From nobody Fri Sep 19 08:34:33 2025 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 D3291C4321E for ; Sat, 26 Nov 2022 04:36:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230134AbiKZEg2 (ORCPT ); Fri, 25 Nov 2022 23:36:28 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42520 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230114AbiKZEgX (ORCPT ); Fri, 25 Nov 2022 23:36:23 -0500 Received: from szxga01-in.huawei.com (szxga01-in.huawei.com [45.249.212.187]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 165B440466; Fri, 25 Nov 2022 20:36:22 -0800 (PST) Received: from dggemv704-chm.china.huawei.com (unknown [172.30.72.53]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4NJzSK2KMKzmW95; Sat, 26 Nov 2022 12:35:45 +0800 (CST) Received: from kwepemm600020.china.huawei.com (7.193.23.147) by dggemv704-chm.china.huawei.com (10.3.19.47) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.31; Sat, 26 Nov 2022 12:36:20 +0800 Received: from localhost.localdomain (10.175.112.125) by kwepemm600020.china.huawei.com (7.193.23.147) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.31; Sat, 26 Nov 2022 12:36:19 +0800 From: Peng Zhang To: , CC: , , , , ZhangPeng , Subject: [PATCH] hfs: Fix OOB Write in hfs_asc2mac Date: Sat, 26 Nov 2022 04:36:12 +0000 Message-ID: <20221126043612.853428-1-zhangpeng362@huawei.com> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Originating-IP: [10.175.112.125] X-ClientProxiedBy: dggems703-chm.china.huawei.com (10.3.19.180) To kwepemm600020.china.huawei.com (7.193.23.147) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" From: ZhangPeng Syzbot reported a OOB Write bug: loop0: detected capacity change from 0 to 64 =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D BUG: KASAN: slab-out-of-bounds in hfs_asc2mac+0x467/0x9a0 fs/hfs/trans.c:133 Write of size 1 at addr ffff88801848314e by task syz-executor391/3632 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x1b1/0x28e lib/dump_stack.c:106 print_address_description+0x74/0x340 mm/kasan/report.c:284 print_report+0x107/0x1f0 mm/kasan/report.c:395 kasan_report+0xcd/0x100 mm/kasan/report.c:495 hfs_asc2mac+0x467/0x9a0 fs/hfs/trans.c:133 hfs_cat_build_key+0x92/0x170 fs/hfs/catalog.c:28 hfs_lookup+0x1ab/0x2c0 fs/hfs/dir.c:31 lookup_open fs/namei.c:3391 [inline] open_last_lookups fs/namei.c:3481 [inline] path_openat+0x10e6/0x2df0 fs/namei.c:3710 do_filp_open+0x264/0x4f0 fs/namei.c:3740 If in->len is much larger than HFS_NAMELEN(31) which is the maximum length of an HFS filename, a OOB Write could occur in hfs_asc2mac(). In that case, when the dst reaches the boundary, the srclen is still greater than 0, which causes a OOB Write. Fix this by adding a Check on dstlen before Writing to dst address. Fixes: 328b92278650 ("[PATCH] hfs: NLS support") Reported-by: syzbot+dc3b1cf9111ab5fe98e7@syzkaller.appspotmail.com Signed-off-by: ZhangPeng Reviewed-by: Viacheslav Dubeyko --- fs/hfs/trans.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/fs/hfs/trans.c b/fs/hfs/trans.c index 39f5e343bf4d..886158db07b3 100644 --- a/fs/hfs/trans.c +++ b/fs/hfs/trans.c @@ -130,6 +130,8 @@ void hfs_asc2mac(struct super_block *sb, struct hfs_nam= e *out, const struct qstr dst +=3D size; dstlen -=3D size; } else { + if (dstlen =3D=3D 0) + goto out; *dst++ =3D ch > 0xff ? '?' : ch; dstlen--; } --=20 2.25.1