On Thu, 20 Aug 2020 at 22:40, Krzysztof Kozlowski <k...@kernel.org> wrote:
>
> On Thu, Aug 20, 2020 at 06:03:33PM -0700, Markus Mayer wrote:
> > We would overrun the error_text array if we hit a TIMEOUT condition,
> > because we were using the error code "ETIMEDOUT" (which is 110) as an
> > array index.
> >
> > We fix the problem by correcting the array index and by providing a
> > function to retrieve error messages rather than accessing the array
> > directly. The function includes a bounds check that prevents the array
> > from being overrun.
> >
> > Signed-off-by: Markus Mayer <mma...@broadcom.com>
> > ---
> >
> > This patch was prepared in response to https://lkml.org/lkml/2020/8/18/505.
> >
> > drivers/memory/brcmstb_dpfe.c | 23 ++++++++++++++++-------
> > 1 file changed, 16 insertions(+), 7 deletions(-)
> >
> > diff --git a/drivers/memory/brcmstb_dpfe.c b/drivers/memory/brcmstb_dpfe.c
> > index 81abc4a98a27..a986a849f58e 100644
> > --- a/drivers/memory/brcmstb_dpfe.c
> > +++ b/drivers/memory/brcmstb_dpfe.c
> > @@ -190,11 +190,6 @@ struct brcmstb_dpfe_priv {
> > struct mutex lock;
> > };
> >
> > -static const char * const error_text[] = {
> > - "Success", "Header code incorrect", "Unknown command or argument",
> > - "Incorrect checksum", "Malformed command", "Timed out",
> > -};
> > -
> > /*
> > * Forward declaration of our sysfs attribute functions, so we can declare
> > the
> > * attribute data structures early.
> > @@ -307,6 +302,20 @@ static const struct dpfe_api dpfe_api_v3 = {
> > },
> > };
> >
> > +static const char * const get_error_text(unsigned int i)
>
> The pointer itself is returned by value and you cannot return a const
> value. I mean, you can but it does not have an effect. Only pointed
> memory should be const (const const char*).
v2 is on the way.
Regards,
-Markus
> > +{
> > + static const char * const error_text[] = {
> > + "Success", "Header code incorrect",
> > + "Unknown command or argument", "Incorrect checksum",
> > + "Malformed command", "Timed out", "Unknown error",
> > + };
> > +
> > + if (unlikely(i >= ARRAY_SIZE(error_text)))
> > + i = ARRAY_SIZE(error_text) - 1;
> > +
> > + return error_text[i];
> > +}
> > +
> > static bool is_dcpu_enabled(struct brcmstb_dpfe_priv *priv)
> > {
> > u32 val;
> > @@ -446,7 +455,7 @@ static int __send_command(struct brcmstb_dpfe_priv
> > *priv, unsigned int cmd,
> > }
> > if (resp != 0) {
> > mutex_unlock(&priv->lock);
> > - return -ETIMEDOUT;
> > + return -ffs(DCPU_RET_ERR_TIMEDOUT);
> > }
> >
> > /* Compute checksum over the message */
> > @@ -695,7 +704,7 @@ static ssize_t generic_show(unsigned int command, u32
> > response[],
> >
> > ret = __send_command(priv, command, response);
> > if (ret < 0)
> > - return sprintf(buf, "ERROR: %s\n", error_text[-ret]);
> > + return sprintf(buf, "ERROR: %s\n", get_error_text(-ret));
> >
> > return 0;
> > }
> > --
> > 2.17.1
> >
