From 3859a271a003aba01e45b85c9d8b355eb7bf25f9 Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Fri, 28 Oct 2016 01:22:25 -0700 Subject: randstruct: Mark various structs for randomization This marks many critical kernel structures for randomization. These are structures that have been targeted in the past in security exploits, or contain functions pointers, pointers to function pointer tables, lists, workqueues, ref-counters, credentials, permissions, or are otherwise sensitive. This initial list was extracted from Brad Spengler/PaX Team's code in the last public patch of grsecurity/PaX based on my understanding of the code. Changes or omissions from the original code are mine and don't reflect the original grsecurity/PaX code. Left out of this list is task_struct, which requires special handling and will be covered in a subsequent patch. Signed-off-by: Kees Cook --- include/linux/module.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'include/linux/module.h') diff --git a/include/linux/module.h b/include/linux/module.h index 21f56393602f..d93111d7def6 100644 --- a/include/linux/module.h +++ b/include/linux/module.h @@ -45,7 +45,7 @@ struct module_kobject { struct kobject *drivers_dir; struct module_param_attrs *mp; struct completion *kobj_completion; -}; +} __randomize_layout; struct module_attribute { struct attribute attr; @@ -475,7 +475,7 @@ struct module { ctor_fn_t *ctors; unsigned int num_ctors; #endif -} ____cacheline_aligned; +} ____cacheline_aligned __randomize_layout; #ifndef MODULE_ARCH_INIT #define MODULE_ARCH_INIT {} #endif -- cgit v1.2.3 From 0bf8bf50eddc7511b52461bae798cbfaa0157a34 Mon Sep 17 00:00:00 2001 From: Matthias Kaehlcke Date: Mon, 24 Jul 2017 18:27:25 -0700 Subject: module: Remove const attribute from alias for MODULE_DEVICE_TABLE MODULE_DEVICE_TABLE(type, name) creates an alias of type 'extern const typeof(name)'. If 'name' is already constant the 'const' attribute is specified twice, which is not allowed in C89 (see discussion at https://lkml.org/lkml/2017/5/23/1440). Since the kernel is built with -std=gnu89 clang generates warnings like this: drivers/thermal/x86_pkg_temp_thermal.c:509:1: warning: duplicate 'const' declaration specifier [-Wduplicate-decl-specifier] MODULE_DEVICE_TABLE(x86cpu, pkg_temp_thermal_ids); ^ ./include/linux/module.h:212:8: note: expanded from macro 'MODULE_DEVICE_TABLE' extern const typeof(name) __mod_##type##__##name##_device_table Remove the const attribute from the alias to avoid the duplicate specifier. After all it is only an alias and the attribute shouldn't have any effect. Signed-off-by: Matthias Kaehlcke Signed-off-by: Jessica Yu --- include/linux/module.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'include/linux/module.h') diff --git a/include/linux/module.h b/include/linux/module.h index e7bdd549e527..fe5aa3736707 100644 --- a/include/linux/module.h +++ b/include/linux/module.h @@ -209,7 +209,7 @@ extern void cleanup_module(void); #ifdef MODULE /* Creates an alias so file2alias.c can find device table. */ #define MODULE_DEVICE_TABLE(type, name) \ -extern const typeof(name) __mod_##type##__##name##_device_table \ +extern typeof(name) __mod_##type##__##name##_device_table \ __attribute__ ((unused, alias(__stringify(name)))) #else /* !MODULE */ #define MODULE_DEVICE_TABLE(type, name) -- cgit v1.2.3