Handle QEMU kernels better, especially ARM kernels

- When examining the bounds of a mapping, do not wrap the address space
- Do not attempt to walk the stack looking for AUXV

pwndbg/auxv.py

@@ -15,6 +15,7 @@ import pwndbg.arch
 import pwndbg.events
 import pwndbg.info
 import pwndbg.memory
+import pwndbg.qemu
 import pwndbg.regs
 import pwndbg.stack
 import pwndbg.typeinfo
@@ -149,6 +150,9 @@ def find_stack_boundary(addr):
     return addr
 
 def walk_stack():
+    if pwndbg.qemu.is_qemu_kernel():
+        return None
+
     auxv = walk_stack2(0)
 
     if not auxv:

pwndbg/memory.py

@@ -146,6 +146,8 @@ def find_upper_boundary(addr, max_pages=1024):
             # import sys
             # sys.stdout.write(hex(addr) + '\n')
             addr += pwndbg.memory.PAGE_SIZE
+            if addr > pwndbg.arch.ptrmask:
+                break
     except gdb.MemoryError:
         pass
     return addr
@@ -156,6 +158,8 @@ def find_lower_boundary(addr, max_pages=1024):
         for i in range(max_pages):
             pwndbg.memory.read(addr, 1)
             addr -= pwndbg.memory.PAGE_SIZE
+            if addr < 0:
+                break
     except gdb.MemoryError:
         pass
     return addr

pwndbg/qemu.py

@@ -54,6 +54,10 @@ def is_qemu_usermode():
 
     return is_qemu() and is_usermode()
 
+@pwndbg.memoize.reset_on_stop
+def is_qemu_kernel():
+    return is_qemu() and not is_usermode()
+
 @pwndbg.events.start
 @pwndbg.memoize.reset_on_stop
 def root():