From: Shuhao Fu <sfual@cse.ust.hk>
To: Henrique Carvalho <henrique.carvalho@suse.com>
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 16:56:35 +0000 [thread overview]
Message-ID: <aQowQ7gCdDruGVro@chcpu18> (raw)
In-Reply-To: <648b7b14-d285-449a-a1b3-4cd062a55b02@suse.com>
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`.
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
next prev parent reply other threads:[~2025-11-04 16:57 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 [this message]
2025-11-04 18:34 ` Henrique Carvalho
2025-11-04 16:54 ` Shuhao Fu
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