Merge bitcoin/bitcoin#27038: security-check: test for _FORTIFY_SOURCE usage in release binaries

be4f782 contrib: test for FORTIFY_SOURCE in security-check.py (fanquake)

Pull request description:

  Test for the existence of fortified functions in the ELF release binaries.
  Currently skips `bitcoin-util` and checks for RISC-V.

ACKs for top commit:
  TheCharlatan:
    ACK be4f782

Tree-SHA512: decea5f359f1e673aa0119916f674f409a13b69db7da366cd95c1540201e117ff5a979da67bc2517fe786c2ac23d1006a9aaf662d7eadeec35da6aae4998c065

Author: fanquake

contrib/devtools/security-check.py

@@ -7,6 +7,7 @@
 Exit status will be 0 if successful, and the program will be silent.
 Otherwise the exit status will be 1 and it will log which executables failed which checks.
 '''
+import re
 import sys
 
 import lief
@@ -116,6 +117,25 @@ def check_ELF_CONTROL_FLOW(binary) -> bool:
         return True
     return False
 
+def check_ELF_FORTIFY(binary) -> bool:
+
+    # bitcoin-util does not currently contain any fortified functions
+    if 'Bitcoin Core bitcoin-util utility version ' in binary.strings:
+        return True
+
+    chk_funcs = set()
+
+    for sym in binary.imported_symbols:
+        match = re.search(r'__[a-z]*_chk', sym.name)
+        if match:
+            chk_funcs.add(match.group(0))
+
+    # ignore stack-protector and bdb
+    chk_funcs.discard('__stack_chk')
+    chk_funcs.discard('__db_chk')
+
+    return len(chk_funcs) >= 1
+
 def check_PE_DYNAMIC_BASE(binary) -> bool:
     '''PIE: DllCharacteristics bit 0x40 signifies dynamicbase (ASLR)'''
     return lief.PE.DLL_CHARACTERISTICS.DYNAMIC_BASE in binary.optional_header.dll_characteristics_lists
@@ -228,11 +248,11 @@ def check_MACHO_BRANCH_PROTECTION(binary) -> bool:
 
 CHECKS = {
     lief.EXE_FORMATS.ELF: {
-        lief.ARCHITECTURES.X86: BASE_ELF + [('CONTROL_FLOW', check_ELF_CONTROL_FLOW)],
-        lief.ARCHITECTURES.ARM: BASE_ELF,
-        lief.ARCHITECTURES.ARM64: BASE_ELF,
-        lief.ARCHITECTURES.PPC: BASE_ELF,
-        lief.ARCHITECTURES.RISCV: BASE_ELF,
+        lief.ARCHITECTURES.X86: BASE_ELF + [('CONTROL_FLOW', check_ELF_CONTROL_FLOW), ('FORTIFY', check_ELF_FORTIFY)],
+        lief.ARCHITECTURES.ARM: BASE_ELF + [('FORTIFY', check_ELF_FORTIFY)],
+        lief.ARCHITECTURES.ARM64: BASE_ELF + [('FORTIFY', check_ELF_FORTIFY)],
+        lief.ARCHITECTURES.PPC: BASE_ELF + [('FORTIFY', check_ELF_FORTIFY)],
+        lief.ARCHITECTURES.RISCV: BASE_ELF, # Skip FORTIFY. See https://github.com/lief-project/LIEF/issues/1082.
     },
     lief.EXE_FORMATS.PE: {
         lief.ARCHITECTURES.X86: BASE_PE,

contrib/devtools/test-security-check.py

@@ -59,17 +59,22 @@ def test_ELF(self):
         arch = get_arch(cxx, source, executable)
 
         if arch == lief.ARCHITECTURES.X86:
-            pass_flags = ['-Wl,-znoexecstack', '-Wl,-zrelro', '-Wl,-z,now', '-pie', '-fPIE', '-Wl,-z,separate-code', '-fcf-protection=full']
+            pass_flags = ['-D_FORTIFY_SOURCE=3', '-Wl,-znoexecstack', '-Wl,-zrelro', '-Wl,-z,now', '-pie', '-fPIE', '-Wl,-z,separate-code', '-fcf-protection=full']
             self.assertEqual(call_security_check(cxx, source, executable, pass_flags + ['-Wl,-zexecstack']), (1, executable + ': failed NX'))
             self.assertEqual(call_security_check(cxx, source, executable, pass_flags + ['-no-pie','-fno-PIE']), (1, executable + ': failed PIE'))
             self.assertEqual(call_security_check(cxx, source, executable, pass_flags + ['-Wl,-znorelro']), (1, executable + ': failed RELRO'))
             self.assertEqual(call_security_check(cxx, source, executable, pass_flags + ['-Wl,-z,noseparate-code']), (1, executable + ': failed SEPARATE_CODE'))
             self.assertEqual(call_security_check(cxx, source, executable, pass_flags + ['-fcf-protection=none']), (1, executable + ': failed CONTROL_FLOW'))
+            self.assertEqual(call_security_check(cxx, source, executable, pass_flags + ['-U_FORTIFY_SOURCE']), (1, executable + ': failed FORTIFY'))
             self.assertEqual(call_security_check(cxx, source, executable, pass_flags), (0, ''))
         else:
-            pass_flags = ['-Wl,-znoexecstack', '-Wl,-zrelro', '-Wl,-z,now', '-pie', '-fPIE', '-Wl,-z,separate-code']
+            pass_flags = ['-D_FORTIFY_SOURCE=3', '-Wl,-znoexecstack', '-Wl,-zrelro', '-Wl,-z,now', '-pie', '-fPIE', '-Wl,-z,separate-code']
             self.assertEqual(call_security_check(cxx, source, executable, pass_flags + ['-Wl,-zexecstack']), (1, executable + ': failed NX'))
-            self.assertEqual(call_security_check(cxx, source, executable, pass_flags + ['-no-pie','-fno-PIE']), (1, executable + ': failed PIE'))
+            # LIEF fails to parse RISC-V with no PIE correctly, and doesn't detect the fortified function,
+            # so skip this test for RISC-V (for now). See https://github.com/lief-project/LIEF/issues/1082.
+            if arch != lief.ARCHITECTURES.RISCV:
+                self.assertEqual(call_security_check(cxx, source, executable, pass_flags + ['-no-pie','-fno-PIE']), (1, executable + ': failed PIE'))
+                self.assertEqual(call_security_check(cxx, source, executable, pass_flags + ['-U_FORTIFY_SOURCE']), (1, executable + ': failed FORTIFY'))
             self.assertEqual(call_security_check(cxx, source, executable, pass_flags + ['-Wl,-znorelro']), (1, executable + ': failed RELRO'))
             self.assertEqual(call_security_check(cxx, source, executable, pass_flags + ['-Wl,-z,noseparate-code']), (1, executable + ': failed SEPARATE_CODE'))
             self.assertEqual(call_security_check(cxx, source, executable, pass_flags), (0, ''))