Added a workaround to correctly handle broken registers in unicorn (#2587)

* Added a workaround to correctly handle broken registers in unicorn

* Disable emulate when unicorn report error

* Refactor: disable emulate when error

pwndbg/commands/context.py

@@ -14,7 +14,9 @@ from typing import Dict
 from typing import List
 from typing import Optional
 from typing import Tuple
+from typing import TypeVar
 
+import unicorn as U
 from typing_extensions import ParamSpec
 
 import pwndbg
@@ -48,6 +50,7 @@ if pwndbg.dbg.is_gdblib_available():
 
 log = logging.getLogger(__name__)
 
+T = TypeVar("T")
 P = ParamSpec("P")
 
 theme.add_param("backtrace-prefix", "►", "prefix for current backtrace label")
@@ -853,6 +856,20 @@ disasm_lines = pwndbg.config.add_param(
 )
 
 
+def try_emulate_if_bug_disable(handler: Callable[[], T]) -> T:
+    try:
+        return handler()
+    except U.UcError as e:
+        print(
+            message.warn(
+                f"Warning: Emulation context disabled due to a Unicorn error: \n{str(e)}\n"
+                "If you want to enable it again, use `set emulate on`."
+            )
+        )
+        pwndbg.config.emulate.value = "off"
+        return handler()
+
+
 @serve_context_history
 def context_disasm(target=sys.stdout, with_banner=True, width=None):
     flavor = pwndbg.dbg.x86_disassembly_flavor()
@@ -865,10 +882,12 @@ def context_disasm(target=sys.stdout, with_banner=True, width=None):
     if cs is not None and cs.syntax != syntax:
         pwndbg.lib.cache.clear_caches()
 
-    result = pwndbg.aglib.nearpc.nearpc(
-        lines=disasm_lines // 2,
-        emulate=bool(not pwndbg.config.emulate == "off"),
-        use_cache=True,
+    result = try_emulate_if_bug_disable(
+        lambda: pwndbg.aglib.nearpc.nearpc(
+            lines=disasm_lines // 2,
+            emulate=bool(not pwndbg.config.emulate == "off"),
+            use_cache=True,
+        )
     )
 
     # Note: we must fetch emulate value again after disasm since

pwndbg/emu/emulator.py

@@ -286,6 +286,16 @@ class Emulator:
         reg = self.get_reg_enum(name)
 
         if reg:
+            if self.arch == "aarch64":
+                # Workaround for an issue from upstream: https://github.com/pwndbg/pwndbg/issues/2548
+                # Remove this after upgrading to unicorn > 2.1.1
+                if reg == U.arm64_const.UC_ARM64_REG_WSP:
+                    return self.uc.reg_read(U.arm64_const.UC_ARM64_REG_SP) & 0xFFFFFFFF
+                elif reg == U.arm64_const.UC_ARM64_REG_XZR:
+                    return 0
+                elif reg == U.arm64_const.UC_ARM64_REG_WZR:
+                    return 0
+
             return self.uc.reg_read(reg)
 
         return None