Kbuild: remove structleak gcc plugin
gcc-12 and higher support the -ftrivial-auto-var-init= flag, after gcc-8 is the minimum version, this is half of the supported ones, and the vast majority of the versions that users are actually likely to have, so it seems like a good time to stop having the fallback plugin implementation Older toolchains are still able to build kernels normally without this plugin, but won't be able to use variable initialization.. Signed-off-by: Arnd Bergmann <arnd@arndb.de>pull/1253/head
Arnd Bergmann
parent
2555d4c687
commit
8530ea3c9b
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@ -86,11 +86,7 @@ struct td028ttec1_panel {
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#define to_td028ttec1_device(p) container_of(p, struct td028ttec1_panel, panel)
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/*
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* noinline_for_stack so we don't get multiple copies of tx_buf
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* on the stack in case of gcc-plugin-structleak
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*/
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static int noinline_for_stack
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static int
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jbt_ret_write_0(struct td028ttec1_panel *lcd, u8 reg, int *err)
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{
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struct spi_device *spi = lcd->spi;
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@ -2870,9 +2870,7 @@ config STACKINIT_KUNIT_TEST
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help
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Test if the kernel is zero-initializing stack variables and
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padding. Coverage is controlled by compiler flags,
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CONFIG_INIT_STACK_ALL_PATTERN, CONFIG_INIT_STACK_ALL_ZERO,
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CONFIG_GCC_PLUGIN_STRUCTLEAK, CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF,
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or CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF_ALL.
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CONFIG_INIT_STACK_ALL_PATTERN or CONFIG_INIT_STACK_ALL_ZERO.
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config FORTIFY_KUNIT_TEST
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tristate "Test fortified str*() and mem*() function internals at runtime" if !KUNIT_ALL_TESTS
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@ -1,7 +1,7 @@
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// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* Test cases for compiler-based stack variable zeroing via
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* -ftrivial-auto-var-init={zero,pattern} or CONFIG_GCC_PLUGIN_STRUCTLEAK*.
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* -ftrivial-auto-var-init={zero,pattern}.
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* For example, see:
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* "Running tests with kunit_tool" at Documentation/dev-tools/kunit/start.rst
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* ./tools/testing/kunit/kunit.py run stackinit [--raw_output] \
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@ -376,14 +376,6 @@ union test_small_end {
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# define USER_PASS XFAIL
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# define BYREF_PASS XFAIL
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# define STRONG_PASS XFAIL
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#elif defined(CONFIG_GCC_PLUGIN_STRUCTLEAK_USER)
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# define USER_PASS WANT_SUCCESS
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# define BYREF_PASS XFAIL
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# define STRONG_PASS XFAIL
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#elif defined(CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF)
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# define USER_PASS WANT_SUCCESS
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# define BYREF_PASS WANT_SUCCESS
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# define STRONG_PASS XFAIL
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#else
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# define USER_PASS WANT_SUCCESS
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# define BYREF_PASS WANT_SUCCESS
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@ -2668,12 +2668,6 @@ static void __init report_meminit(void)
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stack = "all(pattern)";
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else if (IS_ENABLED(CONFIG_INIT_STACK_ALL_ZERO))
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stack = "all(zero)";
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else if (IS_ENABLED(CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF_ALL))
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stack = "byref_all(zero)";
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else if (IS_ENABLED(CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF))
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stack = "byref(zero)";
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else if (IS_ENABLED(CONFIG_GCC_PLUGIN_STRUCTLEAK_USER))
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stack = "__user(zero)";
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else
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stack = "off";
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@ -8,20 +8,6 @@ ifdef CONFIG_GCC_PLUGIN_LATENT_ENTROPY
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endif
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export DISABLE_LATENT_ENTROPY_PLUGIN
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gcc-plugin-$(CONFIG_GCC_PLUGIN_STRUCTLEAK) += structleak_plugin.so
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gcc-plugin-cflags-$(CONFIG_GCC_PLUGIN_STRUCTLEAK_VERBOSE) \
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+= -fplugin-arg-structleak_plugin-verbose
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gcc-plugin-cflags-$(CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF) \
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+= -fplugin-arg-structleak_plugin-byref
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gcc-plugin-cflags-$(CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF_ALL) \
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+= -fplugin-arg-structleak_plugin-byref-all
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ifdef CONFIG_GCC_PLUGIN_STRUCTLEAK
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DISABLE_STRUCTLEAK_PLUGIN += -fplugin-arg-structleak_plugin-disable
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endif
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export DISABLE_STRUCTLEAK_PLUGIN
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gcc-plugin-cflags-$(CONFIG_GCC_PLUGIN_STRUCTLEAK) \
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+= -DSTRUCTLEAK_PLUGIN
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gcc-plugin-$(CONFIG_GCC_PLUGIN_STACKLEAK) += stackleak_plugin.so
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gcc-plugin-cflags-$(CONFIG_GCC_PLUGIN_STACKLEAK) \
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+= -DSTACKLEAK_PLUGIN
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@ -1,257 +0,0 @@
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// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Copyright 2013-2017 by PaX Team <pageexec@freemail.hu>
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*
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* Note: the choice of the license means that the compilation process is
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* NOT 'eligible' as defined by gcc's library exception to the GPL v3,
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* but for the kernel it doesn't matter since it doesn't link against
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* any of the gcc libraries
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*
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* gcc plugin to forcibly initialize certain local variables that could
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* otherwise leak kernel stack to userland if they aren't properly initialized
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* by later code
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*
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* Homepage: https://pax.grsecurity.net/
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*
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* Options:
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* -fplugin-arg-structleak_plugin-disable
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* -fplugin-arg-structleak_plugin-verbose
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* -fplugin-arg-structleak_plugin-byref
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* -fplugin-arg-structleak_plugin-byref-all
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*
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* Usage:
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* $ # for 4.5/4.6/C based 4.7
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* $ gcc -I`gcc -print-file-name=plugin`/include -I`gcc -print-file-name=plugin`/include/c-family -fPIC -shared -O2 -o structleak_plugin.so structleak_plugin.c
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* $ # for C++ based 4.7/4.8+
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* $ g++ -I`g++ -print-file-name=plugin`/include -I`g++ -print-file-name=plugin`/include/c-family -fPIC -shared -O2 -o structleak_plugin.so structleak_plugin.c
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* $ gcc -fplugin=./structleak_plugin.so test.c -O2
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*
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* TODO: eliminate redundant initializers
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*/
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#include "gcc-common.h"
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/* unused C type flag in all versions 4.5-6 */
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#define TYPE_USERSPACE(TYPE) TYPE_LANG_FLAG_5(TYPE)
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__visible int plugin_is_GPL_compatible;
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static struct plugin_info structleak_plugin_info = {
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.version = PLUGIN_VERSION,
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.help = "disable\tdo not activate plugin\n"
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"byref\tinit structs passed by reference\n"
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"byref-all\tinit anything passed by reference\n"
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"verbose\tprint all initialized variables\n",
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};
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#define BYREF_STRUCT 1
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#define BYREF_ALL 2
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static bool verbose;
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static int byref;
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static tree handle_user_attribute(tree *node, tree name, tree args, int flags, bool *no_add_attrs)
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{
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*no_add_attrs = true;
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/* check for types? for now accept everything linux has to offer */
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if (TREE_CODE(*node) != FIELD_DECL)
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return NULL_TREE;
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*no_add_attrs = false;
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return NULL_TREE;
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}
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static struct attribute_spec user_attr = { };
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static void register_attributes(void *event_data, void *data)
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{
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user_attr.name = "user";
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user_attr.handler = handle_user_attribute;
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user_attr.affects_type_identity = true;
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register_attribute(&user_attr);
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}
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static tree get_field_type(tree field)
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{
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return strip_array_types(TREE_TYPE(field));
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}
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static bool is_userspace_type(tree type)
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{
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tree field;
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for (field = TYPE_FIELDS(type); field; field = TREE_CHAIN(field)) {
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tree fieldtype = get_field_type(field);
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enum tree_code code = TREE_CODE(fieldtype);
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if (code == RECORD_TYPE || code == UNION_TYPE)
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if (is_userspace_type(fieldtype))
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return true;
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if (lookup_attribute("user", DECL_ATTRIBUTES(field)))
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return true;
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}
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return false;
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}
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static void finish_type(void *event_data, void *data)
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{
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tree type = (tree)event_data;
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if (type == NULL_TREE || type == error_mark_node)
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return;
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if (TREE_CODE(type) == ENUMERAL_TYPE)
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return;
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if (TYPE_USERSPACE(type))
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return;
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if (is_userspace_type(type))
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TYPE_USERSPACE(type) = 1;
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}
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static void initialize(tree var)
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{
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basic_block bb;
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gimple_stmt_iterator gsi;
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tree initializer;
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gimple init_stmt;
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tree type;
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/* this is the original entry bb before the forced split */
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bb = single_succ(ENTRY_BLOCK_PTR_FOR_FN(cfun));
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/* first check if variable is already initialized, warn otherwise */
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for (gsi = gsi_start_bb(bb); !gsi_end_p(gsi); gsi_next(&gsi)) {
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gimple stmt = gsi_stmt(gsi);
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tree rhs1;
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/* we're looking for an assignment of a single rhs... */
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if (!gimple_assign_single_p(stmt))
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continue;
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rhs1 = gimple_assign_rhs1(stmt);
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/* ... of a non-clobbering expression... */
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if (TREE_CLOBBER_P(rhs1))
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continue;
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/* ... to our variable... */
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if (gimple_get_lhs(stmt) != var)
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continue;
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/* if it's an initializer then we're good */
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if (TREE_CODE(rhs1) == CONSTRUCTOR)
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return;
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}
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/* these aren't the 0days you're looking for */
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if (verbose)
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inform(DECL_SOURCE_LOCATION(var),
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"%s variable will be forcibly initialized",
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(byref && TREE_ADDRESSABLE(var)) ? "byref"
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: "userspace");
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/* build the initializer expression */
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type = TREE_TYPE(var);
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if (AGGREGATE_TYPE_P(type))
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initializer = build_constructor(type, NULL);
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else
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initializer = fold_convert(type, integer_zero_node);
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/* build the initializer stmt */
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init_stmt = gimple_build_assign(var, initializer);
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gsi = gsi_after_labels(single_succ(ENTRY_BLOCK_PTR_FOR_FN(cfun)));
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gsi_insert_before(&gsi, init_stmt, GSI_NEW_STMT);
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update_stmt(init_stmt);
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}
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static unsigned int structleak_execute(void)
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{
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basic_block bb;
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tree var;
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unsigned int i;
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/* split the first bb where we can put the forced initializers */
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gcc_assert(single_succ_p(ENTRY_BLOCK_PTR_FOR_FN(cfun)));
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bb = single_succ(ENTRY_BLOCK_PTR_FOR_FN(cfun));
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if (!single_pred_p(bb)) {
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split_edge(single_succ_edge(ENTRY_BLOCK_PTR_FOR_FN(cfun)));
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gcc_assert(single_succ_p(ENTRY_BLOCK_PTR_FOR_FN(cfun)));
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}
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/* enumerate all local variables and forcibly initialize our targets */
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FOR_EACH_LOCAL_DECL(cfun, i, var) {
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tree type = TREE_TYPE(var);
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gcc_assert(DECL_P(var));
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if (!auto_var_in_fn_p(var, current_function_decl))
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continue;
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/* only care about structure types unless byref-all */
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if (byref != BYREF_ALL && TREE_CODE(type) != RECORD_TYPE && TREE_CODE(type) != UNION_TYPE)
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continue;
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/* if the type is of interest, examine the variable */
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if (TYPE_USERSPACE(type) ||
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(byref && TREE_ADDRESSABLE(var)))
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initialize(var);
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}
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return 0;
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}
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#define PASS_NAME structleak
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#define NO_GATE
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#define PROPERTIES_REQUIRED PROP_cfg
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#define TODO_FLAGS_FINISH TODO_verify_il | TODO_verify_ssa | TODO_verify_stmts | TODO_dump_func | TODO_remove_unused_locals | TODO_update_ssa | TODO_ggc_collect | TODO_verify_flow
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#include "gcc-generate-gimple-pass.h"
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__visible int plugin_init(struct plugin_name_args *plugin_info, struct plugin_gcc_version *version)
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{
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int i;
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const char * const plugin_name = plugin_info->base_name;
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const int argc = plugin_info->argc;
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const struct plugin_argument * const argv = plugin_info->argv;
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bool enable = true;
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PASS_INFO(structleak, "early_optimizations", 1, PASS_POS_INSERT_BEFORE);
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if (!plugin_default_version_check(version, &gcc_version)) {
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error(G_("incompatible gcc/plugin versions"));
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return 1;
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}
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if (strncmp(lang_hooks.name, "GNU C", 5) && !strncmp(lang_hooks.name, "GNU C+", 6)) {
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inform(UNKNOWN_LOCATION, G_("%s supports C only, not %s"), plugin_name, lang_hooks.name);
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enable = false;
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}
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for (i = 0; i < argc; ++i) {
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if (!strcmp(argv[i].key, "disable")) {
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enable = false;
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continue;
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}
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if (!strcmp(argv[i].key, "verbose")) {
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verbose = true;
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continue;
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}
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if (!strcmp(argv[i].key, "byref")) {
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byref = BYREF_STRUCT;
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continue;
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}
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if (!strcmp(argv[i].key, "byref-all")) {
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byref = BYREF_ALL;
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continue;
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}
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error(G_("unknown option '-fplugin-arg-%s-%s'"), plugin_name, argv[i].key);
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}
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register_callback(plugin_name, PLUGIN_INFO, NULL, &structleak_plugin_info);
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if (enable) {
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register_callback(plugin_name, PLUGIN_PASS_MANAGER_SETUP, NULL, &structleak_pass_info);
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register_callback(plugin_name, PLUGIN_FINISH_TYPE, finish_type, NULL);
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}
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register_callback(plugin_name, PLUGIN_ATTRIBUTES, register_attributes, NULL);
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return 0;
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}
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@ -1,22 +1,6 @@
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# SPDX-License-Identifier: GPL-2.0-only
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menu "Kernel hardening options"
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config GCC_PLUGIN_STRUCTLEAK
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bool
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help
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While the kernel is built with warnings enabled for any missed
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stack variable initializations, this warning is silenced for
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anything passed by reference to another function, under the
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occasionally misguided assumption that the function will do
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the initialization. As this regularly leads to exploitable
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flaws, this plugin is available to identify and zero-initialize
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such variables, depending on the chosen level of coverage.
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This plugin was originally ported from grsecurity/PaX. More
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information at:
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* https://grsecurity.net/
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* https://pax.grsecurity.net/
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menu "Memory initialization"
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config CC_HAS_AUTO_VAR_INIT_PATTERN
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@ -36,7 +20,6 @@ config CC_HAS_AUTO_VAR_INIT_ZERO
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choice
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prompt "Initialize kernel stack variables at function entry"
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default GCC_PLUGIN_STRUCTLEAK_BYREF_ALL if COMPILE_TEST && GCC_PLUGINS
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default INIT_STACK_ALL_PATTERN if COMPILE_TEST && CC_HAS_AUTO_VAR_INIT_PATTERN
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default INIT_STACK_ALL_ZERO if CC_HAS_AUTO_VAR_INIT_ZERO
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default INIT_STACK_NONE
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@ -60,55 +43,6 @@ choice
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classes of uninitialized stack variable exploits
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and information exposures.
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config GCC_PLUGIN_STRUCTLEAK_USER
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bool "zero-init structs marked for userspace (weak)"
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# Plugin can be removed once the kernel only supports GCC 12+
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depends on GCC_PLUGINS && !CC_HAS_AUTO_VAR_INIT_ZERO
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select GCC_PLUGIN_STRUCTLEAK
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help
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Zero-initialize any structures on the stack containing
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a __user attribute. This can prevent some classes of
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uninitialized stack variable exploits and information
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exposures, like CVE-2013-2141:
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https://git.kernel.org/linus/b9e146d8eb3b9eca
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config GCC_PLUGIN_STRUCTLEAK_BYREF
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bool "zero-init structs passed by reference (strong)"
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# Plugin can be removed once the kernel only supports GCC 12+
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depends on GCC_PLUGINS && !CC_HAS_AUTO_VAR_INIT_ZERO
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depends on !(KASAN && KASAN_STACK)
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select GCC_PLUGIN_STRUCTLEAK
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help
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Zero-initialize any structures on the stack that may
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be passed by reference and had not already been
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explicitly initialized. This can prevent most classes
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of uninitialized stack variable exploits and information
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exposures, like CVE-2017-1000410:
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https://git.kernel.org/linus/06e7e776ca4d3654
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As a side-effect, this keeps a lot of variables on the
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stack that can otherwise be optimized out, so combining
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this with CONFIG_KASAN_STACK can lead to a stack overflow
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and is disallowed.
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config GCC_PLUGIN_STRUCTLEAK_BYREF_ALL
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bool "zero-init everything passed by reference (very strong)"
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# Plugin can be removed once the kernel only supports GCC 12+
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depends on GCC_PLUGINS && !CC_HAS_AUTO_VAR_INIT_ZERO
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depends on !(KASAN && KASAN_STACK)
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select GCC_PLUGIN_STRUCTLEAK
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help
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Zero-initialize any stack variables that may be passed
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by reference and had not already been explicitly
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initialized. This is intended to eliminate all classes
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of uninitialized stack variable exploits and information
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exposures.
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As a side-effect, this keeps a lot of variables on the
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stack that can otherwise be optimized out, so combining
|
||||
this with CONFIG_KASAN_STACK can lead to a stack overflow
|
||||
and is disallowed.
|
||||
|
||||
config INIT_STACK_ALL_PATTERN
|
||||
bool "pattern-init everything (strongest)"
|
||||
depends on CC_HAS_AUTO_VAR_INIT_PATTERN
|
||||
|
|
@ -148,16 +82,6 @@ choice
|
|||
|
||||
endchoice
|
||||
|
||||
config GCC_PLUGIN_STRUCTLEAK_VERBOSE
|
||||
bool "Report forcefully initialized variables"
|
||||
depends on GCC_PLUGIN_STRUCTLEAK
|
||||
depends on !COMPILE_TEST # too noisy
|
||||
help
|
||||
This option will cause a warning to be printed each time the
|
||||
structleak plugin finds a variable it thinks needs to be
|
||||
initialized. Since not all existing initializers are detected
|
||||
by the plugin, this can produce false positive warnings.
|
||||
|
||||
config GCC_PLUGIN_STACKLEAK
|
||||
bool "Poison kernel stack before returning from syscalls"
|
||||
depends on GCC_PLUGINS
|
||||
|
|
|
|||
Loading…
Reference in New Issue