installer/chromeos_setimage.cc - chromiumos/platform2 - Git at Google

 // Copyright (c) 2012 The Chromium OS Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.

 #include "installer/chromeos_setimage.h"

 #include <stdio.h>
 #include <stdlib.h>
 #include <unistd.h>

 #include <vector>

 #include "installer/chromeos_install_config.h"
 #include "installer/chromeos_verity.h"
 #include "installer/inst_util.h"

 using std::string;

 //
 // There is nothing in our codebase that calls chromeos-setimage,
 // except for post install, so only it's use case is required
 // here. I think.
 //
 // New dm argument syntax:
 // TODO(taysom:defect 32847)
 // In the future, the <num> field will be mandatory.
 //
 // <device>        ::= [<num>] <device-mapper>+
 // <device-mapper> ::= <head> "," <target>+
 // <head>          ::= <name> <uuid> <mode> [<num>]
 // <target>        ::= <start> <length> <type> <options> ","
 // <mode>          ::= "ro" | "rw"
 // <uuid>          ::= xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx | "none"
 // <type>          ::= "verity" | "bootcache" | ...
 //
 // Notes:
 //  1. uuid is a label for the device and we set it to "none".
 //  2. The <num> field will be optional initially and assumed to be 1.
 //     Once all the scripts that set these fields have been set, it will
 //     made mandatory.
 //
 // Coming attractions:
 // The upstream version of verity does not use name/value pairs for
 // arguments. All arguments are positional. The current code for
 // finding the root_hexdigest and salt will need to change accordingly.
 //
 // Don't know if we can make the code parse both types of arguments.


 bool SetImage(const InstallConfig& install_config) {
   printf("SetImage\n");

   // Re-hash the root filesystem and use the table for dm-verity.
   // We extract the parameters for verification from the kernel
   // partition, but we regenerate and reappend the hash tree to
   // keep the updater from needing to manage them explicitly.
   // Instead, rootfs integrity will be validated on next boot through
   // the verified kernel configuration.

   string kernel_config = DumpKernelConfig(install_config.kernel.device());

   printf("KERNEL_CONFIG: %s\n", kernel_config.c_str());

   // An example value: <root_hexdigest and salt values shortened>
   //
   // quiet loglevel=1 console=tty2 init=/sbin/init add_efi_memmap boot=local
   // noresume noswap i915.modeset=1 cros_secure tpm_tis.force=1
   // tpm_tis.interrupts=0 nmi_watchdog=panic,lapic root=/dev/dm-0 rootwait
   // ro dm_verity.error_behavior=3 dm_verity.max_bios=-1 dm_verity.dev_wait=1
   // dm="vroot none ro,0 1740800 verity payload=%U+1 hashtree=%U+1
   // hashstart=1740800 alg=sha1 root_hexdigest=30348c07f salt=a9864eaf11f4
   // 66fc48dffef" noinitrd cros_debug vt.global_cursor_default=0 kern_guid=%U
   //

   string kernel_config_root = ExtractKernelArg(kernel_config, "root");
   string dm_config = ExtractKernelArg(kernel_config, "dm");
   std::vector<string> dm_parts;
   SplitString(dm_config, ',', &dm_parts);

   // Extract verity specific options
   string verity_args;
   for (unsigned i = 0; i < dm_parts.size(); i++) {
     if (dm_parts[i].find(" verity ") != string::npos) {
       verity_args = dm_parts[i];
       break;
     }
   }
   if (verity_args.empty()) {
     printf("Didn't find verity args in the dm command line: '%s'\n",
            dm_config.c_str());
     return false;
   }

   // Extract specific verity arguments
   string rootfs_sectors = ExtractKernelArg(verity_args, "hashstart");
   string verity_algorithm = ExtractKernelArg(verity_args, "alg");
   string expected_hash = ExtractKernelArg(verity_args, "root_hexdigest");
   string salt = ExtractKernelArg(verity_args, "salt");

   bool enable_rootfs_verification = IsReadonly(kernel_config_root);

   if (!enable_rootfs_verification)
     MakeFileSystemRw(install_config.root.device(), true);

   printf("Setting up verity.\n");
   LoggingTimerStart();
   int result = chromeos_verity(verity_algorithm.c_str(),
                                install_config.root.device().c_str(),
                                getpagesize(),
                                (uint64_t)(atoi(rootfs_sectors.c_str()) / 8),
                                salt.c_str(), expected_hash.c_str(),
                                enable_rootfs_verification);
   LoggingTimerFinish();

   return result == 0;
 }
	// Copyright (c) 2012 The Chromium OS Authors. All rights reserved.
	// Use of this source code is governed by a BSD-style license that can be
	// found in the LICENSE file.

	#include "installer/chromeos_setimage.h"

	#include <stdio.h>
	#include <stdlib.h>
	#include <unistd.h>

	#include <vector>

	#include "installer/chromeos_install_config.h"
	#include "installer/chromeos_verity.h"
	#include "installer/inst_util.h"

	using std::string;

	//
	// There is nothing in our codebase that calls chromeos-setimage,
	// except for post install, so only it's use case is required
	// here. I think.
	//
	// New dm argument syntax:
	// TODO(taysom:defect 32847)
	// In the future, the <num> field will be mandatory.
	//
	// <device> ::= [<num>] <device-mapper>+
	// <device-mapper> ::= <head> "," <target>+
	// <head> ::= <name> <uuid> <mode> [<num>]
	// <target> ::= <start> <length> <type> <options> ","
	// <mode> ::= "ro" \| "rw"
	// <uuid> ::= xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx \| "none"
	// <type> ::= "verity" \| "bootcache" \| ...
	//
	// Notes:
	// 1. uuid is a label for the device and we set it to "none".
	// 2. The <num> field will be optional initially and assumed to be 1.
	// Once all the scripts that set these fields have been set, it will
	// made mandatory.
	//
	// Coming attractions:
	// The upstream version of verity does not use name/value pairs for
	// arguments. All arguments are positional. The current code for
	// finding the root_hexdigest and salt will need to change accordingly.
	//
	// Don't know if we can make the code parse both types of arguments.


	bool SetImage(const InstallConfig& install_config) {
	printf("SetImage\n");

	// Re-hash the root filesystem and use the table for dm-verity.
	// We extract the parameters for verification from the kernel
	// partition, but we regenerate and reappend the hash tree to
	// keep the updater from needing to manage them explicitly.
	// Instead, rootfs integrity will be validated on next boot through
	// the verified kernel configuration.

	string kernel_config = DumpKernelConfig(install_config.kernel.device());

	printf("KERNEL_CONFIG: %s\n", kernel_config.c_str());

	// An example value: <root_hexdigest and salt values shortened>
	//
	// quiet loglevel=1 console=tty2 init=/sbin/init add_efi_memmap boot=local
	// noresume noswap i915.modeset=1 cros_secure tpm_tis.force=1
	// tpm_tis.interrupts=0 nmi_watchdog=panic,lapic root=/dev/dm-0 rootwait
	// ro dm_verity.error_behavior=3 dm_verity.max_bios=-1 dm_verity.dev_wait=1
	// dm="vroot none ro,0 1740800 verity payload=%U+1 hashtree=%U+1
	// hashstart=1740800 alg=sha1 root_hexdigest=30348c07f salt=a9864eaf11f4
	// 66fc48dffef" noinitrd cros_debug vt.global_cursor_default=0 kern_guid=%U
	//

	string kernel_config_root = ExtractKernelArg(kernel_config, "root");
	string dm_config = ExtractKernelArg(kernel_config, "dm");
	std::vector<string> dm_parts;
	SplitString(dm_config, ',', &dm_parts);

	// Extract verity specific options
	string verity_args;
	for (unsigned i = 0; i < dm_parts.size(); i++) {
	if (dm_parts[i].find(" verity ") != string::npos) {
	verity_args = dm_parts[i];
	break;
	}
	}
	if (verity_args.empty()) {
	printf("Didn't find verity args in the dm command line: '%s'\n",
	dm_config.c_str());
	return false;
	}

	// Extract specific verity arguments
	string rootfs_sectors = ExtractKernelArg(verity_args, "hashstart");
	string verity_algorithm = ExtractKernelArg(verity_args, "alg");
	string expected_hash = ExtractKernelArg(verity_args, "root_hexdigest");
	string salt = ExtractKernelArg(verity_args, "salt");

	bool enable_rootfs_verification = IsReadonly(kernel_config_root);

	if (!enable_rootfs_verification)
	MakeFileSystemRw(install_config.root.device(), true);

	printf("Setting up verity.\n");
	LoggingTimerStart();
	int result = chromeos_verity(verity_algorithm.c_str(),
	install_config.root.device().c_str(),
	getpagesize(),
	(uint64_t)(atoi(rootfs_sectors.c_str()) / 8),
	salt.c_str(), expected_hash.c_str(),
	enable_rootfs_verification);
	LoggingTimerFinish();

	return result == 0;
	}