merged into cifs-2.6.git for-next
On Wed, Dec 12, 2018 at 4:06 PM Ronnie Sahlberg <lsahlber@xxxxxxxxxx> wrote:
>
> RHBZ: 1021460
>
> There is an issue where when multiple threads open/close the same directory
> ntwrk_buf_start might end up being NULL, causing the call to smbCalcSize
> later to ops with a NULL deref.
>
> The real bug is why this happens and why this can become NULL for an
> open cfile, which should not be allowed.
> This patch tries to avoid a oops until the time when we fix the underlying
> issue.
>
> Signed-off-by: Ronnie Sahlberg <lsahlber@xxxxxxxxxx>
> ---
> fs/cifs/readdir.c | 9 ++++++++-
> 1 file changed, 8 insertions(+), 1 deletion(-)
>
> diff --git a/fs/cifs/readdir.c b/fs/cifs/readdir.c
> index e169e1a5fd35..3925a7bfc74d 100644
> --- a/fs/cifs/readdir.c
> +++ b/fs/cifs/readdir.c
> @@ -655,7 +655,14 @@ find_cifs_entry(const unsigned int xid, struct cifs_tcon *tcon, loff_t pos,
> /* scan and find it */
> int i;
> char *cur_ent;
> - char *end_of_smb = cfile->srch_inf.ntwrk_buf_start +
> + char *end_of_smb;
> +
> + if (cfile->srch_inf.ntwrk_buf_start == NULL) {
> + cifs_dbg(VFS, "ntwrk_buf_start is NULL during readdir\n");
> + return -EIO;
> + }
> +
> + end_of_smb = cfile->srch_inf.ntwrk_buf_start +
> server->ops->calc_smb_size(
> cfile->srch_inf.ntwrk_buf_start,
> server);
> --
> 2.13.6
>
--
Thanks,
Steve
