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-rw-r--r--lib/livepatch/test_klp_shadow_vars.c301
1 files changed, 301 insertions, 0 deletions
diff --git a/lib/livepatch/test_klp_shadow_vars.c b/lib/livepatch/test_klp_shadow_vars.c
new file mode 100644
index 000000000..b99116490
--- /dev/null
+++ b/lib/livepatch/test_klp_shadow_vars.c
@@ -0,0 +1,301 @@
+// 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");