Merge #18796: scripts: security-check.py refactors

eacedfb0230978748cbcfb13817fed7e7c756ba7 scripts: add additional type annotations to security-check.py (fanquake)
83d063e9541cc9ea41ea86919eb9435c73efb14e scripts: add run_command to security-check.py (fanquake)
13f606b4f940e5820ff21ea62fc27a5a91774b05 scripts: remove NONFATAL from security-check.py (fanquake)
061acf62a15ad3dbb9f055b7c2569b9832ed623a scripts: no-longer check for 32 bit windows in security-check.py (fanquake)

Pull request description:

  * Remove 32-bit Windows checks.
  * Remove NONFATAL checking. Added in #8249, however unused since #13764.
  * Add `run_command` to de-duplicate all of the subprocess calls. Mentioned in #18713.
  * Add additional type annotations.
  * Print stderr when there is an issue running a command.

ACKs for top commit:
  laanwj:
    ACK eacedfb0230978748cbcfb13817fed7e7c756ba7

Tree-SHA512: 69a7ccfdf346ee202b3e8f940634c5daed1d2b5a5d15ac9800252866ba3284ec66e391a66a0b341f5a4e5e8482fe1b614d4671e8e766112ff059405081184a85
This commit is contained in:
Wladimir J. van der Laan 2020-05-14 19:59:54 +02:00 committed by pasta
parent f7a94b58d4
commit 33c473a8e3
No known key found for this signature in database
GPG Key ID: 52527BEDABE87984

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@ -12,33 +12,33 @@ import subprocess
import sys
import os
from typing import List, Optional
READELF_CMD = os.getenv('READELF', '/usr/bin/readelf')
OBJDUMP_CMD = os.getenv('OBJDUMP', '/usr/bin/objdump')
OTOOL_CMD = os.getenv('OTOOL', '/usr/bin/otool')
NONFATAL = {} # checks which are non-fatal for now but only generate a warning
def check_ELF_PIE(executable):
def run_command(command) -> str:
p = subprocess.run(command, stdout=subprocess.PIPE, check=True, universal_newlines=True)
return p.stdout
def check_ELF_PIE(executable) -> bool:
'''
Check for position independent executable (PIE), allowing for address space randomization.
'''
p = subprocess.Popen([READELF_CMD, '-h', '-W', executable], stdout=subprocess.PIPE, stderr=subprocess.PIPE, stdin=subprocess.PIPE, universal_newlines=True)
(stdout, stderr) = p.communicate()
if p.returncode:
raise IOError('Error opening file')
stdout = run_command([READELF_CMD, '-h', '-W', executable])
ok = False
for line in stdout.splitlines():
line = line.split()
if len(line)>=2 and line[0] == 'Type:' and line[1] == 'DYN':
tokens = line.split()
if len(line)>=2 and tokens[0] == 'Type:' and tokens[1] == 'DYN':
ok = True
return ok
def get_ELF_program_headers(executable):
'''Return type and flags for ELF program headers'''
p = subprocess.Popen([READELF_CMD, '-l', '-W', executable], stdout=subprocess.PIPE, stderr=subprocess.PIPE, stdin=subprocess.PIPE, universal_newlines=True)
(stdout, stderr) = p.communicate()
if p.returncode:
raise IOError('Error opening file')
stdout = run_command([READELF_CMD, '-l', '-W', executable])
in_headers = False
count = 0
headers = []
@ -62,7 +62,7 @@ def get_ELF_program_headers(executable):
count += 1
return headers
def check_ELF_NX(executable):
def check_ELF_NX(executable) -> bool:
'''
Check that no sections are writable and executable (including the stack)
'''
@ -75,7 +75,7 @@ def check_ELF_NX(executable):
have_wx = True
return have_gnu_stack and not have_wx
def check_ELF_RELRO(executable):
def check_ELF_RELRO(executable) -> bool:
'''
Check for read-only relocations.
GNU_RELRO program header must exist
@ -84,7 +84,8 @@ def check_ELF_RELRO(executable):
have_gnu_relro = False
for (typ, flags) in get_ELF_program_headers(executable):
# Note: not checking flags == 'R': here as linkers set the permission differently
# This does not affect security: the permission flags of the GNU_RELRO program header are ignored, the PT_LOAD header determines the effective permissions.
# This does not affect security: the permission flags of the GNU_RELRO program
# header are ignored, the PT_LOAD header determines the effective permissions.
# However, the dynamic linker need to write to this area so these are RW.
# Glibc itself takes care of mprotecting this area R after relocations are finished.
# See also https://marc.info/?l=binutils&m=1498883354122353
@ -92,93 +93,69 @@ def check_ELF_RELRO(executable):
have_gnu_relro = True
have_bindnow = False
p = subprocess.Popen([READELF_CMD, '-d', '-W', executable], stdout=subprocess.PIPE, stderr=subprocess.PIPE, stdin=subprocess.PIPE, universal_newlines=True)
(stdout, stderr) = p.communicate()
if p.returncode:
raise IOError('Error opening file')
stdout = run_command([READELF_CMD, '-d', '-W', executable])
for line in stdout.splitlines():
tokens = line.split()
if len(tokens)>1 and tokens[1] == '(BIND_NOW)' or (len(tokens)>2 and tokens[1] == '(FLAGS)' and 'BIND_NOW' in tokens[2:]):
have_bindnow = True
return have_gnu_relro and have_bindnow
def check_ELF_Canary(executable):
def check_ELF_Canary(executable) -> bool:
'''
Check for use of stack canary
'''
p = subprocess.Popen([READELF_CMD, '--dyn-syms', '-W', executable], stdout=subprocess.PIPE, stderr=subprocess.PIPE, stdin=subprocess.PIPE, universal_newlines=True)
(stdout, stderr) = p.communicate()
if p.returncode:
raise IOError('Error opening file')
stdout = run_command([READELF_CMD, '--dyn-syms', '-W', executable])
ok = False
for line in stdout.splitlines():
if '__stack_chk_fail' in line:
ok = True
return ok
def get_PE_dll_characteristics(executable):
'''
Get PE DllCharacteristics bits.
Returns a tuple (arch,bits) where arch is 'i386:x86-64' or 'i386'
and bits is the DllCharacteristics value.
'''
p = subprocess.Popen([OBJDUMP_CMD, '-x', executable], stdout=subprocess.PIPE, stderr=subprocess.PIPE, stdin=subprocess.PIPE, universal_newlines=True)
(stdout, stderr) = p.communicate()
if p.returncode:
raise IOError('Error opening file')
arch = ''
def get_PE_dll_characteristics(executable) -> int:
'''Get PE DllCharacteristics bits'''
stdout = run_command([OBJDUMP_CMD, '-x', executable])
bits = 0
for line in stdout.splitlines():
tokens = line.split()
if len(tokens)>=2 and tokens[0] == 'architecture:':
arch = tokens[1].rstrip(',')
if len(tokens)>=2 and tokens[0] == 'DllCharacteristics':
bits = int(tokens[1],16)
return (arch,bits)
return bits
IMAGE_DLL_CHARACTERISTICS_HIGH_ENTROPY_VA = 0x0020
IMAGE_DLL_CHARACTERISTICS_DYNAMIC_BASE = 0x0040
IMAGE_DLL_CHARACTERISTICS_NX_COMPAT = 0x0100
def check_PE_DYNAMIC_BASE(executable):
def check_PE_DYNAMIC_BASE(executable) -> bool:
'''PIE: DllCharacteristics bit 0x40 signifies dynamicbase (ASLR)'''
(arch,bits) = get_PE_dll_characteristics(executable)
reqbits = IMAGE_DLL_CHARACTERISTICS_DYNAMIC_BASE
return (bits & reqbits) == reqbits
bits = get_PE_dll_characteristics(executable)
return (bits & IMAGE_DLL_CHARACTERISTICS_DYNAMIC_BASE) == IMAGE_DLL_CHARACTERISTICS_DYNAMIC_BASE
# On 64 bit, must support high-entropy 64-bit address space layout randomization in addition to DYNAMIC_BASE
# to have secure ASLR.
def check_PE_HIGH_ENTROPY_VA(executable):
# Must support high-entropy 64-bit address space layout randomization
# in addition to DYNAMIC_BASE to have secure ASLR.
def check_PE_HIGH_ENTROPY_VA(executable) -> bool:
'''PIE: DllCharacteristics bit 0x20 signifies high-entropy ASLR'''
(arch,bits) = get_PE_dll_characteristics(executable)
if arch == 'i386:x86-64':
reqbits = IMAGE_DLL_CHARACTERISTICS_HIGH_ENTROPY_VA
else: # Unnecessary on 32-bit
assert(arch == 'i386')
reqbits = 0
return (bits & reqbits) == reqbits
bits = get_PE_dll_characteristics(executable)
return (bits & IMAGE_DLL_CHARACTERISTICS_HIGH_ENTROPY_VA) == IMAGE_DLL_CHARACTERISTICS_HIGH_ENTROPY_VA
def check_PE_RELOC_SECTION(executable) -> bool:
'''Check for a reloc section. This is required for functional ASLR.'''
p = subprocess.Popen([OBJDUMP_CMD, '-h', executable], stdout=subprocess.PIPE, stderr=subprocess.PIPE, stdin=subprocess.PIPE, universal_newlines=True)
(stdout, stderr) = p.communicate()
if p.returncode:
raise IOError('Error opening file')
stdout = run_command([OBJDUMP_CMD, '-h', executable])
for line in stdout.splitlines():
if '.reloc' in line:
return True
return False
def check_PE_NX(executable):
def check_PE_NX(executable) -> bool:
'''NX: DllCharacteristics bit 0x100 signifies nxcompat (DEP)'''
(arch,bits) = get_PE_dll_characteristics(executable)
bits = get_PE_dll_characteristics(executable)
return (bits & IMAGE_DLL_CHARACTERISTICS_NX_COMPAT) == IMAGE_DLL_CHARACTERISTICS_NX_COMPAT
def get_MACHO_executable_flags(executable):
p = subprocess.Popen([OTOOL_CMD, '-vh', executable], stdout=subprocess.PIPE, stderr=subprocess.PIPE, stdin=subprocess.PIPE, universal_newlines=True)
(stdout, stderr) = p.communicate()
if p.returncode:
raise IOError('Error opening file')
def get_MACHO_executable_flags(executable) -> List[str]:
stdout = run_command([OTOOL_CMD, '-vh', executable])
flags = []
for line in stdout.splitlines():
@ -222,10 +199,7 @@ def check_MACHO_LAZY_BINDINGS(executable) -> bool:
Check for no lazy bindings.
We don't use or check for MH_BINDATLOAD. See #18295.
'''
p = subprocess.Popen([OTOOL_CMD, '-l', executable], stdout=subprocess.PIPE, stderr=subprocess.PIPE, stdin=subprocess.PIPE, universal_newlines=True)
(stdout, stderr) = p.communicate()
if p.returncode:
raise IOError('Error opening file')
stdout = run_command([OTOOL_CMD, '-l', executable])
for line in stdout.splitlines():
tokens = line.split()
@ -238,10 +212,8 @@ def check_MACHO_Canary(executable) -> bool:
'''
Check for use of stack canary
'''
p = subprocess.Popen([OTOOL_CMD, '-Iv', executable], stdout=subprocess.PIPE, stderr=subprocess.PIPE, stdin=subprocess.PIPE, universal_newlines=True)
(stdout, stderr) = p.communicate()
if p.returncode:
raise IOError('Error opening file')
stdout = run_command([OTOOL_CMD, '-Iv', executable])
ok = False
for line in stdout.splitlines():
if '___stack_chk_fail' in line:
@ -270,7 +242,7 @@ CHECKS = {
]
}
def identify_executable(executable):
def identify_executable(executable) -> Optional[str]:
with open(filename, 'rb') as f:
magic = f.read(4)
if magic.startswith(b'MZ'):
@ -292,18 +264,12 @@ if __name__ == '__main__':
continue
failed = []
warning = []
for (name, func) in CHECKS[etype]:
if not func(filename):
if name in NONFATAL:
warning.append(name)
else:
failed.append(name)
failed.append(name)
if failed:
print('%s: failed %s' % (filename, ' '.join(failed)))
retval = 1
if warning:
print('%s: warning %s' % (filename, ' '.join(warning)))
except IOError:
print('%s: cannot open' % filename)
retval = 1