From: Henrique Carvalho <henrique.carvalho@suse.com>
To: Shuhao Fu <sfual@cse.ust.hk>
Cc: Steve French <smfrench@gmail.com>, Tom Talpey <tom@talpey.com>,
Shyam Prasad N <sprasad@microsoft.com>,
Paulo Alcantara <pc@manguebit.org>,
linux-cifs@vger.kernel.org, samba-technical@lists.samba.org,
linux-kernel@vger.kernel.org, Steve French <sfrench@samba.org>,
Bharath SM <bharathsm@microsoft.com>
Subject: Re: [PATCH] smb: client: fix refcount leak in smb2_set_path_attr
Date: Tue, 4 Nov 2025 15:34:12 -0300 [thread overview]
Message-ID: <33de0eaf-474b-4e88-a445-2f12387bc36c@suse.com> (raw)
In-Reply-To: <aQowQ7gCdDruGVro@chcpu18>
On 11/4/25 1:56 PM, Shuhao Fu wrote:
> On Tue, Nov 04, 2025 at 01:23:33PM -0300, Henrique Carvalho wrote:
>>
>>
>> On 11/4/25 1:12 PM, Steve French via samba-technical wrote:
>>> There are multiple callers - are there callers that don't call
>>> "set_writeable_path()" ? And so could cause the reverse refcount
>>> issue?
>>
>> Yes... Even if it does not cause an issue today, that fix looks like it
>> belongs inside smb2_rename_path?
>
> I placed decrement in `smb2_set_path_attr` since it seems like a wrapper
> of `smb2_compound_op`. I figured that this wrapper should handle the
> failure cases the same way as `smb2_compound_op`.
Makes sense.
Acked-by: Henrique Carvalho <henrique.carvalho@suse.com>
>
> Thanks,
> Shuhao
>>
>>>
>>> On Tue, Nov 4, 2025 at 9:21 AM Shuhao Fu <sfual@cse.ust.hk> wrote:
>>>>
>>>> Fix refcount leak in `smb2_set_path_attr` when path conversion fails.
>>>>
>>>> Function `cifs_get_writable_path` returns `cfile` with its reference
>>>> counter `cfile->count` increased on success. Function `smb2_compound_op`
>>>> would decrease the reference counter for `cfile`, as stated in its
>>>> comment. By calling `smb2_rename_path`, the reference counter of `cfile`
>>>> would leak if `cifs_convert_path_to_utf16` fails in `smb2_set_path_attr`.
>>>>
>>>> Fixes: 8de9e86c67ba ("cifs: create a helper to find a writeable handle by path name")
>>>> Signed-off-by: Shuhao Fu <sfual@cse.ust.hk>
>>>> ---
>>>> fs/smb/client/smb2inode.c | 2 ++
>>>> 1 file changed, 2 insertions(+)
>>>>
>>>> diff --git a/fs/smb/client/smb2inode.c b/fs/smb/client/smb2inode.c
>>>> index 09e3fc81d..69cb81fa0 100644
>>>> --- a/fs/smb/client/smb2inode.c
>>>> +++ b/fs/smb/client/smb2inode.c
>>>> @@ -1294,6 +1294,8 @@ static int smb2_set_path_attr(const unsigned int xid, struct cifs_tcon *tcon,
>>>> smb2_to_name = cifs_convert_path_to_utf16(to_name, cifs_sb);
>>>> if (smb2_to_name == NULL) {
>>>> rc = -ENOMEM;
>>>> + if (cfile)
>>>> + cifsFileInfo_put(cfile);
>>>> goto smb2_rename_path;
>>>> }
>>>> in_iov.iov_base = smb2_to_name;
>>>> --
>>>> 2.39.5 (Apple Git-154)
>>>>
>>>>
>>>
>>>
>>
>> --
>> Henrique
>> SUSE Labs
--
Henrique
SUSE Labs
next prev parent reply other threads:[~2025-11-04 18:36 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-11-04 15:13 [PATCH] smb: client: fix refcount leak in smb2_set_path_attr Shuhao Fu
2025-11-04 16:12 ` Steve French
2025-11-04 16:23 ` Henrique Carvalho
2025-11-04 16:56 ` Shuhao Fu
2025-11-04 18:34 ` Henrique Carvalho [this message]
2025-11-04 16:54 ` Shuhao Fu
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