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1// SPDX-License-Identifier: GPL-2.02// Copyright (C) 2018 Joe Lawrence <joe.lawrence@redhat.com>3 4#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt5 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>11 12/*13 * Keep a small list of pointers so that we can print address-agnostic14 * pointer values. Use a rolling integer count to differentiate the values.15 * Ironically we could have used the shadow variable API to do this, but16 * let's not lean too heavily on the very code we're testing.17 */18static LIST_HEAD(ptr_list);19struct shadow_ptr {20 void *ptr;21 int id;22 struct list_head list;23};24 25static void free_ptr_list(void)26{27 struct shadow_ptr *sp, *tmp_sp;28 29 list_for_each_entry_safe(sp, tmp_sp, &ptr_list, list) {30 list_del(&sp->list);31 kfree(sp);32 }33}34 35static int ptr_id(void *ptr)36{37 struct shadow_ptr *sp;38 static int count;39 40 list_for_each_entry(sp, &ptr_list, list) {41 if (sp->ptr == ptr)42 return sp->id;43 }44 45 sp = kmalloc(sizeof(*sp), GFP_ATOMIC);46 if (!sp)47 return -ENOMEM;48 sp->ptr = ptr;49 sp->id = count++;50 51 list_add(&sp->list, &ptr_list);52 53 return sp->id;54}55 56/*57 * Shadow variable wrapper functions that echo the function and arguments58 * to the kernel log for testing verification. Don't display raw pointers,59 * but use the ptr_id() value instead.60 */61static void *shadow_get(void *obj, unsigned long id)62{63 int **sv;64 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));68 69 return sv;70}71 72static void *shadow_alloc(void *obj, unsigned long id, size_t size,73 gfp_t gfp_flags, klp_shadow_ctor_t ctor,74 void *ctor_data)75{76 int **var = ctor_data;77 int **sv;78 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));83 84 return sv;85}86 87static void *shadow_get_or_alloc(void *obj, unsigned long id, size_t size,88 gfp_t gfp_flags, klp_shadow_ctor_t ctor,89 void *ctor_data)90{91 int **var = ctor_data;92 int **sv;93 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));98 99 return sv;100}101 102static void shadow_free(void *obj, unsigned long id, klp_shadow_dtor_t dtor)103{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));107}108 109static void shadow_free_all(unsigned long id, klp_shadow_dtor_t dtor)110{111 klp_shadow_free_all(id, dtor);112 pr_info("klp_%s(id=0x%lx, dtor=PTR%d)\n", __func__, id, ptr_id(dtor));113}114 115 116/* Shadow variable constructor - remember simple pointer data */117static int shadow_ctor(void *obj, void *shadow_data, void *ctor_data)118{119 int **sv = shadow_data;120 int **var = ctor_data;121 122 if (!var)123 return -EINVAL;124 125 *sv = *var;126 pr_info("%s: PTR%d -> PTR%d\n", __func__, ptr_id(sv), ptr_id(*var));127 128 return 0;129}130 131/*132 * With more than one item to free in the list, order is not determined and133 * shadow_dtor will not be passed to shadow_free_all() which would make the134 * test fail. (see pass 6)135 */136static void shadow_dtor(void *obj, void *shadow_data)137{138 int **sv = shadow_data;139 140 pr_info("%s(obj=PTR%d, shadow_data=PTR%d)\n",141 __func__, ptr_id(obj), ptr_id(sv));142}143 144/* number of objects we simulate that need shadow vars */145#define NUM_OBJS 3146 147/* dynamically created obj fields have the following shadow var id values */148#define SV_ID1 0x1234149#define SV_ID2 0x1235150 151/*152 * The main test case adds/removes new fields (shadow var) to each of these153 * test structure instances. The last group of fields in the struct represent154 * the idea that shadow variables may be added and removed to and from the155 * struct during execution.156 */157struct test_object {158 /* add anything here below and avoid to define an empty struct */159 struct shadow_ptr sp;160 161 /* these represent shadow vars added and removed with SV_ID{1,2} */162 /* char nfield1; */163 /* int nfield2; */164};165 166static int test_klp_shadow_vars_init(void)167{168 struct test_object objs[NUM_OBJS];169 char nfields1[NUM_OBJS], *pnfields1[NUM_OBJS], **sv1[NUM_OBJS];170 char *pndup[NUM_OBJS];171 int nfields2[NUM_OBJS], *pnfields2[NUM_OBJS], **sv2[NUM_OBJS];172 void **sv;173 int ret;174 int i;175 176 ptr_id(NULL);177 178 /*179 * With an empty shadow variable hash table, expect not to find180 * any matches.181 */182 sv = shadow_get(&objs[0], SV_ID1);183 if (!sv)184 pr_info(" got expected NULL result\n");185 186 /* pass 1: init & alloc a char+int pair of svars for each objs */187 for (i = 0; i < NUM_OBJS; i++) {188 pnfields1[i] = &nfields1[i];189 ptr_id(pnfields1[i]);190 191 if (i % 2) {192 sv1[i] = shadow_alloc(&objs[i], SV_ID1,193 sizeof(pnfields1[i]), GFP_KERNEL,194 shadow_ctor, &pnfields1[i]);195 } else {196 sv1[i] = shadow_get_or_alloc(&objs[i], SV_ID1,197 sizeof(pnfields1[i]), GFP_KERNEL,198 shadow_ctor, &pnfields1[i]);199 }200 if (!sv1[i]) {201 ret = -ENOMEM;202 goto out;203 }204 205 pnfields2[i] = &nfields2[i];206 ptr_id(pnfields2[i]);207 sv2[i] = shadow_alloc(&objs[i], SV_ID2, sizeof(pnfields2[i]),208 GFP_KERNEL, shadow_ctor, &pnfields2[i]);209 if (!sv2[i]) {210 ret = -ENOMEM;211 goto out;212 }213 }214 215 /* pass 2: verify we find allocated svars and where they point to */216 for (i = 0; i < NUM_OBJS; i++) {217 /* check the "char" svar for all objects */218 sv = shadow_get(&objs[i], SV_ID1);219 if (!sv) {220 ret = -EINVAL;221 goto out;222 }223 if ((char **)sv == sv1[i] && *sv1[i] == pnfields1[i])224 pr_info(" got expected PTR%d -> PTR%d result\n",225 ptr_id(sv1[i]), ptr_id(*sv1[i]));226 227 /* check the "int" svar for all objects */228 sv = shadow_get(&objs[i], SV_ID2);229 if (!sv) {230 ret = -EINVAL;231 goto out;232 }233 if ((int **)sv == sv2[i] && *sv2[i] == pnfields2[i])234 pr_info(" got expected PTR%d -> PTR%d result\n",235 ptr_id(sv2[i]), ptr_id(*sv2[i]));236 }237 238 /* pass 3: verify that 'get_or_alloc' returns already allocated svars */239 for (i = 0; i < NUM_OBJS; i++) {240 pndup[i] = &nfields1[i];241 ptr_id(pndup[i]);242 243 sv = shadow_get_or_alloc(&objs[i], SV_ID1, sizeof(pndup[i]),244 GFP_KERNEL, shadow_ctor, &pndup[i]);245 if (!sv) {246 ret = -EINVAL;247 goto out;248 }249 if ((char **)sv == sv1[i] && *sv1[i] == pnfields1[i])250 pr_info(" got expected PTR%d -> PTR%d result\n",251 ptr_id(sv1[i]), ptr_id(*sv1[i]));252 }253 254 /* pass 4: free <objs[*], SV_ID1> pairs of svars, verify removal */255 for (i = 0; i < NUM_OBJS; i++) {256 shadow_free(&objs[i], SV_ID1, shadow_dtor); /* 'char' pairs */257 sv = shadow_get(&objs[i], SV_ID1);258 if (!sv)259 pr_info(" got expected NULL result\n");260 }261 262 /* pass 5: check we still find <objs[*], SV_ID2> svar pairs */263 for (i = 0; i < NUM_OBJS; i++) {264 sv = shadow_get(&objs[i], SV_ID2); /* 'int' pairs */265 if (!sv) {266 ret = -EINVAL;267 goto out;268 }269 if ((int **)sv == sv2[i] && *sv2[i] == pnfields2[i])270 pr_info(" got expected PTR%d -> PTR%d result\n",271 ptr_id(sv2[i]), ptr_id(*sv2[i]));272 }273 274 /* pass 6: free all the <objs[*], SV_ID2> svar pairs too. */275 shadow_free_all(SV_ID2, NULL); /* 'int' pairs */276 for (i = 0; i < NUM_OBJS; i++) {277 sv = shadow_get(&objs[i], SV_ID2);278 if (!sv)279 pr_info(" got expected NULL result\n");280 }281 282 free_ptr_list();283 284 return 0;285out:286 shadow_free_all(SV_ID1, NULL); /* 'char' pairs */287 shadow_free_all(SV_ID2, NULL); /* 'int' pairs */288 free_ptr_list();289 290 return ret;291}292 293static void test_klp_shadow_vars_exit(void)294{295}296 297module_init(test_klp_shadow_vars_init);298module_exit(test_klp_shadow_vars_exit);299MODULE_LICENSE("GPL");300MODULE_AUTHOR("Joe Lawrence <joe.lawrence@redhat.com>");301MODULE_DESCRIPTION("Livepatch test: shadow variables");302