From: Shuhao Fu <sfual@cse.ust.hk>
To: Steve French <smfrench@gmail.com>
Cc: Steve French <sfrench@samba.org>,
Paulo Alcantara <pc@manguebit.org>,
Ronnie Sahlberg <ronniesahlberg@gmail.com>,
Shyam Prasad N <sprasad@microsoft.com>,
Tom Talpey <tom@talpey.com>, Bharath SM <bharathsm@microsoft.com>,
linux-cifs@vger.kernel.org, samba-technical@lists.samba.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] smb: client: fix refcount leak in smb2_set_path_attr
Date: Tue, 4 Nov 2025 16:54:48 +0000 [thread overview]
Message-ID: <aQov2KFhe8Ro3CtC@chcpu18> (raw)
In-Reply-To: <CAH2r5mu7s4p88RhUbCm5mqUvEVM60OOTTJOZ+rz09nFfc+t3mQ@mail.gmail.com>
On Tue, Nov 04, 2025 at 10:12:13AM -0600, Steve French wrote:
> There are multiple callers - are there callers that don't call
> "set_writeable_path()" ? And so could cause the reverse refcount
> issue?
I found three calls to `smb2_set_path_attr`. Two in `smb2_rename_path`
and one in `smb2_create_hardlink`. The one in `smb2_create_hardlink`
passes NULL for cfile. Therefore, it would not cause reverse refcount
issue here.
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)
> >
> >
>
>
> --
> Thanks,
>
> Steve
prev parent reply other threads:[~2025-11-04 16:55 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
2025-11-04 16:54 ` Shuhao Fu [this message]
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