ich9utils/src/ich9deblob.c

/*
 *  ich9deblob.c
 *  This file is part of the ich9deblob utility from the libreboot project
 *
 * Purpose: disable and remove the ME from ich9m/gm45 systems in coreboot.
 *
 *  Copyright (C) 2014 Steve Shenton <sgsit@libreboot.org>
 *  Copyright (C) 2014,2015,2019 Leah Rowe <info@minifree.org>
 *
 *  This program is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation, either version 3 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

/* Initially based on proof of concept by Steve Shenton. */
/* Original utility can be found at https://gitorious.org/ich9descriptortool */

/*
 * Read a factory.rom dump (ich9m/gm45 systems) and
 * modify the flash descriptor to remove all regions except descriptor,
 * Gbe and BIOS. Set BIOS region to full size of the ROM image (after
 * the flash descriptor and gbe). Basically, deblob the descriptor.
 *
 * This will will generate a concatenated descriptor+gbe dump suitable
 * for use in libreboot. Currently tested: ThinkPad X200 (coreboot/libreboot)
 */

/*
 * See docs/hardware/x200_remove_me.html for info plus links to datasheet (also linked below)
 *
 * Info about flash descriptor (read page 845 onwards):
 * http://www.intel.co.uk/content/dam/doc/datasheet/io-controller-hub-9-datasheet.pdf
 *
 * Info about Gbe region (read whole datasheet):
 * http://www.intel.co.uk/content/dam/doc/application-note/i-o-controller-hub-9m-82567lf-lm-v-nvm-map-appl-note.pdf
 * https://web.archive.org/web/20150912070329/https://communities.intel.com/community/wired/blog/2010/10/14/how-to-basic-eeprom-checksums
 */

#include "ich9deblob.h"

int main(int argc, char *argv[])
{
	struct DESCRIPTORREGIONRECORD descriptorStruct;
	uint8_t* descriptorBuffer = (uint8_t*)&descriptorStruct;

	struct GBEREGIONRECORD_8K gbeStruct8k;
	uint8_t* gbeBuffer8k = (uint8_t*)&gbeStruct8k;
	uint32_t gbeRegionStart;

	char* romFilename = "factory.rom";
    if(argc>1) {
        romFilename = argv[1];
    }

	char* descriptorGbeFilename = "deblobbed_descriptor.bin";
	char* descriptorNoGbeFilename = "deblobbed_4kdescriptor.bin";

	unsigned int bufferLength;
	unsigned int romSize;

	/*
	 * ------------------------------------------------------------------
	 * Compatibility checks. This version of ich9deblob is not yet portable.
	 * ------------------------------------------------------------------
	 */

	if (systemOrCompilerIncompatible(descriptorStruct, gbeStruct8k)) return 1;
	/* If true, fail with error message */

	/*
	 * ------------------------------------------------------------------
	 * Extract the descriptor and gbe regions from the factory.rom dump
	 * ------------------------------------------------------------------
	 */
	FILE* fp = NULL;
	fp = fopen(romFilename, "rb"); /* open factory.rom */
	if (NULL == fp)
	{
		printf("\nerror: could not open %s\n", romFilename);
		fclose(fp);
		return 1;
	}
	printf("\n%s opened successfully\n", romFilename);

	/*
	 * Get the descriptor region dump from the factory.rom
	 * (goes in factoryDescriptorBuffer variable)
	 */
	bufferLength = fread(descriptorBuffer, 1, DESCRIPTORREGIONSIZE, fp);
	if (DESCRIPTORREGIONSIZE != bufferLength) //
	{
		printf("\nerror: could not read descriptor from %s (%i) bytes read\n", romFilename, bufferLength);
		fclose(fp);
		return 1;
	}
	printf("\ndescriptor region read successfully\n");

    if(!validDescriptor(descriptorStruct)) {
        printf("Invalid input: incorrect signature in the given descriptor.");
        fclose(fp);
        return 1;
    }

	if (descriptorDefinesGbeRegion(descriptorStruct))
	{
		gbeRegionStart = descriptorStruct.regionSection.flReg3.BASE << FLREGIONBITSHIFT;

		/*
		 * Set offset so that we can read the data from
		 * the gbe region
		 */
		fseek(fp, gbeRegionStart, SEEK_SET);
		/* Read the gbe data from the factory.rom and put it in factoryGbeBuffer8k */
		bufferLength = fread(gbeBuffer8k, 1, GBEREGIONSIZE_8K, fp);
		if (GBEREGIONSIZE_8K != bufferLength)
		{
			printf("\nerror: could not read GBe region from %s (%i) bytes read\n", romFilename, bufferLength);
			fclose(fp);
			return 1;
		}
		printf("\ngbe (8KiB) region read successfully\n");
	}

	fseek(fp, 0L, SEEK_END);
	romSize = ftell(fp);
	printf("\n%s size: [%i] bytes\n", romFilename, romSize);

	fclose(fp);
	
	/* Debugging (before modification) */
	printDescriptorRegionLocations(descriptorStruct, "Original");
	if (descriptorDefinesGbeRegion(descriptorStruct)) 
		printGbeChecksumDataFromStruct8k(gbeStruct8k, "Original");
	else printf("NO GBE REGION\n");
	
	/*
	 * ------------------------------------------------------------------
	 * Modify the descriptor and gbe regions, ready to go in libreboot.rom
	 * ------------------------------------------------------------------
	 */

	/* Delete the ME/Platform regions, place Gbe after the descriptor, resize BIOS region to fill the gap */
	descriptorStruct = librebootDescriptorStructFromFactory(descriptorStruct, romSize);

	/* The ME is disallowed read-write access to all regions
	 * (this is probably redundant, since the ME firmware is already removed from libreboot) */
	descriptorStruct = descriptorMeRegionsForbidden(descriptorStruct);
	/* Host/CPU is allowed to read/write all regions.
	 * This makes flashrom -p internal work */
	descriptorStruct = descriptorHostRegionsUnlocked(descriptorStruct);

	/* Set OEM string */
	descriptorStruct = descriptorOemString(descriptorStruct);

	/* Modify the Gbe region (see function for details) */
	if (descriptorDefinesGbeRegion(descriptorStruct))
		gbeStruct8k = deblobbedGbeStructFromFactory(gbeStruct8k);

	/* Debugging (after modifying the descriptor and gbe regions) */
	printDescriptorRegionLocations(descriptorStruct, "Modified");
	if (descriptorDefinesGbeRegion(descriptorStruct))
		printGbeChecksumDataFromStruct8k(gbeStruct8k, "Modified");
	else printf("NO GBE REGION\n");

	/*
	 * ------------------------------------------------------------------
	 * Create the file with the modified descriptor and gbe inside
	 * ------------------------------------------------------------------
	 */
	printf("\n");
	if (descriptorDefinesGbeRegion(descriptorStruct))
	{
		if (notCreatedDescriptorGbeFile(descriptorStruct, gbeStruct8k, descriptorGbeFilename)) {
			return 1;
		}
	}
	else
	{
		if (notCreated4kDescriptorFile(descriptorStruct, descriptorNoGbeFilename)) {
			return 1;
		}
	}
	
	/*
	 * ------------------------------------------------------------------
	 * Generate ich9gen data (C code that will recreate the deblobbed descriptor+gbe from scratch)
	 * ------------------------------------------------------------------
	 */
	/* Code for generating the Descriptor struct */
	/* mkdescriptor.h */
	if (notCreatedHFileForDescriptorCFile("mkdescriptor.h", "mkdescriptor.c")) {
		return 1;
	} /* and now mkdescriptor.c */
	if (notCreatedCFileFromDescriptorStruct(descriptorStruct, "mkdescriptor.c", "mkdescriptor.h")) {
		return 1;
	}

	if (descriptorDefinesGbeRegion(descriptorStruct))
	{
		/* Code for generating the Gbe struct */
		/* mkgbe.h */
		if (notCreatedHFileForGbeCFile("mkgbe.h", "mkgbe.c")) {
			return 1;
		} /* and now mkgbe.c */
		if (notCreatedCFileFromGbeStruct4k(gbeStruct8k.backup, "mkgbe.c", "mkgbe.h")) {
			return 1;
		}
	}
	
	if (descriptorDefinesGbeRegion(descriptorStruct))
	{
		printf("The modified descriptor and gbe regions have also been dumped as src files: mkdescriptor.c, mkdescriptor.h, mkgbe.c, mkgbe.h\n");
		printf("To use these in ich9gen, place them in src/ich9gen/ and re-build ich9gen.\n\n");
	}
	else
	{
		printf("The modified descriptor region have also been dumped as src files: mkdescriptor.c, mkdescriptor.h\n");
		printf("To use these in ich9gen, place them in src/ich9gen/ and re-build ich9gen.\n\n");
	}

	return 0;
}