From abe696877ba789a05e2ebe64c88a6d0d2e0f7a87 Mon Sep 17 00:00:00 2001
From: chrchr <christian.riesch@live.com>
Date: Mon, 12 Sep 2022 15:57:37 +0200
Subject: [PATCH] Fix #1655 wrong usage of std::string in memcpy

---
 lib/checkclass.cpp | 21 +++++++++++++--------
 lib/checkclass.h   |  2 +-
 test/testclass.cpp | 10 ++++++++++
 3 files changed, 24 insertions(+), 9 deletions(-)

diff --git a/lib/checkclass.cpp b/lib/checkclass.cpp
index d081afb12c0..cce0e0fc25e 100644
--- a/lib/checkclass.cpp
+++ b/lib/checkclass.cpp
@@ -1353,6 +1353,10 @@ void CheckClass::checkMemset()
 
                         if (numIndirToVariableType == 1)
                             type = var->typeScope();
+
+                        if (!type && mSettings->library.detectContainerOrIterator(var->typeStartToken())) {
+                            memsetError(tok, tok->str(), var->getTypeName(), {}, /*isContainer*/ true);
+                        }
                     }
                 }
 
@@ -1468,15 +1472,16 @@ void CheckClass::mallocOnClassError(const Token* tok, const std::string &memfunc
                 "since no constructor is called and class members remain uninitialized. Consider using 'new' instead.", CWE665, Certainty::normal);
 }
 
-void CheckClass::memsetError(const Token *tok, const std::string &memfunc, const std::string &classname, const std::string &type)
+void CheckClass::memsetError(const Token *tok, const std::string &memfunc, const std::string &classname, const std::string &type, bool isContainer)
 {
-    reportError(tok, Severity::error, "memsetClass",
-                "$symbol:" + memfunc +"\n"
-                "$symbol:" + classname +"\n"
-                "Using '" + memfunc + "' on " + type + " that contains a " + classname + ".\n"
-                "Using '" + memfunc + "' on " + type + " that contains a " + classname + " is unsafe, because constructor, destructor "
-                "and copy operator calls are omitted. These are necessary for this non-POD type to ensure that a valid object "
-                "is created.", CWE762, Certainty::normal);
+    const std::string typeStr = isContainer ? std::string() : (type + " that contains a ");
+    const std::string msg = "$symbol:" + memfunc + "\n"
+                            "$symbol:" + classname + "\n"
+                            "Using '" + memfunc + "' on " + typeStr + classname + ".\n"
+                            "Using '" + memfunc + "' on " + typeStr + classname + " is unsafe, because constructor, destructor "
+                            "and copy operator calls are omitted. These are necessary for this non-POD type to ensure that a valid object "
+                            "is created.";
+    reportError(tok, Severity::error, "memsetClass", msg, CWE762, Certainty::normal);
 }
 
 void CheckClass::memsetErrorReference(const Token *tok, const std::string &memfunc, const std::string &type)
diff --git a/lib/checkclass.h b/lib/checkclass.h
index cc7bcf9cd7a..19e2ca07709 100644
--- a/lib/checkclass.h
+++ b/lib/checkclass.h
@@ -206,7 +206,7 @@ class CPPCHECKLIB CheckClass : public Check {
     void missingMemberCopyError(const Token *tok, Function::Type functionType, const std::string& classname, const std::string& varname);
     void operatorEqVarError(const Token *tok, const std::string &classname, const std::string &varname, bool inconclusive);
     void unusedPrivateFunctionError(const Token *tok, const std::string &classname, const std::string &funcname);
-    void memsetError(const Token *tok, const std::string &memfunc, const std::string &classname, const std::string &type);
+    void memsetError(const Token *tok, const std::string &memfunc, const std::string &classname, const std::string &type, bool isContainer = false);
     void memsetErrorReference(const Token *tok, const std::string &memfunc, const std::string &type);
     void memsetErrorFloat(const Token *tok, const std::string &type);
     void mallocOnClassError(const Token* tok, const std::string &memfunc, const Token* classTok, const std::string &classname);
diff --git a/test/testclass.cpp b/test/testclass.cpp
index 2aa74cedd11..683739cc131 100644
--- a/test/testclass.cpp
+++ b/test/testclass.cpp
@@ -3109,6 +3109,16 @@ class TestClass : public TestFixture {
                       "  memset(b, 0, sizeof(b));\n"
                       "}");
         ASSERT_EQUALS("", errout.str());
+
+        // #1655
+        Settings s;
+        LOAD_LIB_2(s.library, "std.cfg");
+        checkNoMemset("void f() {\n"
+                      "    char c[] = \"abc\";\n"
+                      "    std::string s;\n"
+                      "    memcpy(&s, c, strlen(c) + 1);\n"
+                      "}\n", s);
+        ASSERT_EQUALS("[test.cpp:4]: (error) Using 'memcpy' on std::string.\n", errout.str());
     }
 
     void memsetOnInvalid() { // Ticket #5425