| // 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 <base/logging.h> |
| #include <base/strings/string_split.h> |
| #include <base/strings/string_util.h> |
| |
| #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) { |
| LOG(INFO) << "SetImage"; |
| |
| // 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()); |
| |
| LOG(INFO) << "KERNEL_CONFIG: " << kernel_config; |
| |
| // 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 = base::SplitString( |
| dm_config, ",", base::KEEP_WHITESPACE, base::SPLIT_WANT_ALL); |
| |
| // 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()) { |
| LOG(ERROR) << "Didn't find verity args in the dm command line: " |
| << dm_config; |
| 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()); |
| |
| LOG(INFO) << "Setting up verity."; |
| LoggingTimerStart(); |
| int result = chromeos_verity(verity_algorithm, install_config.root.device(), |
| getpagesize(), |
| (uint64_t)(atoi(rootfs_sectors.c_str()) / 8), |
| salt, expected_hash, enable_rootfs_verification); |
| LoggingTimerFinish(); |
| |
| return result == 0; |
| } |
