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Use zend_long for resource ID
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Currently, resource IDs are limited to 32-bits. As resource IDs
are not reused, this means that resource ID overflow for
long-running processes is very possible.

This patch switches resource IDs to use zend_long instead, which
means that on 64-bit systems, 64-bit resource IDs will be used.
This makes resource ID overflow practically impossible.

The tradeoff is an 8 byte increase in zend_resource size.

Closes GH-7436.
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nikic committed Aug 31, 2021
1 parent 9b170a4 commit 14f599e
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Showing 8 changed files with 15 additions and 10 deletions.
4 changes: 4 additions & 0 deletions UPGRADING.INTERNALS
Original file line number Diff line number Diff line change
Expand Up @@ -9,6 +9,7 @@ PHP 8.1 INTERNALS UPGRADE NOTES
f. Non-serializable classes should use ZEND_ACC_NOT_SERIALIZABLE
g. _zend_hash_find_known_hash renamed to zend_hash_find_known_hash
h. Renaming of ZEND_TYPE_HAS_CLASS() into ZEND_TYPE_IS_COMPLEX()
i. zend_resource handle is now zend_long

2. Build system changes
a. New compiler flags
Expand Down Expand Up @@ -58,6 +59,9 @@ PHP 8.1 INTERNALS UPGRADE NOTES
h. ZEND_TYPE_HAS_CLASS() has been renamed to ZEND_TYPE_IS_COMPLEX() for clarity.
A zend_type element can contain a zend_type_list which might be either a union or an intersection,
or a single class stored as either a zend_string* or a zend_class_entry*.
i. The handle member of zend_resource (the resource ID) now has type zend_long
rather than int. This should be transparent to most code, but uses in
printf may need to switch from "%d" to ZEND_LONG_FMT.

========================
2. Build system changes
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4 changes: 3 additions & 1 deletion Zend/zend_execute.c
Original file line number Diff line number Diff line change
Expand Up @@ -2166,7 +2166,9 @@ static zend_never_inline ZEND_COLD void ZEND_FASTCALL zend_cannot_add_element(vo

ZEND_API ZEND_COLD void ZEND_FASTCALL zend_use_resource_as_offset(const zval *dim)
{
zend_error(E_WARNING, "Resource ID#%d used as offset, casting to integer (%d)", Z_RES_HANDLE_P(dim), Z_RES_HANDLE_P(dim));
zend_error(E_WARNING,
"Resource ID#" ZEND_LONG_FMT " used as offset, casting to integer (" ZEND_LONG_FMT ")",
Z_RES_HANDLE_P(dim), Z_RES_HANDLE_P(dim));
}

static zend_never_inline ZEND_COLD void ZEND_FASTCALL zend_use_new_element_for_string(void)
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5 changes: 2 additions & 3 deletions Zend/zend_list.c
Original file line number Diff line number Diff line change
Expand Up @@ -31,13 +31,12 @@ static HashTable list_destructors;

ZEND_API zval* ZEND_FASTCALL zend_list_insert(void *ptr, int type)
{
int index;
zval zv;

index = zend_hash_next_free_element(&EG(regular_list));
zend_long index = zend_hash_next_free_element(&EG(regular_list));
if (index == 0) {
index = 1;
} else if (index == INT_MAX) {
} else if (index == ZEND_LONG_MAX) {
zend_error_noreturn(E_ERROR, "Resource ID space overflow");
}
ZVAL_NEW_RES(&zv, index, ptr, type);
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2 changes: 1 addition & 1 deletion Zend/zend_types.h
Original file line number Diff line number Diff line change
Expand Up @@ -485,7 +485,7 @@ struct _zend_object {

struct _zend_resource {
zend_refcounted_h gc;
int handle; // TODO: may be removed ???
zend_long handle; // TODO: may be removed ???
int type;
void *ptr;
};
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2 changes: 1 addition & 1 deletion ext/oci8/oci8.c
Original file line number Diff line number Diff line change
Expand Up @@ -1711,7 +1711,7 @@ int php_oci_column_to_zval(php_oci_out_column *column, zval *value, int mode)
descriptor = (php_oci_descriptor *) column->descid->ptr;

if (!descriptor) {
php_error_docref(NULL, E_WARNING, "Unable to find LOB descriptor #%d", column->descid->handle);
php_error_docref(NULL, E_WARNING, "Unable to find LOB descriptor #" ZEND_LONG_FMT, column->descid->handle);
return 1;
}

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2 changes: 1 addition & 1 deletion ext/standard/file.c
Original file line number Diff line number Diff line change
Expand Up @@ -908,7 +908,7 @@ PHPAPI PHP_FUNCTION(fclose)
PHP_STREAM_TO_ZVAL(stream, res);

if ((stream->flags & PHP_STREAM_FLAG_NO_FCLOSE) != 0) {
php_error_docref(NULL, E_WARNING, "%d is not a valid stream resource", stream->res->handle);
php_error_docref(NULL, E_WARNING, ZEND_LONG_FMT " is not a valid stream resource", stream->res->handle);
RETURN_FALSE;
}

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4 changes: 2 additions & 2 deletions ext/standard/var.c
Original file line number Diff line number Diff line change
Expand Up @@ -195,7 +195,7 @@ PHPAPI void php_var_dump(zval *struc, int level) /* {{{ */
}
case IS_RESOURCE: {
const char *type_name = zend_rsrc_list_get_rsrc_type(Z_RES_P(struc));
php_printf("%sresource(%d) of type (%s)\n", COMMON, Z_RES_P(struc)->handle, type_name ? type_name : "Unknown");
php_printf("%sresource(" ZEND_LONG_FMT ") of type (%s)\n", COMMON, Z_RES_P(struc)->handle, type_name ? type_name : "Unknown");
break;
}
case IS_REFERENCE:
Expand Down Expand Up @@ -380,7 +380,7 @@ PHPAPI void php_debug_zval_dump(zval *struc, int level) /* {{{ */
break;
case IS_RESOURCE: {
const char *type_name = zend_rsrc_list_get_rsrc_type(Z_RES_P(struc));
php_printf("resource(%d) of type (%s) refcount(%u)\n", Z_RES_P(struc)->handle, type_name ? type_name : "Unknown", Z_REFCOUNT_P(struc));
php_printf("resource(" ZEND_LONG_FMT ") of type (%s) refcount(%u)\n", Z_RES_P(struc)->handle, type_name ? type_name : "Unknown", Z_REFCOUNT_P(struc));
break;
}
case IS_REFERENCE:
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2 changes: 1 addition & 1 deletion sapi/phpdbg/phpdbg_utils.c
Original file line number Diff line number Diff line change
Expand Up @@ -702,7 +702,7 @@ char *phpdbg_short_zval_print(zval *zv, int maxlen) /* {{{ */
zend_string_release(str);
} break;
case IS_RESOURCE:
spprintf(&decode, 0, "Rsrc #%d", Z_RES_HANDLE_P(zv));
spprintf(&decode, 0, "Rsrc #" ZEND_LONG_FMT, Z_RES_HANDLE_P(zv));
break;
case IS_ARRAY:
spprintf(&decode, 0, "array(%d)", zend_hash_num_elements(Z_ARR_P(zv)));
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