Re: [PATCH] drm/amdgpu: fix out of bounds write

[Guenter Roeck]

On 10/27/21 8:22 AM, Harry Wentland wrote:
> On 2021-10-27 10:39, Guenter Roeck wrote:
> > On Wed, Oct 13, 2021 at 04:04:13PM -0400, Thelford Williams wrote:
> > > Size can be any value and is user controlled resulting in overwriting the
> > > 40 byte array wr_buf with an arbitrary length of data from buf.
> > >
> > > Signed-off-by: Thelford Williams <tdwilliamsiv@xxxxxxxxx>
> > > Signed-off-by: Alex Deucher <alexander.deucher@xxxxxxx>
> >
> > The fix works, but unless I am missing something it is incomplete.
> > parse_write_buffer_into_params() is called several times, and the
> > size parameter is always wrong. This patch only fixes one of several
> > instances of the problem.
>
> Patrik sent a patch that covers all cases:
> https://patchwork.freedesktop.org/patch/461554/?series=96341&rev=2
>
> Harry
Thanks!

Guenter

> > Guenter
> >
> > > ---
> > >   drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_debugfs.c | 2 +-
> > >   1 file changed, 1 insertion(+), 1 deletion(-)
> > >
> > > diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_debugfs.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_debugfs.c
> > > index 814f67d86a3c..9b3ad56607bb 100644
> > > --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_debugfs.c
> > > +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_debugfs.c
> > > @@ -264,7 +264,7 @@ static ssize_t dp_link_settings_write(struct file *f, const char __user *buf,
> > >   	if (!wr_buf)
> > >   		return -ENOSPC;
> > >   
> > > -	if (parse_write_buffer_into_params(wr_buf, size,
> > > +	if (parse_write_buffer_into_params(wr_buf, wr_buf_size,
> > >   					   (long *)param, buf,
> > >   					   max_param_num,
> > >   					   &param_nums)) {
> > > --
> > > 2.33.0