Re: [Ocfs2-devel] [PATCH] ocfs2: check new file size on fallocate call
From: Joseph Qi
Date: Wed May 31 2023 - 21:23:17 EST
On 6/1/23 6:11 AM, Andrew Morton wrote:
> On Mon, 29 May 2023 16:26:45 +0100 Luís Henriques via Ocfs2-devel <ocfs2-devel@xxxxxxxxxxxxxx> wrote:
>
>> When changing a file size with fallocate() the new size isn't being
>> checked. In particular, the FSIZE ulimit isn't being checked, which makes
>> fstest generic/228 fail. Simply adding a call to inode_newsize_ok() fixes
>> this issue.
>>
>> ...
>>
>> --- a/fs/ocfs2/file.c
>> +++ b/fs/ocfs2/file.c
>> @@ -2100,14 +2100,20 @@ static long ocfs2_fallocate(struct file *file, int mode, loff_t offset,
>> struct ocfs2_space_resv sr;
>> int change_size = 1;
>> int cmd = OCFS2_IOC_RESVSP64;
>> + int ret = 0;
>>
>> if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE))
>> return -EOPNOTSUPP;
>> if (!ocfs2_writes_unwritten_extents(osb))
>> return -EOPNOTSUPP;
>>
>> - if (mode & FALLOC_FL_KEEP_SIZE)
>> + if (mode & FALLOC_FL_KEEP_SIZE) {
>> change_size = 0;
>> + } else {
>> + ret = inode_newsize_ok(inode, offset + len);
>> + if (ret)
>> + return ret;
>> + }
>>
>
> So userspace can exceed rlimit(RLIMIT_FSIZE).
>
> Do we think this flaw is serious enough to justify backporting the fix
> into earlier -stable kernels?
I think it's worth ccing stable kernel as well.
Thanks,
Joseph