StringCompareRule: add NULL check

moevm · May 14, 2024 · 0748849 · 0748849
1 parent f922e1a
commit 0748849
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Showing 2 changed files with 15 additions and 1 deletion.
diff --git a/examples/ex-string-compare/main.c b/examples/ex-string-compare/main.c
@@ -10,6 +10,10 @@ void wide_strings()
  wchar_t str1[32] = L"Hello";
  wchar_t *str2 = wcsdup(L"World");
 
+ if (str2 == NULL) {
+ abort();
+ }
+
  if (str1 == str2) {
  puts("One");
  }
@@ -40,6 +44,10 @@ void compare_const_and_not_const()
 {
  char *str = (char*)malloc(1024 * sizeof(char));
 
+ if (str == NULL) {
+ abort();
+ }
+
  scanf("%1023s", str);
  if (str == "Bad!") {
  puts("Something");

diff --git a/rules/StringCompareRule.cpp b/rules/StringCompareRule.cpp
@@ -1,6 +1,7 @@
 #include "oclint/AbstractASTVisitorRule.h"
 #include "oclint/RuleConfiguration.h"
 #include "oclint/RuleSet.h"
+#include "clang/Basic/Specifiers.h"
 #include <iostream>
 
 namespace oclint {
@@ -83,6 +84,11 @@ namespace oclint {
  return type->isAnyCharacterType() || type.getAsString() == "wchar_t";
  }
 
+ bool IsNull(clang::Expr *expr)
+ {
+ return expr->isNullPointerConstant(*this->_carrier->getASTContext(), clang::Expr::NPC_ValueDependentIsNotNull);
+ }
+
  const char *OpcodeAsString(Opcode opcode)
  {
  switch (opcode) {
@@ -105,7 +111,7 @@ namespace oclint {
  clang::Expr *left = binop->getLHS();
  clang::Expr *right = binop->getRHS();
 
- if (IsString(left) || IsString(right))
+ if (!IsNull(left) && !IsNull(right) && (IsString(left) || IsString(right)))
  addViolation(binop, this, std::string("comparing 2 strings by using ") + OpcodeAsString(opcode) + ".");
 
  return true;