[mirror_ubuntu-hirsute-kernel.git] / lib / livepatch / test_klp_shadow_vars.c

// SPDX-License-Identifier: GPL-2.0
// Copyright (C) 2018 Joe Lawrence <joe.lawrence@redhat.com>

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/livepatch.h>
#include <linux/slab.h>

/*
 * Keep a small list of pointers so that we can print address-agnostic
 * pointer values.  Use a rolling integer count to differentiate the values.
 * Ironically we could have used the shadow variable API to do this, but
 * let's not lean too heavily on the very code we're testing.
 */
static LIST_HEAD(ptr_list);
struct shadow_ptr {
	void *ptr;
	int id;
	struct list_head list;
};

static void free_ptr_list(void)
{
	struct shadow_ptr *sp, *tmp_sp;

	list_for_each_entry_safe(sp, tmp_sp, &ptr_list, list) {
		list_del(&sp->list);
		kfree(sp);
	}
}

static int ptr_id(void *ptr)
{
	struct shadow_ptr *sp;
	static int count;

	list_for_each_entry(sp, &ptr_list, list) {
		if (sp->ptr == ptr)
			return sp->id;
	}

	sp = kmalloc(sizeof(*sp), GFP_ATOMIC);
	if (!sp)
		return -ENOMEM;
	sp->ptr = ptr;
	sp->id = count++;

	list_add(&sp->list, &ptr_list);

	return sp->id;
}

/*
 * Shadow variable wrapper functions that echo the function and arguments
 * to the kernel log for testing verification.  Don't display raw pointers,
 * but use the ptr_id() value instead.
 */
static void *shadow_get(void *obj, unsigned long id)
{
	int **sv;

	sv = klp_shadow_get(obj, id);
	pr_info("klp_%s(obj=PTR%d, id=0x%lx) = PTR%d\n",
		__func__, ptr_id(obj), id, ptr_id(sv));

	return sv;
}

static void *shadow_alloc(void *obj, unsigned long id, size_t size,
			  gfp_t gfp_flags, klp_shadow_ctor_t ctor,
			  void *ctor_data)
{
	int **var = ctor_data;
	int **sv;

	sv = klp_shadow_alloc(obj, id, size, gfp_flags, ctor, var);
	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",
		__func__, ptr_id(obj), id, size, &gfp_flags, ptr_id(ctor),
		ptr_id(*var), ptr_id(sv));

	return sv;
}

static void *shadow_get_or_alloc(void *obj, unsigned long id, size_t size,
				 gfp_t gfp_flags, klp_shadow_ctor_t ctor,
				 void *ctor_data)
{
	int **var = ctor_data;
	int **sv;

	sv = klp_shadow_get_or_alloc(obj, id, size, gfp_flags, ctor, var);
	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",
		__func__, ptr_id(obj), id, size, &gfp_flags, ptr_id(ctor),
		ptr_id(*var), ptr_id(sv));

	return sv;
}

static void shadow_free(void *obj, unsigned long id, klp_shadow_dtor_t dtor)
{
	klp_shadow_free(obj, id, dtor);
	pr_info("klp_%s(obj=PTR%d, id=0x%lx, dtor=PTR%d)\n",
		__func__, ptr_id(obj), id, ptr_id(dtor));
}

static void shadow_free_all(unsigned long id, klp_shadow_dtor_t dtor)
{
	klp_shadow_free_all(id, dtor);
	pr_info("klp_%s(id=0x%lx, dtor=PTR%d)\n", __func__, id, ptr_id(dtor));
}


/* Shadow variable constructor - remember simple pointer data */
static int shadow_ctor(void *obj, void *shadow_data, void *ctor_data)
{
	int **sv = shadow_data;
	int **var = ctor_data;

	if (!var)
		return -EINVAL;

	*sv = *var;
	pr_info("%s: PTR%d -> PTR%d\n", __func__, ptr_id(sv), ptr_id(*var));

	return 0;
}

/*
 * With more than one item to free in the list, order is not determined and
 * shadow_dtor will not be passed to shadow_free_all() which would make the
 * test fail. (see pass 6)
 */
static void shadow_dtor(void *obj, void *shadow_data)
{
	int **sv = shadow_data;

	pr_info("%s(obj=PTR%d, shadow_data=PTR%d)\n",
		__func__, ptr_id(obj), ptr_id(sv));
}

/* number of objects we simulate that need shadow vars */
#define NUM_OBJS 3

/* dynamically created obj fields have the following shadow var id values */
#define SV_ID1 0x1234
#define SV_ID2 0x1235

/*
 * The main test case adds/removes new fields (shadow var) to each of these
 * test structure instances. The last group of fields in the struct represent
 * the idea that shadow variables may be added and removed to and from the
 * struct during execution.
 */
struct test_object {
	 /* add anything here below and avoid to define an empty struct */
	struct shadow_ptr sp;

	/* these represent shadow vars added and removed with SV_ID{1,2} */
	/* char nfield1; */
	/* int  nfield2; */
};

static int test_klp_shadow_vars_init(void)
{
	struct test_object objs[NUM_OBJS];
	char nfields1[NUM_OBJS], *pnfields1[NUM_OBJS], **sv1[NUM_OBJS];
	char *pndup[NUM_OBJS];
	int nfields2[NUM_OBJS], *pnfields2[NUM_OBJS], **sv2[NUM_OBJS];
	void **sv;
	int ret;
	int i;

	ptr_id(NULL);

	/*
	 * With an empty shadow variable hash table, expect not to find
	 * any matches.
	 */
	sv = shadow_get(&objs[0], SV_ID1);
	if (!sv)
		pr_info("  got expected NULL result\n");

	/* pass 1: init & alloc a char+int pair of svars for each objs */
	for (i = 0; i < NUM_OBJS; i++) {
		pnfields1[i] = &nfields1[i];
		ptr_id(pnfields1[i]);

		if (i % 2) {
			sv1[i] = shadow_alloc(&objs[i], SV_ID1,
					sizeof(pnfields1[i]), GFP_KERNEL,
					shadow_ctor, &pnfields1[i]);
		} else {
			sv1[i] = shadow_get_or_alloc(&objs[i], SV_ID1,
					sizeof(pnfields1[i]), GFP_KERNEL,
					shadow_ctor, &pnfields1[i]);
		}
		if (!sv1[i]) {
			ret = -ENOMEM;
			goto out;
		}

		pnfields2[i] = &nfields2[i];
		ptr_id(pnfields2[i]);
		sv2[i] = shadow_alloc(&objs[i], SV_ID2, sizeof(pnfields2[i]),
					GFP_KERNEL, shadow_ctor, &pnfields2[i]);
		if (!sv2[i]) {
			ret = -ENOMEM;
			goto out;
		}
	}

	/* pass 2: verify we find allocated svars and where they point to */
	for (i = 0; i < NUM_OBJS; i++) {
		/* check the "char" svar for all objects */
		sv = shadow_get(&objs[i], SV_ID1);
		if (!sv) {
			ret = -EINVAL;
			goto out;
		}
		if ((char **)sv == sv1[i] && *sv1[i] == pnfields1[i])
			pr_info("  got expected PTR%d -> PTR%d result\n",
				ptr_id(sv1[i]), ptr_id(*sv1[i]));

		/* check the "int" svar for all objects */
		sv = shadow_get(&objs[i], SV_ID2);
		if (!sv) {
			ret = -EINVAL;
			goto out;
		}
		if ((int **)sv == sv2[i] && *sv2[i] == pnfields2[i])
			pr_info("  got expected PTR%d -> PTR%d result\n",
				ptr_id(sv2[i]), ptr_id(*sv2[i]));
	}

	/* pass 3: verify that 'get_or_alloc' returns already allocated svars */
	for (i = 0; i < NUM_OBJS; i++) {
		pndup[i] = &nfields1[i];
		ptr_id(pndup[i]);

		sv = shadow_get_or_alloc(&objs[i], SV_ID1, sizeof(pndup[i]),
					GFP_KERNEL, shadow_ctor, &pndup[i]);
		if (!sv) {
			ret = -EINVAL;
			goto out;
		}
		if ((char **)sv == sv1[i] && *sv1[i] == pnfields1[i])
			pr_info("  got expected PTR%d -> PTR%d result\n",
					ptr_id(sv1[i]), ptr_id(*sv1[i]));
	}

	/* pass 4: free <objs[*], SV_ID1> pairs of svars, verify removal */
	for (i = 0; i < NUM_OBJS; i++) {
		shadow_free(&objs[i], SV_ID1, shadow_dtor); /* 'char' pairs */
		sv = shadow_get(&objs[i], SV_ID1);
		if (!sv)
			pr_info("  got expected NULL result\n");
	}

	/* pass 5: check we still find <objs[*], SV_ID2> svar pairs */
	for (i = 0; i < NUM_OBJS; i++) {
		sv = shadow_get(&objs[i], SV_ID2);	/* 'int' pairs */
		if (!sv) {
			ret = -EINVAL;
			goto out;
		}
		if ((int **)sv == sv2[i] && *sv2[i] == pnfields2[i])
			pr_info("  got expected PTR%d -> PTR%d result\n",
					ptr_id(sv2[i]), ptr_id(*sv2[i]));
	}

	/* pass 6: free all the <objs[*], SV_ID2> svar pairs too. */
	shadow_free_all(SV_ID2, NULL);		/* 'int' pairs */
	for (i = 0; i < NUM_OBJS; i++) {
		sv = shadow_get(&objs[i], SV_ID2);
		if (!sv)
			pr_info("  got expected NULL result\n");
	}

	free_ptr_list();

	return 0;
out:
	shadow_free_all(SV_ID1, NULL);		/* 'char' pairs */
	shadow_free_all(SV_ID2, NULL);		/* 'int' pairs */
	free_ptr_list();

	return ret;
}

static void test_klp_shadow_vars_exit(void)
{
}

module_init(test_klp_shadow_vars_init);
module_exit(test_klp_shadow_vars_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Joe Lawrence <joe.lawrence@redhat.com>");
MODULE_DESCRIPTION("Livepatch test: shadow variables");
Commit	Line	Data
a2818ee4 JL	1	// SPDX-License-Identifier: GPL-2.0
	2	// Copyright (C) 2018 Joe Lawrence <joe.lawrence@redhat.com>
	3
	4	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
	5
	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-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.
	17	*/
	18	static LIST_HEAD(ptr_list);
	19	struct shadow_ptr {
	20	void *ptr;
	21	int id;
	22	struct list_head list;
	23	};
	24
	25	static 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
	35	static 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)
86e43f23	47	return -ENOMEM;
a2818ee4 JL	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 arguments
	58	* to the kernel log for testing verification. Don't display raw pointers,
	59	* but use the ptr_id() value instead.
	60	*/
	61	static void shadow_get(void obj, unsigned long id)
	62	{
c24c57a4	63	int **sv;
a2818ee4	64
c24c57a4	65	sv = klp_shadow_get(obj, id);
a2818ee4	66	pr_info("klp_%s(obj=PTR%d, id=0x%lx) = PTR%d\n",
c24c57a4	67	__func__, ptr_id(obj), id, ptr_id(sv));
a2818ee4	68
c24c57a4	69	return sv;
a2818ee4 JL	70	}
	71
	72	static 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	{
be6da984	76	int **var = ctor_data;
c24c57a4 PM	77	int **sv;
	78
	79	sv = klp_shadow_alloc(obj, id, size, gfp_flags, ctor, var);
a2818ee4 JL	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",
a2818ee4 JL	81	__func__, ptr_id(obj), id, size, &gfp_flags, ptr_id(ctor),
be6da984	82	ptr_id(*var), ptr_id(sv));
c24c57a4 PM	83
c24c57a4 PM	84	return sv;
a2818ee4 JL	85	}
	86
	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,
	89	void *ctor_data)
	90	{
be6da984	91	int **var = ctor_data;
c24c57a4 PM	92	int **sv;
	93
	94	sv = klp_shadow_get_or_alloc(obj, id, size, gfp_flags, ctor, var);
a2818ee4 JL	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",
a2818ee4 JL	96	__func__, ptr_id(obj), id, size, &gfp_flags, ptr_id(ctor),
be6da984	97	ptr_id(*var), ptr_id(sv));
c24c57a4 PM	98
c24c57a4 PM	99	return sv;
a2818ee4 JL	100	}
	101
	102	static 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
	109	static void shadow_free_all(unsigned long id, klp_shadow_dtor_t dtor)
	110	{
	111	klp_shadow_free_all(id, dtor);
6a26a9df	112	pr_info("klp_%s(id=0x%lx, dtor=PTR%d)\n", __func__, id, ptr_id(dtor));
a2818ee4 JL	113	}
	114
	115
	116	/* Shadow variable constructor - remember simple pointer data */
	117	static int shadow_ctor(void obj, void shadow_data, void *ctor_data)
	118	{
c24c57a4	119	int **sv = shadow_data;
be6da984	120	int **var = ctor_data;
c24c57a4	121
be6da984 PM	122	if (!var)
	123	return -EINVAL;
	124
	125	sv = var;
6a26a9df	126	pr_info("%s: PTR%d -> PTR%d\n", __func__, ptr_id(sv), ptr_id(*var));
a2818ee4 JL	127
	128	return 0;
	129	}
	130
76efe6da YC	131	/*
	132	* With more than one item to free in the list, order is not determined and
	133	* shadow_dtor will not be passed to shadow_free_all() which would make the
	134	* test fail. (see pass 6)
	135	*/
a2818ee4 JL	136	static void shadow_dtor(void obj, void shadow_data)
a2818ee4 JL	137	{
c24c57a4 PM	138	int **sv = shadow_data;
c24c57a4 PM	139
a2818ee4	140	pr_info("%s(obj=PTR%d, shadow_data=PTR%d)\n",
c24c57a4	141	__func__, ptr_id(obj), ptr_id(sv));
a2818ee4 JL	142	}
a2818ee4 JL	143
76efe6da YC	144	/* number of objects we simulate that need shadow vars */
	145	#define NUM_OBJS 3
	146
6a26a9df YC	147	/* dynamically created obj fields have the following shadow var id values */
	148	#define SV_ID1 0x1234
	149	#define SV_ID2 0x1235
a2818ee4	150
6a26a9df YC	151	/*
	152	* The main test case adds/removes new fields (shadow var) to each of these
	153	* test structure instances. The last group of fields in the struct represent
	154	* the idea that shadow variables may be added and removed to and from the
	155	* struct during execution.
	156	*/
	157	struct test_object {
	158	/* add anything here below and avoid to define an empty struct */
	159	struct shadow_ptr sp;
a2818ee4	160
6a26a9df YC	161	/* these represent shadow vars added and removed with SV_ID{1,2} */
	162	/* char nfield1; */
	163	/* int nfield2; */
	164	};
a2818ee4	165
6a26a9df YC	166	static int test_klp_shadow_vars_init(void)
6a26a9df YC	167	{
76efe6da YC	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];
6a26a9df	172	void **sv;
270f7806	173	int ret;
76efe6da	174	int i;
be6da984	175
a2818ee4	176	ptr_id(NULL);
a2818ee4 JL	177
	178	/*
	179	* With an empty shadow variable hash table, expect not to find
	180	* any matches.
	181	*/
76efe6da	182	sv = shadow_get(&objs[0], SV_ID1);
c24c57a4	183	if (!sv)
a2818ee4 JL	184	pr_info(" got expected NULL result\n");
a2818ee4 JL	185
76efe6da YC	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	}
270f7806 YC	200	if (!sv1[i]) {
	201	ret = -ENOMEM;
	202	goto out;
	203	}
76efe6da YC	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]);
270f7806 YC	209	if (!sv2[i]) {
	210	ret = -ENOMEM;
	211	goto out;
	212	}
76efe6da	213	}
a2818ee4	214
76efe6da YC	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);
270f7806 YC	219	if (!sv) {
	220	ret = -EINVAL;
	221	goto out;
	222	}
76efe6da YC	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);
270f7806 YC	229	if (!sv) {
	230	ret = -EINVAL;
	231	goto out;
	232	}
76efe6da YC	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	}
a2818ee4	237
76efe6da YC	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]);
270f7806 YC	245	if (!sv) {
	246	ret = -EINVAL;
	247	goto out;
	248	}
76efe6da YC	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	}
a2818ee4	253
76efe6da YC	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	}
a2818ee4	261
76efe6da YC	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 */
270f7806 YC	265	if (!sv) {
	266	ret = -EINVAL;
	267	goto out;
	268	}
76efe6da YC	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	}
a2818ee4	273
76efe6da YC	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	}
a2818ee4 JL	281
	282	free_ptr_list();
	283
	284	return 0;
270f7806 YC	285	out:
	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;
a2818ee4 JL	291	}
	292
	293	static void test_klp_shadow_vars_exit(void)
	294	{
	295	}
	296
	297	module_init(test_klp_shadow_vars_init);
	298	module_exit(test_klp_shadow_vars_exit);
	299	MODULE_LICENSE("GPL");
	300	MODULE_AUTHOR("Joe Lawrence <joe.lawrence@redhat.com>");
	301	MODULE_DESCRIPTION("Livepatch test: shadow variables");