disable xml/curl/g_ string transform compare

vanhauser-thc · vanhauser-thc · commit b6c4f3775a22 · 2024-05-14T12:34:51.000+02:00
diff --git a/docs/Changelog.md b/docs/Changelog.md
@@ -15,6 +15,8 @@
     - re-enable i386 support that was accidently disabled
     - fixes for LTO and outdated afl-gcc mode
     - fix COMPCOV split compare for old LLVMs
+    - disable xml/curl/g_ string transform functions because we do not check
+      for null pointers ... TODO
     - ensure shared memory variables are visible in weird build setups
   * afl-cmin
     - work with input files that have a space
diff --git a/instrumentation/compare-transform-pass.so.cc b/instrumentation/compare-transform-pass.so.cc
@@ -230,38 +230,38 @@ bool CompareTransform::transformCmps(Module &M, const bool processStrcmp,
           if (callInst->getCallingConv() != llvm::CallingConv::C) continue;
           StringRef FuncName = Callee->getName();
           isStrcmp &=
-              (!FuncName.compare("strcmp") || !FuncName.compare("xmlStrcmp") ||
+              (!FuncName.compare("strcmp") /*|| !FuncName.compare("xmlStrcmp") ||
                !FuncName.compare("xmlStrEqual") ||
                !FuncName.compare("curl_strequal") ||
                !FuncName.compare("strcsequal") ||
-               !FuncName.compare("g_strcmp0"));
+               !FuncName.compare("g_strcmp0")*/);
           isMemcmp &=
               (!FuncName.compare("memcmp") || !FuncName.compare("bcmp") ||
                !FuncName.compare("CRYPTO_memcmp") ||
                !FuncName.compare("OPENSSL_memcmp") ||
                !FuncName.compare("memcmp_const_time") ||
                !FuncName.compare("memcmpct"));
-          isStrncmp &= (!FuncName.compare("strncmp") ||
+          isStrncmp &= (!FuncName.compare("strncmp")/* ||
                         !FuncName.compare("curl_strnequal") ||
-                        !FuncName.compare("xmlStrncmp"));
+                        !FuncName.compare("xmlStrncmp")*/);
           isStrcasecmp &= (!FuncName.compare("strcasecmp") ||
                            !FuncName.compare("stricmp") ||
                            !FuncName.compare("ap_cstr_casecmp") ||
                            !FuncName.compare("OPENSSL_strcasecmp") ||
-                           !FuncName.compare("xmlStrcasecmp") ||
+                           /*!FuncName.compare("xmlStrcasecmp") ||
                            !FuncName.compare("g_strcasecmp") ||
                            !FuncName.compare("g_ascii_strcasecmp") ||
                            !FuncName.compare("Curl_strcasecompare") ||
-                           !FuncName.compare("Curl_safe_strcasecompare") ||
+                           !FuncName.compare("Curl_safe_strcasecompare") ||*/
                            !FuncName.compare("cmsstrcasecmp"));
           isStrncasecmp &= (!FuncName.compare("strncasecmp") ||
                             !FuncName.compare("strnicmp") ||
                             !FuncName.compare("ap_cstr_casecmpn") ||
-                            !FuncName.compare("OPENSSL_strncasecmp") ||
+                            !FuncName.compare("OPENSSL_strncasecmp") /*||
                             !FuncName.compare("xmlStrncasecmp") ||
                             !FuncName.compare("g_ascii_strncasecmp") ||
                             !FuncName.compare("Curl_strncasecompare") ||
-                            !FuncName.compare("g_strncasecmp"));
+                            !FuncName.compare("g_strncasecmp")*/);
           isIntMemcpy &= !FuncName.compare("llvm.memcpy.p0i8.p0i8.i64");
 
           if (!isStrcmp && !isMemcmp && !isStrncmp && !isStrcasecmp &&
@@ -465,8 +465,19 @@ bool CompareTransform::transformCmps(Module &M, const bool processStrcmp,
     bool        isCaseInsensitive = false;
     bool        needs_null = false;
     bool        success_is_one = false;
+    bool        nullCheck = false;
     Function   *Callee = callInst->getCalledFunction();
 
+    fprintf(stderr, "%s - %s - %s\n",
+            callInst->getParent()
+                ->getParent()
+                ->getParent()
+                ->getName()
+                .str()
+                .c_str(),
+            callInst->getParent()->getParent()->getName().str().c_str(),
+            Callee ? Callee->getName().str().c_str() : "NULL");
+
     if (Callee) {
 
       if (!Callee->getName().compare("memcmp") ||
@@ -520,6 +531,11 @@ bool CompareTransform::transformCmps(Module &M, const bool processStrcmp,
     }
 
     if (!isSizedcmp) needs_null = true;
+    if (Callee->getName().startswith("g_") ||
+        Callee->getName().startswith("curl_") ||
+        Callee->getName().startswith("Curl_") ||
+        Callee->getName().startswith("xml"))
+      nullCheck = true;
 
     Value *sizedValue = isSizedcmp ? callInst->getArgOperand(2) : NULL;
     bool   isConstSized = sizedValue && isa<ConstantInt>(sizedValue);
@@ -604,8 +620,10 @@ bool CompareTransform::transformCmps(Module &M, const bool processStrcmp,
     /* split before the call instruction */
     BasicBlock *bb = callInst->getParent();
     BasicBlock *end_bb = bb->splitBasicBlock(BasicBlock::iterator(callInst));
-
     BasicBlock *next_lenchk_bb = NULL;
+
+    if (nullCheck) { fprintf(stderr, "TODO: null check\n"); }
+
     if (isSizedcmp && !isConstSized) {
 
       next_lenchk_bb =
