { .extra2 = SYSCTL_ONE, }, #endif + { + .procname = "warn_limit", + .data = &warn_limit, + .maxlen = sizeof(warn_limit), + .mode = 0644, + .proc_handler = proc_douintvec, + }, { } }; @@ -195,8 +203,14 @@ static void panic_print_sys_info(void) void check_panic_on_warn(const char *origin) { + static atomic_t warn_count = ATOMIC_INIT(0); + if (panic_on_warn) panic("%s: panic_on_warn set ...\n", origin); + + if (atomic_inc_return(&warn_count) >= READ_ONCE(warn_limit) && warn_limit) + panic("%s: system warned too often (kernel.warn_limit is %d)", + origin, warn_limit); } /**