From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out30-118.freemail.mail.aliyun.com (out30-118.freemail.mail.aliyun.com [115.124.30.118]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C522C39BFFF for ; Fri, 10 Apr 2026 11:20:05 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=115.124.30.118 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775820008; cv=none; b=unbrOCG8WT2i4IvvDdNsHVXcP0YzNo0wI0sku123ZmPrYGUTCzfRuge+4CCO+lJmYZRsVmzfUBsn/GhWikX9Mq5VNbD/zYK3dSXOIj+ihtgarXPZkAmPgt9kVf3AnWVDSTCIQzgOdx30c4n9LCT+1mz0rDn0F+uyUfMi0smoPK8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775820008; c=relaxed/simple; bh=zbReux8eWS2QUjpvqqXGDw1JkXQbyMVJ+JFIRL3Qe8A=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=eHhmblw9u1q1Z47OB1iErqmV3P0gGS8cdnrbCMQPq9oChvG46vds+1k7q8c9P+GD0wy6DeHS+VaWaGzAAcLbgYNJwOSB/FwT4emNymwgNa93+4Kz2aGaZu32mY6+hJwyQEm/qJT3v8i3quTCXhUlcBzsDDJhdyiWkFXOERvSfGE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.alibaba.com; spf=pass smtp.mailfrom=linux.alibaba.com; dkim=pass (1024-bit key) header.d=linux.alibaba.com header.i=@linux.alibaba.com header.b=U8qXThbu; arc=none smtp.client-ip=115.124.30.118 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.alibaba.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.alibaba.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.alibaba.com header.i=@linux.alibaba.com header.b="U8qXThbu" DKIM-Signature:v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.alibaba.com; s=default; t=1775820002; h=Message-ID:Date:MIME-Version:Subject:To:From:Content-Type; bh=e0jjetCAJ+07gZdA13Xj13l0kcxFTteRog9u5ixsQQA=; b=U8qXThbuKwRKDK6DujoikX8MCZYTswRgtGQU2rtN7jhUvVA4zdopoU6gTMyHa4roRZ0LV3uYffII6GQYauCof8666oAcvOhZyBtDP212qgmvUy5hdlE+xt+pzvPbMZwCYt39O2X0sYY1MHYo7AuQaGizm7H+cKB2L1i6FdvYfTM= X-Alimail-AntiSpam:AC=PASS;BC=-1|-1;BR=01201311R101e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=maildocker-contentspam033045098064;MF=joseph.qi@linux.alibaba.com;NM=1;PH=DS;RN=10;SR=0;TI=SMTPD_---0X0l9.Ef_1775820001; Received: from 30.221.145.28(mailfrom:joseph.qi@linux.alibaba.com fp:SMTPD_---0X0l9.Ef_1775820001 cluster:ay36) by smtp.aliyun-inc.com; Fri, 10 Apr 2026 19:20:02 +0800 Message-ID: <8d9a93d4-6a38-4b34-bfbf-311a05fcee69@linux.alibaba.com> Date: Fri, 10 Apr 2026 19:20:01 +0800 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] ocfs2: fix listxattr handling when the buffer is full To: ZhengYuan Huang , akpm , Heming Zhao Cc: ocfs2-devel@lists.linux.dev, linux-kernel@vger.kernel.org, baijiaju1990@gmail.com, r33s3n6@gmail.com, zzzccc427@gmail.com, Mark Fasheh , Joel Becker References: <20260410040339.3837162-1-gality369@gmail.com> From: Joseph Qi In-Reply-To: <20260410040339.3837162-1-gality369@gmail.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 4/10/26 12:03 PM, ZhengYuan Huang wrote: > [BUG] > If an OCFS2 inode has both inline and block-based xattrs, listxattr() > can return a size larger than the caller's buffer when the inline names > consume that buffer exactly. > > kernel BUG at mm/usercopy.c:102! > Oops: invalid opcode: 0000 [#1] SMP KASAN NOPTI > RIP: 0010:usercopy_abort+0xb7/0xd0 mm/usercopy.c:102 > Call Trace: > __check_heap_object+0xe3/0x120 mm/slub.c:8243 > check_heap_object mm/usercopy.c:196 [inline] > __check_object_size mm/usercopy.c:250 [inline] > __check_object_size+0x5c5/0x780 mm/usercopy.c:215 > check_object_size include/linux/ucopysize.h:22 [inline] > check_copy_size include/linux/ucopysize.h:59 [inline] > copy_to_user include/linux/uaccess.h:219 [inline] > listxattr+0xb0/0x170 fs/xattr.c:926 > filename_listxattr fs/xattr.c:958 [inline] > path_listxattrat+0x137/0x320 fs/xattr.c:988 > __do_sys_listxattr fs/xattr.c:1001 [inline] > __se_sys_listxattr fs/xattr.c:998 [inline] > __x64_sys_listxattr+0x7f/0xd0 fs/xattr.c:998 > ... > > [CAUSE] > Commit 936b8834366e ("ocfs2: Refactor xattr list and remove > ocfs2_xattr_handler().") replaced the old per-handler list accounting > with ocfs2_xattr_list_entry(), but it kept using size == 0 to detect > probe mode. > > That assumption stops being true once ocfs2_listxattr() finishes the > inline-xattr pass. If the inline names fill the caller buffer exactly, > the block-xattr pass runs with a non-NULL buffer and a remaining size of > zero. ocfs2_xattr_list_entry() then skips the bounds check, keeps > counting block names, and returns a positive size larger than the > supplied buffer. > > [FIX] > Detect probe mode by testing whether the destination buffer pointer is > NULL instead of whether the remaining size is zero. > > That restores the pre-refactor behavior and matches the OCFS2 getxattr > helpers. Once the remaining buffer reaches zero while more names are > left, the block-xattr pass now returns -ERANGE instead of reporting a > size larger than the allocated list buffer. > > Fixes: 936b8834366e ("ocfs2: Refactor xattr list and remove ocfs2_xattr_handler().") > Signed-off-by: ZhengYuan Huang Looks good. Reviewed-by: Joseph Qi > --- > fs/ocfs2/xattr.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/fs/ocfs2/xattr.c b/fs/ocfs2/xattr.c > --- a/fs/ocfs2/xattr.c > +++ b/fs/ocfs2/xattr.c > @@ -906,8 +906,8 @@ static int ocfs2_xattr_list_entry(struct super_block *sb, > prefix_len = strlen(prefix); > total_len = prefix_len + name_len + 1; > *result += total_len; > > - /* we are just looking for how big our buffer needs to be */ > - if (!size) > + /* No buffer means we are only looking for the required size. */ > + if (!buffer) > return 0; > > if (*result > size)