safe-linking: use __libc_version when debug symbols loaded

pwndbg/glibc.py

@@ -4,26 +4,48 @@
 Get information about the GLibc
 """
 
+import functools
 import re
 
 import gdb
 
+import pwndbg.config
+import pwndbg.heap
 import pwndbg.memoize
 import pwndbg.memory
+import pwndbg.proc
+import pwndbg.search
 import pwndbg.symbol
 
+safe_lnk = pwndbg.config.Parameter('safe-linking', 'auto', 'whether glibc use safe-linking (on/off/auto)')
 
-@pwndbg.memoize.reset_on_start
+
+@pwndbg.proc.OnlyWhenRunning
+@pwndbg.memoize.reset_on_objfile
 def get_version():
-    addr = pwndbg.symbol.address('banner')
-    if addr is None:
-        return (0, 0)
-    banner = pwndbg.memory.string(addr)
-    ret = re.search(rb"release version (\d+)\.(\d+)", banner)
-    if ret:
-        return tuple(int(_) for _ in ret.groups())
-    return (0, 0)
-
-@pwndbg.memoize.reset_on_start
+    if pwndbg.heap.current.libc_has_debug_syms():
+        addr = pwndbg.symbol.address(b'__libc_version')
+        if addr is not None:
+            ver = pwndbg.memory.string(addr)
+            return tuple([int(_) for _ in ver.split(b'.')])
+    for addr in pwndbg.search.search(b'GNU C Library'):
+        banner = pwndbg.memory.string(addr)
+        ret = re.search(rb"release version (\d+)\.(\d+)", banner)
+        if ret:
+            return tuple(int(_) for _ in ret.groups())
+    return None
+
+
+def OnlyWhenGlibcLoaded(function):
+    @functools.wraps(function)
+    def _OnlyWhenGlibcLoaded(*a, **kw):
+        if get_version() is not None:
+            return function(*a, **kw)
+        else:
+            print('%s: GLibc not loaded yet.' % function.__name__)
+    return _OnlyWhenGlibcLoaded
+
+
+@OnlyWhenGlibcLoaded
 def check_safe_linking():
-    return get_version() >= (2, 32)
+    return (get_version() >= (2, 32) or safe_lnk == "on") and safe_lnk != "off"