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-rw-r--r--kernel/module.c43
1 files changed, 43 insertions, 0 deletions
diff --git a/kernel/module.c b/kernel/module.c
index 30479355ab85..20fb004e7d8d 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -2146,6 +2146,8 @@ void __weak module_arch_freeing_init(struct module *mod)
{
}
+static void cfi_cleanup(struct module *mod);
+
/* Free a module, remove from lists, etc. */
static void free_module(struct module *mod)
{
@@ -2187,6 +2189,9 @@ static void free_module(struct module *mod)
synchronize_rcu();
mutex_unlock(&module_mutex);
+ /* Clean up CFI for the module. */
+ cfi_cleanup(mod);
+
/* This may be empty, but that's OK */
module_arch_freeing_init(mod);
module_memfree(mod->init_layout.base);
@@ -3866,6 +3871,8 @@ 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.
@@ -3997,6 +4004,9 @@ 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)) {
@@ -4070,6 +4080,7 @@ static int load_module(struct load_info *info, const char __user *uargs,
synchronize_rcu();
kfree(mod->args);
free_arch_cleanup:
+ cfi_cleanup(mod);
module_arch_cleanup(mod);
free_modinfo:
free_modinfo(mod);
@@ -4415,6 +4426,38 @@ int module_kallsyms_on_each_symbol(int (*fn)(void *, const char *,
#endif /* CONFIG_LIVEPATCH */
#endif /* CONFIG_KALLSYMS */
+static void cfi_init(struct module *mod)
+{
+#ifdef CONFIG_CFI_CLANG
+ initcall_t *init;
+ exitcall_t *exit;
+
+ 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");
+ exit = (exitcall_t *)
+ find_kallsyms_symbol_value(mod, "__cfi_jt_cleanup_module");
+ rcu_read_unlock_sched();
+
+ /* Fix init/exit functions to point to the CFI jump table */
+ if (init)
+ mod->init = *init;
+ if (exit)
+ mod->exit = *exit;
+
+ cfi_module_add(mod, module_addr_min);
+#endif
+}
+
+static void cfi_cleanup(struct module *mod)
+{
+#ifdef CONFIG_CFI_CLANG
+ cfi_module_remove(mod, module_addr_min);
+#endif
+}
+
/* Maximum number of characters written by module_flags() */
#define MODULE_FLAGS_BUF_SIZE (TAINT_FLAGS_COUNT + 4)

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