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Commit 5b46b5e0 authored by Borislav Petkov's avatar Borislav Petkov Committed by Thomas Gleixner
Browse files

x86/microcode/intel: Improve microcode sanity-checking error messages 



Turn them into proper sentences. Add comments to microcode_sanity_check() to
explain what it does.

Signed-off-by: default avatarBorislav Petkov <bp@suse.de>
Link: http://lkml.kernel.org/r/1457345404-28884-5-git-send-email-bp@alien8.de


Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
parent 7d016156

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

+26 −10
Original line number Diff line number Diff line
@@ -57,15 +57,16 @@ int microcode_sanity_check(void *mc, int print_err) 


	if (data_size + MC_HEADER_SIZE > total_size) {

		if (print_err)

			pr_err("error! Bad data size in microcode data file\n");

			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! Unknown microcode update format\n");

			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;
@@ -74,43 +75,58 @@ int microcode_sanity_check(void *mc, int print_err) 
		if ((ext_table_size < EXT_HEADER_SIZE)

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

			if (print_err)

				pr_err("error! Small exttable size in microcode data file\n");

				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! Bad exttable size in microcode data file\n");

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

			return -EFAULT;

		}



		ext_sigcount = ext_header->count;



		/* check extended table checksum */

		/*

		 * 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("aborting, bad extended signature table checksum\n");

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

			return -EINVAL;

		}

	}



	/* calculate the checksum */

	/*

	 * 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("aborting, bad checksum\n");

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

		return -EINVAL;

	}



	if (!ext_table_size)

		return 0;

	/* check extended signature checksum */



	/*

	 * 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;
@@ -119,7 +135,7 @@ int microcode_sanity_check(void *mc, int print_err) 
			+ (ext_sig->sig + ext_sig->pf + ext_sig->cksum);

		if (sum) {

			if (print_err)

				pr_err("aborting, bad checksum\n");

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

			return -EINVAL;

		}

	}