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Fixed false negatives in CheckBufferOverrun::arrayIndexThenCheck()

This commit is contained in:
PKEuS 2017-03-27 11:07:34 +02:00
parent d54744b70e
commit 171e1b8244
2 changed files with 28 additions and 24 deletions
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41
lib/checkbufferoverrun.cpp
View File

@ -1864,35 +1864,28 @@ void CheckBufferOverrun::arrayIndexThenCheck()
}
if (Token::Match(tok, "%name% [ %var% ]")) {
tok = tok->tokAt(2);
const unsigned int indexID = tok->varId();
const std::string& indexName(tok->str());
// skip array index..
tok = tok->tokAt(2);
while (tok && tok->str() == "[")
tok = tok->link()->next();
// syntax error
if (!tok)
return;
// skip comparison
if (tok->tokType() == Token::eComparisonOp)
tok = tok->tokAt(2);
if (!tok)
break;
// skip close parentheses
if (tok->str() == ")")
tok = tok->next();
const unsigned int indexID = tok->next()->varId();
const std::string& indexName(tok->strAt(1));
// Iterate AST upwards
const Token* tok2 = tok;
const Token* tok3 = tok2;
while (tok2->astParent() && tok2->tokType() != Token::eLogicalOp) {
tok3 = tok2;
tok2 = tok2->astParent();
}
// Ensure that we ended at a logical operator and that we came from its left side
if (tok2->tokType() != Token::eLogicalOp || tok2->astOperand1() != tok3)
continue;
// check if array index is ok
// statement can be closed in parentheses, so "(| " is using
if (Token::Match(tok, "&& (| %varid% <|<=", indexID))
if (Token::Match(tok2, "&& (| %varid% <|<=", indexID))
arrayIndexThenCheckError(tok, indexName);
else if (Token::Match(tok, "&& (| %any% >|>= %varid% !!+", indexID))
else if (Token::Match(tok2, "&& (| %any% >|>= %varid% !!+", indexID))
arrayIndexThenCheckError(tok, indexName);
}
}

15
test/testbufferoverrun.cpp
View File

@ -3876,12 +3876,23 @@ private:
"}");
ASSERT_EQUALS("", errout.str());
// this one doesn't work for now, hopefully in the future
check("void f(const int a[], unsigned i) {\n"
" if(a[i] < func(i) && i <= 42) {\n"
" }\n"
"}");
TODO_ASSERT_EQUALS("[test.cpp:2]: (style) Array index 'i' is used before limits check.\n", "", errout.str());
ASSERT_EQUALS("[test.cpp:2]: (style) Array index 'i' is used before limits check.\n", errout.str());
check("void f(const int a[], unsigned i) {\n"
" if (i <= 42 && a[i] < func(i)) {\n"
" }\n"
"}");
ASSERT_EQUALS("", errout.str());
check("void f(const int a[], unsigned i) {\n"
" if (foo(a[i] + 3) < func(i) && i <= 42) {\n"
" }\n"
"}");
ASSERT_EQUALS("[test.cpp:2]: (style) Array index 'i' is used before limits check.\n", errout.str());
check("void f(int i) {\n" // sizeof
" sizeof(a)/sizeof(a[i]) && i < 10;\n"