--- dyld/dyld-239.3/src/dyldNew.cpp
+++ dyld/dyld-640.2/src/dyldNew.cpp
@@ -41,7 +41,7 @@
 
 #if __LP64__
 	// room for about ~1000 initial dylibs
-	#define DYLD_POOL_CHUNK_SIZE 224*1024
+	#define DYLD_POOL_CHUNK_SIZE 200*1024
 #else
 	// room for about ~900 initial dylibs
 	#define DYLD_POOL_CHUNK_SIZE 150*1024
@@ -62,12 +62,16 @@
 
 void* malloc(size_t size)
 {
-	if ( dyld::gLibSystemHelpers != NULL) {
+	if ( (dyld::gLibSystemHelpers != NULL) && dyld::gProcessInfo->libSystemInitialized ) {
 		void* p = dyld::gLibSystemHelpers->malloc(size);
 		//dyld::log("malloc(%lu) => %p from libSystem\n", size, p);
 		return p;
 	}
 	else {
+		if ( size > DYLD_POOL_CHUNK_SIZE ) {
+			dyld::log("dyld malloc overflow: size=%lu\n", size);
+			dyld::halt("dyld malloc overflow\n");
+		}
 		size = (size+sizeof(void*)-1) & (-sizeof(void*)); // pointer align
 		uint8_t* result = currentPool->current;
 		currentPool->current += size;
@@ -75,8 +79,7 @@
 			vm_address_t addr = 0;
 			kern_return_t r = vm_allocate(mach_task_self(), &addr, DYLD_POOL_CHUNK_SIZE, VM_FLAGS_ANYWHERE);
 			if ( r != KERN_SUCCESS ) {
-				dyld::log("out of address space for dyld memory pool\n");
-				exit(1);
+				dyld::halt("out of address space for dyld memory pool\n");
 			}
 			dyld_static_pool* newPool = (dyld_static_pool*)addr;
 			newPool->previousPool = NULL;
@@ -86,7 +89,7 @@
 			currentPool = newPool;
 			if ( (currentPool->current + size) > currentPool->end ) {
 				dyld::log("dyld memory pool exhausted: size=%lu\n", size);
-				exit(1);
+				dyld::halt("dyld memory pool exhausted\n");
 			}
 			result = currentPool->current;
 			currentPool->current += size;
@@ -102,8 +105,8 @@
 	// ignore any pointer within dyld (i.e. stuff from pool or static strings)
 	if ( (dyld::gLibSystemHelpers != NULL) && ((ptr < &__dso_handle) || (ptr >= &initialPoolContent[DYLD_POOL_CHUNK_SIZE])) ) {
 		// ignore stuff in any dynamically alloated dyld pools
-		for (dyld_static_pool* p = initialPool.previousPool; p != NULL; p = p->previousPool) {
-			if ( (p->pool < ptr) && (ptr < p->end) ) {
+		for (dyld_static_pool* p = currentPool; p != NULL; p = p->previousPool) {
+			if ( (p->pool <= ptr) && (ptr < p->end) ) {
 				// do nothing, pool entries can't be reclaimed
 				//dyld::log("free(%p) from dynamic pool\n", ptr);
 				return;
@@ -122,13 +125,21 @@
 
 void* calloc(size_t count, size_t size)
 {
+    // Check for overflow of integer multiplication
+    size_t total = count * size;
+    if ( total/count != size ) {
+        dyld::log("dyld calloc overflow: count=%zu, size=%zu\n", count, size);
+        dyld::halt("dyld calloc overflow");
+    }
 	if ( dyld::gLibSystemHelpers != NULL ) {
-		void* result = dyld::gLibSystemHelpers->malloc(size*count);
-		bzero(result, size*count);
+		void* result = dyld::gLibSystemHelpers->malloc(total);
+        if ( result != NULL )
+		    bzero(result, total);
 		return result;
 	}
 	else {
-		return malloc(count*size);
+        // this allocates out of static buffer which is already zero filled
+		return malloc(total);
 	}
 }