Updated canary.py for better display

pwndbg/commands/canary.py

@@ -38,16 +38,34 @@ def canary() -> None:
     )
     print(message.notice("Canary    = 0x%x (may be incorrect on != glibc)" % global_canary))
 
-    stack_canaries = list(
-        pwndbg.search.search(
-            pwndbg.gdblib.arch.pack(global_canary), mappings=pwndbg.gdblib.stack.stacks.values()
-        )
-    )
+    current_thread = pwndbg.proc.current_thread_id()
+    current_rsp = pwndbg.regs.rsp
+    stack_canaries = []
+
+    for stack in pwndbg.stack.stacks.values():
+        stack_start = stack.start
+        stack_end = stack.end
+        if stack_start <= current_rsp < stack_end:
+            stack_canaries = list(
+                pwndbg.search.search(pwndbg.gdblib.arch.pack(global_canary), mappings=[stack])
+            )
+            break
 
     if not stack_canaries:
-        print(message.warn("No valid canaries found on the stacks."))
+        print(message.warn("No valid canaries found on the current stack."))
         return
 
-    print(message.success("Found valid canaries on the stacks:"))
+    print(
+        message.success(
+            f"Found valid canaries on the current stack (thread {current_thread}):"
+        )
+    )
+
     for stack_canary in stack_canaries:
+        offset_from_rsp = stack_canary - current_rsp
+        print(
+            message.address(
+                f"Canary at offset {offset_from_rsp:#x} from RSP: {stack_canary:#x}"
+            )
+        )
         pwndbg.commands.telescope.telescope(address=stack_canary, count=1)