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.
--
Best regards,
Pavel Shilovsky
