Fix deference-limit changes not being reflected due to an early cast to int() (#2422)

* Added types to hexdump()'s parameters

* hexdump(): upgraded format strings to f-strings, while fixing the offset when data is empty

* hexdump(): offset is now correctly computed and updated accross repeated calls to hexdump.

This fixes two bugs:
1. Offset was increased by the number of lines displayed by the hexdump() command,
	which was incorrect, as some lines may be compressed;
2. When dumping a number of bytes that is not divisible by the number of bytes per line,
	offset would be incorrectly updated.

* Linter

* hexdump: fixed type of retrieved config entry hexdump_group_use_big_endian

* Fixed test_hexdump_saved_address_and_offset test to account for random stack address

* Upgraded the linked-lists.c test program to 6 items in order to test the "deference-limit" setting

* Chain: changes to the deference-limit parameter were not reflected in the program due to an early cast to int()

* Linter

pwndbg/chain.py

@@ -30,7 +30,7 @@ c = ColorConfig(
 
 def get(
     address: int | None,
-    limit: int = int(LIMIT),
+    limit: int = LIMIT,
     offset: int = 0,
     hard_stop: int | None = None,
     hard_end: int = 0,
@@ -98,7 +98,7 @@ config_contiguous = theme.add_param(
 
 def format(
     value: int | List[int] | None,
-    limit: int = int(LIMIT),
+    limit: int = LIMIT,
     code: bool = True,
     offset: int = 0,
     hard_stop: int | None = None,

tests/gdb-tests/tests/binaries/linked-lists.c

@@ -6,7 +6,10 @@ struct node {
     int value;
     struct node *next;
 };
-struct node node_c = { 2, NULL };
+struct node node_f = { 5, NULL };
+struct node node_e = { 4, &node_f };
+struct node node_d = { 3, &node_e };
+struct node node_c = { 2, &node_d };
 struct node node_b = { 1, &node_c };
 struct node node_a = { 0, &node_b };
 

tests/gdb-tests/tests/test_command_plist.py

@@ -9,7 +9,7 @@ import tests
 LINKED_LISTS_BINARY = tests.binaries.get("linked-lists.out")
 
 
-def startup(start_binary):
+def startup(start_binary) -> None:
     start_binary(LINKED_LISTS_BINARY)
 
     gdb.execute("break break_here")
@@ -17,6 +17,66 @@ def startup(start_binary):
     gdb.execute("up")
 
 
+def test_command_plist_dereference_limit_change_has_impact_on_plist(start_binary):
+    """
+    Tests the plist command with different dereference limits
+    """
+    startup(start_binary)
+    gdb.execute("set dereference-limit 5")
+    expected_out = re.compile(
+        """\
+0[xX][0-9a-fA-F]+ <node_a>: {\\s*
+  value = 0,\\s*
+  next = 0[xX][0-9a-fA-F]+ <node_b>\\s*
+}\\s*
+0[xX][0-9a-fA-F]+ <node_b>: {\\s*
+  value = 1,\\s*
+  next = 0[xX][0-9a-fA-F]+ <node_c>\\s*
+}\\s*
+0[xX][0-9a-fA-F]+ <node_c>: {\\s*
+  value = 2,\\s*
+  next = 0[xX][0-9a-fA-F]+ <node_d>\\s*
+}\\s*
+0[xX][0-9a-fA-F]+ <node_d>: {\\s*
+  value = 3,\\s*
+  next = 0[xX][0-9a-fA-F]+ <node_e>\\s*
+}\\s*
+0[xX][0-9a-fA-F]+ <node_e>: {\\s*
+  value = 4,\\s*
+  next = 0[xX][0-9a-fA-F]+ <node_f>\\s*
+}\\s*
+0[xX][0-9a-fA-F]+ <node_f>: {\\s*
+  value = 5,\\s*
+  next = 0x0\\s*
+}\
+"""
+    )
+
+    result_str = gdb.execute("plist node_a next", to_string=True)
+    assert expected_out.match(result_str) is not None
+
+    gdb.execute("set dereference-limit 1")
+    expected_out = re.compile(
+        """\
+0[xX][0-9a-fA-F]+ <node_a>: {\\s*
+  value = 0,\\s*
+  next = 0[xX][0-9a-fA-F]+ <node_b>\\s*
+}\\s*
+0[xX][0-9a-fA-F]+ <node_b>: {\\s*
+  value = 1,\\s*
+  next = 0[xX][0-9a-fA-F]+ <node_c>\\s*
+}\\s*
+0[xX][0-9a-fA-F]+ <node_c>: {\\s*
+  value = 2,\\s*
+  next = 0[xX][0-9a-fA-F]+ <node_d>\\s*
+}\
+"""
+    )
+
+    result_str = gdb.execute("plist node_a next", to_string=True)
+    assert expected_out.match(result_str) is not None
+
+
 def test_command_plist_flat_no_flags(start_binary):
     """
     Tests the plist for a non-nested linked list
@@ -35,8 +95,21 @@ def test_command_plist_flat_no_flags(start_binary):
 }\\s*
 0[xX][0-9a-fA-F]+ <node_c>: {\\s*
   value = 2,\\s*
+  next = 0[xX][0-9a-fA-F]+ <node_d>\\s*
+}\\s*
+0[xX][0-9a-fA-F]+ <node_d>: {\\s*
+  value = 3,\\s*
+  next = 0[xX][0-9a-fA-F]+ <node_e>\\s*
+}\\s*
+0[xX][0-9a-fA-F]+ <node_e>: {\\s*
+  value = 4,\\s*
+  next = 0[xX][0-9a-fA-F]+ <node_f>\\s*
+}\\s*
+0[xX][0-9a-fA-F]+ <node_f>: {\\s*
+  value = 5,\\s*
   next = 0x0\\s*
-}"""
+}\
+"""
     )
 
     result_str = gdb.execute("plist node_a next", to_string=True)