On Thu, Jul 28, 2022 at 02:44:17PM +0300, Serge Semin wrote:
> On Wed, Jul 20, 2022 at 09:28:18PM +0300, Dan Carpenter wrote:
> > The call to:
> >
> > ret = simple_write_to_buffer(buf, size, offp, ubuf, size);
> >
> > will return success if it is able to write even one byte to "buf".
> > The value of "*offp" controls which byte. This could result in
> > reading uninitialized data when we do the sscanf() on the next line.
> >
> > This code is not really desigined to handle partial writes where
> > *offp is non-zero and the "buf" is preserved and re-used between writes.
> > Just ban partial writes and replace the simple_write_to_buffer() with
> > copy_from_user().
> >
> > Fixes: 578b881ba9c4 ("NTB: Add tool test client")
>
> Looks good. Thanks.
> Reviewed-by: Serge Semin <fancer.lancer@xxxxxxxxx>
>
> -Sergey
Sorry for the extremely long delay in response. This series is in my
ntb branch and will be in my pull request for v5.20 which should be
going out later today.
Thanks,
Jon
>
> > Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
> > ---
> > drivers/ntb/test/ntb_tool.c | 8 +++++---
> > 1 file changed, 5 insertions(+), 3 deletions(-)
> >
> > diff --git a/drivers/ntb/test/ntb_tool.c b/drivers/ntb/test/ntb_tool.c
> > index b7bf3f863d79..5ee0afa621a9 100644
> > --- a/drivers/ntb/test/ntb_tool.c
> > +++ b/drivers/ntb/test/ntb_tool.c
> > @@ -367,14 +367,16 @@ static ssize_t tool_fn_write(struct tool_ctx *tc,
> > u64 bits;
> > int n;
> >
> > + if (*offp)
> > + return 0;
> > +
> > buf = kmalloc(size + 1, GFP_KERNEL);
> > if (!buf)
> > return -ENOMEM;
> >
> > - ret = simple_write_to_buffer(buf, size, offp, ubuf, size);
> > - if (ret < 0) {
> > + if (copy_from_user(buf, ubuf, size)) {
> > kfree(buf);
> > - return ret;
> > + return -EFAULT;
> > }
> >
> > buf[size] = 0;
> > --
> > 2.35.1
> >
> >
