1 // SPDX-License-Identifier: GPL-2.0
2 // Copyright (C) 2018 Joe Lawrence <joe.lawrence@redhat.com>
4 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
6 #include <linux/module.h>
7 #include <linux/kernel.h>
8 #include <linux/list.h>
9 #include <linux/livepatch.h>
10 #include <linux/slab.h>
13 * Keep a small list of pointers so that we can print address-agnostic
14 * pointer values. Use a rolling integer count to differentiate the values.
15 * Ironically we could have used the shadow variable API to do this, but
16 * let's not lean too heavily on the very code we're testing.
18 static LIST_HEAD(ptr_list);
22 struct list_head list;
25 static void free_ptr_list(void)
27 struct shadow_ptr *sp, *tmp_sp;
29 list_for_each_entry_safe(sp, tmp_sp, &ptr_list, list) {
35 static int ptr_id(void *ptr)
37 struct shadow_ptr *sp;
40 list_for_each_entry(sp, &ptr_list, list) {
45 sp = kmalloc(sizeof(*sp), GFP_ATOMIC);
51 list_add(&sp->list, &ptr_list);
57 * Shadow variable wrapper functions that echo the function and arguments
58 * to the kernel log for testing verification. Don't display raw pointers,
59 * but use the ptr_id() value instead.
61 static void *shadow_get(void *obj, unsigned long id)
65 sv = klp_shadow_get(obj, id);
66 pr_info("klp_%s(obj=PTR%d, id=0x%lx) = PTR%d\n",
67 __func__, ptr_id(obj), id, ptr_id(sv));
72 static void *shadow_alloc(void *obj, unsigned long id, size_t size,
73 gfp_t gfp_flags, klp_shadow_ctor_t ctor,
76 int **var = ctor_data;
79 sv = klp_shadow_alloc(obj, id, size, gfp_flags, ctor, var);
80 pr_info("klp_%s(obj=PTR%d, id=0x%lx, size=%zx, gfp_flags=%pGg), ctor=PTR%d, ctor_data=PTR%d = PTR%d\n",
81 __func__, ptr_id(obj), id, size, &gfp_flags, ptr_id(ctor),
82 ptr_id(*var), ptr_id(sv));
87 static void *shadow_get_or_alloc(void *obj, unsigned long id, size_t size,
88 gfp_t gfp_flags, klp_shadow_ctor_t ctor,
91 int **var = ctor_data;
94 sv = klp_shadow_get_or_alloc(obj, id, size, gfp_flags, ctor, var);
95 pr_info("klp_%s(obj=PTR%d, id=0x%lx, size=%zx, gfp_flags=%pGg), ctor=PTR%d, ctor_data=PTR%d = PTR%d\n",
96 __func__, ptr_id(obj), id, size, &gfp_flags, ptr_id(ctor),
97 ptr_id(*var), ptr_id(sv));
102 static void shadow_free(void *obj, unsigned long id, klp_shadow_dtor_t dtor)
104 klp_shadow_free(obj, id, dtor);
105 pr_info("klp_%s(obj=PTR%d, id=0x%lx, dtor=PTR%d)\n",
106 __func__, ptr_id(obj), id, ptr_id(dtor));
109 static void shadow_free_all(unsigned long id, klp_shadow_dtor_t dtor)
111 klp_shadow_free_all(id, dtor);
112 pr_info("klp_%s(id=0x%lx, dtor=PTR%d)\n",
113 __func__, id, ptr_id(dtor));
117 /* Shadow variable constructor - remember simple pointer data */
118 static int shadow_ctor(void *obj, void *shadow_data, void *ctor_data)
120 int **sv = shadow_data;
121 int **var = ctor_data;
127 pr_info("%s: PTR%d -> PTR%d\n",
128 __func__, ptr_id(sv), ptr_id(*var));
133 static void shadow_dtor(void *obj, void *shadow_data)
135 int **sv = shadow_data;
137 pr_info("%s(obj=PTR%d, shadow_data=PTR%d)\n",
138 __func__, ptr_id(obj), ptr_id(sv));
141 static int test_klp_shadow_vars_init(void)
143 void *obj = THIS_MODULE;
145 gfp_t gfp_flags = GFP_KERNEL;
147 int var1, var2, var3, var4;
148 int *pv1, *pv2, *pv3, *pv4;
149 int **sv1, **sv2, **sv3, **sv4;
165 * With an empty shadow variable hash table, expect not to find
168 sv = shadow_get(obj, id);
170 pr_info(" got expected NULL result\n");
173 * Allocate a few shadow variables with different <obj> and <id>.
175 sv1 = shadow_alloc(obj, id, sizeof(pv1), gfp_flags, shadow_ctor, &pv1);
179 sv2 = shadow_alloc(obj + 1, id, sizeof(pv2), gfp_flags, shadow_ctor, &pv2);
183 sv3 = shadow_alloc(obj, id + 1, sizeof(pv3), gfp_flags, shadow_ctor, &pv3);
188 * Verify we can find our new shadow variables and that they point
191 sv = shadow_get(obj, id);
194 if (sv == sv1 && *sv1 == pv1)
195 pr_info(" got expected PTR%d -> PTR%d result\n",
196 ptr_id(sv1), ptr_id(*sv1));
198 sv = shadow_get(obj + 1, id);
201 if (sv == sv2 && *sv2 == pv2)
202 pr_info(" got expected PTR%d -> PTR%d result\n",
203 ptr_id(sv2), ptr_id(*sv2));
204 sv = shadow_get(obj, id + 1);
207 if (sv == sv3 && *sv3 == pv3)
208 pr_info(" got expected PTR%d -> PTR%d result\n",
209 ptr_id(sv3), ptr_id(*sv3));
212 * Allocate or get a few more, this time with the same <obj>, <id>.
213 * The second invocation should return the same shadow var.
215 sv4 = shadow_get_or_alloc(obj + 2, id, sizeof(pv4), gfp_flags, shadow_ctor, &pv4);
219 sv = shadow_get_or_alloc(obj + 2, id, sizeof(pv4), gfp_flags, shadow_ctor, &pv4);
222 if (sv == sv4 && *sv4 == pv4)
223 pr_info(" got expected PTR%d -> PTR%d result\n",
224 ptr_id(sv4), ptr_id(*sv4));
227 * Free the <obj=*, id> shadow variables and check that we can no
230 shadow_free(obj, id, shadow_dtor); /* sv1 */
231 sv = shadow_get(obj, id);
233 pr_info(" got expected NULL result\n");
235 shadow_free(obj + 1, id, shadow_dtor); /* sv2 */
236 sv = shadow_get(obj + 1, id);
238 pr_info(" got expected NULL result\n");
240 shadow_free(obj + 2, id, shadow_dtor); /* sv4 */
241 sv = shadow_get(obj + 2, id);
243 pr_info(" got expected NULL result\n");
246 * We should still find an <id+1> variable.
248 sv = shadow_get(obj, id + 1);
251 if (sv == sv3 && *sv3 == pv3)
252 pr_info(" got expected PTR%d -> PTR%d result\n",
253 ptr_id(sv3), ptr_id(*sv3));
256 * Free all the <id+1> variables, too.
258 shadow_free_all(id + 1, shadow_dtor); /* sv3 */
259 sv = shadow_get(obj, id);
261 pr_info(" shadow_get() got expected NULL result\n");
269 static void test_klp_shadow_vars_exit(void)
273 module_init(test_klp_shadow_vars_init);
274 module_exit(test_klp_shadow_vars_exit);
275 MODULE_LICENSE("GPL");
276 MODULE_AUTHOR("Joe Lawrence <joe.lawrence@redhat.com>");
277 MODULE_DESCRIPTION("Livepatch test: shadow variables");