On Thu, Mar 28, 2019 at 10:17 AM Pavel Shilovsky <piastryyy@xxxxxxxxx> wrote:
>
> ср, 27 мар. 2019 г. в 16:58, Ronnie Sahlberg <lsahlber@xxxxxxxxxx>:
> >
> > Fix a bug where we used to not initialize the cached fid structure at all
> > in open_shroot() if the open was successful but we did not get a lease.
> > This would leave the structure uninitialized and later when we close the handle
> > we would in close_shroot() try to kref_put() an uninitialized refcount.
> >
> > Fix this by always initializing this structure when we are about to return
> > 0/success but make the extra kref_get() on the refcount conditional to
> > whether we got a lease or not.
> > This extra get() is only used to hold the structure until we get a lease
> > break from the server at which point we will kref_put() it during lease
> > processing.
> >
> > Signed-off-by: Ronnie Sahlberg <lsahlber@xxxxxxxxxx>
> > ---
> > fs/cifs/smb2ops.c | 22 ++++++++++++++--------
> > 1 file changed, 14 insertions(+), 8 deletions(-)
> >
> > diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c
> > index 1022a3771e14..4f0fb53cd0de 100644
> > --- a/fs/cifs/smb2ops.c
> > +++ b/fs/cifs/smb2ops.c
> > @@ -724,14 +724,6 @@ int open_shroot(unsigned int xid, struct cifs_tcon *tcon, struct cifs_fid *pfid)
> > else
> > goto oshr_exit;
> >
> > -
> > - memcpy(tcon->crfid.fid, pfid, sizeof(struct cifs_fid));
> > - tcon->crfid.tcon = tcon;
> > - tcon->crfid.is_valid = true;
> > - kref_init(&tcon->crfid.refcount);
> > - kref_get(&tcon->crfid.refcount);
> > -
> > -
> > qi_rsp = (struct smb2_query_info_rsp *)rsp_iov[1].iov_base;
> > if (le32_to_cpu(qi_rsp->OutputBufferLength) < sizeof(struct smb2_file_all_info))
> > goto oshr_exit;
> > @@ -745,6 +737,20 @@ int open_shroot(unsigned int xid, struct cifs_tcon *tcon, struct cifs_fid *pfid)
> > tcon->crfid.file_all_info_is_valid = 1;
> >
> > oshr_exit:
> > + /*
> > + * If we return 0/success then we must also initialize this struct.
> > + * If we got a lease we need to take out an extra get() to keep
> > + * the structure around until we receive the actual lease break.
> > + */
> > + if (rc == 0) {
> ^^^
> This will still leak a handle if smb2_validate_and_copy_iov failed above.
Right. I will resend.
>
> --
> Best regards,
> Pavel Shilovsky
