Re: [PATCH] nfsd: Return EPERM on utime/utimes/lutimes calls instead of EACCESS in some cases

zhengbin (A)
2018-12-05T01:04:35Z

thanks,
>>> As the man(3) page for utime/utimes/lutimes, EPERM is returned

-------->this should be As the man page for utime/utimes/lutimes, my little mistake. utime/utimes are man(2), lutimes is man(3)

I send v2 patch?Or when you apply, help modify it?

On 2018/12/5 4:13, J. Bruce Fields wrote:
> On Mon, Dec 03, 2018 at 04:36:27PM +0800, zhengbin (A) wrote:
>> hi, J. Bruce Fields, Jeff Layton
>>
>> When you have time, confirm it? thanks
>
> Sorry for the delay.
>
> The patch looks good to me.
>
> As far as I can tell, we've done this forever. And I'm a little worried
> about changing such long-standing behavior, but I think you're right.
>
> So, applying for for 4.21.
>
> --b.
>
>> On 2018/11/30 15:51, zhengbin wrote:
>>> As the man(3) page for utime/utimes/lutimes, EPERM is returned
>>> when the second parameter of utime/utimes/lutimes is not NULL,
>>> the caller's effective UID does not match the owner of the file,
>>> and the caller is not privileged.
>>>
>>> However, in a NFS directory, it will return EACCESS(nfsd_setattr->
>>> fh_verify->nfsd_permission), This patch fix this.
>>>
>>> Signed-off-by: zhengbin <zhengbin13@huawei.com>
>>> ---
>>> fs/nfsd/vfs.c | 17 +++++++++++++++--
>>> 1 file changed, 15 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
>>> index eb67098..9824e32 100644
>>> --- a/fs/nfsd/vfs.c
>>> +++ b/fs/nfsd/vfs.c
>>> @@ -396,10 +396,23 @@ nfsd_setattr(struct svc_rqst *rqstp, struct svc_fh *fhp, struct iattr *iap,
>>> bool get_write_count;
>>> bool size_change = (iap->ia_valid & ATTR_SIZE);
>>>
>>> - if (iap->ia_valid & (ATTR_ATIME | ATTR_MTIME | ATTR_SIZE))
>>> + if (iap->ia_valid & ATTR_SIZE) {
>>> accmode |= NFSD_MAY_WRITE|NFSD_MAY_OWNER_OVERRIDE;
>>> - if (iap->ia_valid & ATTR_SIZE)
>>> ftype = S_IFREG;
>>> + }
>>> +
>>> + /*
>>> + * If utimes(2) and friends are called with times not NULL, we should
>>> + * not set NFSD_MAY_WRITE bit. Otherwise fh_verify->nfsd_permission
>>> + * will return EACCESS, when the caller's effective UID does not match
>>> + * the owner of the file, and the caller is not privileged. In this
>>> + * situation, we should return EPERM(notify_change will return this).
>>> + */
>>> + if (iap->ia_valid & (ATTR_ATIME | ATTR_MTIME)) {
>>> + accmode |= NFSD_MAY_OWNER_OVERRIDE;
>>> + if (!(iap->ia_valid & (ATTR_ATIME_SET | ATTR_MTIME_SET)))
>>> + accmode |= NFSD_MAY_WRITE;
>>> + }
>>>
>>> /* Callers that do fh_verify should do the fh_want_write: */
>>> get_write_count = !fhp->fh_dentry;
>>> --
>>> 2.7.4
>>>
>>>
>>> .
>>>
>
> .
>