Add OnlyWhenUserspace Decorator #1459 (#1729)

* Add OnlyWhenUserspace Decorator #1459

* The decorator is implemented as the inverse of OnlyWhenQemuKernel

* Apply the decorator to all of the heap commands and tls, auxv and environ/envp

* Update pwndbg/commands/__init__.py

---------

Co-authored-by: Disconnect3d <dominik.b.czarnota@gmail.com>

pwndbg/commands/__init__.py

@@ -263,6 +263,20 @@ def OnlyWhenQemuKernel(function):
     return _OnlyWhenQemuKernel
 
 
+def OnlyWhenUserspace(function):
+    @functools.wraps(function)
+    def _OnlyWhenUserspace(*a, **kw):
+        if not pwndbg.gdblib.qemu.is_qemu_kernel():
+            return function(*a, **kw)
+        else:
+            print(
+                "%s: This command may only be run when not debugging a QEMU kernel target."
+                % function.__name__
+            )
+
+    return _OnlyWhenUserspace
+
+
 def OnlyWithArch(arch_names: List[str]):
     """Decorates function to work only with the specified archictectures."""
     for arch in arch_names:

pwndbg/commands/argv.py

@@ -46,6 +46,7 @@ parser.add_argument(
     parser, aliases=["env", "environ"], category=CommandCategory.LINUX
 )
 @pwndbg.commands.OnlyWhenRunning
+@pwndbg.commands.OnlyWhenUserspace
 def envp(name=None):
     """
     Prints out the contents of the environment.

pwndbg/commands/auxv.py

@@ -8,6 +8,7 @@ from pwndbg.commands import CommandCategory
     "Print information from the Auxiliary ELF Vector.", category=CommandCategory.LINUX
 )
 @pwndbg.commands.OnlyWhenRunning
+@pwndbg.commands.OnlyWhenUserspace
 def auxv() -> None:
     for k, v in pwndbg.auxv.get().items():
         if v is not None:

pwndbg/commands/heap.py

@@ -160,6 +160,7 @@ parser.add_argument(
 @pwndbg.commands.OnlyWhenRunning
 @pwndbg.commands.OnlyWithResolvedHeapSyms
 @pwndbg.commands.OnlyWhenHeapIsInitialized
+@pwndbg.commands.OnlyWhenUserspace
 def heap(addr=None, verbose=False, simple=False) -> None:
     """Iteratively print chunks on a heap, default to the current thread's
     active heap.
@@ -196,6 +197,7 @@ parser.add_argument("addr", nargs="?", type=int, default=None, help="Address of
 @pwndbg.commands.OnlyWhenRunning
 @pwndbg.commands.OnlyWithResolvedHeapSyms
 @pwndbg.commands.OnlyWhenHeapIsInitialized
+@pwndbg.commands.OnlyWhenUserspace
 def arena(addr=None) -> None:
     """Print the contents of an arena, default to the current thread's arena."""
     allocator = pwndbg.heap.current
@@ -225,6 +227,7 @@ parser = argparse.ArgumentParser(description="List this process's arenas.")
 @pwndbg.commands.OnlyWhenRunning
 @pwndbg.commands.OnlyWithResolvedHeapSyms
 @pwndbg.commands.OnlyWhenHeapIsInitialized
+@pwndbg.commands.OnlyWhenUserspace
 def arenas() -> None:
     """Lists this process's arenas."""
     allocator = pwndbg.heap.current
@@ -291,6 +294,7 @@ parser.add_argument("addr", nargs="?", type=int, default=None, help="Address of
 @pwndbg.commands.OnlyWithResolvedHeapSyms
 @pwndbg.commands.OnlyWhenHeapIsInitialized
 @pwndbg.commands.OnlyWithTcache
+@pwndbg.commands.OnlyWhenUserspace
 def tcache(addr=None) -> None:
     """Print a thread's tcache contents, default to the current thread's
     tcache.
@@ -318,6 +322,7 @@ parser = argparse.ArgumentParser(description="Print the mp_ struct's contents.")
 @pwndbg.commands.OnlyWhenRunning
 @pwndbg.commands.OnlyWithResolvedHeapSyms
 @pwndbg.commands.OnlyWhenHeapIsInitialized
+@pwndbg.commands.OnlyWhenUserspace
 def mp() -> None:
     """Print the mp_ struct's contents."""
     allocator = pwndbg.heap.current
@@ -338,6 +343,7 @@ parser.add_argument("addr", nargs="?", type=int, default=None, help="Address of
 @pwndbg.commands.OnlyWhenRunning
 @pwndbg.commands.OnlyWithResolvedHeapSyms
 @pwndbg.commands.OnlyWhenHeapIsInitialized
+@pwndbg.commands.OnlyWhenUserspace
 def top_chunk(addr=None) -> None:
     """Print relevant information about an arena's top chunk, default to the
     current thread's arena.
@@ -373,6 +379,7 @@ parser.add_argument(
 @pwndbg.commands.OnlyWhenRunning
 @pwndbg.commands.OnlyWithResolvedHeapSyms
 @pwndbg.commands.OnlyWhenHeapIsInitialized
+@pwndbg.commands.OnlyWhenUserspace
 def malloc_chunk(addr, fake=False, verbose=False, simple=False) -> None:
     """Print a malloc_chunk struct's contents."""
     allocator = pwndbg.heap.current
@@ -457,6 +464,7 @@ parser.add_argument("tcache_addr", nargs="?", type=int, default=None, help="Addr
 @pwndbg.commands.OnlyWhenRunning
 @pwndbg.commands.OnlyWithResolvedHeapSyms
 @pwndbg.commands.OnlyWhenHeapIsInitialized
+@pwndbg.commands.OnlyWhenUserspace
 def bins(addr=None, tcache_addr=None) -> None:
     """Print the contents of all an arena's bins and a thread's tcache,
     default to the current thread's arena and tcache.
@@ -491,6 +499,7 @@ parser.add_argument(
 @pwndbg.commands.OnlyWhenRunning
 @pwndbg.commands.OnlyWithResolvedHeapSyms
 @pwndbg.commands.OnlyWhenHeapIsInitialized
+@pwndbg.commands.OnlyWhenUserspace
 def fastbins(addr=None, verbose=False) -> None:
     """Print the contents of an arena's fastbins, default to the current
     thread's arena.
@@ -525,6 +534,7 @@ parser.add_argument(
 @pwndbg.commands.OnlyWhenRunning
 @pwndbg.commands.OnlyWithResolvedHeapSyms
 @pwndbg.commands.OnlyWhenHeapIsInitialized
+@pwndbg.commands.OnlyWhenUserspace
 def unsortedbin(addr=None, verbose=False) -> None:
     """Print the contents of an arena's unsortedbin, default to the current
     thread's arena.
@@ -559,6 +569,7 @@ parser.add_argument(
 @pwndbg.commands.OnlyWhenRunning
 @pwndbg.commands.OnlyWithResolvedHeapSyms
 @pwndbg.commands.OnlyWhenHeapIsInitialized
+@pwndbg.commands.OnlyWhenUserspace
 def smallbins(addr=None, verbose=False) -> None:
     """Print the contents of an arena's smallbins, default to the current
     thread's arena.
@@ -593,6 +604,7 @@ parser.add_argument(
 @pwndbg.commands.OnlyWhenRunning
 @pwndbg.commands.OnlyWithResolvedHeapSyms
 @pwndbg.commands.OnlyWhenHeapIsInitialized
+@pwndbg.commands.OnlyWhenUserspace
 def largebins(addr=None, verbose=False) -> None:
     """Print the contents of an arena's largebins, default to the current
     thread's arena.
@@ -628,6 +640,7 @@ parser.add_argument(
 @pwndbg.commands.OnlyWithResolvedHeapSyms
 @pwndbg.commands.OnlyWhenHeapIsInitialized
 @pwndbg.commands.OnlyWithTcache
+@pwndbg.commands.OnlyWhenUserspace
 def tcachebins(addr=None, verbose=False) -> None:
     """Print the contents of a tcache, default to the current thread's tcache."""
     allocator = pwndbg.heap.current
@@ -676,6 +689,7 @@ parser.add_argument(
 @pwndbg.commands.OnlyWhenRunning
 @pwndbg.commands.OnlyWithResolvedHeapSyms
 @pwndbg.commands.OnlyWhenHeapIsInitialized
+@pwndbg.commands.OnlyWhenUserspace
 def find_fake_fast(
     target_address, max_candidate_size=None, align=False, glibc_fastbin_bug=False
 ) -> None:
@@ -827,6 +841,7 @@ group.add_argument(
 @pwndbg.commands.OnlyWhenRunning
 @pwndbg.commands.OnlyWithResolvedHeapSyms
 @pwndbg.commands.OnlyWhenHeapIsInitialized
+@pwndbg.commands.OnlyWhenUserspace
 def vis_heap_chunks(
     addr=None, count=None, beyond_top=None, no_truncate=None, all_chunks=None
 ) -> None:
@@ -1019,6 +1034,7 @@ try_free_parser.add_argument("addr", nargs="?", help="Address passed to free")
 @pwndbg.commands.ArgparsedCommand(try_free_parser, category=CommandCategory.HEAP)
 @pwndbg.commands.OnlyWhenRunning
 @pwndbg.commands.OnlyWhenHeapIsInitialized
+@pwndbg.commands.OnlyWhenUserspace
 def try_free(addr) -> None:
     addr = int(addr)
 

pwndbg/commands/tls.py

@@ -24,6 +24,7 @@ parser.add_argument(
 
 @pwndbg.commands.ArgparsedCommand(parser, category=CommandCategory.LINUX)
 @pwndbg.commands.OnlyWhenRunning
+@pwndbg.commands.OnlyWhenUserspace
 def tls(pthread_self=False) -> None:
     tls_base = (
         pwndbg.gdblib.tls.find_address_with_register()