Re: [PATCH v6 04/12] drivers/infiniband: make setup_ctxt always get a nul terminated task comm

[Yafang Shao]

On Tue, Oct 26, 2021 at 5:16 AM Kees Cook <keescook@xxxxxxxxxxxx> wrote:
>
> On Mon, Oct 25, 2021 at 08:33:07AM +0000, Yafang Shao wrote:
> > Use strscpy_pad() instead of strlcpy() to make the comm always nul
> > terminated. As the comment above the hard-coded 16, we can replace it
> > with TASK_COMM_LEN, then it will adopt to the comm size change.
> >
> > Signed-off-by: Yafang Shao <laoar.shao@xxxxxxxxx>
> > Cc: Mathieu Desnoyers <mathieu.desnoyers@xxxxxxxxxxxx>
> > Cc: Arnaldo Carvalho de Melo <arnaldo.melo@xxxxxxxxx>
> > Cc: Andrii Nakryiko <andrii.nakryiko@xxxxxxxxx>
> > Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
> > Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
> > Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
> > Cc: Kees Cook <keescook@xxxxxxxxxxxx>
> > Cc: Petr Mladek <pmladek@xxxxxxxx>
> > ---
> >  drivers/infiniband/hw/qib/qib.h          | 2 +-
> >  drivers/infiniband/hw/qib/qib_file_ops.c | 2 +-
> >  2 files changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/infiniband/hw/qib/qib.h b/drivers/infiniband/hw/qib/qib.h
> > index 9363bccfc6e7..a8e1c30c370f 100644
> > --- a/drivers/infiniband/hw/qib/qib.h
> > +++ b/drivers/infiniband/hw/qib/qib.h
> > @@ -196,7 +196,7 @@ struct qib_ctxtdata {
> >       pid_t pid;
> >       pid_t subpid[QLOGIC_IB_MAX_SUBCTXT];
> >       /* same size as task_struct .comm[], command that opened context */
> > -     char comm[16];
> > +     char comm[TASK_COMM_LEN];
> >       /* pkeys set by this use of this ctxt */
> >       u16 pkeys[4];
> >       /* so file ops can get at unit */
> > diff --git a/drivers/infiniband/hw/qib/qib_file_ops.c b/drivers/infiniband/hw/qib/qib_file_ops.c
> > index 63854f4b6524..7ab2b448c183 100644
> > --- a/drivers/infiniband/hw/qib/qib_file_ops.c
> > +++ b/drivers/infiniband/hw/qib/qib_file_ops.c
> > @@ -1321,7 +1321,7 @@ static int setup_ctxt(struct qib_pportdata *ppd, int ctxt,
> >       rcd->tid_pg_list = ptmp;
> >       rcd->pid = current->pid;
> >       init_waitqueue_head(&dd->rcd[ctxt]->wait);
> > -     strlcpy(rcd->comm, current->comm, sizeof(rcd->comm));
> > +     strscpy_pad(rcd->comm, current->comm, sizeof(rcd->comm));
>
> This should use (the adjusted) get_task_comm() instead of leaving this
> open-coded.
>

Sure, that is better.

> >       ctxt_fp(fp) = rcd;
> >       qib_stats.sps_ctxts++;
> >       dd->freectxts--;
> > --
> > 2.17.1
> >
>
> --
> Kees Cook



-- 
Thanks
Yafang