Datasets:
File size: 14,715 Bytes
0e239c6 | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 | """Restore an exact, hash-bound Docker build context into a new directory."""
import argparse
from contextlib import contextmanager
import hashlib
import json
from pathlib import Path, PurePosixPath
import shutil
import tarfile
import tempfile
def digest(path):
value = hashlib.sha256()
with Path(path).open('rb') as stream:
for block in iter(lambda: stream.read(1024 * 1024), b''):
value.update(block)
return value.hexdigest()
def relative(name):
path = PurePosixPath(name)
if (not name or path.is_absolute() or '..' in path.parts or '.' in name.split('/')
or '\\' in name or str(path) != name):
raise ValueError('Unsafe context member: ' + name)
return path
def declared_container_links(manifest, entries, tar):
"""Allow only exact Git-bound links to a declared paired container checkout."""
absolute = {name: row for name, row in entries.items()
if row.get('kind') == 'symlink' and PurePosixPath(row['target']).is_absolute()}
if not absolute:
return {}
if manifest.get('schema_version', 1) < 3 or 'instance.json' not in entries:
raise ValueError('Absolute source link requires a version 3 instance binding')
member = tar.getmember('instance.json'); row = entries['instance.json']
if not member.isfile() or member.size != row['bytes'] or member.size > 2 * 1024 * 1024:
raise ValueError('Invalid source link declaration')
data = tar.extractfile(member).read()
if hashlib.sha256(data).hexdigest() != row['sha256']:
raise ValueError('Source link declaration hash mismatch')
instance = json.loads(data)
repositories = {r['key']: r for r in instance['repositories']}
allowed = {}
for repo in repositories.values():
path = PurePosixPath(repo['path'])
if not path.is_absolute() or path.parts[:2] != ('/', 'testbed') or '..' in path.parts or '.git' in path.parts:
raise ValueError('Invalid declared repository path')
for link in repo.get('workspace_links', []):
target = repositories[link['target_repository']]['path']
if target == repo['path'] or link['original_target'] != target:
raise ValueError('Container link does not bind a distinct paired repository')
blob = target.encode()
oid = hashlib.sha1(b'blob ' + str(len(blob)).encode() + b'\0' + blob).hexdigest()
if oid != link['expected_blob']:
raise ValueError('Container link differs from its original Git blob')
name = str(PurePosixPath(repo['path'].lstrip('/')) / relative(link['path']))
if name in allowed:
raise ValueError('Duplicate container link declaration')
allowed[name] = target
if any(allowed.get(name) != row['target'] for name, row in absolute.items()):
raise ValueError('Undeclared absolute context link')
return {name: row['target'].lstrip('/') for name, row in absolute.items()}
def check_virtual_links(entries, container_links):
"""Resolve link graphs without touching an absolute container path on the host."""
links = {name: row['target'] for name, row in entries.items() if row.get('kind') == 'symlink'}
for name in links:
pending = list(PurePosixPath(name).parts); stack = []; followed = 0
while pending:
part = pending.pop(0)
if part in ('', '.'):
continue
if part == '..':
if not stack:
raise ValueError('Context link escapes output')
stack.pop(); continue
stack.append(part); prefix = '/'.join(stack)
if prefix in links:
followed += 1
if followed > 40:
raise ValueError('Cyclic or excessive context link graph')
target = links[prefix]
if PurePosixPath(target).is_absolute():
if prefix not in container_links:
raise ValueError('Undeclared absolute context link')
stack = []; target = container_links[prefix]
else:
stack.pop()
pending = list(PurePosixPath(target).parts) + pending
@contextmanager
def archive_stream(root, reference):
parts=reference.get('parts')
if parts is not None:
if not isinstance(parts,list) or not parts:
raise ValueError('Archive parts must be nonempty')
with tempfile.TemporaryFile() as output:
total=0;whole=hashlib.sha256()
for part in parts:
source=root/relative(part['path'])
if source.is_symlink() or part['offset']!=total or source.stat().st_size!=part['bytes']:
raise ValueError('Archive part path/order/size mismatch')
actual=hashlib.sha256()
with source.open('rb') as stream:
for block in iter(lambda:stream.read(1024*1024),b''):
actual.update(block);whole.update(block);output.write(block);total+=len(block)
if actual.hexdigest()!=part['sha256']:
raise ValueError('Archive part hash mismatch')
if total!=reference['bytes'] or whole.hexdigest()!=reference['sha256']:
raise ValueError('Reconstructed archive hash/size mismatch')
output.seek(0)
yield output
else:
source=root/relative(reference['path'])
if source.is_symlink() or source.stat().st_size!=reference['bytes'] or digest(source)!=reference['sha256']:
raise ValueError('Context archive hash/size mismatch')
with source.open('rb') as stream:yield stream
def materialize(manifest_path, output, verify_only=False):
manifest_path, output = Path(manifest_path), Path(output) if output is not None else None
if output is not None and (output.exists() or output.is_symlink()):
raise FileExistsError(output)
manifest = json.loads(manifest_path.read_text())
reference = manifest['archive']
entries = {str(relative(row['path'])): row for row in manifest['files']}
if len(entries) != len(manifest['files']):
raise ValueError('Duplicate manifest members')
for name in entries:
if any(str(parent) in entries for parent in PurePosixPath(name).parents):
raise ValueError('File/directory context collision')
with archive_stream(manifest_path.parent,reference) as source, tarfile.open(fileobj=source,mode='r:gz') as tar:
members = tar.getmembers()
names = [str(relative(member.name)) for member in members]
if len(names) != len(set(names)) or set(names) != set(entries):
raise ValueError('Unlisted, missing or duplicate archive members')
container_links = declared_container_links(manifest, entries, tar)
for member in members:
row = entries[member.name]
if member.mode != row['mode'] or not 0 <= member.mode <= 0o777:
raise ValueError('Context member type/size/mode mismatch')
if row.get('kind','file')=='symlink':
target=row['target']
if (not member.issym() or member.linkname!=target or not target
or (PurePosixPath(target).is_absolute() and member.name not in container_links)
or '\\' in target or '\x00' in target):
raise ValueError('Unsafe or changed context link')
data=target.encode()
if len(data)!=row['bytes']:
raise ValueError('Context link size mismatch')
actual=hashlib.sha256(data).hexdigest()
elif row.get('kind','file')=='file' and member.isfile() and member.size==row['bytes']:
actual_hash=hashlib.sha256()
with tar.extractfile(member) as stream:
for block in iter(lambda:stream.read(1024*1024),b''):actual_hash.update(block)
actual=actual_hash.hexdigest()
else:
raise ValueError('Unsupported or changed context member')
if actual != row['sha256']:
raise ValueError('Context member hash mismatch: ' + member.name)
check_virtual_links(entries, container_links)
if verify_only:
return {'files':len(entries),'archive_sha256':reference['sha256'],'state':'ARCHIVE_VERIFIED'}
output.mkdir(parents=True, exist_ok=False)
try:
for member in members:(output/member.name).parent.mkdir(parents=True,exist_ok=True)
for member in members:
if member.isfile():
target=output/member.name
with tar.extractfile(member) as source,target.open('xb') as destination:shutil.copyfileobj(source,destination)
target.chmod(member.mode)
# No regular-file write occurs after creating any source link.
for member in members:
if member.issym():(output/member.name).symlink_to(member.linkname)
except BaseException:
shutil.rmtree(output)
raise
return {'files': len(entries), 'symlinks':sum(row.get('kind')=='symlink' for row in entries.values()),
'declared_container_symlinks': len(container_links), 'archive_sha256': reference['sha256'], 'output': str(output)}
# crossswe repair publication context compatibility v1
def descriptor_ref(folder, reference):
path = folder / relative(reference['path'])
if any(p.is_symlink() for p in (path, *path.parents)) or not path.is_file():
raise ValueError('Unsafe descriptor reference')
if path.stat().st_size != reference['bytes'] or digest(path) != reference['sha256']:
raise ValueError('Descriptor reference hash/size mismatch')
return path
def current_context(root, instance_id):
folder = root / 'environments' / relative(instance_id)
image_path = folder / 'image.json'
if any(p.is_symlink() for p in (image_path, *image_path.parents)):
raise ValueError('Unsafe image descriptor path')
image = json.loads(image_path.read_text())
if image['instance_id'] != instance_id:
raise ValueError('Image descriptor instance differs')
manifest = descriptor_ref(folder, image['context_manifest'])
recipe = None
if image.get('recipe'):
recipe = json.loads(descriptor_ref(folder, image['recipe']).read_text())
import re
if (recipe.get('kind') != 'immutable-parent-delta'
or not re.fullmatch(r'[^@\s]+@sha256:[0-9a-f]{64}', recipe.get('parent_image_ref', ''))
or recipe['actual_context'] != image['context_manifest']
or descriptor_ref(folder, recipe['actual_context']) != manifest):
raise ValueError('Invalid immutable parent/delta recipe')
parent = json.loads(descriptor_ref(folder, recipe['parent_image_descriptor']).read_text())
if parent.get('image_ref') != recipe['parent_image_ref']:
raise ValueError('Recipe parent descriptor identity differs')
descriptor_ref(folder, parent['context_manifest'])
descriptor_ref(folder, recipe['source_authority'])
descriptor_ref(folder, recipe['build_receipt'])
# Every parent descriptor uses environment-root-relative refs, including an
# exact historical descriptor stored below history/. Never rebase its refs
# to the history directory.
recipe_chain(folder, image)
return manifest, recipe
def recipe_chain(folder, image, seen=None):
seen = set() if seen is None else seen
identity = image['image_ref']
if identity in seen or len(seen) >= 40:
raise ValueError('Cyclic or excessive recipe chain')
seen.add(identity)
if image.get('provenance_only'):
if image.get('registry_digest') != 'sha256:e6c20a1727d4eb758737a9c2710a2e0a805bc534fc056929d7ddb2279b55437c' or identity != 'silinchen0617/crossrepo-bench@sha256:e6c20a1727d4eb758737a9c2710a2e0a805bc534fc056929d7ddb2279b55437c':
raise ValueError('Unsupported provenance-only immutable parent')
context = descriptor_ref(folder, image['context_manifest'])
for reference in image['verified_provenance'].values():
descriptor_ref(folder, reference)
original = json.loads(descriptor_ref(folder, image['original_descriptor']).read_text())
if original['registry_digest'] != 'sha256:dd0cf3223f7e9524c4c21aafce54a1b59a7e53288027a1332ddeb1577cad6dda':
raise ValueError('Historical original parent differs')
return [{'image_ref': identity, 'context_manifest': str(context), 'context_kind': 'verified-registry-parent-reference'}] + recipe_chain(folder, original, seen)
context = descriptor_ref(folder, image['context_manifest'])
result = [{'image_ref': identity, 'context_manifest': str(context),
'context_kind': 'delta' if image.get('recipe') else 'full'}]
if image.get('recipe'):
recipe = json.loads(descriptor_ref(folder, image['recipe']).read_text())
parent = json.loads(descriptor_ref(folder, recipe['parent_image_descriptor']).read_text())
if parent['image_ref'] != recipe['parent_image_ref'] or recipe['actual_context'] != image['context_manifest']:
raise ValueError('Recipe chain identity differs')
result.extend(recipe_chain(folder, parent, seen))
return result
def verify_manifest(manifest_path):
return materialize(manifest_path, None, verify_only=True)
def materialize_image(root, instance_id, output):
manifest, recipe = current_context(Path(root), instance_id)
result = materialize(manifest, output)
result['context_manifest'] = str(manifest)
result['context_kind'] = 'delta' if recipe else 'full'
if recipe:
result['parent_image_ref'] = recipe['parent_image_ref']
result['source_authority_full_build_context'] = recipe['source_authority_full_build_context']
result['recipe_note'] = 'Build this actual delta with its pinned parent; historical full context remains preserved.'
return result
def main():
parser = argparse.ArgumentParser(description=__doc__)
parser.add_argument('--instance-id', required=True)
parser.add_argument('--output-dir', type=Path, required=True)
args = parser.parse_args()
if Path(args.instance_id).name != args.instance_id or args.instance_id in ('','.', '..'):
parser.error('Use a canonical instance ID')
root = Path(__file__).resolve().parents[1]
print(json.dumps(materialize_image(root, args.instance_id, args.output_dir)))
if __name__ == '__main__':
main()
|