1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Init code for a livepatch kernel module 4 */ 5 6 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 7 8 #include <linux/kernel.h> 9 #include <linux/slab.h> 10 #include <linux/livepatch.h> 11 12 static struct klp_patch *patch; 13 14 static int __init livepatch_mod_init(void) 15 { 16 struct klp_object_ext *obj_exts; 17 size_t obj_exts_sec_size; 18 struct klp_object *objs; 19 unsigned int nr_objs; 20 int ret; 21 22 obj_exts = klp_find_section_by_name(THIS_MODULE, ".init.klp_objects", 23 &obj_exts_sec_size); 24 nr_objs = obj_exts_sec_size / sizeof(*obj_exts); 25 if (!nr_objs) { 26 pr_err("nothing to patch!\n"); 27 ret = -EINVAL; 28 goto err; 29 } 30 31 patch = kzalloc(sizeof(*patch), GFP_KERNEL); 32 if (!patch) { 33 ret = -ENOMEM; 34 goto err; 35 } 36 37 objs = kzalloc(sizeof(struct klp_object) * (nr_objs + 1), GFP_KERNEL); 38 if (!objs) { 39 ret = -ENOMEM; 40 goto err_free_patch; 41 } 42 43 for (int i = 0; i < nr_objs; i++) { 44 struct klp_object_ext *obj_ext = obj_exts + i; 45 struct klp_func_ext *funcs_ext = obj_ext->funcs; 46 unsigned int nr_funcs = obj_ext->nr_funcs; 47 struct klp_func *funcs = objs[i].funcs; 48 struct klp_object *obj = objs + i; 49 50 funcs = kzalloc(sizeof(struct klp_func) * (nr_funcs + 1), GFP_KERNEL); 51 if (!funcs) { 52 ret = -ENOMEM; 53 for (int j = 0; j < i; j++) 54 kfree(objs[i].funcs); 55 goto err_free_objs; 56 } 57 58 for (int j = 0; j < nr_funcs; j++) { 59 funcs[j].old_name = funcs_ext[j].old_name; 60 funcs[j].new_func = funcs_ext[j].new_func; 61 funcs[j].old_sympos = funcs_ext[j].sympos; 62 } 63 64 obj->name = obj_ext->name; 65 obj->funcs = funcs; 66 67 memcpy(&obj->callbacks, &obj_ext->callbacks, sizeof(struct klp_callbacks)); 68 } 69 70 patch->mod = THIS_MODULE; 71 patch->objs = objs; 72 73 /* TODO patch->states */ 74 75 #ifdef KLP_NO_REPLACE 76 patch->replace = false; 77 #else 78 patch->replace = true; 79 #endif 80 81 return klp_enable_patch(patch); 82 83 err_free_objs: 84 kfree(objs); 85 err_free_patch: 86 kfree(patch); 87 err: 88 return ret; 89 } 90 91 static void __exit livepatch_mod_exit(void) 92 { 93 struct klp_object *obj; 94 95 klp_for_each_object_static(patch, obj) 96 kfree(obj->funcs); 97 98 kfree(patch->objs); 99 kfree(patch); 100 } 101 102 module_init(livepatch_mod_init); 103 module_exit(livepatch_mod_exit); 104 MODULE_LICENSE("GPL"); 105 MODULE_INFO(livepatch, "Y"); 106 MODULE_DESCRIPTION("Livepatch module"); 107