Invoke heap commands only with libc debug symbols. (#635)

* * Invoke heap command only with libc debug symbols.

* changed message

pwndbg/commands/__init__.py

@@ -238,6 +238,16 @@ def OnlyWhenHeapIsInitialized(function):
             print("%s: Heap is not initialized yet." % function.__name__)
     return _OnlyWhenHeapIsInitialized
 
+def OnlyWithLibcDebugSyms(function):
+    @functools.wraps(function)
+    def _OnlyWithLibcDebugSyms(*a, **kw):
+        if pwndbg.heap.current.libc_has_debug_syms():
+            return function(*a, **kw)
+        else:
+            print('''%s: This command only works with libc debug symbols.
+They can probably be installed via the package manager of your choice.
+See also: https://sourceware.org/gdb/onlinedocs/gdb/Separate-Debug-Files.html''' % function.__name__)
+    return _OnlyWithLibcDebugSyms
 
 class QuietSloppyParsedCommand(ParsedCommand):
     def __init__(self, *a, **kw):

pwndbg/commands/heap.py

@@ -85,6 +85,7 @@ parser.description = "Prints out chunks starting from the address specified by `
 parser.add_argument("addr", nargs="?", type=int, default=None, help="The address of the heap.")
 @pwndbg.commands.ArgparsedCommand(parser)
 @pwndbg.commands.OnlyWhenRunning
+@pwndbg.commands.OnlyWithLibcDebugSyms
 @pwndbg.commands.OnlyWhenHeapIsInitialized
 def heap(addr=None):
     """
@@ -123,6 +124,7 @@ parser.description = "Prints out the main arena or the arena at the specified by
 parser.add_argument("addr", nargs="?", type=int, default=None, help="The address of the arena.")
 @pwndbg.commands.ArgparsedCommand(parser)
 @pwndbg.commands.OnlyWhenRunning
+@pwndbg.commands.OnlyWithLibcDebugSyms
 @pwndbg.commands.OnlyWhenHeapIsInitialized
 def arena(addr=None):
     """
@@ -141,6 +143,7 @@ parser = argparse.ArgumentParser()
 parser.description = "Prints out allocated arenas."
 @pwndbg.commands.ArgparsedCommand(parser)
 @pwndbg.commands.OnlyWhenRunning
+@pwndbg.commands.OnlyWithLibcDebugSyms
 @pwndbg.commands.OnlyWhenHeapIsInitialized
 def arenas():
     """
@@ -156,6 +159,7 @@ parser.description = "Print malloc thread cache info."
 parser.add_argument("addr", nargs="?", type=int, default=None, help="The address of the tcache.")
 @pwndbg.commands.ArgparsedCommand(parser)
 @pwndbg.commands.OnlyWhenRunning
+@pwndbg.commands.OnlyWithLibcDebugSyms
 @pwndbg.commands.OnlyWhenHeapIsInitialized
 def tcache(addr=None):
     """
@@ -177,6 +181,7 @@ parser = argparse.ArgumentParser()
 parser.description = "Prints out the mp_ structure from glibc."
 @pwndbg.commands.ArgparsedCommand(parser)
 @pwndbg.commands.OnlyWhenRunning
+@pwndbg.commands.OnlyWithLibcDebugSyms
 @pwndbg.commands.OnlyWhenHeapIsInitialized
 def mp():
     """
@@ -192,6 +197,7 @@ parser.description = "Prints out the address of the top chunk of the main arena,
 parser.add_argument("addr", nargs="?", type=int, default=None, help="The address of the arena.")
 @pwndbg.commands.ArgparsedCommand(parser)
 @pwndbg.commands.OnlyWhenRunning
+@pwndbg.commands.OnlyWithLibcDebugSyms
 @pwndbg.commands.OnlyWhenHeapIsInitialized
 def top_chunk(addr=None):
     """
@@ -237,6 +243,7 @@ parser.add_argument("addr", nargs="?", type=int, default=None, help="The address
 parser.add_argument("fake", nargs="?", type=bool, default=False, help="If the chunk is a fake chunk.")#TODO describe this better
 @pwndbg.commands.ArgparsedCommand(parser)
 @pwndbg.commands.OnlyWhenRunning
+@pwndbg.commands.OnlyWithLibcDebugSyms
 @pwndbg.commands.OnlyWhenHeapIsInitialized
 def malloc_chunk(addr,fake=False):
     """
@@ -282,6 +289,7 @@ parser.add_argument("addr", nargs="?", type=int, default=None, help="The address
 parser.add_argument("tcache_addr", nargs="?", type=int, default=None, help="The address of the tcache.")
 @pwndbg.commands.ArgparsedCommand(parser)
 @pwndbg.commands.OnlyWhenRunning
+@pwndbg.commands.OnlyWithLibcDebugSyms
 @pwndbg.commands.OnlyWhenHeapIsInitialized
 def bins(addr=None, tcache_addr=None):
     """
@@ -305,6 +313,7 @@ parser.add_argument("addr", nargs="?", type=int, default=None, help="The address
 parser.add_argument("verbose", nargs="?", type=bool, default=True, help="Whether to show more details or not.")
 @pwndbg.commands.ArgparsedCommand(parser)
 @pwndbg.commands.OnlyWhenRunning
+@pwndbg.commands.OnlyWithLibcDebugSyms
 @pwndbg.commands.OnlyWhenHeapIsInitialized
 def fastbins(addr=None, verbose=True):
     """
@@ -333,6 +342,7 @@ parser.add_argument("addr", nargs="?", type=int, default=None, help="The address
 parser.add_argument("verbose", nargs="?", type=bool, default=True, help="Whether to show more details or not.")
 @pwndbg.commands.ArgparsedCommand(parser)
 @pwndbg.commands.OnlyWhenRunning
+@pwndbg.commands.OnlyWithLibcDebugSyms
 @pwndbg.commands.OnlyWhenHeapIsInitialized
 def unsortedbin(addr=None, verbose=True):
     """
@@ -361,6 +371,7 @@ parser.add_argument("addr", nargs="?", type=int, default=None, help="The address
 parser.add_argument("verbose", nargs="?", type=bool, default=False, help="Whether to show more details or not.")
 @pwndbg.commands.ArgparsedCommand(parser)
 @pwndbg.commands.OnlyWhenRunning
+@pwndbg.commands.OnlyWithLibcDebugSyms
 @pwndbg.commands.OnlyWhenHeapIsInitialized
 def smallbins(addr=None, verbose=False):
     """
@@ -389,6 +400,7 @@ parser.add_argument("addr", nargs="?", type=int, default=None, help="The address
 parser.add_argument("verbose", nargs="?", type=bool, default=False, help="Whether to show more details or not.")
 @pwndbg.commands.ArgparsedCommand(parser)
 @pwndbg.commands.OnlyWhenRunning
+@pwndbg.commands.OnlyWithLibcDebugSyms
 @pwndbg.commands.OnlyWhenHeapIsInitialized
 def largebins(addr=None, verbose=False):
     """
@@ -417,6 +429,7 @@ parser.add_argument("addr", nargs="?", type=int, default=None, help="The address
 parser.add_argument("verbose", nargs="?", type=bool, default=False, help="Whether to show more details or not.")
 @pwndbg.commands.ArgparsedCommand(parser)
 @pwndbg.commands.OnlyWhenRunning
+@pwndbg.commands.OnlyWithLibcDebugSyms
 @pwndbg.commands.OnlyWhenHeapIsInitialized
 def tcachebins(addr=None, verbose=False):
     """
@@ -445,6 +458,7 @@ parser.add_argument("addr", type=int, help="The start address.") #TODO describe
 parser.add_argument("size", type=int, help="The size.")
 @pwndbg.commands.ArgparsedCommand(parser)
 @pwndbg.commands.OnlyWhenRunning
+@pwndbg.commands.OnlyWithLibcDebugSyms
 @pwndbg.commands.OnlyWhenHeapIsInitialized
 def find_fake_fast(addr, size):
     """
@@ -483,6 +497,7 @@ vis_heap_chunks_parser.add_argument('--naive', '-n', help='Don\'t use end-of-hea
 
 @pwndbg.commands.ArgparsedCommand(vis_heap_chunks_parser)
 @pwndbg.commands.OnlyWhenRunning
+@pwndbg.commands.OnlyWithLibcDebugSyms
 @pwndbg.commands.OnlyWhenHeapIsInitialized
 def vis_heap_chunks(address=None, count=None, naive=None):
     address = int(address) if address else pwndbg.heap.current.get_heap_boundaries().vaddr

pwndbg/heap/heap.py

@@ -53,3 +53,11 @@ class BaseHeap(object):
             A boolean.
         """
         raise NotImplementedError()
+
+    def libc_has_debug_syms(self):
+        """Returns whether the libc has debug symbols or not.
+
+        Returns:
+            A boolean.
+        """
+        raise NotImplementedError()

pwndbg/heap/ptmalloc.py

@@ -571,3 +571,6 @@ class Heap(pwndbg.heap.heap.BaseHeap):
         making it one of the ways to check if the allocator is initialized or not.
         """
         return self.global_max_fast != 0
+
+    def libc_has_debug_syms(self):
+        return pwndbg.symbol.address('global_max_fast') is not None