135 lines
4.4 KiB
Python
135 lines
4.4 KiB
Python
#!/usr/bin/env python
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#
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# Cert: Some extra CERT checkers
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#
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# Cppcheck itself handles many CERT rules. Cppcheck warns when there is undefined behaviour.
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#
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# Example usage of this addon (scan a sourcefile main.cpp)
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# cppcheck --dump main.cpp
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# python cert.py main.cpp.dump
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import cppcheckdata
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import sys
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import re
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def reportError(token, severity, msg, id):
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sys.stderr.write(
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'[' + token.file + ':' + str(token.linenr) + '] (' + severity + '): ' + msg + ' [' + id + ']\n')
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def simpleMatch(token, pattern):
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for p in pattern.split(' '):
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if not token or token.str != p:
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return False
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token = token.next
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return True
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def isUnpackedStruct(var):
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decl = var.typeStartToken
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while decl and decl.isName:
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if decl.str == 'struct':
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structScope = decl.next.typeScope
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if structScope:
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linenr = int(structScope.classStart.linenr)
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for line in open(structScope.classStart.file):
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linenr -= 1
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if linenr == 0:
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return True
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if re.match(r'#pragma\s+pack\s*\(', line):
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return False
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break
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decl = decl.next
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return False
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def isLocalUnpackedStruct(arg):
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if arg and arg.str == '&' and not arg.astOperand2:
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arg = arg.astOperand1
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return arg and arg.variable and (arg.variable.isLocal or arg.variable.isArgument) and isUnpackedStruct(arg.variable)
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def isBitwiseOp(token):
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return token and (token.str in {'&', '|', '^'})
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def isComparisonOp(token):
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return token and (token.str in {'==', '!=', '>', '>=', '<', '<='})
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def isCast(expr):
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if not expr or expr.str != '(' or not expr.astOperand1 or expr.astOperand2:
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return False
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if simpleMatch(expr, '( )'):
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return False
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return True
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# EXP42-C
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# do not compare padding data
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def exp42(data):
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for token in data.tokenlist:
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if token.str != '(' or not token.astOperand1:
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continue
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arg1 = None
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arg2 = None
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if token.astOperand2 and token.astOperand2.str == ',':
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if token.astOperand2.astOperand1 and token.astOperand2.astOperand1.str == ',':
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arg1 = token.astOperand2.astOperand1.astOperand1
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arg2 = token.astOperand2.astOperand1.astOperand2
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if token.astOperand1.str == 'memcmp' and (isLocalUnpackedStruct(arg1) or isLocalUnpackedStruct(arg2)):
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reportError(
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token, 'style', "Comparison of struct padding data " +
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"(fix either by packing the struct using '#pragma pack' or by rewriting the comparison)", 'cert-EXP42-C')
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# EXP46-C
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# Do not use a bitwise operator with a Boolean-like operand
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# int x = (a == b) & c;
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def exp46(data):
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for token in data.tokenlist:
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if isBitwiseOp(token) and (isComparisonOp(token.astOperand1) or isComparisonOp(token.astOperand2)):
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reportError(
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token, 'style', 'Bitwise operator is used with a Boolean-like operand', 'cert-EXP46-c')
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# INT31-C
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# Ensure that integer conversions do not result in lost or misinterpreted data
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def int31(data, platform):
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if not platform:
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return
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for token in data.tokenlist:
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if not isCast(token):
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continue
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if not token.valueType or not token.astOperand1.values:
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continue
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bits = None
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if token.valueType.type == 'char':
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bits = platform.char_bit
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elif token.valueType.type == 'short':
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bits = platform.short_bit
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elif token.valueType.type == 'int':
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bits = platform.int_bit
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elif token.valueType.type == 'long':
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bits = platform.long_bit
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else:
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continue
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if bits >= 64:
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continue
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maxval = (1 << (bits - 1) - 1)
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for value in token.astOperand1.values:
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if value.intvalue > maxval:
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reportError(
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token,
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'style',
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'Loss of information when casting ' + str(value.intvalue) + ' to ' + token.valueType.type,
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'cert-INT31-c')
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for arg in sys.argv[1:]:
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print('Checking ' + arg + '...')
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data = cppcheckdata.parsedump(arg)
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for cfg in data.configurations:
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if len(data.configurations) > 1:
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print('Checking ' + arg + ', config "' + cfg.name + '"...')
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exp42(cfg)
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exp46(cfg)
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int31(cfg, data.platform)
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