Re: [PATCH v3 06/11] platform/x86/intel/ifs: Check IFS Image sanity

Greg KH
2022-04-19T17:16:21Z

On Tue, Apr 19, 2022 at 09:38:54AM -0700, Tony Luck wrote:
> From: Jithu Joseph <jithu.joseph@intel.com>
>
> IFS image is designed specifically for a given family, model and
> stepping of the processor. Like Intel microcode header, the IFS image
> has the Processor Signature, Checksum and Processor Flags that must be
> matched with the information returned by the CPUID.
>
> Reviewed-by: Dan Williams <dan.j.williams@intel.com>
> Signed-off-by: Jithu Joseph <jithu.joseph@intel.com>
> Co-developed-by: Tony Luck <tony.luck@intel.com>
> Signed-off-by: Tony Luck <tony.luck@intel.com>
> ---
> drivers/platform/x86/intel/ifs/load.c | 69 +++++++++++++++++++++++++++
> 1 file changed, 69 insertions(+)
>
> diff --git a/drivers/platform/x86/intel/ifs/load.c b/drivers/platform/x86/intel/ifs/load.c
> index fa6c64707a73..b05d9055c391 100644
> --- a/drivers/platform/x86/intel/ifs/load.c
> +++ b/drivers/platform/x86/intel/ifs/load.c
> @@ -3,9 +3,73 @@
>
> #include <linux/firmware.h>
> #include <linux/platform_device.h>
> +#include <asm/cpu.h>
> +#include <asm/microcode_intel.h>
>
> static const char *ifs_path = "intel/ifs/";
>
> +static int ifs_sanity_check(struct device *dev, void *mc)
> +{
> + struct microcode_header_intel *mc_header = mc;
> + unsigned long total_size, data_size;
> + u32 sum, i;
> +
> + total_size = get_totalsize(mc_header);
> + data_size = get_datasize(mc_header);
> +
> + if ((data_size + MC_HEADER_SIZE > total_size) || (total_size % sizeof(u32))) {
> + dev_err(dev, "bad ifs data file size.\n");
> + return -EINVAL;
> + }
> +
> + if (mc_header->ldrver != 1 || mc_header->hdrver != 1) {
> + dev_err(dev, "invalid/unknown ifs update format.\n");
> + return -EINVAL;
> + }
> +
> + sum = 0;
> + i = total_size / sizeof(u32);
> + while (i--)
> + sum += ((u32 *)mc)[i];
> +
> + if (sum) {
> + dev_err(dev, "bad ifs data checksum, aborting.\n");
> + return -EINVAL;
> + }
> +
> + return 0;
> +}
> +
> +static bool find_ifs_matching_signature(struct device *dev, struct ucode_cpu_info *uci, void *mc)
> +{
> + struct microcode_header_intel *shdr;
> + unsigned int mc_size;
> +
> + shdr = (struct microcode_header_intel *)mc;
> + mc_size = get_totalsize(shdr);
> +
> + if (!mc_size || ifs_sanity_check(dev, shdr) < 0) {
> + dev_err(dev, "ifs sanity check failure\n");
> + return false;
> + }
> +
> + if (!intel_cpu_signatures_match(uci->cpu_sig.sig, uci->cpu_sig.pf, shdr->sig, shdr->pf)) {
> + dev_err(dev, "ifs signature, pf not matching\n");
> + return false;
> + }
> +
> + return true;
> +}
> +
> +static bool ifs_image_sanity_check(struct device *dev, void *data)

u8 *data?

> +{
> + struct ucode_cpu_info uci;
> +
> + intel_cpu_collect_info_early(&uci);
> +
> + return find_ifs_matching_signature(dev, &uci, data);
> +}
> +
> /*
> * Load ifs image. Before loading ifs module, the ifs image must be located
> * in /lib/firmware/intel/ifs and named as {family/model/stepping}.{testname}.
> @@ -25,6 +89,11 @@ int load_ifs_binary(struct device *dev)
> return ret;
> }
>
> + if (!ifs_image_sanity_check(dev, (void *)fw->data)) {

It's not a void pointer, it's a pointer to u8. Why cast it away?

thanks,

greg k-h