Harden wolfSSL and wolfSSH validation

Enable validated ECC imports and X25519 all-zero rejection through PUBLIC build policy. Tighten wolfSSH parser bounds, overflow handling, and signature framing with guard-page and crypto vector contracts.
2026-09-15 23:54:39 +02:00
parent c010e1a1d5
commit 4d3bb490c9
17 changed files with 1495 additions and 99 deletions
@@ -0,0 +1,79 @@
+#!/usr/bin/env python3
+"""Host contracts from freshly generated, original-hash-verified wolfSSH source."""
+import os
+import resource
+from pathlib import Path
+import subprocess
+import sys
+import tempfile
+
+sys.dont_write_bytecode = True
+ROOT = Path(__file__).resolve().parents[2]
+HERE = Path(__file__).resolve().parent
+sys.path.insert(0, str(ROOT / 'tests/wolfssh_auth_contract'))
+from run import extract
+from security_overrides import ENTRIES, render_entry
+
+entry = next(e for e in ENTRIES if e.name == 'wolfssh_internal')
+assert entry.sha256 == '81ff1f9166708abd5c2911e9fe57c0aee01c88b5d3f68c909ee8a856d37f36a9'
+original, generated = render_entry(entry, {'project': ROOT})
+names = ('GetUint32', 'GetSize', 'GetString', 'GetSkip', 'GetStringRef',
+         'DoIgnore', 'DoServiceRequest', 'DoChannelWindowAdjust', 'DoUserAuthRequestEcc',
+                  'DoUserAuthRequestEd25519')
+# Verify this slice cannot accidentally change ordering or existing password logic.
+from security_overrides import apply_edits, MODIFICATION_NOTICE, WOLFSSH_PARSER_EDITS
+baseline = MODIFICATION_NOTICE + apply_edits(original.read_text(), entry.edits[len(WOLFSSH_PARSER_EDITS):])
+for name in ('DoUserAuthRequestPassword', 'DoPacket', 'DoChannelFailure',
+             'ParseRSAPubKey', 'ParseECCPubKey', 'DoUserAuthRequestPublicKey'):
+    assert extract(generated.decode(), name) == extract(baseline, name), name
+with tempfile.TemporaryDirectory(prefix='wolfssh-parser-') as directory:
+    work = Path(directory)
+    # Read back the actual generated bytes, not a parallel implementation.
+    source = work / 'internal.c'
+    source.write_bytes(generated)
+    functions = '\n'.join(extract(source.read_text(), n) for n in names)
+    (work / 'actual.c').write_text(functions)
+    for small in (False, True):
+        binary = work / ('contract-small' if small else 'contract')
+        subprocess.run(['cc', '-std=gnu11', '-O2', '-Wall', '-Wextra', '-Werror',
+                        '-Wno-unused-parameter', '-fsanitize=undefined',
+                        '-fsanitize-undefined-trap-on-error',
+                        *(['-DWOLFSSH_SMALL_STACK'] if small else []),
+                        '-I', str(work), str(HERE / 'contract.c'), '-o', str(binary)],
+                       check=True, timeout=30, env={**os.environ, 'CCACHE_DISABLE': '1'})
+        subprocess.run([str(binary)], check=True, timeout=30)
+    # Prove negative fixtures detect removal of each new boundary/type guard.
+    # Mutations affect only temporary extracted host copies, never the override.
+    mutations = (
+        ('ECC nested read boundary', 'DoUserAuthRequestEcc',
+         (('pk->signature, sz, &i)', 'pk->signature, pk->signatureSz, &i)'),)),
+        ('ECC inner exact consumption', 'DoUserAuthRequestEcc',
+         (('(i != sz || sz != pk->signatureSz)', '(sz != pk->signatureSz)'),)),
+        ('ECC outer exact consumption', 'DoUserAuthRequestEcc',
+         (('(i != sz || sz != pk->signatureSz)', '(i != sz)'),)),
+        ('Ed25519 key label', 'DoUserAuthRequestEd25519',
+         (('|| WMEMCMP(publicKeyType,', '&& WMEMCMP(publicKeyType,'),)),
+        ('Ed25519 signature label', 'DoUserAuthRequestEd25519',
+         (('pk->publicKeyTypeSz ||', 'pk->publicKeyTypeSz &&'),)),
+        ('Ed25519 outer exact consumption', 'DoUserAuthRequestEd25519',
+         (('if (ret == WS_SUCCESS && sz != pk->signatureSz - i)', 'if (0)'),)),
+    )
+    resource.setrlimit(resource.RLIMIT_CORE, (0, 0))
+    for label, name, replacements in mutations:
+        body = extract(source.read_text(), name)
+        changed = body
+        for old, new in replacements:
+            assert old in changed, label
+            changed = changed.replace(old, new)
+        assert changed != body, label
+        (work / 'actual.c').write_text(functions.replace(body, changed))
+        binary = work / 'mutation'
+        subprocess.run(['cc', '-std=gnu11', '-O2', '-Wall', '-Wextra', '-Werror',
+                        '-Wno-unused-parameter', '-I', str(work),
+                        str(HERE / 'contract.c'), '-o', str(binary)],
+                       check=True, timeout=30, env={**os.environ, 'CCACHE_DISABLE': '1'})
+        result = subprocess.run([str(binary)], capture_output=True, timeout=30)
+        assert result.returncode != 0, f'Undetected mutation: {label}'
+    print(f'PASS: {len(mutations)} parser guard-removal mutations rejected')
+print('PASS: exact original hash; generated parser; unchanged ordering/password/deferred functions')
+print('NOTE: production build-tree registration/firmware not regenerated or validated')