On Thu, Nov 02, 2023 at 06:37:40PM +0100, Andrew Lunn wrote:
> > +/* AQR firmware doesn't have fixed offsets for iram and dram section
> > + * but instead provide an header with the offset to use on reading
> > + * and parsing the firmware.
> > + *
> > + * AQR firmware can't be trusted and each offset is validated to be
> > + * not negative and be in the size of the firmware itself.
> > + */
> > +static inline bool aqr_fw_validate_get(size_t size, size_t offset, size_t get_size)
> > +{
> > + return size + offset > 0 && offset + get_size <= size;
> > +}
>
> Please don't user inline in .c files. The compiler is better at
> deciding than we are.
>
OK.
> Also, i wounder about size + offset > 0. size_t is unsigned. So they
> cannot be negative. So does this test make sense?
>
The idea was to check case where it's subtracted too much. (example
where we check the CRC at the end of the fw) but since it's unsigned i
guess it will always be zero. I will drop. (or should i use ssize_t?)
> > +static int aqr_fw_boot(struct phy_device *phydev, const u8 *data, size_t size,
> > + enum aqr_fw_src fw_src)
> > +{
> > + u16 calculated_crc, read_crc, read_primary_offset;
> > + u32 iram_offset = 0, iram_size = 0;
> > + u32 dram_offset = 0, dram_size = 0;
> > + char version[VERSION_STRING_SIZE];
> > + u32 primary_offset = 0;
> > + int ret;
> > +
> > + /* extract saved CRC at the end of the fw
> > + * CRC is saved in big-endian as PHY is BE
> > + */
> > + ret = aqr_fw_get_be16(data, size - sizeof(u16), size, &read_crc);
> > + if (ret) {
> > + phydev_err(phydev, "bad firmware CRC in firmware\n");
> > + return ret;
> > + }
>
> So if size < sizeof(u16), we get a very big positive number. The > 0
> test does nothing for you here, but the other half of the test does
> trap the issue.
>
> So i think you can remove the > 0 test.
>
Yes that single check was done because of this, but didn't notice size_t
is unsigned and it won't ever fall in negative cases.
--
Ansuel
