On Tue, Jan 4, 2022 at 9:29 AM Hector Martin <marcan@xxxxxxxxx> wrote:
>
> On Device Tree platforms, it is customary to be able to set the MAC
> address via the Device Tree, as it is often stored in system firmware.
> This is particularly relevant for Apple ARM64 platforms, where this
> information comes from system configuration and passed through by the
> bootloader into the DT.
>
> Implement support for this by fetching the platform MAC address and
> adding or replacing the macaddr= property in nvram. This becomes the
> dongle's default MAC address.
>
> On platforms with an SROM MAC address, this overrides it. On platforms
> without one, such as Apple ARM64 devices, this is required for the
> firmware to boot (it will fail if it does not have a valid MAC at all).
...
> +#define BRCMF_FW_MACADDR_FMT "macaddr=%pM"
> +#define BRCMF_FW_MACADDR_LEN (7 + ETH_ALEN * 3)
...
> if (strncmp(&nvp->data[nvp->entry], "boardrev", 8) == 0)
> nvp->boardrev_found = true;
> + /* strip macaddr if platform MAC overrides */
> + if (nvp->strip_mac &&
> + strncmp(&nvp->data[nvp->entry], "macaddr", 7) == 0)
If it has no side effects, I would rather swap the operands of && so
you match string first (it will be in align with above code at least,
although I haven't checked bigger context).
....
> +static void brcmf_fw_add_macaddr(struct nvram_parser *nvp, u8 *mac)
> +{
> + snprintf(&nvp->nvram[nvp->nvram_len], BRCMF_FW_MACADDR_LEN + 1,
> + BRCMF_FW_MACADDR_FMT, mac);
Please, avoid using implict format string, it's dangerous from security p.o.v.
> + nvp->nvram_len += BRCMF_FW_MACADDR_LEN + 1;
Also, with temporary variable the code can be better to read
size_t mac_len = ...;
> +}
--
With Best Regards,
Andy Shevchenko
