[PATCH] regmap: Check for out-of-range offsets before mapping them

[Pratyush Yadav]

Hi Simon,

On 07/06/20 08:43PM, Simon Glass wrote:
> Hi Pratyush,
> 
> On Tue, 26 May 2020 at 06:06, Pratyush Yadav <p.yadav at ti.com> wrote:
> >
> > In regmap_raw_{read,write}_range(), offsets are checked to make sure
> > they aren't out of range. But this check happens _after_ the address is
> > mapped from physical memory. Input should be sanity-checked before using
> > it. Mapping the address before validating it leaves the door open to
> > passing an invalid address to map_physmem(). So check for out of range
> > offsets _before_ mapping them.
> >
> > This fixes a segmentation fault in sandbox when -1 is used as an offset
> > to regmap_{read,write}().
> >
> > Signed-off-by: Pratyush Yadav <p.yadav at ti.com>
> > ---
> >  drivers/core/regmap.c | 8 ++++----
> >  1 file changed, 4 insertions(+), 4 deletions(-)
> >
> 
> Reviewed-by: Simon Glass <sjg at chromium.org>

Thanks.
 
> Please add a sandbox test to catch this problem.

The test "dm_test_devm_regmap" proposed in [0] should catch this:

    ut_asserteq(-ERANGE, regmap_write(priv->cfg_regmap, -1, val));
    ut_asserteq(-ERANGE, regmap_read(priv->cfg_regmap, -1, &val));

[0] https://patchwork.ozlabs.org/project/uboot/patch/20200605203025.15466-9-p.yadav@ti.com/

-- 
Regards,
Pratyush Yadav
Texas Instruments India