Add local libc database provider for libcdb

Author: the-soloist

pwnlib/args.py

@@ -159,6 +159,10 @@ def STDERR(v):
     """Sends logging to ``stderr`` by default, instead of ``stdout``"""
     context.log_console = sys.stderr
 
+def LOCAL_LIBCDB(v):
+    """Sets local libcdb path"""
+    context.defaults['local_libcdb'] = v
+
 hooks = {
     'LOG_LEVEL': LOG_LEVEL,
     'LOG_FILE': LOG_FILE,
@@ -170,6 +174,7 @@ def STDERR(v):
     'NOASLR': NOASLR,
     'NOPTRACE': NOPTRACE,
     'STDERR': STDERR,
+    'LOCAL_LIBCDB': LOCAL_LIBCDB,
 }
 
 def initialize():

pwnlib/context/__init__.py

@@ -360,6 +360,7 @@ class ContextType(object):
         'endian': 'little',
         'gdbinit': "",
         'kernel': None,
+        'local_libcdb': "/var/lib/libc-database",
         'log_level': logging.INFO,
         'log_file': _devnull(),
         'log_console': sys.stdout,
@@ -1071,6 +1072,10 @@ def log_console(self, stream):
             stream = open(stream, 'wt')
         return stream
 
+    @_validator
+    def local_libcdb(self, path):
+        return path
+
     @property
     def mask(self):
         return (1 << self.bits) - 1

pwnlib/libcdb.py

@@ -11,6 +11,7 @@
 
 from pwnlib.context import context
 from pwnlib.elf import ELF
+from pwnlib.filesystem.path import Path
 from pwnlib.log import getLogger
 from pwnlib.tubes.process import process
 from pwnlib.util.fiddling import enhex
@@ -126,7 +127,24 @@ def provider_local_system(hex_encoded_id, hash_type):
         return local_libc.data
     return None
 
-PROVIDERS = [provider_local_system, provider_libcdb, provider_libc_rip]
+# Offline search https://github.com/niklasb/libc-database for hash type
+def provider_local_database(hex_encoded_id, hash_type):
+    assert context.local_libcdb
+    assert hash_type in HASHES
+
+    localdb = Path(context.local_libcdb)
+    if not localdb.is_dir():
+        log.warn_once("%s does not exist, please download libc-database first.", str(localdb))
+        return None
+
+    log.debug("Searching local libc database, %s: %s", hash_type, hex_encoded_id)
+    for libc_path in localdb.rglob("*.so"):
+        if hex_encoded_id == HASHES[hash_type](libc_path):
+            return read(libc_path)
+
+    return None
+
+PROVIDERS = [provider_local_database, provider_local_system, provider_libcdb, provider_libc_rip]
 
 def search_by_hash(hex_encoded_id, hash_type='build_id', unstrip=True):
     assert hash_type in HASHES, hash_type