diff options
| author | Sami Tolvanen | 2022-09-08 14:54:47 -0700 |
|---|---|---|
| committer | Kees Cook | 2022-09-26 10:13:13 -0700 |
| commit | 89245600941e4e0f87d77f60ee269b5e61ef4e49 (patch) | |
| tree | a0069b5bd625907cb854091e6dbbeed4964815b0 /kernel/module | |
| parent | 92efda8eb15295a07f450828b2db14485bfc09c2 (diff) | |
cfi: Switch to -fsanitize=kcfi
Switch from Clang's original forward-edge control-flow integrity
implementation to -fsanitize=kcfi, which is better suited for the
kernel, as it doesn't require LTO, doesn't use a jump table that
requires altering function references, and won't break cross-module
function address equality.
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Tested-by: Kees Cook <keescook@chromium.org>
Tested-by: Nathan Chancellor <nathan@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20220908215504.3686827-6-samitolvanen@google.com
Diffstat (limited to 'kernel/module')
| -rw-r--r-- | kernel/module/main.c | 35 |
1 files changed, 3 insertions, 32 deletions
diff --git a/kernel/module/main.c b/kernel/module/main.c index 0228f44b58e5..70c0b2c6fef8 100644 --- a/kernel/module/main.c +++ b/kernel/module/main.c @@ -53,6 +53,7 @@ #include <linux/bsearch.h> #include <linux/dynamic_debug.h> #include <linux/audit.h> +#include <linux/cfi.h> #include <uapi/linux/module.h> #include "internal.h" @@ -2597,8 +2598,9 @@ static int complete_formation(struct module *mod, struct load_info *info) if (err < 0) goto out; - /* This relies on module_mutex for list integrity. */ + /* These rely on module_mutex for list integrity. */ module_bug_finalize(info->hdr, info->sechdrs, mod); + module_cfi_finalize(info->hdr, info->sechdrs, mod); if (module_check_misalignment(mod)) goto out_misaligned; @@ -2660,8 +2662,6 @@ static int unknown_module_param_cb(char *param, char *val, const char *modname, return 0; } -static void cfi_init(struct module *mod); - /* * Allocate and load the module: note that size of section 0 is always * zero, and we rely on this for optional sections. @@ -2791,9 +2791,6 @@ static int load_module(struct load_info *info, const char __user *uargs, flush_module_icache(mod); - /* Setup CFI for the module. */ - cfi_init(mod); - /* Now copy in args */ mod->args = strndup_user(uargs, ~0UL >> 1); if (IS_ERR(mod->args)) { @@ -2955,32 +2952,6 @@ static inline int within(unsigned long addr, void *start, unsigned long size) return ((void *)addr >= start && (void *)addr < start + size); } -static void cfi_init(struct module *mod) -{ -#ifdef CONFIG_CFI_CLANG - initcall_t *init; -#ifdef CONFIG_MODULE_UNLOAD - exitcall_t *exit; -#endif - - rcu_read_lock_sched(); - mod->cfi_check = (cfi_check_fn) - find_kallsyms_symbol_value(mod, "__cfi_check"); - init = (initcall_t *) - find_kallsyms_symbol_value(mod, "__cfi_jt_init_module"); - /* Fix init/exit functions to point to the CFI jump table */ - if (init) - mod->init = *init; -#ifdef CONFIG_MODULE_UNLOAD - exit = (exitcall_t *) - find_kallsyms_symbol_value(mod, "__cfi_jt_cleanup_module"); - if (exit) - mod->exit = *exit; -#endif - rcu_read_unlock_sched(); -#endif -} - /* Keep in sync with MODULE_FLAGS_BUF_SIZE !!! */ char *module_flags(struct module *mod, char *buf, bool show_state) { |