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string: obfuscate all byte arrays with alignment of 1 #31

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22 changes: 7 additions & 15 deletions string/StringObfuscation.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -28,15 +28,6 @@ ConstantDataArray *StringObfuscatorPass::encodeStringDataArray(LLVMContext &ctx,
const char *str,
size_t size,
uint8_t key) {
// Check this is a valid string (not containing zeros)
if (str[size - 1] == '\0') {
if (strnlen(str, size) != size - 1)
return nullptr;
} else {
if (strnlen(str, size) != size)
return nullptr;
}

// Encode the data
char *encodedStr = (char *)malloc(size);
for (unsigned int i = 0; i < size; i++) {
Expand Down Expand Up @@ -94,10 +85,11 @@ bool StringObfuscatorPass::encodeAllStrings(Module &M) {

// For each global variable
for (GlobalVariable &gv : M.globals()) {
if (!gv.isConstant() // constant
|| !gv.hasInitializer() // unitialized
|| gv.hasExternalLinkage() // external
|| gv.getSection() == "llvm.metadata") { // Intrinsic Global Variables
if (!gv.isConstant() // constant
|| !gv.hasInitializer() // unitialized
|| gv.hasExternalLinkage() // external
|| gv.getAlign().valueOrOne().value() != 1 // align == 1
|| gv.getSection() == "llvm.metadata") { // Intrinsic Global Variables
//|| gv.getSection().find("__objc_methname") != string::npos) { // TODO :
// is this necessary ?
continue;
Expand All @@ -109,7 +101,7 @@ bool StringObfuscatorPass::encodeAllStrings(Module &M) {
// Encode the value and update the variable
if (isa<ConstantDataArray>(initializer)) { // Global variable
auto array = cast<ConstantDataArray>(initializer);
if (array->isCString()) {
if (array->isString()) {
encodeGlobalString(ctx, &gv, array);
}
} else if (isa<ConstantStruct>(initializer)) { // Variable in a struct
Expand All @@ -118,7 +110,7 @@ bool StringObfuscatorPass::encodeAllStrings(Module &M) {
auto operand = cs->getOperand(i);
if (isa<ConstantDataArray>(operand)) {
auto array = cast<ConstantDataArray>(operand);
if (array->isCString()) {
if (array->isString()) {
encodeStructString(ctx, &gv, cs, array, i);
}
}
Expand Down