Commit 514ee839 authored by Jithu Joseph's avatar Jithu Joseph Committed by Borislav Petkov
Browse files

x86/microcode/intel: Reuse microcode_sanity_check() 



IFS test image carries the same microcode header as regular Intel
microcode blobs.

Reuse microcode_sanity_check() in the IFS driver to perform sanity check
of the IFS test images too.

Signed-off-by: default avatarJithu Joseph <jithu.joseph@intel.com>
Signed-off-by: default avatarBorislav Petkov <bp@suse.de>
Reviewed-by: default avatarTony Luck <tony.luck@intel.com>
Reviewed-by: default avatarAshok Raj <ashok.raj@intel.com>
Reviewed-by: default avatarSohil Mehta <sohil.mehta@intel.com>
Link: https://lore.kernel.org/r/20221117035935.4136738-8-jithu.joseph@intel.com
parent 2e13ab01

arch/x86/include/asm/cpu.h

+1 −0
Original line number Diff line number Diff line
@@ -96,5 +96,6 @@ static inline bool intel_cpu_signatures_match(unsigned int s1, unsigned int p1, 


extern u64 x86_read_arch_cap_msr(void);

int intel_find_matching_signature(void *mc, unsigned int csig, int cpf);

int intel_microcode_sanity_check(void *mc, bool print_err);



#endif /* _ASM_X86_CPU_H */

arch/x86/kernel/cpu/intel.c

+99 −0
Original line number Diff line number Diff line
@@ -244,6 +244,105 @@ int intel_find_matching_signature(void *mc, unsigned int csig, int cpf) 
}

EXPORT_SYMBOL_GPL(intel_find_matching_signature);



int intel_microcode_sanity_check(void *mc, bool print_err)

{

	unsigned long total_size, data_size, ext_table_size;

	struct microcode_header_intel *mc_header = mc;

	struct extended_sigtable *ext_header = NULL;

	u32 sum, orig_sum, ext_sigcount = 0, i;

	struct extended_signature *ext_sig;



	total_size = get_totalsize(mc_header);

	data_size = get_datasize(mc_header);



	if (data_size + MC_HEADER_SIZE > total_size) {

		if (print_err)

			pr_err("Error: bad microcode data file size.\n");

		return -EINVAL;

	}



	if (mc_header->ldrver != 1 || mc_header->hdrver != 1) {

		if (print_err)

			pr_err("Error: invalid/unknown microcode update format.\n");

		return -EINVAL;

	}



	ext_table_size = total_size - (MC_HEADER_SIZE + data_size);

	if (ext_table_size) {

		u32 ext_table_sum = 0;

		u32 *ext_tablep;



		if (ext_table_size < EXT_HEADER_SIZE ||

		    ((ext_table_size - EXT_HEADER_SIZE) % EXT_SIGNATURE_SIZE)) {

			if (print_err)

				pr_err("Error: truncated extended signature table.\n");

			return -EINVAL;

		}



		ext_header = mc + MC_HEADER_SIZE + data_size;

		if (ext_table_size != exttable_size(ext_header)) {

			if (print_err)

				pr_err("Error: extended signature table size mismatch.\n");

			return -EFAULT;

		}



		ext_sigcount = ext_header->count;



		/*

		 * Check extended table checksum: the sum of all dwords that

		 * comprise a valid table must be 0.

		 */

		ext_tablep = (u32 *)ext_header;



		i = ext_table_size / sizeof(u32);

		while (i--)

			ext_table_sum += ext_tablep[i];



		if (ext_table_sum) {

			if (print_err)

				pr_warn("Bad extended signature table checksum, aborting.\n");

			return -EINVAL;

		}

	}



	/*

	 * Calculate the checksum of update data and header. The checksum of

	 * valid update data and header including the extended signature table

	 * must be 0.

	 */

	orig_sum = 0;

	i = (MC_HEADER_SIZE + data_size) / sizeof(u32);

	while (i--)

		orig_sum += ((u32 *)mc)[i];



	if (orig_sum) {

		if (print_err)

			pr_err("Bad microcode data checksum, aborting.\n");

		return -EINVAL;

	}



	if (!ext_table_size)

		return 0;



	/*

	 * Check extended signature checksum: 0 => valid.

	 */

	for (i = 0; i < ext_sigcount; i++) {

		ext_sig = (void *)ext_header + EXT_HEADER_SIZE +

			  EXT_SIGNATURE_SIZE * i;



		sum = (mc_header->sig + mc_header->pf + mc_header->cksum) -

		      (ext_sig->sig + ext_sig->pf + ext_sig->cksum);

		if (sum) {

			if (print_err)

				pr_err("Bad extended signature checksum, aborting.\n");

			return -EINVAL;

		}

	}

	return 0;

}

EXPORT_SYMBOL_GPL(intel_microcode_sanity_check);



static void early_init_intel(struct cpuinfo_x86 *c)

{

	u64 misc_enable;

arch/x86/kernel/cpu/microcode/intel.c

+2 −100
Original line number Diff line number Diff line
@@ -135,104 +135,6 @@ static void save_microcode_patch(struct ucode_cpu_info *uci, void *data, unsigne 
		intel_ucode_patch = p->data;

}



static int microcode_sanity_check(void *mc, bool print_err)

{

	unsigned long total_size, data_size, ext_table_size;

	struct microcode_header_intel *mc_header = mc;

	struct extended_sigtable *ext_header = NULL;

	u32 sum, orig_sum, ext_sigcount = 0, i;

	struct extended_signature *ext_sig;



	total_size = get_totalsize(mc_header);

	data_size = get_datasize(mc_header);



	if (data_size + MC_HEADER_SIZE > total_size) {

		if (print_err)

			pr_err("Error: bad microcode data file size.\n");

		return -EINVAL;

	}



	if (mc_header->ldrver != 1 || mc_header->hdrver != 1) {

		if (print_err)

			pr_err("Error: invalid/unknown microcode update format.\n");

		return -EINVAL;

	}



	ext_table_size = total_size - (MC_HEADER_SIZE + data_size);

	if (ext_table_size) {

		u32 ext_table_sum = 0;

		u32 *ext_tablep;



		if ((ext_table_size < EXT_HEADER_SIZE)

		 || ((ext_table_size - EXT_HEADER_SIZE) % EXT_SIGNATURE_SIZE)) {

			if (print_err)

				pr_err("Error: truncated extended signature table.\n");

			return -EINVAL;

		}



		ext_header = mc + MC_HEADER_SIZE + data_size;

		if (ext_table_size != exttable_size(ext_header)) {

			if (print_err)

				pr_err("Error: extended signature table size mismatch.\n");

			return -EFAULT;

		}



		ext_sigcount = ext_header->count;



		/*

		 * Check extended table checksum: the sum of all dwords that

		 * comprise a valid table must be 0.

		 */

		ext_tablep = (u32 *)ext_header;



		i = ext_table_size / sizeof(u32);

		while (i--)

			ext_table_sum += ext_tablep[i];



		if (ext_table_sum) {

			if (print_err)

				pr_warn("Bad extended signature table checksum, aborting.\n");

			return -EINVAL;

		}

	}



	/*

	 * Calculate the checksum of update data and header. The checksum of

	 * valid update data and header including the extended signature table

	 * must be 0.

	 */

	orig_sum = 0;

	i = (MC_HEADER_SIZE + data_size) / sizeof(u32);

	while (i--)

		orig_sum += ((u32 *)mc)[i];



	if (orig_sum) {

		if (print_err)

			pr_err("Bad microcode data checksum, aborting.\n");

		return -EINVAL;

	}



	if (!ext_table_size)

		return 0;



	/*

	 * Check extended signature checksum: 0 => valid.

	 */

	for (i = 0; i < ext_sigcount; i++) {

		ext_sig = (void *)ext_header + EXT_HEADER_SIZE +

			  EXT_SIGNATURE_SIZE * i;



		sum = (mc_header->sig + mc_header->pf + mc_header->cksum) -

		      (ext_sig->sig + ext_sig->pf + ext_sig->cksum);

		if (sum) {

			if (print_err)

				pr_err("Bad extended signature checksum, aborting.\n");

			return -EINVAL;

		}

	}

	return 0;

}



/*

 * Get microcode matching with BSP's model. Only CPUs with the same model as

 * BSP can stay in the platform.
@@ -253,7 +155,7 @@ scan_microcode(void *data, size_t size, struct ucode_cpu_info *uci, bool save) 
		mc_size = get_totalsize(mc_header);

		if (!mc_size ||

		    mc_size > size ||

		    microcode_sanity_check(data, false) < 0)

		    intel_microcode_sanity_check(data, false) < 0)

			break;



		size -= mc_size;
@@ -792,7 +694,7 @@ static enum ucode_state generic_load_microcode(int cpu, struct iov_iter *iter) 
		memcpy(mc, &mc_header, sizeof(mc_header));

		data = mc + sizeof(mc_header);

		if (!copy_from_iter_full(data, data_size, iter) ||

		    microcode_sanity_check(mc, true) < 0) {

		    intel_microcode_sanity_check(mc, true) < 0) {

			break;

		}