Handle ELF binary with no program segments

Do not return False for NX and No for RELRO when there is no program
segments in the ELF binary file (e.g. kernel module).

This is inspired from
slimm609/checksec@29aea68

For RELRO, a new NA value is added
For NX, True is returned to avoid changing NX type from boolean to
string

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>

Author: ffontaine

checksec/binary.py

@@ -19,7 +19,12 @@ def __init__(self, bin_path: Path):
 
     @property
     def has_nx(self) -> bool:
-        return self.bin.has_nx
+        # Handle ELF binary with no program segments (e.g., Kernel modules)
+        # In this case, return True
+        if isinstance(self.bin, lief.ELF.Binary) and len(self.bin.segments) == 0:
+            return True
+        else:
+            return self.bin.has_nx
 
     @property
     def checksec_state(self) -> Union["ELFChecksecData", "PEChecksecData"]:

checksec/elf.py

@@ -70,6 +70,7 @@ class RelroType(Enum):
     No = 1
     Partial = 2
     Full = 3
+    NA = 4
 
 
 class PIEType(Enum):
@@ -117,6 +118,11 @@ def set_dyn_syms(self) -> FrozenSet[str]:
 
     @property
     def relro(self) -> RelroType:
+        # Handle binary with no program segments (e.g., Kernel modules)
+        # In this case, return NA
+        if len(self.bin.segments) == 0:
+            return RelroType.NA
+
         if self.bin.get(lief.ELF.Segment.TYPE.GNU_RELRO) is None:
             return RelroType.No
 

tests/binaries

@@ -22,7 +22,7 @@ def test_bool_prop(prop: str, is_enabled: bool):
 
 @pytest.mark.parametrize("relro_type", list(RelroType))
 def test_relro(relro_type: RelroType):
-    """Test that relro type is No/Partial/Full"""
+    """Test that relro type is No/Partial/Full/NA"""
     bin_path = ELF_BINARIES / f"relro_{relro_type.name.lower()}"
     chk_data = run_checksec(bin_path)
     assert chk_data[str(bin_path)]["relro"] == relro_type.name
@@ -37,7 +37,7 @@ def test_relro_full_df1():
 
 @pytest.mark.parametrize("pie_type", list(PIEType))
 def test_pie(pie_type):
-    """Test that PIE is No/Partial/Full"""
+    """Test that PIE is No/Partial/Full/NA"""
     bin_path = ELF_BINARIES / f"pie_{pie_type.name.lower()}"
     chk_data = run_checksec(bin_path)
     assert chk_data[str(bin_path)]["pie"] == pie_type.name