Ensure proper data alignment

Author: dstogov

Zend/zend_alloc.c

@@ -149,8 +149,6 @@ typedef zend_ulong zend_mm_bitset;    /* 4-byte or 8-byte integer */
 	(((size_t)(size)) & ((alignment) - 1))
 #define ZEND_MM_ALIGNED_BASE(size, alignment) \
 	(((size_t)(size)) & ~((alignment) - 1))
-#define ZEND_MM_ALIGNED_SIZE_EX(size, alignment) \
-	(((size_t)(size) + ((alignment) - 1)) & ~((alignment) - 1))
 #define ZEND_MM_SIZE_TO_NUM(size, alignment) \
 	(((size_t)(size) + ((alignment) - 1)) / (alignment))
 

Zend/zend_alloc.h

@@ -42,6 +42,9 @@
 
 #define ZEND_MM_ALIGNED_SIZE(size)	(((size) + ZEND_MM_ALIGNMENT - Z_L(1)) & ZEND_MM_ALIGNMENT_MASK)
 
+#define ZEND_MM_ALIGNED_SIZE_EX(size, alignment) \
+	(((size) + ((alignment) - Z_L(1))) & ~((alignment) - Z_L(1)))
+
 typedef struct _zend_leak_info {
 	void *addr;
 	size_t size;

Zend/zend_string.h

@@ -62,7 +62,7 @@ END_EXTERN_C()
 #define _ZSTR_STRUCT_SIZE(len) (_ZSTR_HEADER_SIZE + len + 1)
 
 #define ZSTR_ALLOCA_ALLOC(str, _len, use_heap) do { \
-	(str) = (zend_string *)do_alloca(ZEND_MM_ALIGNED_SIZE(_ZSTR_STRUCT_SIZE(_len)), (use_heap)); \
+	(str) = (zend_string *)do_alloca(ZEND_MM_ALIGNED_SIZE_EX(_ZSTR_STRUCT_SIZE(_len), 8), (use_heap)); \
 	GC_REFCOUNT(str) = 1; \
 	GC_TYPE_INFO(str) = IS_STRING; \
 	zend_string_forget_hash_val(str); \

ext/opcache/zend_persist.c

@@ -79,6 +79,13 @@ static void zend_hash_persist(HashTable *ht, zend_persist_func_t pPersistElement
 		HT_SET_DATA_ADDR(ht, &uninitialized_bucket);
 		return;
 	}
+	if (ht->nNumUsed == 0) {
+		efree(HT_GET_DATA_ADDR(ht));
+		ht->nTableMask = HT_MIN_MASK;
+		HT_SET_DATA_ADDR(ht, &uninitialized_bucket);
+		ht->u.flags &= ~HASH_FLAG_INITIALIZED;
+		return;
+	}
 	if (ht->u.flags & HASH_FLAG_PACKED) {
 		void *data = HT_GET_DATA_ADDR(ht);
 		zend_accel_store(data, HT_USED_SIZE(ht));
@@ -92,7 +99,11 @@ static void zend_hash_persist(HashTable *ht, zend_persist_func_t pPersistElement
 		while (hash_size >> 1 > ht->nNumUsed) {
 			hash_size >>= 1;
 		}
+		if (hash_size < -HT_MIN_MASK) {
+			hash_size = -HT_MIN_MASK;
+		}
 		ht->nTableMask = -hash_size;
+		ZEND_ASSERT(((zend_uintptr_t)ZCG(mem) & 0x7) == 0); /* should be 8 byte aligned */
 		HT_SET_DATA_ADDR(ht, ZCG(mem));
 		ZCG(mem) = (void*)((char*)ZCG(mem) + ZEND_ALIGNED_SIZE((hash_size * sizeof(uint32_t)) + (ht->nNumUsed * sizeof(Bucket))));
 		HT_HASH_RESET(ht);
@@ -120,6 +131,7 @@ static void zend_hash_persist(HashTable *ht, zend_persist_func_t pPersistElement
 		void *data = ZCG(mem);
 		void *old_data = HT_GET_DATA_ADDR(ht);
 
+		ZEND_ASSERT(((zend_uintptr_t)ZCG(mem) & 0x7) == 0); /* should be 8 byte aligned */
 		ZCG(mem) = (void*)((char*)data + HT_USED_SIZE(ht));
 		memcpy(data, old_data, HT_USED_SIZE(ht));
 		efree(old_data);
@@ -149,6 +161,13 @@ static void zend_hash_persist_immutable(HashTable *ht)
 		HT_SET_DATA_ADDR(ht, &uninitialized_bucket);
 		return;
 	}
+	if (ht->nNumUsed == 0) {
+		efree(HT_GET_DATA_ADDR(ht));
+		ht->nTableMask = HT_MIN_MASK;
+		HT_SET_DATA_ADDR(ht, &uninitialized_bucket);
+		ht->u.flags &= ~HASH_FLAG_INITIALIZED;
+		return;
+	}
 	if (ht->u.flags & HASH_FLAG_PACKED) {
 		HT_SET_DATA_ADDR(ht, zend_accel_memdup(HT_GET_DATA_ADDR(ht), HT_USED_SIZE(ht)));
 	} else if (ht->nNumUsed < -(int32_t)ht->nTableMask / 2) {
@@ -160,7 +179,11 @@ static void zend_hash_persist_immutable(HashTable *ht)
 		while (hash_size >> 1 > ht->nNumUsed) {
 			hash_size >>= 1;
 		}
+		if (hash_size < -HT_MIN_MASK) {
+			hash_size = -HT_MIN_MASK;
+		}
 		ht->nTableMask = -hash_size;
+		ZEND_ASSERT(((zend_uintptr_t)ZCG(mem) & 0x7) == 0); /* should be 8 byte aligned */
 		HT_SET_DATA_ADDR(ht, ZCG(mem));
 		ZCG(mem) = (void*)((char*)ZCG(mem) + (hash_size * sizeof(uint32_t)) + (ht->nNumUsed * sizeof(Bucket)));
 		HT_HASH_RESET(ht);
@@ -187,6 +210,7 @@ static void zend_hash_persist_immutable(HashTable *ht)
 	} else {
 		void *data = ZCG(mem);
 
+		ZEND_ASSERT(((zend_uintptr_t)ZCG(mem) & 0x7) == 0); /* should be 8 byte aligned */
 		ZCG(mem) = (void*)((char*)data + HT_USED_SIZE(ht));
 		memcpy(data, HT_GET_DATA_ADDR(ht), HT_USED_SIZE(ht));
 		HT_SET_DATA_ADDR(ht, data);
@@ -869,6 +893,7 @@ zend_persistent_script *zend_accel_script_persist(zend_persistent_script *script
 {
 	script->mem = ZCG(mem);
 
+	ZEND_ASSERT(((zend_uintptr_t)ZCG(mem) & 0x7) == 0); /* should be 8 byte aligned */
 	zend_shared_alloc_clear_xlat_table();
 
 	zend_accel_store(script, sizeof(zend_persistent_script));
@@ -880,6 +905,8 @@ zend_persistent_script *zend_accel_script_persist(zend_persistent_script *script
 #ifdef __SSE2__
 	/* Align to 64-byte boundary */
 	ZCG(mem) = (void*)(((zend_uintptr_t)ZCG(mem) + 63L) & ~63L);
+#else
+	ZEND_ASSERT(((zend_uintptr_t)ZCG(mem) & 0x7) == 0); /* should be 8 byte aligned */
 #endif
 
 	script->arena_mem = ZCG(arena_mem) = ZCG(mem);

ext/opcache/zend_persist_calc.c

@@ -54,7 +54,7 @@ static void zend_hash_persist_calc(HashTable *ht, void (*pPersistElement)(zval *
 	uint idx;
 	Bucket *p;
 
-	if (!(ht->u.flags & HASH_FLAG_INITIALIZED)) {
+	if (!(ht->u.flags & HASH_FLAG_INITIALIZED) || ht->nNumUsed == 0) {
 		return;
 	}
 
@@ -65,6 +65,9 @@ static void zend_hash_persist_calc(HashTable *ht, void (*pPersistElement)(zval *
 		while (hash_size >> 1 > ht->nNumUsed) {
 			hash_size >>= 1;
 		}
+		if (hash_size < -HT_MIN_MASK) {
+			hash_size = -HT_MIN_MASK;
+		}
 		ADD_SIZE(hash_size * sizeof(uint32_t) + ht->nNumUsed * sizeof(Bucket));
 	} else {
 		ADD_SIZE(HT_USED_SIZE(ht));

ext/opcache/zend_shared_alloc.c

@@ -313,6 +313,7 @@ void *zend_shared_alloc(size_t size)
 			ZSMMG(shared_segments)[i]->pos += block_size;
 			ZSMMG(shared_free) -= block_size;
 			memset(retval, 0, block_size);
+			ZEND_ASSERT(((zend_uintptr_t)retval & 0x7) == 0); /* should be 8 byte aligned */
 			return retval;
 		}
 	}

ext/opcache/zend_shared_alloc.h

@@ -134,13 +134,13 @@ typedef union _align_test {
 } align_test;
 
 #if ZEND_GCC_VERSION >= 2000
-# define PLATFORM_ALIGNMENT (__alignof__ (align_test))
+# define PLATFORM_ALIGNMENT (__alignof__(align_test) < 8 ? 8 : __alignof__(align_test))
 #else
 # define PLATFORM_ALIGNMENT (sizeof(align_test))
 #endif
 
 #define ZEND_ALIGNED_SIZE(size) \
-	((size + PLATFORM_ALIGNMENT - 1) & ~(PLATFORM_ALIGNMENT - 1))
+	ZEND_MM_ALIGNED_SIZE_EX(size, PLATFORM_ALIGNMENT)
 
 /* exclusive locking */
 void zend_shared_alloc_lock(void);