improved testing / output

pwndbg/aglib/kernel/__init__.py

@@ -743,6 +743,12 @@ def paging_enabled() -> bool:
 
 
 def uses_5lvl_paging() -> bool:
+    if not has_debug_syms():
+        pages = pwndbg.aglib.vmmap.get()
+        for page in pages:
+            if page.start & (1 << 63) > 0:
+                return page.start < (0xFFF << (4 * 13))
+        return False
     ops = arch_ops()
     if ops:
         return ops.uses_5lvl_paging()

pwndbg/commands/pagewalk.py

@@ -10,8 +10,8 @@ from pwndbg.commands import CommandCategory
 from pwndbg.lib.regs import BitFlags
 
 parser = argparse.ArgumentParser(description="Performs pagewalk.")
-parser.add_argument("vaddr", type=int, help="virtual address to walk")
+parser.add_argument("vaddr", type=str, help="virtual address to walk")
-parser.add_argument("--pgd", dest="entry", type=int, default=None, help="")
+parser.add_argument("--pgd", dest="entry", type=str, default=None, help="")
 
 
 pageflags = BitFlags([("NX", 63), ("PS", 7), ("A", 5), ("W", 1), ("P", 0)])
@@ -38,6 +38,7 @@ def pg_indices(vaddr, nr_level):
 @pwndbg.commands.OnlyWhenQemuKernel
 @pwndbg.commands.OnlyWhenPagingEnabled
 def pagewalk(vaddr, entry=None):
+    vaddr = int(pwndbg.dbg.selected_frame().evaluate_expression(vaddr))
     # https://blog.zolutal.io/understanding-paging/
     base = pwndbg.aglib.kernel.physmap_base()
     level = 4
@@ -61,7 +62,7 @@ def pagewalk(vaddr, entry=None):
     if entry is None:
         entry = pwndbg.aglib.regs["cr3"]
     else:
-        entry = pwndbg.dbg.selected_frame().evaluate_expression(entry)
+        entry = int(pwndbg.dbg.selected_frame().evaluate_expression(entry))
     if entry > base:
         # user inputted a physmap address as pointer to pgd
         entry -= base
@@ -76,11 +77,11 @@ def pagewalk(vaddr, entry=None):
         idx = (vaddr & (0x1FF << shift)) >> shift
         entry = 0
         try:
-            table = pwndbg.aglib.memory.get_typed_pointer("ulong", cur)
+            table = pwndbg.aglib.memory.get_typed_pointer("unsigned long", cur)
             entry = int(table[idx])
             print_pagetable_entry(names[i], entry, cur)
         except Exception as e:
-            print(M.warn(f"Exception {e} while page walking"))
+            print(M.warn(f"Exception while page walking: {e}"))
             entry = 0
         if entry == 0:
             print(M.warn("address is not mapped"))

tests/qemu-tests/tests/system/test_commands_kernel.py

@@ -187,18 +187,23 @@ def test_command_pagewalk():
         # no kbase? fine
         pages = pwndbg.aglib.vmmap.get()
         address = pages[0].start
+    if not pwndbg.aglib.kernel.has_debug_syms():
+        # even if no debug symbols, still gracefully handle it
+        res = gdb.execute(f"pagewalk {hex(address)}")
+        # now let's guess the phymap base and should work as intended
+        res = gdb.execute("set guess-physmap on")
     res = gdb.execute(f"pagewalk {hex(address)}", to_string=True)
     assert "PMD" in res  # Page Size is only set for PMDe or PTe
     res = res.splitlines()[-1]
-    match = re.find(r"0x[0-9a-fA-F]{16}", res)
+    match = re.findall(r"0x[0-9a-fA-F]{16}", res)[0]
     physmap_addr = int(match, 16)
     # compare the first 0x100 bytes of the page (e.g. first kernel image page) with its physmap conterpart
     expected = pwndbg.aglib.memory.read(address, 0x100)
     actual = pwndbg.aglib.memory.read(physmap_addr, 0x100)
     assert all(expected[i] == actual[i] for i in range(0x100))
     # make sure that when using cr3 for pgd, it still works
-    res2 = gdb.execute(f"pagewalk {address} --pgd $cr3", to_string=True)
+    res2 = gdb.execute(f"pagewalk {hex(address)} --pgd $cr3", to_string=True).splitlines()[-1]
     assert res == res2
     # test non nonexistent address
     res = gdb.execute("pagewalk 0", to_string=True)
-    assert res == "address is not mapped"
+    assert res.splitlines()[-1] == "address is not mapped"