diff options
Diffstat (limited to 'lib/livepatch/test_klp_shadow_vars.c')
| -rw-r--r-- | lib/livepatch/test_klp_shadow_vars.c | 236 |
1 files changed, 236 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 000000000000..02f892f941dc --- /dev/null +++ b/lib/livepatch/test_klp_shadow_vars.c @@ -0,0 +1,236 @@ +// 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 -1; + 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) +{ + void *ret = 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(ret)); + + return ret; +} + +static void *shadow_alloc(void *obj, unsigned long id, size_t size, + gfp_t gfp_flags, klp_shadow_ctor_t ctor, + void *ctor_data) +{ + void *ret = klp_shadow_alloc(obj, id, size, gfp_flags, ctor, + ctor_data); + 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(ctor_data), ptr_id(ret)); + return ret; +} + +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) +{ + void *ret = klp_shadow_get_or_alloc(obj, id, size, gfp_flags, ctor, + ctor_data); + 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(ctor_data), ptr_id(ret)); + return ret; +} + +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 **shadow_int = shadow_data; + *shadow_int = ctor_data; + pr_info("%s: PTR%d -> PTR%d\n", + __func__, ptr_id(shadow_int), ptr_id(ctor_data)); + + return 0; +} + +static void shadow_dtor(void *obj, void *shadow_data) +{ + pr_info("%s(obj=PTR%d, shadow_data=PTR%d)\n", + __func__, ptr_id(obj), ptr_id(shadow_data)); +} + +static int test_klp_shadow_vars_init(void) +{ + void *obj = THIS_MODULE; + int id = 0x1234; + size_t size = sizeof(int *); + gfp_t gfp_flags = GFP_KERNEL; + + int var1, var2, var3, var4; + int **sv1, **sv2, **sv3, **sv4; + + void *ret; + + ptr_id(NULL); + ptr_id(&var1); + ptr_id(&var2); + ptr_id(&var3); + ptr_id(&var4); + + /* + * With an empty shadow variable hash table, expect not to find + * any matches. + */ + ret = shadow_get(obj, id); + if (!ret) + pr_info(" got expected NULL result\n"); + + /* + * Allocate a few shadow variables with different <obj> and <id>. + */ + sv1 = shadow_alloc(obj, id, size, gfp_flags, shadow_ctor, &var1); + sv2 = shadow_alloc(obj + 1, id, size, gfp_flags, shadow_ctor, &var2); + sv3 = shadow_alloc(obj, id + 1, size, gfp_flags, shadow_ctor, &var3); + + /* + * Verify we can find our new shadow variables and that they point + * to expected data. + */ + ret = shadow_get(obj, id); + if (ret == sv1 && *sv1 == &var1) + pr_info(" got expected PTR%d -> PTR%d result\n", + ptr_id(sv1), ptr_id(*sv1)); + ret = shadow_get(obj + 1, id); + if (ret == sv2 && *sv2 == &var2) + pr_info(" got expected PTR%d -> PTR%d result\n", + ptr_id(sv2), ptr_id(*sv2)); + ret = shadow_get(obj, id + 1); + if (ret == sv3 && *sv3 == &var3) + pr_info(" got expected PTR%d -> PTR%d result\n", + ptr_id(sv3), ptr_id(*sv3)); + + /* + * Allocate or get a few more, this time with the same <obj>, <id>. + * The second invocation should return the same shadow var. + */ + sv4 = shadow_get_or_alloc(obj + 2, id, size, gfp_flags, shadow_ctor, &var4); + ret = shadow_get_or_alloc(obj + 2, id, size, gfp_flags, shadow_ctor, &var4); + if (ret == sv4 && *sv4 == &var4) + pr_info(" got expected PTR%d -> PTR%d result\n", + ptr_id(sv4), ptr_id(*sv4)); + + /* + * Free the <obj=*, id> shadow variables and check that we can no + * longer find them. + */ + shadow_free(obj, id, shadow_dtor); /* sv1 */ + ret = shadow_get(obj, id); + if (!ret) + pr_info(" got expected NULL result\n"); + + shadow_free(obj + 1, id, shadow_dtor); /* sv2 */ + ret = shadow_get(obj + 1, id); + if (!ret) + pr_info(" got expected NULL result\n"); + + shadow_free(obj + 2, id, shadow_dtor); /* sv4 */ + ret = shadow_get(obj + 2, id); + if (!ret) + pr_info(" got expected NULL result\n"); + + /* + * We should still find an <id+1> variable. + */ + ret = shadow_get(obj, id + 1); + if (ret == sv3 && *sv3 == &var3) + pr_info(" got expected PTR%d -> PTR%d result\n", + ptr_id(sv3), ptr_id(*sv3)); + + /* + * Free all the <id+1> variables, too. + */ + shadow_free_all(id + 1, shadow_dtor); /* sv3 */ + ret = shadow_get(obj, id); + if (!ret) + pr_info(" shadow_get() got expected NULL result\n"); + + + free_ptr_list(); + + return 0; +} + +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"); |