From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-18.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id BBFB7C433DB for ; Mon, 4 Jan 2021 16:02:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8D2DF22509 for ; Mon, 4 Jan 2021 16:02:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728633AbhADQBl (ORCPT ); Mon, 4 Jan 2021 11:01:41 -0500 Received: from mail.kernel.org ([198.145.29.99]:38806 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728599AbhADQBc (ORCPT ); Mon, 4 Jan 2021 11:01:32 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 3480A22473; Mon, 4 Jan 2021 16:00:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1609776051; bh=ii7id98pONZGgFYKjTPx+BnAxnP6uQmzICQHKYE1HW0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=LURN2o2s4KP4/P/qA4G+x9SradRAw9h1Q+uCFHolPRMEPHfq/MoQ6+4tJ4RZq9eXj gVWhLxaDcsgclWS+1HksT08MJS8vbPHt0NAoldF075WAEQvSGSdWVkNfwxSKc1caQe 91TzHZCPoD24brkPGhWKbRGyX6Hj6jrl/KlcPRb0= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, David Howells , Jamie Iles , Richard Weinberger , Sasha Levin Subject: [PATCH 5.4 17/47] jffs2: Fix NULL pointer dereference in rp_size fs option parsing Date: Mon, 4 Jan 2021 16:57:16 +0100 Message-Id: <20210104155706.569044750@linuxfoundation.org> X-Mailer: git-send-email 2.30.0 In-Reply-To: <20210104155705.740576914@linuxfoundation.org> References: <20210104155705.740576914@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Jamie Iles [ Upstream commit a61df3c413e49b0042f9caf774c58512d1cc71b7 ] syzkaller found the following JFFS2 splat: Unable to handle kernel paging request at virtual address dfffa00000000001 Mem abort info: ESR = 0x96000004 EC = 0x25: DABT (current EL), IL = 32 bits SET = 0, FnV = 0 EA = 0, S1PTW = 0 Data abort info: ISV = 0, ISS = 0x00000004 CM = 0, WnR = 0 [dfffa00000000001] address between user and kernel address ranges Internal error: Oops: 96000004 [#1] SMP Dumping ftrace buffer: (ftrace buffer empty) Modules linked in: CPU: 0 PID: 12745 Comm: syz-executor.5 Tainted: G S 5.9.0-rc8+ #98 Hardware name: linux,dummy-virt (DT) pstate: 20400005 (nzCv daif +PAN -UAO BTYPE=--) pc : jffs2_parse_param+0x138/0x308 fs/jffs2/super.c:206 lr : jffs2_parse_param+0x108/0x308 fs/jffs2/super.c:205 sp : ffff000022a57910 x29: ffff000022a57910 x28: 0000000000000000 x27: ffff000057634008 x26: 000000000000d800 x25: 000000000000d800 x24: ffff0000271a9000 x23: ffffa0001adb5dc0 x22: ffff000023fdcf00 x21: 1fffe0000454af2c x20: ffff000024cc9400 x19: 0000000000000000 x18: 0000000000000000 x17: 0000000000000000 x16: ffffa000102dbdd0 x15: 0000000000000000 x14: ffffa000109e44bc x13: ffffa00010a3a26c x12: ffff80000476e0b3 x11: 1fffe0000476e0b2 x10: ffff80000476e0b2 x9 : ffffa00010a3ad60 x8 : ffff000023b70593 x7 : 0000000000000003 x6 : 00000000f1f1f1f1 x5 : ffff000023fdcf00 x4 : 0000000000000002 x3 : ffffa00010000000 x2 : 0000000000000001 x1 : dfffa00000000000 x0 : 0000000000000008 Call trace: jffs2_parse_param+0x138/0x308 fs/jffs2/super.c:206 vfs_parse_fs_param+0x234/0x4e8 fs/fs_context.c:117 vfs_parse_fs_string+0xe8/0x148 fs/fs_context.c:161 generic_parse_monolithic+0x17c/0x208 fs/fs_context.c:201 parse_monolithic_mount_data+0x7c/0xa8 fs/fs_context.c:649 do_new_mount fs/namespace.c:2871 [inline] path_mount+0x548/0x1da8 fs/namespace.c:3192 do_mount+0x124/0x138 fs/namespace.c:3205 __do_sys_mount fs/namespace.c:3413 [inline] __se_sys_mount fs/namespace.c:3390 [inline] __arm64_sys_mount+0x164/0x238 fs/namespace.c:3390 __invoke_syscall arch/arm64/kernel/syscall.c:36 [inline] invoke_syscall arch/arm64/kernel/syscall.c:48 [inline] el0_svc_common.constprop.0+0x15c/0x598 arch/arm64/kernel/syscall.c:149 do_el0_svc+0x60/0x150 arch/arm64/kernel/syscall.c:195 el0_svc+0x34/0xb0 arch/arm64/kernel/entry-common.c:226 el0_sync_handler+0xc8/0x5b4 arch/arm64/kernel/entry-common.c:236 el0_sync+0x15c/0x180 arch/arm64/kernel/entry.S:663 Code: d2d40001 f2fbffe1 91002260 d343fc02 (38e16841) ---[ end trace 4edf690313deda44 ]--- This is because since ec10a24f10c8, the option parsing happens before fill_super and so the MTD device isn't associated with the filesystem. Defer the size check until there is a valid association. Fixes: ec10a24f10c8 ("vfs: Convert jffs2 to use the new mount API") Cc: Cc: David Howells Signed-off-by: Jamie Iles Signed-off-by: Richard Weinberger Signed-off-by: Sasha Levin --- fs/jffs2/super.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/fs/jffs2/super.c b/fs/jffs2/super.c index 68ce77cbeed3b..6839a61e8ff1e 100644 --- a/fs/jffs2/super.c +++ b/fs/jffs2/super.c @@ -208,12 +208,8 @@ static int jffs2_parse_param(struct fs_context *fc, struct fs_parameter *param) case Opt_rp_size: if (result.uint_32 > UINT_MAX / 1024) return invalf(fc, "jffs2: rp_size unrepresentable"); - opt = result.uint_32 * 1024; - if (opt > c->mtd->size) - return invalf(fc, "jffs2: Too large reserve pool specified, max is %llu KB", - c->mtd->size / 1024); + c->mount_opts.rp_size = result.uint_32 * 1024; c->mount_opts.set_rp_size = true; - c->mount_opts.rp_size = opt; break; default: return -EINVAL; @@ -275,6 +271,10 @@ static int jffs2_fill_super(struct super_block *sb, struct fs_context *fc) c->mtd = sb->s_mtd; c->os_priv = sb; + if (c->mount_opts.rp_size > c->mtd->size) + return invalf(fc, "jffs2: Too large reserve pool specified, max is %llu KB", + c->mtd->size / 1024); + /* Initialize JFFS2 superblock locks, the further initialization will * be done later */ mutex_init(&c->alloc_sem); -- 2.27.0