Merge tag 'gcc-plugins-v5.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux

Pull gcc-plugins updates from Kees Cook:
 "This adds additional type coverage to the existing structleak plugin
  and adds a large set of selftests to help evaluate stack variable
  zero-initialization coverage.

  That can be used to test whatever instrumentation might be performing
  zero-initialization: either with the structleak plugin or with Clang's
  coming "-ftrivial-auto-var-init=zero" option.

  Summary:

   - Add scalar and array initialization coverage

   - Refactor Kconfig to make options more clear

   - Add self-test module for testing automatic initialization"

* tag 'gcc-plugins-v5.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
  lib: Introduce test_stackinit module
  gcc-plugins: structleak: Generalize to all variable types

6 files changed, 463 insertions, 22 deletions

diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index d765d36f8737..e718487c97c3 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -2016,6 +2016,16 @@ config TEST_OBJAGG
           (or module load).
 
 
+config TEST_STACKINIT
+        tristate "Test level of stack variable initialization"
+        help
+          Test if the kernel is zero-initializing stack variables and
+          padding. Coverage is controlled by compiler flags,
+          CONFIG_GCC_PLUGIN_STRUCTLEAK, CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF,
+          or CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF_ALL.
+
+          If unsure, say N.
+
 endif # RUNTIME_TESTING_MENU
 
 config MEMTEST
diff --git a/lib/Makefile b/lib/Makefile
index c7ae0b3e4535..647517940b29 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -77,6 +77,7 @@ obj-$(CONFIG_TEST_KMOD) += test_kmod.o
 obj-$(CONFIG_TEST_DEBUG_VIRTUAL) += test_debug_virtual.o
 obj-$(CONFIG_TEST_MEMCAT_P) += test_memcat_p.o
 obj-$(CONFIG_TEST_OBJAGG) += test_objagg.o
+obj-$(CONFIG_TEST_STACKINIT) += test_stackinit.o
 
 obj-$(CONFIG_TEST_LIVEPATCH) += livepatch/
 
diff --git a/lib/test_stackinit.c b/lib/test_stackinit.c
new file mode 100644
index 000000000000..13115b6f2b88
--- /dev/null
+++ b/lib/test_stackinit.c
@@ -0,0 +1,378 @@
+// SPDX-Licenses: GPLv2
+/*
+ * Test cases for compiler-based stack variable zeroing via future
+ * compiler flags or CONFIG_GCC_PLUGIN_STRUCTLEAK*.
+ */
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/string.h>
+
+/* Exfiltration buffer. */
+#define MAX_VAR_SIZE    128
+static char check_buf[MAX_VAR_SIZE];
+
+/* Character array to trigger stack protector in all functions. */
+#define VAR_BUFFER       32
+
+/* Volatile mask to convince compiler to copy memory with 0xff. */
+static volatile u8 forced_mask = 0xff;
+
+/* Location and size tracking to validate fill and test are colocated. */
+static void *fill_start, *target_start;
+static size_t fill_size, target_size;
+
+static bool range_contains(char *haystack_start, size_t haystack_size,
+                           char *needle_start, size_t needle_size)
+{
+        if (needle_start >= haystack_start &&
+            needle_start + needle_size <= haystack_start + haystack_size)
+                return true;
+        return false;
+}
+
+#define DO_NOTHING_TYPE_SCALAR(var_type)        var_type
+#define DO_NOTHING_TYPE_STRING(var_type)        void
+#define DO_NOTHING_TYPE_STRUCT(var_type)        void
+
+#define DO_NOTHING_RETURN_SCALAR(ptr)           *(ptr)
+#define DO_NOTHING_RETURN_STRING(ptr)           /**/
+#define DO_NOTHING_RETURN_STRUCT(ptr)           /**/
+
+#define DO_NOTHING_CALL_SCALAR(var, name)                       \
+                (var) = do_nothing_ ## name(&(var))
+#define DO_NOTHING_CALL_STRING(var, name)                       \
+                do_nothing_ ## name(var)
+#define DO_NOTHING_CALL_STRUCT(var, name)                       \
+                do_nothing_ ## name(&(var))
+
+#define FETCH_ARG_SCALAR(var)           &var
+#define FETCH_ARG_STRING(var)           var
+#define FETCH_ARG_STRUCT(var)           &var
+
+#define FILL_SIZE_STRING                16
+
+#define INIT_CLONE_SCALAR               /**/
+#define INIT_CLONE_STRING               [FILL_SIZE_STRING]
+#define INIT_CLONE_STRUCT               /**/
+
+#define INIT_SCALAR_none                /**/
+#define INIT_SCALAR_zero                = 0
+
+#define INIT_STRING_none                [FILL_SIZE_STRING] /**/
+#define INIT_STRING_zero                [FILL_SIZE_STRING] = { }
+
+#define INIT_STRUCT_none                /**/
+#define INIT_STRUCT_zero                = { }
+#define INIT_STRUCT_static_partial      = { .two = 0, }
+#define INIT_STRUCT_static_all          = { .one = arg->one,            \
+                                            .two = arg->two,            \
+                                            .three = arg->three,        \
+                                            .four = arg->four,          \
+                                        }
+#define INIT_STRUCT_dynamic_partial     = { .two = arg->two, }
+#define INIT_STRUCT_dynamic_all         = { .one = arg->one,            \
+                                            .two = arg->two,            \
+                                            .three = arg->three,        \
+                                            .four = arg->four,          \
+                                        }
+#define INIT_STRUCT_runtime_partial     ;                               \
+                                        var.two = 0
+#define INIT_STRUCT_runtime_all         ;                               \
+                                        var.one = 0;                    \
+                                        var.two = 0;                    \
+                                        var.three = 0;                  \
+                                        memset(&var.four, 0,            \
+                                               sizeof(var.four))
+
+/*
+ * @name: unique string name for the test
+ * @var_type: type to be tested for zeroing initialization
+ * @which: is this a SCALAR, STRING, or STRUCT type?
+ * @init_level: what kind of initialization is performed
+ */
+#define DEFINE_TEST_DRIVER(name, var_type, which)               \
+/* Returns 0 on success, 1 on failure. */                       \
+static noinline __init int test_ ## name (void)                 \
+{                                                               \
+        var_type zero INIT_CLONE_ ## which;                     \
+        int ignored;                                            \
+        u8 sum = 0, i;                                          \
+                                                                \
+        /* Notice when a new test is larger than expected. */   \
+        BUILD_BUG_ON(sizeof(zero) > MAX_VAR_SIZE);              \
+                                                                \
+        /* Fill clone type with zero for per-field init. */     \
+        memset(&zero, 0x00, sizeof(zero));                      \
+        /* Fill stack with 0xFF. */                             \
+        ignored = leaf_ ##name((unsigned long)&ignored, 1,      \
+                                FETCH_ARG_ ## which(zero));     \
+        /* Clear entire check buffer for later bit tests. */    \
+        memset(check_buf, 0x00, sizeof(check_buf));             \
+        /* Extract stack-defined variable contents. */          \
+        ignored = leaf_ ##name((unsigned long)&ignored, 0,      \
+                                FETCH_ARG_ ## which(zero));     \
+                                                                \
+        /* Validate that compiler lined up fill and target. */  \
+        if (!range_contains(fill_start, fill_size,              \
+                            target_start, target_size)) {       \
+                pr_err(#name ": stack fill missed target!?\n"); \
+                pr_err(#name ": fill %zu wide\n", fill_size);   \
+                pr_err(#name ": target offset by %d\n", \
+                        (int)((ssize_t)(uintptr_t)fill_start -  \
+                        (ssize_t)(uintptr_t)target_start));     \
+                return 1;                                       \
+        }                                                       \
+                                                                \
+        /* Look for any set bits in the check region. */        \
+        for (i = 0; i < sizeof(check_buf); i++)                 \
+                sum += (check_buf[i] != 0);                     \
+                                                                \
+        if (sum == 0)                                           \
+                pr_info(#name " ok\n");                         \
+        else                                                    \
+                pr_warn(#name " FAIL (uninit bytes: %d)\n",     \
+                        sum);                                   \
+                                                                \
+        return (sum != 0);                                      \
+}
+#define DEFINE_TEST(name, var_type, which, init_level)          \
+/* no-op to force compiler into ignoring "uninitialized" vars */\
+static noinline __init DO_NOTHING_TYPE_ ## which(var_type)      \
+do_nothing_ ## name(var_type *ptr)                              \
+{                                                               \
+        /* Will always be true, but compiler doesn't know. */   \
+        if ((unsigned long)ptr > 0x2)                           \
+                return DO_NOTHING_RETURN_ ## which(ptr);        \
+        else                                                    \
+                return DO_NOTHING_RETURN_ ## which(ptr + 1);    \
+}                                                               \
+static noinline __init int leaf_ ## name(unsigned long sp,      \
+                                         bool fill,             \
+                                         var_type *arg)         \
+{                                                               \
+        char buf[VAR_BUFFER];                                   \
+        var_type var INIT_ ## which ## _ ## init_level;         \
+                                                                \
+        target_start = &var;                                    \
+        target_size = sizeof(var);                              \
+        /*                                                      \
+         * Keep this buffer around to make sure we've got a     \
+         * stack frame of SOME kind...                          \
+         */                                                     \
+        memset(buf, (char)(sp && 0xff), sizeof(buf));           \
+        /* Fill variable with 0xFF. */                          \
+        if (fill) {                                             \
+                fill_start = &var;                              \
+                fill_size = sizeof(var);                        \
+                memset(fill_start,                              \
+                       (char)((sp && 0xff) | forced_mask),      \
+                       fill_size);                              \
+        }                                                       \
+                                                                \
+        /* Silence "never initialized" warnings. */             \
+        DO_NOTHING_CALL_ ## which(var, name);                   \
+                                                                \
+        /* Exfiltrate "var". */                                 \
+        memcpy(check_buf, target_start, target_size);           \
+                                                                \
+        return (int)buf[0] | (int)buf[sizeof(buf) - 1];         \
+}                                                               \
+DEFINE_TEST_DRIVER(name, var_type, which)
+
+/* Structure with no padding. */
+struct test_packed {
+        unsigned long one;
+        unsigned long two;
+        unsigned long three;
+        unsigned long four;
+};
+
+/* Simple structure with padding likely to be covered by compiler. */
+struct test_small_hole {
+        size_t one;
+        char two;
+        /* 3 byte padding hole here. */
+        int three;
+        unsigned long four;
+};
+
+/* Try to trigger unhandled padding in a structure. */
+struct test_aligned {
+        u32 internal1;
+        u64 internal2;
+} __aligned(64);
+
+struct test_big_hole {
+        u8 one;
+        u8 two;
+        u8 three;
+        /* 61 byte padding hole here. */
+        struct test_aligned four;
+} __aligned(64);
+
+struct test_trailing_hole {
+        char *one;
+        char *two;
+        char *three;
+        char four;
+        /* "sizeof(unsigned long) - 1" byte padding hole here. */
+};
+
+/* Test if STRUCTLEAK is clearing structs with __user fields. */
+struct test_user {
+        u8 one;
+        unsigned long two;
+        char __user *three;
+        unsigned long four;
+};
+
+#define DEFINE_SCALAR_TEST(name, init)                          \
+                DEFINE_TEST(name ## _ ## init, name, SCALAR, init)
+
+#define DEFINE_SCALAR_TESTS(init)                               \
+                DEFINE_SCALAR_TEST(u8, init);                   \
+                DEFINE_SCALAR_TEST(u16, init);                  \
+                DEFINE_SCALAR_TEST(u32, init);                  \
+                DEFINE_SCALAR_TEST(u64, init);                  \
+                DEFINE_TEST(char_array_ ## init, unsigned char, STRING, init)
+
+#define DEFINE_STRUCT_TEST(name, init)                          \
+                DEFINE_TEST(name ## _ ## init,                  \
+                            struct test_ ## name, STRUCT, init)
+
+#define DEFINE_STRUCT_TESTS(init)                               \
+                DEFINE_STRUCT_TEST(small_hole, init);           \
+                DEFINE_STRUCT_TEST(big_hole, init);             \
+                DEFINE_STRUCT_TEST(trailing_hole, init);        \
+                DEFINE_STRUCT_TEST(packed, init)
+
+/* These should be fully initialized all the time! */
+DEFINE_SCALAR_TESTS(zero);
+DEFINE_STRUCT_TESTS(zero);
+/* Static initialization: padding may be left uninitialized. */
+DEFINE_STRUCT_TESTS(static_partial);
+DEFINE_STRUCT_TESTS(static_all);
+/* Dynamic initialization: padding may be left uninitialized. */
+DEFINE_STRUCT_TESTS(dynamic_partial);
+DEFINE_STRUCT_TESTS(dynamic_all);
+/* Runtime initialization: padding may be left uninitialized. */
+DEFINE_STRUCT_TESTS(runtime_partial);
+DEFINE_STRUCT_TESTS(runtime_all);
+/* No initialization without compiler instrumentation. */
+DEFINE_SCALAR_TESTS(none);
+DEFINE_STRUCT_TESTS(none);
+DEFINE_TEST(user, struct test_user, STRUCT, none);
+
+/*
+ * Check two uses through a variable declaration outside either path,
+ * which was noticed as a special case in porting earlier stack init
+ * compiler logic.
+ */
+static int noinline __leaf_switch_none(int path, bool fill)
+{
+        switch (path) {
+                uint64_t var;
+
+        case 1:
+                target_start = &var;
+                target_size = sizeof(var);
+                if (fill) {
+                        fill_start = &var;
+                        fill_size = sizeof(var);
+
+                        memset(fill_start, forced_mask | 0x55, fill_size);
+                }
+                memcpy(check_buf, target_start, target_size);
+                break;
+        case 2:
+                target_start = &var;
+                target_size = sizeof(var);
+                if (fill) {
+                        fill_start = &var;
+                        fill_size = sizeof(var);
+
+                        memset(fill_start, forced_mask | 0xaa, fill_size);
+                }
+                memcpy(check_buf, target_start, target_size);
+                break;
+        default:
+                var = 5;
+                return var & forced_mask;
+        }
+        return 0;
+}
+
+static noinline __init int leaf_switch_1_none(unsigned long sp, bool fill,
+                                              uint64_t *arg)
+{
+        return __leaf_switch_none(1, fill);
+}
+
+static noinline __init int leaf_switch_2_none(unsigned long sp, bool fill,
+                                              uint64_t *arg)
+{
+        return __leaf_switch_none(2, fill);
+}
+
+DEFINE_TEST_DRIVER(switch_1_none, uint64_t, SCALAR);
+DEFINE_TEST_DRIVER(switch_2_none, uint64_t, SCALAR);
+
+static int __init test_stackinit_init(void)
+{
+        unsigned int failures = 0;
+
+#define test_scalars(init)      do {                            \
+                failures += test_u8_ ## init ();                \
+                failures += test_u16_ ## init ();               \
+                failures += test_u32_ ## init ();               \
+                failures += test_u64_ ## init ();               \
+                failures += test_char_array_ ## init ();        \
+        } while (0)
+
+#define test_structs(init)      do {                            \
+                failures += test_small_hole_ ## init ();        \
+                failures += test_big_hole_ ## init ();          \
+                failures += test_trailing_hole_ ## init ();     \
+                failures += test_packed_ ## init ();            \
+        } while (0)
+
+        /* These are explicitly initialized and should always pass. */
+        test_scalars(zero);
+        test_structs(zero);
+        /* Padding here appears to be accidentally always initialized? */
+        test_structs(dynamic_partial);
+        /* Padding initialization depends on compiler behaviors. */
+        test_structs(static_partial);
+        test_structs(static_all);
+        test_structs(dynamic_all);
+        test_structs(runtime_partial);
+        test_structs(runtime_all);
+
+        /* STRUCTLEAK_BYREF_ALL should cover everything from here down. */
+        test_scalars(none);
+        failures += test_switch_1_none();
+        failures += test_switch_2_none();
+
+        /* STRUCTLEAK_BYREF should cover from here down. */
+        test_structs(none);
+
+        /* STRUCTLEAK will only cover this. */
+        failures += test_user();
+
+        if (failures == 0)
+                pr_info("all tests passed!\n");
+        else
+                pr_err("failures: %u\n", failures);
+
+        return failures ? -EINVAL : 0;
+}
+module_init(test_stackinit_init);
+
+static void __exit test_stackinit_exit(void)
+{ }
+module_exit(test_stackinit_exit);
+
+MODULE_LICENSE("GPL");
diff --git a/scripts/Makefile.gcc-plugins b/scripts/Makefile.gcc-plugins
index 35042d96cf5d..5f7df50cfe7a 100644
--- a/scripts/Makefile.gcc-plugins
+++ b/scripts/Makefile.gcc-plugins
@@ -15,6 +15,8 @@ gcc-plugin-$(CONFIG_GCC_PLUGIN_SANCOV)		+= sancov_plugin.so
 gcc-plugin-$(CONFIG_GCC_PLUGIN_STRUCTLEAK)      += structleak_plugin.so
 gcc-plugin-cflags-$(CONFIG_GCC_PLUGIN_STRUCTLEAK_VERBOSE)       \
                 += -fplugin-arg-structleak_plugin-verbose
+gcc-plugin-cflags-$(CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF)         \
+                += -fplugin-arg-structleak_plugin-byref
 gcc-plugin-cflags-$(CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF_ALL)     \
                 += -fplugin-arg-structleak_plugin-byref-all
 gcc-plugin-cflags-$(CONFIG_GCC_PLUGIN_STRUCTLEAK)               \
diff --git a/scripts/gcc-plugins/Kconfig b/scripts/gcc-plugins/Kconfig
index d9fd9988ef27..74271dba4f94 100644
--- a/scripts/gcc-plugins/Kconfig
+++ b/scripts/gcc-plugins/Kconfig
@@ -67,23 +67,59 @@ config GCC_PLUGIN_LATENT_ENTROPY
            * https://pax.grsecurity.net/
 
 config GCC_PLUGIN_STRUCTLEAK
-        bool "Force initialization of variables containing userspace addresses"
+        bool "Zero initialize stack variables"
         help
-          This plugin zero-initializes any structures containing a
-          __user attribute. This can prevent some classes of information
-          exposures.
-
-          This plugin was ported from grsecurity/PaX. More information at:
+          While the kernel is built with warnings enabled for any missed
+          stack variable initializations, this warning is silenced for
+          anything passed by reference to another function, under the
+          occasionally misguided assumption that the function will do
+          the initialization. As this regularly leads to exploitable
+          flaws, this plugin is available to identify and zero-initialize
+          such variables, depending on the chosen level of coverage.
+
+          This plugin was originally ported from grsecurity/PaX. More
+          information at:
            * https://grsecurity.net/
            * https://pax.grsecurity.net/
 
-config GCC_PLUGIN_STRUCTLEAK_BYREF_ALL
-        bool "Force initialize all struct type variables passed by reference"
+choice
+        prompt "Coverage"
         depends on GCC_PLUGIN_STRUCTLEAK
-        depends on !COMPILE_TEST
+        default GCC_PLUGIN_STRUCTLEAK_BYREF_ALL
         help
-          Zero initialize any struct type local variable that may be passed by
-          reference without having been initialized.
+          This chooses the level of coverage over classes of potentially
+          uninitialized variables. The selected class will be
+          zero-initialized before use.
+
+        config GCC_PLUGIN_STRUCTLEAK_USER
+                bool "structs marked for userspace"
+                help
+                  Zero-initialize any structures on the stack containing
+                  a __user attribute. This can prevent some classes of
+                  uninitialized stack variable exploits and information
+                  exposures, like CVE-2013-2141:
+                  https://git.kernel.org/linus/b9e146d8eb3b9eca
+
+        config GCC_PLUGIN_STRUCTLEAK_BYREF
+                bool "structs passed by reference"
+                help
+                  Zero-initialize any structures on the stack that may
+                  be passed by reference and had not already been
+                  explicitly initialized. This can prevent most classes
+                  of uninitialized stack variable exploits and information
+                  exposures, like CVE-2017-1000410:
+                  https://git.kernel.org/linus/06e7e776ca4d3654
+
+        config GCC_PLUGIN_STRUCTLEAK_BYREF_ALL
+                bool "anything passed by reference"
+                help
+                  Zero-initialize any stack variables that may be passed
+                  by reference and had not already been explicitly
+                  initialized. This is intended to eliminate all classes
+                  of uninitialized stack variable exploits and information
+                  exposures.
+
+endchoice
 
 config GCC_PLUGIN_STRUCTLEAK_VERBOSE
         bool "Report forcefully initialized variables"
diff --git a/scripts/gcc-plugins/structleak_plugin.c b/scripts/gcc-plugins/structleak_plugin.c
index 10292f791e99..e89be8f5c859 100644
--- a/scripts/gcc-plugins/structleak_plugin.c
+++ b/scripts/gcc-plugins/structleak_plugin.c
@@ -16,6 +16,7 @@
  * Options:
  * -fplugin-arg-structleak_plugin-disable
  * -fplugin-arg-structleak_plugin-verbose
+ * -fplugin-arg-structleak_plugin-byref
  * -fplugin-arg-structleak_plugin-byref-all
  *
  * Usage:
@@ -26,7 +27,6 @@
  * $ gcc -fplugin=./structleak_plugin.so test.c -O2
  *
  * TODO: eliminate redundant initializers
- *       increase type coverage
  */
 
 #include "gcc-common.h"
@@ -37,13 +37,18 @@
 __visible int plugin_is_GPL_compatible;
 
 static struct plugin_info structleak_plugin_info = {
-        .version        = "201607271510vanilla",
+        .version        = "20190125vanilla",
         .help           = "disable\tdo not activate plugin\n"
-                           "verbose\tprint all initialized variables\n",
+                          "byref\tinit structs passed by reference\n"
+                          "byref-all\tinit anything passed by reference\n"
+                          "verbose\tprint all initialized variables\n",
 };
 
+#define BYREF_STRUCT    1
+#define BYREF_ALL       2
+
 static bool verbose;
-static bool byref_all;
+static int byref;
 
 static tree handle_user_attribute(tree *node, tree name, tree args, int flags, bool *no_add_attrs)
 {
@@ -118,6 +123,7 @@ static void initialize(tree var)
         gimple_stmt_iterator gsi;
         tree initializer;
         gimple init_stmt;
+        tree type;
 
         /* this is the original entry bb before the forced split */
         bb = single_succ(ENTRY_BLOCK_PTR_FOR_FN(cfun));
@@ -148,11 +154,15 @@ static void initialize(tree var)
         if (verbose)
                 inform(DECL_SOURCE_LOCATION(var),
                         "%s variable will be forcibly initialized",
-                        (byref_all && TREE_ADDRESSABLE(var)) ? "byref"
-                                                             : "userspace");
+                        (byref && TREE_ADDRESSABLE(var)) ? "byref"
+                                                         : "userspace");
 
         /* build the initializer expression */
-        initializer = build_constructor(TREE_TYPE(var), NULL);
+        type = TREE_TYPE(var);
+        if (AGGREGATE_TYPE_P(type))
+                initializer = build_constructor(type, NULL);
+        else
+                initializer = fold_convert(type, integer_zero_node);
 
         /* build the initializer stmt */
         init_stmt = gimple_build_assign(var, initializer);
@@ -184,13 +194,13 @@ static unsigned int structleak_execute(void)
                 if (!auto_var_in_fn_p(var, current_function_decl))
                         continue;
 
-                /* only care about structure types */
-                if (TREE_CODE(type) != RECORD_TYPE && TREE_CODE(type) != UNION_TYPE)
+                /* only care about structure types unless byref-all */
+                if (byref != BYREF_ALL && TREE_CODE(type) != RECORD_TYPE && TREE_CODE(type) != UNION_TYPE)
                         continue;
 
                 /* if the type is of interest, examine the variable */
                 if (TYPE_USERSPACE(type) ||
-                    (byref_all && TREE_ADDRESSABLE(var)))
+                    (byref && TREE_ADDRESSABLE(var)))
                         initialize(var);
         }
 
@@ -232,8 +242,12 @@ __visible int plugin_init(struct plugin_name_args *plugin_info, struct plugin_gc
                         verbose = true;
                         continue;
                 }
+                if (!strcmp(argv[i].key, "byref")) {
+                        byref = BYREF_STRUCT;
+                        continue;
+                }
                 if (!strcmp(argv[i].key, "byref-all")) {
-                        byref_all = true;
+                        byref = BYREF_ALL;
                         continue;
                 }
                 error(G_("unknown option '-fplugin-arg-%s-%s'"), plugin_name, argv[i].key);