1 # Copyright (c) 2012 The Chromium OS Authors. All rights reserved. 2 # Use of this source code is governed by a BSD-style license that can be 3 # found in the LICENSE file. 4 5 import logging 6 import os 7 import re 8 9 from autotest_lib.client.bin import test, utils 10 from autotest_lib.client.common_lib import error 11 12 class firmware_LockedME(test.test): 13 # Needed by autotest 14 version = 1 15 16 # Temporary file to read BIOS image into. We run in a tempdir anyway, so it 17 # doesn't need a path. 18 BIOS_FILE = 'bios.bin' 19 20 def flashrom(self, ignore_status=False, args=()): 21 """Run flashrom, expect it to work. Fail if it doesn't""" 22 extra = ['-p', 'host'] + list(args) 23 return utils.run('flashrom', ignore_status=ignore_status, args=extra) 24 25 def has_ME(self): 26 """See if we can detect an ME. 27 FREG* is printed only when HSFS_FDV is set, which means the descriptor 28 table is valid. If we're running a BIOS without a valid descriptor this 29 step will fail. Unfortunately, we don't know of a simple and reliable 30 way to identify systems that have ME hardware. 31 """ 32 logging.info('See if we have an ME...') 33 r = self.flashrom(args=('-V',)) 34 return r.stdout.find("FREG0") >= 0 35 36 def try_to_rewrite(self, sectname): 37 """If we can modify the ME section, restore it and raise an error.""" 38 logging.info('Try to write section %s...', sectname) 39 size = os.stat(sectname).st_size 40 utils.run('dd', args=('if=/dev/urandom', 'of=newdata', 41 'count=1', 'bs=%d' % (size))) 42 r = self.flashrom(args=('-w', self.BIOS_FILE, 43 '-i' , '%s:newdata' % (sectname), 44 '--fast-verify'), 45 ignore_status=True) 46 if not r.exit_status: 47 logging.info('Oops, it worked! Put it back...') 48 self.flashrom(args=('-w', self.BIOS_FILE, 49 '-i', '%s:%s' % (sectname, sectname), 50 '--fast-verify'), 51 ignore_status=True) 52 raise error.TestFail('%s is writable, ME is unlocked' % sectname) 53 54 def run_once(self, expect_me_present=True): 55 """Fail unless the ME is locked. 56 57 @param expect_me_present: False means the system has no ME. 58 """ 59 60 # See if the system even has an ME, and whether we expected that. 61 if self.has_ME(): 62 if not expect_me_present: 63 raise error.TestFail('We expected no ME, but found one anyway') 64 else: 65 if expect_me_present: 66 raise error.TestNAError("No ME found. That's probably wrong.") 67 else: 68 logging.info('We expected no ME and we have no ME, so pass.') 69 return 70 71 # See if coreboot told us that the ME is still in Manufacturing Mode. 72 # It shouldn't be. We have to look only at the last thing it reports 73 # because it reports the values twice and the first one isn't always 74 # reliable. 75 logging.info('Check for Manufacturing Mode...') 76 last = None 77 with open('/sys/firmware/log') as infile: 78 for line in infile: 79 if re.search('ME: Manufacturing Mode', line): 80 last = line 81 if last is not None and last.find("YES") >= 0: 82 raise error.TestFail("The ME is still in Manufacturing Mode") 83 84 # Get the bios image and extract the ME components 85 logging.info('Pull the ME components from the BIOS...') 86 self.flashrom(args=('-r', self.BIOS_FILE)) 87 utils.run('dump_fmap', args=('-x', self.BIOS_FILE, 'SI_ME', 'SI_DESC')) 88 89 # flashrom should have read the SI_ME section as all 0xff's. If not, 90 # the ME is not locked. 91 logging.info('SI_ME should be all 0xff...') 92 with open('SI_ME', 'rb') as f: 93 for c in f.read(): 94 if c != chr(0xff): 95 raise error.TestFail("SI_ME was readable by flashrom") 96 97 # So far, so good, but we need to be certain. Rather than parse what 98 # flashrom tells us about the ME-related registers, we'll just try to 99 # change the ME components. We shouldn't be able to. 100 self.try_to_rewrite('SI_DESC') 101 self.try_to_rewrite('SI_ME') 102 103 # Okay, that's about all we can try. Looks like it's locked. 104
