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[23.128.96.18]) by mx.google.com with ESMTP id a17si14964496edb.389.2020.12.23.23.44.24; Wed, 23 Dec 2020 23:44:48 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18; Authentication-Results: mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726186AbgLXHny (ORCPT + 99 others); Thu, 24 Dec 2020 02:43:54 -0500 Received: from szxga07-in.huawei.com ([45.249.212.35]:10359 "EHLO szxga07-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725811AbgLXHnx (ORCPT ); Thu, 24 Dec 2020 02:43:53 -0500 Received: from DGGEMS414-HUB.china.huawei.com (unknown [172.30.72.59]) by szxga07-in.huawei.com (SkyGuard) with ESMTP id 4D1hqg1pBwz7Hn0; Thu, 24 Dec 2020 15:42:23 +0800 (CST) Received: from use12-sp2.huawei.com (10.67.189.174) by DGGEMS414-HUB.china.huawei.com (10.3.19.214) with Microsoft SMTP Server id 14.3.498.0; Thu, 24 Dec 2020 15:42:59 +0800 From: Xiaoming Ni To: , , , , , , , , CC: , Subject: [PATCH] proc_sysclt: fix oops caused by incorrect command parameters. Date: Thu, 24 Dec 2020 15:42:56 +0800 Message-ID: <20201224074256.117413-1-nixiaoming@huawei.com> X-Mailer: git-send-email 2.27.0 MIME-Version: 1.0 Content-Transfer-Encoding: 7BIT Content-Type: text/plain; charset=US-ASCII X-Originating-IP: [10.67.189.174] X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The process_sysctl_arg() does not check whether val is empty before invoking strlen(val). If the command line parameter () is incorrectly configured and val is empty, oops is triggered. For example, "hung_task_panic=1" is incorrectly written as "hung_task_panic". log: Kernel command line: .... hung_task_panic .... [000000000000000n] user address but active_mm is swapper Internal error: Oops: 96000005 [#1] SMP Modules linked in: CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.10.1 #1 Hardware name: linux,dummy-virt (DT) pstate: 40000005 (nZcv daif -PAN -UAO -TCO BTYPE=--) pc : __pi_strlen+0x10/0x98 lr : process_sysctl_arg+0x1e4/0x2ac sp : ffffffc01104bd40 x29: ffffffc01104bd40 x28: 0000000000000000 x27: ffffff80c0a4691e x26: ffffffc0102a7c8c x25: 0000000000000000 x24: ffffffc01104be80 x23: ffffff80c22f0b00 x22: ffffff80c02e28c0 x21: ffffffc0109f9000 x20: 0000000000000000 x19: ffffffc0107c08de x18: 0000000000000003 x17: ffffffc01105d000 x16: 0000000000000054 x15: ffffffffffffffff x14: 3030253078413830 x13: 000000000000ffff x12: 0000000000000000 x11: 0101010101010101 x10: 0000000000000005 x9 : 0000000000000003 x8 : ffffff80c0980c08 x7 : 0000000000000000 x6 : 0000000000000002 x5 : ffffff80c0235000 x4 : ffffff810f7c7ee0 x3 : 000000000000043a x2 : 00bdcc4ebacf1a54 x1 : 0000000000000000 x0 : 0000000000000000 Call trace: __pi_strlen+0x10/0x98 parse_args+0x278/0x344 do_sysctl_args+0x8c/0xfc kernel_init+0x5c/0xf4 ret_from_fork+0x10/0x30 Code: b200c3eb 927cec01 f2400c07 54000301 (a8c10c22) Fixes: 3db978d480e2843 ("kernel/sysctl: support setting sysctl parameters from kernel command line") Signed-off-by: Xiaoming Ni --- fs/proc/proc_sysctl.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/fs/proc/proc_sysctl.c b/fs/proc/proc_sysctl.c index 317899222d7f..4516411a2b44 100644 --- a/fs/proc/proc_sysctl.c +++ b/fs/proc/proc_sysctl.c @@ -1757,6 +1757,9 @@ static int process_sysctl_arg(char *param, char *val, loff_t pos = 0; ssize_t wret; + if (!val) + return 0; + if (strncmp(param, "sysctl", sizeof("sysctl") - 1) == 0) { param += sizeof("sysctl") - 1; -- 2.27.0