Make HashContexts serializable.

* Modify php_hash_ops to contain the algorithm name and
  serialize and unserialize methods.
* Implement __serialize and __unserialize magic methods on
  HashContext.

Note that serialized HashContexts are not necessarily portable
between PHP versions or from architecture to architecture.
(Most are, but fast SHA3s are not necessarily.)

A ValueError is thrown when an unsupported serialization is
attempted.

Because of security concerns, HASH_HMAC contexts are not
currently serializable; attempting to serialize one throws
an error.

Serialization exposes the state of HashContext memory, so ensure
that memory is zeroed before use by allocating it with a new
php_hash_alloc_context function. Performance impact is
negligible.

Author: kohler

ext/hash/hash.c

@@ -53,4 +53,8 @@ function mhash(int $hash, string $data, string $key = UNKNOWN): string|false {}
 final class HashContext
 {
     private function __construct() {}
+
+    public function __serialize(): array {}
+
+    public function __unserialize(array $serialized): void {}
 }

ext/hash/hash.stub.php

@@ -59,10 +59,14 @@ PHP_HASH_API int PHP_ADLER32Copy(const php_hash_ops *ops, PHP_ADLER32_CTX *orig_
 }
 
 const php_hash_ops php_hash_adler32_ops = {
+	"adler32",
 	(php_hash_init_func_t) PHP_ADLER32Init,
 	(php_hash_update_func_t) PHP_ADLER32Update,
 	(php_hash_final_func_t) PHP_ADLER32Final,
 	(php_hash_copy_func_t) PHP_ADLER32Copy,
+	php_hash_serialize,
+	php_hash_unserialize,
+	PHP_ADLER32_SPEC,
 	4, /* what to say here? */
 	4,
 	sizeof(PHP_ADLER32_CTX),

ext/hash/hash_adler32.c

@@ -117,6 +117,12 @@ ZEND_END_ARG_INFO()
 ZEND_BEGIN_ARG_INFO_EX(arginfo_class_HashContext___construct, 0, 0, 0)
 ZEND_END_ARG_INFO()
 
+#define arginfo_class_HashContext___serialize arginfo_hash_algos
+
+ZEND_BEGIN_ARG_WITH_RETURN_TYPE_INFO_EX(arginfo_class_HashContext___unserialize, 0, 1, IS_VOID, 0)
+	ZEND_ARG_TYPE_INFO(0, serialized, IS_ARRAY, 0)
+ZEND_END_ARG_INFO()
+
 
 ZEND_FUNCTION(hash);
 ZEND_FUNCTION(hash_file);
@@ -149,6 +155,8 @@ ZEND_FUNCTION(mhash_count);
 ZEND_FUNCTION(mhash);
 #endif
 ZEND_METHOD(HashContext, __construct);
+ZEND_METHOD(HashContext, __serialize);
+ZEND_METHOD(HashContext, __unserialize);
 
 
 static const zend_function_entry ext_functions[] = {
@@ -188,5 +196,7 @@ static const zend_function_entry ext_functions[] = {
 
 static const zend_function_entry class_HashContext_methods[] = {
 	ZEND_ME(HashContext, __construct, arginfo_class_HashContext___construct, ZEND_ACC_PRIVATE)
+	ZEND_ME(HashContext, __serialize, arginfo_class_HashContext___serialize, ZEND_ACC_PUBLIC)
+	ZEND_ME(HashContext, __unserialize, arginfo_class_HashContext___unserialize, ZEND_ACC_PUBLIC)
 	ZEND_FE_END
 };

ext/hash/hash_arginfo.h

@@ -78,32 +78,44 @@ PHP_HASH_API int PHP_CRC32Copy(const php_hash_ops *ops, PHP_CRC32_CTX *orig_cont
 }
 
 const php_hash_ops php_hash_crc32_ops = {
+	"crc32",
 	(php_hash_init_func_t) PHP_CRC32Init,
 	(php_hash_update_func_t) PHP_CRC32Update,
 	(php_hash_final_func_t) PHP_CRC32LEFinal,
 	(php_hash_copy_func_t) PHP_CRC32Copy,
+	php_hash_serialize,
+	php_hash_unserialize,
+	PHP_CRC32_SPEC,
 	4, /* what to say here? */
 	4,
 	sizeof(PHP_CRC32_CTX),
 	0
 };
 
 const php_hash_ops php_hash_crc32b_ops = {
+	"crc32b",
 	(php_hash_init_func_t) PHP_CRC32Init,
 	(php_hash_update_func_t) PHP_CRC32BUpdate,
 	(php_hash_final_func_t) PHP_CRC32BEFinal,
 	(php_hash_copy_func_t) PHP_CRC32Copy,
+	php_hash_serialize,
+	php_hash_unserialize,
+	PHP_CRC32_SPEC,
 	4, /* what to say here? */
 	4,
 	sizeof(PHP_CRC32_CTX),
 	0
 };
 
 const php_hash_ops php_hash_crc32c_ops = {
+	"crc32c",
 	(php_hash_init_func_t) PHP_CRC32Init,
 	(php_hash_update_func_t) PHP_CRC32CUpdate,
 	(php_hash_final_func_t) PHP_CRC32BEFinal,
 	(php_hash_copy_func_t) PHP_CRC32Copy,
+	php_hash_serialize,
+	php_hash_unserialize,
+	PHP_CRC32_SPEC,
 	4, /* what to say here? */
 	4,
 	sizeof(PHP_CRC32_CTX),

ext/hash/hash_crc32.c

@@ -21,43 +21,59 @@
 #include "php_hash_fnv.h"
 
 const php_hash_ops php_hash_fnv132_ops = {
+	"fnv132",
 	(php_hash_init_func_t) PHP_FNV132Init,
 	(php_hash_update_func_t) PHP_FNV132Update,
 	(php_hash_final_func_t) PHP_FNV132Final,
-	(php_hash_copy_func_t) php_hash_copy,
+	php_hash_copy,
+	php_hash_serialize,
+	php_hash_unserialize,
+	PHP_FNV132_SPEC,
 	4,
 	4,
 	sizeof(PHP_FNV132_CTX),
 	0
 };
 
 const php_hash_ops php_hash_fnv1a32_ops = {
+	"fnv1a32",
 	(php_hash_init_func_t) PHP_FNV132Init,
 	(php_hash_update_func_t) PHP_FNV1a32Update,
- 	(php_hash_final_func_t) PHP_FNV132Final,
-	(php_hash_copy_func_t) php_hash_copy,
+	(php_hash_final_func_t) PHP_FNV132Final,
+	php_hash_copy,
+	php_hash_serialize,
+	php_hash_unserialize,
+	PHP_FNV132_SPEC,
 	4,
 	4,
 	sizeof(PHP_FNV132_CTX),
 	0
 };
 
 const php_hash_ops php_hash_fnv164_ops = {
+	"fnv164",
 	(php_hash_init_func_t) PHP_FNV164Init,
 	(php_hash_update_func_t) PHP_FNV164Update,
 	(php_hash_final_func_t) PHP_FNV164Final,
-	(php_hash_copy_func_t) php_hash_copy,
+	php_hash_copy,
+	php_hash_serialize,
+	php_hash_unserialize,
+	PHP_FNV164_SPEC,
 	8,
 	4,
 	sizeof(PHP_FNV164_CTX),
 	0
 };
 
 const php_hash_ops php_hash_fnv1a64_ops = {
+	"fnv1a64",
 	(php_hash_init_func_t) PHP_FNV164Init,
 	(php_hash_update_func_t) PHP_FNV1a64Update,
- 	(php_hash_final_func_t) PHP_FNV164Final,
-	(php_hash_copy_func_t) php_hash_copy,
+	(php_hash_final_func_t) PHP_FNV164Final,
+	php_hash_copy,
+	php_hash_serialize,
+	php_hash_unserialize,
+	PHP_FNV164_SPEC,
 	8,
 	4,
 	sizeof(PHP_FNV164_CTX),

ext/hash/hash_fnv.c

@@ -305,21 +305,29 @@ PHP_HASH_API void PHP_GOSTFinal(unsigned char digest[32], PHP_GOST_CTX *context)
 }
 
 const php_hash_ops php_hash_gost_ops = {
+	"gost",
 	(php_hash_init_func_t) PHP_GOSTInit,
 	(php_hash_update_func_t) PHP_GOSTUpdate,
 	(php_hash_final_func_t) PHP_GOSTFinal,
-	(php_hash_copy_func_t) php_hash_copy,
+	php_hash_copy,
+	php_hash_serialize,
+	php_hash_unserialize,
+	PHP_GOST_SPEC,
 	32,
 	32,
 	sizeof(PHP_GOST_CTX),
 	1
 };
 
 const php_hash_ops php_hash_gost_crypto_ops = {
+	"gost-crypto",
 	(php_hash_init_func_t) PHP_GOSTInitCrypto,
 	(php_hash_update_func_t) PHP_GOSTUpdate,
 	(php_hash_final_func_t) PHP_GOSTFinal,
-	(php_hash_copy_func_t) php_hash_copy,
+	php_hash_copy,
+	php_hash_serialize,
+	php_hash_unserialize,
+	PHP_GOST_SPEC,
 	32,
 	32,
 	sizeof(PHP_GOST_CTX),

ext/hash/hash_gost.c

@@ -247,10 +247,14 @@ static void PHP_5HAVALTransform(uint32_t state[8], const unsigned char block[128
 
 #define PHP_HASH_HAVAL_INIT(p,b) \
 const php_hash_ops php_hash_##p##haval##b##_ops = { \
+	"haval" #b "," #p, \
 	(php_hash_init_func_t) PHP_##p##HAVAL##b##Init, \
 	(php_hash_update_func_t) PHP_HAVALUpdate, \
 	(php_hash_final_func_t) PHP_HAVAL##b##Final, \
-	(php_hash_copy_func_t) php_hash_copy, \
+	php_hash_copy, \
+	php_hash_serialize, \
+	php_hash_unserialize, \
+	PHP_HAVAL_SPEC, \
 	((b) / 8), 128, sizeof(PHP_HAVAL_CTX), 1 }; \
 PHP_HASH_API void PHP_##p##HAVAL##b##Init(PHP_HAVAL_CTX *context) \
 {	int i; context->count[0] = 	context->count[1] = 	0; \

ext/hash/hash_haval.c

@@ -22,10 +22,14 @@
 #include "php_hash_joaat.h"
 
 const php_hash_ops php_hash_joaat_ops = {
+	"joaat",
 	(php_hash_init_func_t) PHP_JOAATInit,
 	(php_hash_update_func_t) PHP_JOAATUpdate,
 	(php_hash_final_func_t) PHP_JOAATFinal,
-	(php_hash_copy_func_t) php_hash_copy,
+	php_hash_copy,
+	php_hash_serialize,
+	php_hash_unserialize,
+	PHP_JOAAT_SPEC,
 	4,
 	4,
 	sizeof(PHP_JOAAT_CTX),

ext/hash/hash_joaat.c

@@ -18,32 +18,44 @@
 #include "php_hash_md.h"
 
 const php_hash_ops php_hash_md5_ops = {
+	"md5",
 	(php_hash_init_func_t) PHP_MD5Init,
 	(php_hash_update_func_t) PHP_MD5Update,
 	(php_hash_final_func_t) PHP_MD5Final,
-	(php_hash_copy_func_t) php_hash_copy,
+	php_hash_copy,
+	php_hash_serialize,
+	php_hash_unserialize,
+	PHP_MD5_SPEC,
 	16,
 	64,
 	sizeof(PHP_MD5_CTX),
 	1
 };
 
 const php_hash_ops php_hash_md4_ops = {
+	"md4",
 	(php_hash_init_func_t) PHP_MD4Init,
 	(php_hash_update_func_t) PHP_MD4Update,
 	(php_hash_final_func_t) PHP_MD4Final,
-	(php_hash_copy_func_t) php_hash_copy,
+	php_hash_copy,
+	php_hash_serialize,
+	php_hash_unserialize,
+	PHP_MD4_SPEC,
 	16,
 	64,
 	sizeof(PHP_MD4_CTX),
 	1
 };
 
 const php_hash_ops php_hash_md2_ops = {
+	"md2",
 	(php_hash_init_func_t) PHP_MD2Init,
 	(php_hash_update_func_t) PHP_MD2Update,
 	(php_hash_final_func_t) PHP_MD2Final,
-	(php_hash_copy_func_t) php_hash_copy,
+	php_hash_copy,
+	php_hash_serialize,
+	php_hash_unserialize,
+	PHP_MD2_SPEC,
 	16,
 	16,
 	sizeof(PHP_MD2_CTX),