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backups: introduce configurable HMAC/encryption algo

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For now always set it to default values (no frontend application uses
those parameters), but be prepared for further improvements.
This commit is contained in:
Marek Marczykowski-Górecki 2014-01-15 03:50:29 +01:00
parent 4b493b6d9a
commit 4c29d743c8
1 changed files with 43 additions and 21 deletions
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64
core/backup.py
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@ -39,6 +39,8 @@ from multiprocessing import Queue,Process
BACKUP_DEBUG = False BACKUP_DEBUG = False
DEFAULT_CRYPTO_ALGORITHM = 'aes-256-cbc'
DEFAULT_HMAC_ALGORITHM = 'SHA1'
# Maximum size of error message get from process stderr (including VM process) # Maximum size of error message get from process stderr (including VM process)
MAX_STDERR_BYTES = 1024 MAX_STDERR_BYTES = 1024
# header + qubes.xml max size # header + qubes.xml max size
@ -344,7 +346,8 @@ class SendWorker(Process):
def backup_do(base_backup_dir, files_to_backup, passphrase, def backup_do(base_backup_dir, files_to_backup, passphrase,
progress_callback = None, encrypted=False, appvm=None, progress_callback = None, encrypted=False, appvm=None,
compressed=False): compressed=False, hmac_algorithm=DEFAULT_HMAC_ALGORITHM,
crypto_algorithm=DEFAULT_CRYPTO_ALGORITHM):
total_backup_sz = 0 total_backup_sz = 0
for file in files_to_backup: for file in files_to_backup:
total_backup_sz += file["size"] total_backup_sz += file["size"]
@ -450,8 +453,9 @@ def backup_do(base_backup_dir, files_to_backup, passphrase,
pipe = open(backup_pipe,'rb') pipe = open(backup_pipe,'rb')
# Start HMAC # Start HMAC
hmac = subprocess.Popen (["openssl", "dgst", "-hmac", passphrase], hmac = subprocess.Popen (["openssl", "dgst",
stdin=subprocess.PIPE, stdout=subprocess.PIPE) "-" + hmac_algorithm, "-hmac", passphrase],
stdin=subprocess.PIPE, stdout=subprocess.PIPE)
# Prepare a first chunk # Prepare a first chunk
chunkfile = backup_tempfile + "." + "%03d" % i chunkfile = backup_tempfile + "." + "%03d" % i
@ -469,8 +473,8 @@ def backup_do(base_backup_dir, files_to_backup, passphrase,
if encrypted: if encrypted:
# Start encrypt # Start encrypt
# If no cipher is provided, the data is forwarded unencrypted !!! # If no cipher is provided, the data is forwarded unencrypted !!!
encryptor = subprocess.Popen (["openssl", "enc", encryptor = subprocess.Popen (["openssl", "enc",
"-e", "-aes-256-cbc", "-e", "-" + crypto_algorithm,
"-pass", "pass:"+passphrase] + "-pass", "pass:"+passphrase] +
(["-z"] if compressed else []), (["-z"] if compressed else []),
stdin=pipe, stdout=subprocess.PIPE) stdin=pipe, stdout=subprocess.PIPE)
@ -628,7 +632,7 @@ def wait_backup_feedback(progress_callback, in_stream, streamproc,
return run_error return run_error
def verify_hmac(filename, hmacfile, passphrase): def verify_hmac(filename, hmacfile, passphrase, algorithm):
if BACKUP_DEBUG: if BACKUP_DEBUG:
print "Verifying file "+filename print "Verifying file "+filename
@ -637,7 +641,8 @@ def verify_hmac(filename, hmacfile, passphrase):
"ERROR: expected hmac for {}, but got {}".\ "ERROR: expected hmac for {}, but got {}".\
format(filename, hmacfile)) format(filename, hmacfile))
hmac_proc = subprocess.Popen (["openssl", "dgst", "-hmac", passphrase], hmac_proc = subprocess.Popen (["openssl", "dgst", "-" + algorithm,
"-hmac", passphrase],
stdin=open(filename,'rb'), stdin=open(filename,'rb'),
stdout=subprocess.PIPE, stderr=subprocess.PIPE) stdout=subprocess.PIPE, stderr=subprocess.PIPE)
hmac_stdout, hmac_stderr = hmac_proc.communicate() hmac_stdout, hmac_stderr = hmac_proc.communicate()
@ -666,13 +671,14 @@ def verify_hmac(filename, hmacfile, passphrase):
class ExtractWorker(Process): class ExtractWorker(Process):
def __init__(self, queue, base_dir, passphrase, encrypted, total_size, def __init__(self, queue, base_dir, passphrase, encrypted, total_size,
print_callback, error_callback, progress_callback, vmproc=None, print_callback, error_callback, progress_callback, vmproc=None,
compressed = False): compressed = False, crypto_algorithm=DEFAULT_CRYPTO_ALGORITHM):
super(ExtractWorker, self).__init__() super(ExtractWorker, self).__init__()
self.queue = queue self.queue = queue
self.base_dir = base_dir self.base_dir = base_dir
self.passphrase = passphrase self.passphrase = passphrase
self.encrypted = encrypted self.encrypted = encrypted
self.compressed = compressed self.compressed = compressed
self.crypto_algorithm = crypto_algorithm
self.total_size = total_size self.total_size = total_size
self.blocks_backedup = 0 self.blocks_backedup = 0
self.tar2_process = None self.tar2_process = None
@ -766,7 +772,7 @@ class ExtractWorker(Process):
if self.encrypted: if self.encrypted:
# Start decrypt # Start decrypt
self.decryptor_process = subprocess.Popen (["openssl", "enc", self.decryptor_process = subprocess.Popen (["openssl", "enc",
"-d", "-aes-256-cbc", "-d", "-" + self.crypto_algorithm,
"-pass", "pass:"+self.passphrase] + "-pass", "pass:"+self.passphrase] +
(["-z"] if self.compressed else []), (["-z"] if self.compressed else []),
stdin=open(filename,'rb'), stdin=open(filename,'rb'),
@ -832,7 +838,8 @@ class ExtractWorker(Process):
def restore_vm_dirs (backup_source, restore_tmpdir, passphrase, vms_dirs, vms, def restore_vm_dirs (backup_source, restore_tmpdir, passphrase, vms_dirs, vms,
vms_size, print_callback=None, error_callback=None, vms_size, print_callback=None, error_callback=None,
progress_callback=None, encrypted=False, appvm=None, progress_callback=None, encrypted=False, appvm=None,
compressed = False): compressed = False, hmac_algorithm=DEFAULT_HMAC_ALGORITHM,
crypto_algorithm=DEFAULT_CRYPTO_ALGORITHM):
# Setup worker to extract encrypted data chunks to the restore dirs # Setup worker to extract encrypted data chunks to the restore dirs
to_extract = Queue() to_extract = Queue()
@ -841,6 +848,7 @@ def restore_vm_dirs (backup_source, restore_tmpdir, passphrase, vms_dirs, vms,
passphrase=passphrase, passphrase=passphrase,
encrypted=encrypted, encrypted=encrypted,
compressed=compressed, compressed=compressed,
crypto_algorithm = crypto_algorithm,
total_size=vms_size, total_size=vms_size,
print_callback=print_callback, print_callback=print_callback,
error_callback=error_callback, error_callback=error_callback,
@ -923,7 +931,7 @@ def restore_vm_dirs (backup_source, restore_tmpdir, passphrase, vms_dirs, vms,
if verify_hmac(os.path.join(restore_tmpdir,filename), if verify_hmac(os.path.join(restore_tmpdir,filename),
os.path.join(restore_tmpdir,hmacfile), os.path.join(restore_tmpdir,hmacfile),
passphrase): passphrase, hmac_algorithm):
to_extract.put(os.path.join(restore_tmpdir, filename)) to_extract.put(os.path.join(restore_tmpdir, filename))
if command.wait() != 0: if command.wait() != 0:
@ -988,7 +996,9 @@ def backup_detect_format_version(backup_location):
def backup_restore_header(source, passphrase, def backup_restore_header(source, passphrase,
print_callback = print_stdout, error_callback = print_stderr, print_callback = print_stdout, error_callback = print_stderr,
encrypted=False, appvm=None, compressed = False, format_version = None): encrypted=False, appvm=None, compressed = False, format_version = None,
hmac_algorithm = DEFAULT_HMAC_ALGORITHM,
crypto_algorithm = DEFAULT_CRYPTO_ALGORITHM):
vmproc = None vmproc = None
@ -1013,6 +1023,8 @@ def backup_restore_header(source, passphrase,
vms_dirs=extract_filter, vms_dirs=extract_filter,
vms=None, vms=None,
vms_size=HEADER_QUBES_XML_MAX_SIZE, vms_size=HEADER_QUBES_XML_MAX_SIZE,
hmac_algorithm=hmac_algorithm,
crypto_algorithm=crypto_algorithm,
print_callback=print_callback, print_callback=print_callback,
error_callback=error_callback, error_callback=error_callback,
progress_callback=None, progress_callback=None,
@ -1089,7 +1101,8 @@ def restore_info_verify(restore_info, host_collection):
def backup_restore_prepare(backup_location, passphrase, options = {}, def backup_restore_prepare(backup_location, passphrase, options = {},
host_collection = None, encrypted=False, appvm=None, host_collection = None, encrypted=False, appvm=None,
compressed = False, print_callback = print_stdout, error_callback = print_stderr, compressed = False, print_callback = print_stdout, error_callback = print_stderr,
format_version=None): format_version=None, hmac_algorithm=DEFAULT_HMAC_ALGORITHM,
crypto_algorithm=DEFAULT_CRYPTO_ALGORITHM):
# Defaults # Defaults
backup_restore_set_defaults(options) backup_restore_set_defaults(options)
@ -1134,14 +1147,17 @@ def backup_restore_prepare(backup_location, passphrase, options = {},
else: else:
raise QubesException("Unknown backup format version: %s" % str(format_version)) raise QubesException("Unknown backup format version: %s" % str(format_version))
(restore_tmpdir, qubes_xml) = backup_restore_header(backup_location, (restore_tmpdir, qubes_xml) = backup_restore_header(
passphrase, backup_location,
encrypted=encrypted, passphrase,
appvm=appvm, encrypted=encrypted,
compressed=compressed, appvm=appvm,
print_callback=print_callback, compressed=compressed,
error_callback=error_callback, hmac_algorithm=hmac_algorithm,
format_version=format_version) crypto_algorithm=crypto_algorithm,
print_callback=print_callback,
error_callback=error_callback,
format_version=format_version)
if BACKUP_DEBUG: if BACKUP_DEBUG:
print "Loading file", qubes_xml print "Loading file", qubes_xml
@ -1193,6 +1209,8 @@ def backup_restore_prepare(backup_location, passphrase, options = {},
options['passphrase'] = passphrase options['passphrase'] = passphrase
options['encrypted'] = encrypted options['encrypted'] = encrypted
options['compressed'] = compressed options['compressed'] = compressed
options['hmac_algorithm'] = hmac_algorithm
options['crypto_algorithm'] = crypto_algorithm
options['appvm'] = appvm options['appvm'] = appvm
options['format_version'] = format_version options['format_version'] = format_version
vms_to_restore['$OPTIONS$'] = options vms_to_restore['$OPTIONS$'] = options
@ -1352,6 +1370,8 @@ def backup_restore_do(restore_info,
passphrase = options['passphrase'] passphrase = options['passphrase']
encrypted = options['encrypted'] encrypted = options['encrypted']
compressed = options['compressed'] compressed = options['compressed']
hmac_algorithm = options['hmac_algorithm']
crypto_algorithm = options['crypto_algorithm']
appvm = options['appvm'] appvm = options['appvm']
format_version = options['format_version'] format_version = options['format_version']
@ -1391,6 +1411,8 @@ def backup_restore_do(restore_info,
vms_dirs=vms_dirs, vms_dirs=vms_dirs,
vms=vms, vms=vms,
vms_size=vms_size, vms_size=vms_size,
hmac_algorithm=hmac_algorithm,
crypto_algorithm=crypto_algorithm,
print_callback=print_callback, print_callback=print_callback,
error_callback=error_callback, error_callback=error_callback,
progress_callback=progress_callback, progress_callback=progress_callback,