On Sun, 11 May 2025 15:27:07 +0100
Jonathan Cameron <ji...@kernel.org> wrote:
> On Thu, 8 May 2025 15:06:07 +0200
> Markus Burri <markus.bu...@mt.com> wrote:
>
> > The buffer is set to 80 character. If a caller write more characters,
> > count is truncated to the max available space in "simple_write_to_buffer".
> > But afterwards a string terminator is written to the buffer at offset count
> > without boundary check. The zero termination is written OUT-OF-BOUND.
> >
> > Add a check that the given buffer is smaller then the buffer to prevent.
> >
> > Fixes: 035b4989211d ("iio: backend: make sure to NULL terminate stack
> > buffer")
> > Signed-off-by: Markus Burri <markus.bu...@mt.com>
> I'm looking for a tag from Nuno on this one before applying.
Please make sure to pick up tags on earlier versions. Nuno had sent a RB for
this one which I've now added.
People don't tend to look again at patches that they've already tagged so Nuno
probably didn't see my ask for a tag above.
Anyhow, now applied but will have to wait for a rebase of my fixes-togreg tree
on rc1 once available.
Thanks,
Jonathan
>
> J
> > ---
> > drivers/iio/industrialio-backend.c | 5 ++++-
> > 1 file changed, 4 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/iio/industrialio-backend.c
> > b/drivers/iio/industrialio-backend.c
> > index a43c8d1bb3d0..31fe793e345e 100644
> > --- a/drivers/iio/industrialio-backend.c
> > +++ b/drivers/iio/industrialio-backend.c
> > @@ -155,11 +155,14 @@ static ssize_t iio_backend_debugfs_write_reg(struct
> > file *file,
> > ssize_t rc;
> > int ret;
> >
> > + if (count >= sizeof(buf))
> > + return -ENOSPC;
> > +
> > rc = simple_write_to_buffer(buf, sizeof(buf) - 1, ppos, userbuf, count);
> > if (rc < 0)
> > return rc;
> >
> > - buf[count] = '\0';
> > + buf[rc] = '\0';
> >
> > ret = sscanf(buf, "%i %i", &back->cached_reg_addr, &val);
> >
>
>
