1e886bf9dSAndrey Konovalov // SPDX-License-Identifier: GPL-2.0 20b24beccSAndrey Ryabinin /* 359fd51b2SAndrey Konovalov * This file contains common KASAN error reporting code. 40b24beccSAndrey Ryabinin * 50b24beccSAndrey Ryabinin * Copyright (c) 2014 Samsung Electronics Co., Ltd. 62baf9e89SAndrey Ryabinin * Author: Andrey Ryabinin <ryabinin.a.a@gmail.com> 70b24beccSAndrey Ryabinin * 85d0926efSAndrey Konovalov * Some code borrowed from https://github.com/xairy/kasan-prototype by 95f21f3a8SAndrey Konovalov * Andrey Konovalov <andreyknvl@gmail.com> 100b24beccSAndrey Ryabinin */ 110b24beccSAndrey Ryabinin 12b0845ce5SMark Rutland #include <linux/bitops.h> 134f40c6e5SPeter Zijlstra #include <linux/ftrace.h> 14b0845ce5SMark Rutland #include <linux/init.h> 150b24beccSAndrey Ryabinin #include <linux/kernel.h> 16c32caa26SAndrey Konovalov #include <linux/lockdep.h> 170b24beccSAndrey Ryabinin #include <linux/mm.h> 180b24beccSAndrey Ryabinin #include <linux/printk.h> 190b24beccSAndrey Ryabinin #include <linux/sched.h> 200b24beccSAndrey Ryabinin #include <linux/slab.h> 21cd11016eSAlexander Potapenko #include <linux/stackdepot.h> 220b24beccSAndrey Ryabinin #include <linux/stacktrace.h> 230b24beccSAndrey Ryabinin #include <linux/string.h> 240b24beccSAndrey Ryabinin #include <linux/types.h> 250b24beccSAndrey Ryabinin #include <linux/kasan.h> 26527f215bSAneesh Kumar K.V #include <linux/module.h> 27e8969219SMarco Elver #include <linux/sched/task_stack.h> 284fba3758SAndrey Konovalov #include <linux/uaccess.h> 29d3a61f74SAlexander Potapenko #include <trace/events/error_report.h> 300b24beccSAndrey Ryabinin 31bebf56a1SAndrey Ryabinin #include <asm/sections.h> 32bebf56a1SAndrey Ryabinin 3383c4e7a0SPatricia Alfonso #include <kunit/test.h> 3483c4e7a0SPatricia Alfonso 350b24beccSAndrey Ryabinin #include "kasan.h" 360316bec2SAndrey Ryabinin #include "../slab.h" 370b24beccSAndrey Ryabinin 3811cd3cd6SAndrey Konovalov static unsigned long kasan_flags; 3911cd3cd6SAndrey Konovalov 4011cd3cd6SAndrey Konovalov #define KASAN_BIT_REPORTED 0 4111cd3cd6SAndrey Konovalov #define KASAN_BIT_MULTI_SHOT 1 4211cd3cd6SAndrey Konovalov 43c9d1af2bSWoody Lin enum kasan_arg_fault { 44c9d1af2bSWoody Lin KASAN_ARG_FAULT_DEFAULT, 45c9d1af2bSWoody Lin KASAN_ARG_FAULT_REPORT, 46c9d1af2bSWoody Lin KASAN_ARG_FAULT_PANIC, 47c9d1af2bSWoody Lin }; 48c9d1af2bSWoody Lin 49c9d1af2bSWoody Lin static enum kasan_arg_fault kasan_arg_fault __ro_after_init = KASAN_ARG_FAULT_DEFAULT; 50c9d1af2bSWoody Lin 51c9d1af2bSWoody Lin /* kasan.fault=report/panic */ 52c9d1af2bSWoody Lin static int __init early_kasan_fault(char *arg) 53c9d1af2bSWoody Lin { 54c9d1af2bSWoody Lin if (!arg) 55c9d1af2bSWoody Lin return -EINVAL; 56c9d1af2bSWoody Lin 57c9d1af2bSWoody Lin if (!strcmp(arg, "report")) 58c9d1af2bSWoody Lin kasan_arg_fault = KASAN_ARG_FAULT_REPORT; 59c9d1af2bSWoody Lin else if (!strcmp(arg, "panic")) 60c9d1af2bSWoody Lin kasan_arg_fault = KASAN_ARG_FAULT_PANIC; 61c9d1af2bSWoody Lin else 62c9d1af2bSWoody Lin return -EINVAL; 63c9d1af2bSWoody Lin 64c9d1af2bSWoody Lin return 0; 65c9d1af2bSWoody Lin } 66c9d1af2bSWoody Lin early_param("kasan.fault", early_kasan_fault); 67c9d1af2bSWoody Lin 6811cd3cd6SAndrey Konovalov static int __init kasan_set_multi_shot(char *str) 690b24beccSAndrey Ryabinin { 7011cd3cd6SAndrey Konovalov set_bit(KASAN_BIT_MULTI_SHOT, &kasan_flags); 7111cd3cd6SAndrey Konovalov return 1; 720b24beccSAndrey Ryabinin } 7311cd3cd6SAndrey Konovalov __setup("kasan_multi_shot", kasan_set_multi_shot); 740b24beccSAndrey Ryabinin 75865bfa28SAndrey Konovalov /* 76865bfa28SAndrey Konovalov * Used to suppress reports within kasan_disable/enable_current() critical 77865bfa28SAndrey Konovalov * sections, which are used for marking accesses to slab metadata. 78865bfa28SAndrey Konovalov */ 79865bfa28SAndrey Konovalov static bool report_suppressed(void) 805e82cd12SAndrey Konovalov { 81865bfa28SAndrey Konovalov #if defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS) 82865bfa28SAndrey Konovalov if (current->kasan_depth) 83865bfa28SAndrey Konovalov return true; 84865bfa28SAndrey Konovalov #endif 85865bfa28SAndrey Konovalov return false; 8631c65110SAndrey Konovalov } 8731c65110SAndrey Konovalov 88865bfa28SAndrey Konovalov /* 89865bfa28SAndrey Konovalov * Used to avoid reporting more than one KASAN bug unless kasan_multi_shot 90865bfa28SAndrey Konovalov * is enabled. Note that KASAN tests effectively enable kasan_multi_shot 91865bfa28SAndrey Konovalov * for their duration. 92865bfa28SAndrey Konovalov */ 93865bfa28SAndrey Konovalov static bool report_enabled(void) 94865bfa28SAndrey Konovalov { 95865bfa28SAndrey Konovalov if (test_bit(KASAN_BIT_MULTI_SHOT, &kasan_flags)) 96865bfa28SAndrey Konovalov return true; 97865bfa28SAndrey Konovalov return !test_and_set_bit(KASAN_BIT_REPORTED, &kasan_flags); 980b24beccSAndrey Ryabinin } 990b24beccSAndrey Ryabinin 10080207910SAndrey Konovalov #if IS_ENABLED(CONFIG_KASAN_KUNIT_TEST) || IS_ENABLED(CONFIG_KASAN_MODULE_TEST) 10180207910SAndrey Konovalov 10280207910SAndrey Konovalov bool kasan_save_enable_multi_shot(void) 10380207910SAndrey Konovalov { 10480207910SAndrey Konovalov return test_and_set_bit(KASAN_BIT_MULTI_SHOT, &kasan_flags); 10580207910SAndrey Konovalov } 10680207910SAndrey Konovalov EXPORT_SYMBOL_GPL(kasan_save_enable_multi_shot); 10780207910SAndrey Konovalov 10880207910SAndrey Konovalov void kasan_restore_multi_shot(bool enabled) 10980207910SAndrey Konovalov { 11080207910SAndrey Konovalov if (!enabled) 11180207910SAndrey Konovalov clear_bit(KASAN_BIT_MULTI_SHOT, &kasan_flags); 11280207910SAndrey Konovalov } 11380207910SAndrey Konovalov EXPORT_SYMBOL_GPL(kasan_restore_multi_shot); 11480207910SAndrey Konovalov 11580207910SAndrey Konovalov #endif 11680207910SAndrey Konovalov 117a260d281SAndrey Konovalov #if IS_ENABLED(CONFIG_KASAN_KUNIT_TEST) 118a260d281SAndrey Konovalov static void update_kunit_status(bool sync) 119a260d281SAndrey Konovalov { 120a260d281SAndrey Konovalov struct kunit *test; 121a260d281SAndrey Konovalov struct kunit_resource *resource; 122a260d281SAndrey Konovalov struct kunit_kasan_status *status; 123a260d281SAndrey Konovalov 124a260d281SAndrey Konovalov test = current->kunit_test; 125a260d281SAndrey Konovalov if (!test) 126a260d281SAndrey Konovalov return; 127a260d281SAndrey Konovalov 128a260d281SAndrey Konovalov resource = kunit_find_named_resource(test, "kasan_status"); 129a260d281SAndrey Konovalov if (!resource) { 130a260d281SAndrey Konovalov kunit_set_failure(test); 131a260d281SAndrey Konovalov return; 132a260d281SAndrey Konovalov } 133a260d281SAndrey Konovalov 134a260d281SAndrey Konovalov status = (struct kunit_kasan_status *)resource->data; 135a260d281SAndrey Konovalov WRITE_ONCE(status->report_found, true); 136a260d281SAndrey Konovalov WRITE_ONCE(status->sync_fault, sync); 137a260d281SAndrey Konovalov 138a260d281SAndrey Konovalov kunit_put_resource(resource); 139a260d281SAndrey Konovalov } 140a260d281SAndrey Konovalov #else 141a260d281SAndrey Konovalov static void update_kunit_status(bool sync) { } 142a260d281SAndrey Konovalov #endif 143a260d281SAndrey Konovalov 1447e088978SAndrey Ryabinin static DEFINE_SPINLOCK(report_lock); 1457e088978SAndrey Ryabinin 146a260d281SAndrey Konovalov static void start_report(unsigned long *flags, bool sync) 1477e088978SAndrey Ryabinin { 1480a6e8a07SAndrey Konovalov /* Respect the /proc/sys/kernel/traceoff_on_warning interface. */ 1490a6e8a07SAndrey Konovalov disable_trace_on_warning(); 150a260d281SAndrey Konovalov /* Update status of the currently running KASAN test. */ 151a260d281SAndrey Konovalov update_kunit_status(sync); 152c32caa26SAndrey Konovalov /* Do not allow LOCKDEP mangling KASAN reports. */ 153c32caa26SAndrey Konovalov lockdep_off(); 154a260d281SAndrey Konovalov /* Make sure we don't end up in loop. */ 1557e088978SAndrey Ryabinin kasan_disable_current(); 1567e088978SAndrey Ryabinin spin_lock_irqsave(&report_lock, *flags); 1577e088978SAndrey Ryabinin pr_err("==================================================================\n"); 1587e088978SAndrey Ryabinin } 1597e088978SAndrey Ryabinin 1609d7b7dd9SAndrey Konovalov static void end_report(unsigned long *flags, void *addr) 1617e088978SAndrey Ryabinin { 162476b1dc2SAndrey Konovalov if (addr) 1639d7b7dd9SAndrey Konovalov trace_error_report_end(ERROR_DETECTOR_KASAN, 1649d7b7dd9SAndrey Konovalov (unsigned long)addr); 1657e088978SAndrey Ryabinin pr_err("==================================================================\n"); 1667e088978SAndrey Ryabinin spin_unlock_irqrestore(&report_lock, *flags); 167e7ce7500STiezhu Yang if (panic_on_warn && !test_bit(KASAN_BIT_MULTI_SHOT, &kasan_flags)) 1685c5c1f36SDmitry Vyukov panic("panic_on_warn set ...\n"); 169c9d1af2bSWoody Lin if (kasan_arg_fault == KASAN_ARG_FAULT_PANIC) 1708028caacSAndrey Konovalov panic("kasan.fault=panic set ...\n"); 171c32caa26SAndrey Konovalov add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE); 172c32caa26SAndrey Konovalov lockdep_on(); 1737e088978SAndrey Ryabinin kasan_enable_current(); 1747e088978SAndrey Ryabinin } 1757e088978SAndrey Ryabinin 176865bfa28SAndrey Konovalov static void print_error_description(struct kasan_report_info *info) 177865bfa28SAndrey Konovalov { 178865bfa28SAndrey Konovalov if (info->type == KASAN_REPORT_INVALID_FREE) { 179865bfa28SAndrey Konovalov pr_err("BUG: KASAN: double-free or invalid-free in %pS\n", 180865bfa28SAndrey Konovalov (void *)info->ip); 181865bfa28SAndrey Konovalov return; 182865bfa28SAndrey Konovalov } 183865bfa28SAndrey Konovalov 184865bfa28SAndrey Konovalov pr_err("BUG: KASAN: %s in %pS\n", 185865bfa28SAndrey Konovalov kasan_get_bug_type(info), (void *)info->ip); 186865bfa28SAndrey Konovalov if (info->access_size) 187865bfa28SAndrey Konovalov pr_err("%s of size %zu at addr %px by task %s/%d\n", 188865bfa28SAndrey Konovalov info->is_write ? "Write" : "Read", info->access_size, 189865bfa28SAndrey Konovalov info->access_addr, current->comm, task_pid_nr(current)); 190865bfa28SAndrey Konovalov else 191865bfa28SAndrey Konovalov pr_err("%s at addr %px by task %s/%d\n", 192865bfa28SAndrey Konovalov info->is_write ? "Write" : "Read", 193865bfa28SAndrey Konovalov info->access_addr, current->comm, task_pid_nr(current)); 194865bfa28SAndrey Konovalov } 195865bfa28SAndrey Konovalov 196b6b72f49SAndrey Konovalov static void print_track(struct kasan_track *track, const char *prefix) 1977ed2f9e6SAlexander Potapenko { 198b6b72f49SAndrey Konovalov pr_err("%s by task %u:\n", prefix, track->pid); 199cd11016eSAlexander Potapenko if (track->stack) { 200505be481SImran Khan stack_depot_print(track->stack); 201cd11016eSAlexander Potapenko } else { 202cd11016eSAlexander Potapenko pr_err("(stack is not available)\n"); 203cd11016eSAlexander Potapenko } 2047ed2f9e6SAlexander Potapenko } 2057ed2f9e6SAlexander Potapenko 206ae8f06b3SWalter Wu struct page *kasan_addr_to_page(const void *addr) 207db429f16SAndrey Konovalov { 208db429f16SAndrey Konovalov if ((addr >= (void *)PAGE_OFFSET) && 209db429f16SAndrey Konovalov (addr < high_memory)) 210db429f16SAndrey Konovalov return virt_to_head_page(addr); 211db429f16SAndrey Konovalov return NULL; 212db429f16SAndrey Konovalov } 213db429f16SAndrey Konovalov 2146e48a966SMatthew Wilcox (Oracle) struct slab *kasan_addr_to_slab(const void *addr) 2156e48a966SMatthew Wilcox (Oracle) { 2166e48a966SMatthew Wilcox (Oracle) if ((addr >= (void *)PAGE_OFFSET) && 2176e48a966SMatthew Wilcox (Oracle) (addr < high_memory)) 2186e48a966SMatthew Wilcox (Oracle) return virt_to_slab(addr); 2196e48a966SMatthew Wilcox (Oracle) return NULL; 2206e48a966SMatthew Wilcox (Oracle) } 2216e48a966SMatthew Wilcox (Oracle) 2220c06f1f8SAndrey Konovalov static void describe_object_addr(struct kmem_cache *cache, void *object, 2230c06f1f8SAndrey Konovalov const void *addr) 2240c06f1f8SAndrey Konovalov { 2250c06f1f8SAndrey Konovalov unsigned long access_addr = (unsigned long)addr; 2260c06f1f8SAndrey Konovalov unsigned long object_addr = (unsigned long)object; 2270c06f1f8SAndrey Konovalov const char *rel_type; 2280c06f1f8SAndrey Konovalov int rel_bytes; 2290c06f1f8SAndrey Konovalov 2306424f6bbSTobin C. Harding pr_err("The buggy address belongs to the object at %px\n" 2310c06f1f8SAndrey Konovalov " which belongs to the cache %s of size %d\n", 2320c06f1f8SAndrey Konovalov object, cache->name, cache->object_size); 2330c06f1f8SAndrey Konovalov 2340c06f1f8SAndrey Konovalov if (access_addr < object_addr) { 2350c06f1f8SAndrey Konovalov rel_type = "to the left"; 2360c06f1f8SAndrey Konovalov rel_bytes = object_addr - access_addr; 2370c06f1f8SAndrey Konovalov } else if (access_addr >= object_addr + cache->object_size) { 2380c06f1f8SAndrey Konovalov rel_type = "to the right"; 2390c06f1f8SAndrey Konovalov rel_bytes = access_addr - (object_addr + cache->object_size); 2400c06f1f8SAndrey Konovalov } else { 2410c06f1f8SAndrey Konovalov rel_type = "inside"; 2420c06f1f8SAndrey Konovalov rel_bytes = access_addr - object_addr; 2430c06f1f8SAndrey Konovalov } 2440c06f1f8SAndrey Konovalov 2450c06f1f8SAndrey Konovalov pr_err("The buggy address is located %d bytes %s of\n" 2466424f6bbSTobin C. Harding " %d-byte region [%px, %px)\n", 2470c06f1f8SAndrey Konovalov rel_bytes, rel_type, cache->object_size, (void *)object_addr, 2480c06f1f8SAndrey Konovalov (void *)(object_addr + cache->object_size)); 2490c06f1f8SAndrey Konovalov } 2500c06f1f8SAndrey Konovalov 2518028caacSAndrey Konovalov static void describe_object_stacks(struct kmem_cache *cache, void *object, 252ae8f06b3SWalter Wu const void *addr, u8 tag) 2537ed2f9e6SAlexander Potapenko { 25497593cadSAndrey Konovalov struct kasan_alloc_meta *alloc_meta; 255ae8f06b3SWalter Wu struct kasan_track *free_track; 256ae8f06b3SWalter Wu 25797593cadSAndrey Konovalov alloc_meta = kasan_get_alloc_meta(cache, object); 25897593cadSAndrey Konovalov if (alloc_meta) { 2596476792fSAndrey Konovalov print_track(&alloc_meta->alloc_track, "Allocated"); 260b1938599SAndrey Konovalov pr_err("\n"); 26197593cadSAndrey Konovalov } 26297593cadSAndrey Konovalov 263ae8f06b3SWalter Wu free_track = kasan_get_free_track(cache, object, tag); 264e4b7818bSWalter Wu if (free_track) { 265ae8f06b3SWalter Wu print_track(free_track, "Freed"); 266b1938599SAndrey Konovalov pr_err("\n"); 267e4b7818bSWalter Wu } 26826e760c9SWalter Wu 26926e760c9SWalter Wu #ifdef CONFIG_KASAN_GENERIC 27097593cadSAndrey Konovalov if (!alloc_meta) 27197593cadSAndrey Konovalov return; 2726476792fSAndrey Konovalov if (alloc_meta->aux_stack[0]) { 273ef133461SWalter Wu pr_err("Last potentially related work creation:\n"); 274505be481SImran Khan stack_depot_print(alloc_meta->aux_stack[0]); 27526e760c9SWalter Wu pr_err("\n"); 27626e760c9SWalter Wu } 2776476792fSAndrey Konovalov if (alloc_meta->aux_stack[1]) { 278ef133461SWalter Wu pr_err("Second to last potentially related work creation:\n"); 279505be481SImran Khan stack_depot_print(alloc_meta->aux_stack[1]); 28026e760c9SWalter Wu pr_err("\n"); 28126e760c9SWalter Wu } 28226e760c9SWalter Wu #endif 2837ed2f9e6SAlexander Potapenko } 2847ed2f9e6SAlexander Potapenko 2858028caacSAndrey Konovalov static void describe_object(struct kmem_cache *cache, void *object, 2868028caacSAndrey Konovalov const void *addr, u8 tag) 2878028caacSAndrey Konovalov { 2888028caacSAndrey Konovalov if (kasan_stack_collection_enabled()) 2898028caacSAndrey Konovalov describe_object_stacks(cache, object, addr, tag); 2900c06f1f8SAndrey Konovalov describe_object_addr(cache, object, addr); 2910c06f1f8SAndrey Konovalov } 2920c06f1f8SAndrey Konovalov 29311cd3cd6SAndrey Konovalov static inline bool kernel_or_module_addr(const void *addr) 29411cd3cd6SAndrey Konovalov { 2953298cbe8SKefeng Wang if (is_kernel((unsigned long)addr)) 29611cd3cd6SAndrey Konovalov return true; 29711cd3cd6SAndrey Konovalov if (is_module_address((unsigned long)addr)) 29811cd3cd6SAndrey Konovalov return true; 29911cd3cd6SAndrey Konovalov return false; 30011cd3cd6SAndrey Konovalov } 30111cd3cd6SAndrey Konovalov 30211cd3cd6SAndrey Konovalov static inline bool init_task_stack_addr(const void *addr) 30311cd3cd6SAndrey Konovalov { 30411cd3cd6SAndrey Konovalov return addr >= (void *)&init_thread_union.stack && 30511cd3cd6SAndrey Konovalov (addr <= (void *)&init_thread_union.stack + 30611cd3cd6SAndrey Konovalov sizeof(init_thread_union.stack)); 30711cd3cd6SAndrey Konovalov } 30811cd3cd6SAndrey Konovalov 309ae8f06b3SWalter Wu static void print_address_description(void *addr, u8 tag) 3107e088978SAndrey Ryabinin { 311ae8f06b3SWalter Wu struct page *page = kasan_addr_to_page(addr); 312b8c73fc2SAndrey Ryabinin 313336abff6SAlexander Potapenko dump_stack_lvl(KERN_ERR); 314b1938599SAndrey Konovalov pr_err("\n"); 315db429f16SAndrey Konovalov 316db429f16SAndrey Konovalov if (page && PageSlab(page)) { 3176e48a966SMatthew Wilcox (Oracle) struct slab *slab = page_slab(page); 3186e48a966SMatthew Wilcox (Oracle) struct kmem_cache *cache = slab->slab_cache; 3196e48a966SMatthew Wilcox (Oracle) void *object = nearest_obj(cache, slab, addr); 320db429f16SAndrey Konovalov 321ae8f06b3SWalter Wu describe_object(cache, object, addr, tag); 322038fd2b4SAndrey Konovalov pr_err("\n"); 323b8c73fc2SAndrey Ryabinin } 324b8c73fc2SAndrey Ryabinin 325430a05f9SAndrey Konovalov if (kernel_or_module_addr(addr) && !init_task_stack_addr(addr)) { 326430a05f9SAndrey Konovalov pr_err("The buggy address belongs to the variable:\n"); 327430a05f9SAndrey Konovalov pr_err(" %pS\n", addr); 328038fd2b4SAndrey Konovalov pr_err("\n"); 329430a05f9SAndrey Konovalov } 330430a05f9SAndrey Konovalov 3310f9b35f3SAndrey Konovalov if (object_is_on_stack(addr)) { 3320f9b35f3SAndrey Konovalov /* 3330f9b35f3SAndrey Konovalov * Currently, KASAN supports printing frame information only 3340f9b35f3SAndrey Konovalov * for accesses to the task's own stack. 3350f9b35f3SAndrey Konovalov */ 3360f9b35f3SAndrey Konovalov kasan_print_address_stack_frame(addr); 3370f9b35f3SAndrey Konovalov pr_err("\n"); 3380f9b35f3SAndrey Konovalov } 3390f9b35f3SAndrey Konovalov 340c056a364SAndrey Konovalov if (is_vmalloc_addr(addr)) { 341c056a364SAndrey Konovalov struct vm_struct *va = find_vm_area(addr); 342c056a364SAndrey Konovalov 343c056a364SAndrey Konovalov if (va) { 344c056a364SAndrey Konovalov pr_err("The buggy address belongs to the virtual mapping at\n" 345c056a364SAndrey Konovalov " [%px, %px) created by:\n" 346c056a364SAndrey Konovalov " %pS\n", 347c056a364SAndrey Konovalov va->addr, va->addr + va->size, va->caller); 348038fd2b4SAndrey Konovalov pr_err("\n"); 349c056a364SAndrey Konovalov 350*fbf4df06SKefeng Wang page = vmalloc_to_page(addr); 351c056a364SAndrey Konovalov } 352c056a364SAndrey Konovalov } 353c056a364SAndrey Konovalov 354430a05f9SAndrey Konovalov if (page) { 355c056a364SAndrey Konovalov pr_err("The buggy address belongs to the physical page:\n"); 356430a05f9SAndrey Konovalov dump_page(page, "kasan: bad access detected"); 357038fd2b4SAndrey Konovalov pr_err("\n"); 358bebf56a1SAndrey Ryabinin } 3590b24beccSAndrey Ryabinin } 3600b24beccSAndrey Ryabinin 36196e0279dSAndrey Konovalov static bool meta_row_is_guilty(const void *row, const void *addr) 3620b24beccSAndrey Ryabinin { 36396e0279dSAndrey Konovalov return (row <= addr) && (addr < row + META_MEM_BYTES_PER_ROW); 3640b24beccSAndrey Ryabinin } 3650b24beccSAndrey Ryabinin 36696e0279dSAndrey Konovalov static int meta_pointer_offset(const void *row, const void *addr) 3670b24beccSAndrey Ryabinin { 36896e0279dSAndrey Konovalov /* 36996e0279dSAndrey Konovalov * Memory state around the buggy address: 37096e0279dSAndrey Konovalov * ff00ff00ff00ff00: 00 00 00 05 fe fe fe fe fe fe fe fe fe fe fe fe 37196e0279dSAndrey Konovalov * ... 37296e0279dSAndrey Konovalov * 37396e0279dSAndrey Konovalov * The length of ">ff00ff00ff00ff00: " is 3740b24beccSAndrey Ryabinin * 3 + (BITS_PER_LONG / 8) * 2 chars. 37596e0279dSAndrey Konovalov * The length of each granule metadata is 2 bytes 37696e0279dSAndrey Konovalov * plus 1 byte for space. 3770b24beccSAndrey Ryabinin */ 37896e0279dSAndrey Konovalov return 3 + (BITS_PER_LONG / 8) * 2 + 37996e0279dSAndrey Konovalov (addr - row) / KASAN_GRANULE_SIZE * 3 + 1; 3800b24beccSAndrey Ryabinin } 3810b24beccSAndrey Ryabinin 382db3de8f7SAndrey Konovalov static void print_memory_metadata(const void *addr) 3830b24beccSAndrey Ryabinin { 3840b24beccSAndrey Ryabinin int i; 38596e0279dSAndrey Konovalov void *row; 3860b24beccSAndrey Ryabinin 38796e0279dSAndrey Konovalov row = (void *)round_down((unsigned long)addr, META_MEM_BYTES_PER_ROW) 38896e0279dSAndrey Konovalov - META_ROWS_AROUND_ADDR * META_MEM_BYTES_PER_ROW; 3890b24beccSAndrey Ryabinin 3900b24beccSAndrey Ryabinin pr_err("Memory state around the buggy address:\n"); 3910b24beccSAndrey Ryabinin 39288b86597SAndrey Konovalov for (i = -META_ROWS_AROUND_ADDR; i <= META_ROWS_AROUND_ADDR; i++) { 3930b24beccSAndrey Ryabinin char buffer[4 + (BITS_PER_LONG / 8) * 2]; 39496e0279dSAndrey Konovalov char metadata[META_BYTES_PER_ROW]; 3950b24beccSAndrey Ryabinin 3960b24beccSAndrey Ryabinin snprintf(buffer, sizeof(buffer), 39796e0279dSAndrey Konovalov (i == 0) ? ">%px: " : " %px: ", row); 39896e0279dSAndrey Konovalov 399f2377d4eSAneesh Kumar K.V /* 400f2377d4eSAneesh Kumar K.V * We should not pass a shadow pointer to generic 401f2377d4eSAneesh Kumar K.V * function, because generic functions may try to 402f2377d4eSAneesh Kumar K.V * access kasan mapping for the passed address. 403f2377d4eSAneesh Kumar K.V */ 404f00748bfSAndrey Konovalov kasan_metadata_fetch_row(&metadata[0], row); 40596e0279dSAndrey Konovalov 4060b24beccSAndrey Ryabinin print_hex_dump(KERN_ERR, buffer, 40788b86597SAndrey Konovalov DUMP_PREFIX_NONE, META_BYTES_PER_ROW, 1, 40896e0279dSAndrey Konovalov metadata, META_BYTES_PER_ROW, 0); 4090b24beccSAndrey Ryabinin 41096e0279dSAndrey Konovalov if (meta_row_is_guilty(row, addr)) 41196e0279dSAndrey Konovalov pr_err("%*c\n", meta_pointer_offset(row, addr), '^'); 4120b24beccSAndrey Ryabinin 41396e0279dSAndrey Konovalov row += META_MEM_BYTES_PER_ROW; 4140b24beccSAndrey Ryabinin } 4150b24beccSAndrey Ryabinin } 4160b24beccSAndrey Ryabinin 417c965cdd6SAndrey Konovalov static void print_report(struct kasan_report_info *info) 4189d7b7dd9SAndrey Konovalov { 4199d7b7dd9SAndrey Konovalov void *tagged_addr = info->access_addr; 4209d7b7dd9SAndrey Konovalov void *untagged_addr = kasan_reset_tag(tagged_addr); 4219d7b7dd9SAndrey Konovalov u8 tag = get_tag(tagged_addr); 4229d7b7dd9SAndrey Konovalov 4239d7b7dd9SAndrey Konovalov print_error_description(info); 4249d7b7dd9SAndrey Konovalov if (addr_has_metadata(untagged_addr)) 4259d7b7dd9SAndrey Konovalov kasan_print_tags(tag, info->first_bad_addr); 4269d7b7dd9SAndrey Konovalov pr_err("\n"); 4279d7b7dd9SAndrey Konovalov 4289d7b7dd9SAndrey Konovalov if (addr_has_metadata(untagged_addr)) { 4299d7b7dd9SAndrey Konovalov print_address_description(untagged_addr, tag); 4309d7b7dd9SAndrey Konovalov print_memory_metadata(info->first_bad_addr); 4319d7b7dd9SAndrey Konovalov } else { 4329d7b7dd9SAndrey Konovalov dump_stack_lvl(KERN_ERR); 4339d7b7dd9SAndrey Konovalov } 4349d7b7dd9SAndrey Konovalov } 4359d7b7dd9SAndrey Konovalov 43631c65110SAndrey Konovalov void kasan_report_invalid_free(void *ptr, unsigned long ip) 43731c65110SAndrey Konovalov { 43831c65110SAndrey Konovalov unsigned long flags; 439c965cdd6SAndrey Konovalov struct kasan_report_info info; 44031c65110SAndrey Konovalov 441c068664cSAndrey Konovalov /* 442c068664cSAndrey Konovalov * Do not check report_suppressed(), as an invalid-free cannot be 443c068664cSAndrey Konovalov * caused by accessing slab metadata and thus should not be 444c068664cSAndrey Konovalov * suppressed by kasan_disable/enable_current() critical sections. 445c068664cSAndrey Konovalov */ 446c068664cSAndrey Konovalov if (unlikely(!report_enabled())) 447c068664cSAndrey Konovalov return; 448c068664cSAndrey Konovalov 44931c65110SAndrey Konovalov start_report(&flags, true); 45031c65110SAndrey Konovalov 45131c65110SAndrey Konovalov info.type = KASAN_REPORT_INVALID_FREE; 45231c65110SAndrey Konovalov info.access_addr = ptr; 45331c65110SAndrey Konovalov info.first_bad_addr = kasan_reset_tag(ptr); 45431c65110SAndrey Konovalov info.access_size = 0; 45531c65110SAndrey Konovalov info.is_write = false; 45631c65110SAndrey Konovalov info.ip = ip; 45731c65110SAndrey Konovalov 45831c65110SAndrey Konovalov print_report(&info); 45931c65110SAndrey Konovalov 46031c65110SAndrey Konovalov end_report(&flags, ptr); 46131c65110SAndrey Konovalov } 46231c65110SAndrey Konovalov 463795b760fSAndrey Konovalov /* 464795b760fSAndrey Konovalov * kasan_report() is the only reporting function that uses 465795b760fSAndrey Konovalov * user_access_save/restore(): kasan_report_invalid_free() cannot be called 466795b760fSAndrey Konovalov * from a UACCESS region, and kasan_report_async() is not used on x86. 467795b760fSAndrey Konovalov */ 4684fba3758SAndrey Konovalov bool kasan_report(unsigned long addr, size_t size, bool is_write, 4694fba3758SAndrey Konovalov unsigned long ip) 4704fba3758SAndrey Konovalov { 471b3bb1d70SAndrey Konovalov bool ret = true; 472be8631a1SAndrey Konovalov void *ptr = (void *)addr; 473be8631a1SAndrey Konovalov unsigned long ua_flags = user_access_save(); 474be8631a1SAndrey Konovalov unsigned long irq_flags; 475c965cdd6SAndrey Konovalov struct kasan_report_info info; 4764fba3758SAndrey Konovalov 477c068664cSAndrey Konovalov if (unlikely(report_suppressed()) || unlikely(!report_enabled())) { 478b3bb1d70SAndrey Konovalov ret = false; 479b3bb1d70SAndrey Konovalov goto out; 4804fba3758SAndrey Konovalov } 4814fba3758SAndrey Konovalov 482be8631a1SAndrey Konovalov start_report(&irq_flags, true); 483be8631a1SAndrey Konovalov 48431c65110SAndrey Konovalov info.type = KASAN_REPORT_ACCESS; 485be8631a1SAndrey Konovalov info.access_addr = ptr; 486be8631a1SAndrey Konovalov info.first_bad_addr = kasan_find_first_bad_addr(ptr, size); 487be8631a1SAndrey Konovalov info.access_size = size; 488be8631a1SAndrey Konovalov info.is_write = is_write; 489be8631a1SAndrey Konovalov info.ip = ip; 490be8631a1SAndrey Konovalov 491be8631a1SAndrey Konovalov print_report(&info); 492be8631a1SAndrey Konovalov 493be8631a1SAndrey Konovalov end_report(&irq_flags, ptr); 494b3bb1d70SAndrey Konovalov 495b3bb1d70SAndrey Konovalov out: 496b3bb1d70SAndrey Konovalov user_access_restore(ua_flags); 4974fba3758SAndrey Konovalov 4984fba3758SAndrey Konovalov return ret; 4994fba3758SAndrey Konovalov } 5004fba3758SAndrey Konovalov 501bb2f967cSAndrey Konovalov #ifdef CONFIG_KASAN_HW_TAGS 502bb2f967cSAndrey Konovalov void kasan_report_async(void) 503bb2f967cSAndrey Konovalov { 504bb2f967cSAndrey Konovalov unsigned long flags; 505bb2f967cSAndrey Konovalov 506c068664cSAndrey Konovalov /* 507c068664cSAndrey Konovalov * Do not check report_suppressed(), as kasan_disable/enable_current() 508c068664cSAndrey Konovalov * critical sections do not affect Hardware Tag-Based KASAN. 509c068664cSAndrey Konovalov */ 510c068664cSAndrey Konovalov if (unlikely(!report_enabled())) 511c068664cSAndrey Konovalov return; 512c068664cSAndrey Konovalov 513bb2f967cSAndrey Konovalov start_report(&flags, false); 514bb2f967cSAndrey Konovalov pr_err("BUG: KASAN: invalid-access\n"); 515bb2f967cSAndrey Konovalov pr_err("Asynchronous fault: no details available\n"); 516bb2f967cSAndrey Konovalov pr_err("\n"); 517bb2f967cSAndrey Konovalov dump_stack_lvl(KERN_ERR); 518bb2f967cSAndrey Konovalov end_report(&flags, NULL); 519bb2f967cSAndrey Konovalov } 520bb2f967cSAndrey Konovalov #endif /* CONFIG_KASAN_HW_TAGS */ 521bb2f967cSAndrey Konovalov 5222f004eeaSJann Horn #ifdef CONFIG_KASAN_INLINE 5232f004eeaSJann Horn /* 5242f004eeaSJann Horn * With CONFIG_KASAN_INLINE, accesses to bogus pointers (outside the high 5252f004eeaSJann Horn * canonical half of the address space) cause out-of-bounds shadow memory reads 5262f004eeaSJann Horn * before the actual access. For addresses in the low canonical half of the 5272f004eeaSJann Horn * address space, as well as most non-canonical addresses, that out-of-bounds 5282f004eeaSJann Horn * shadow memory access lands in the non-canonical part of the address space. 5292f004eeaSJann Horn * Help the user figure out what the original bogus pointer was. 5302f004eeaSJann Horn */ 5312f004eeaSJann Horn void kasan_non_canonical_hook(unsigned long addr) 5322f004eeaSJann Horn { 5332f004eeaSJann Horn unsigned long orig_addr; 5342f004eeaSJann Horn const char *bug_type; 5352f004eeaSJann Horn 5362f004eeaSJann Horn if (addr < KASAN_SHADOW_OFFSET) 5372f004eeaSJann Horn return; 5382f004eeaSJann Horn 5392f004eeaSJann Horn orig_addr = (addr - KASAN_SHADOW_OFFSET) << KASAN_SHADOW_SCALE_SHIFT; 5402f004eeaSJann Horn /* 5412f004eeaSJann Horn * For faults near the shadow address for NULL, we can be fairly certain 5422f004eeaSJann Horn * that this is a KASAN shadow memory access. 5432f004eeaSJann Horn * For faults that correspond to shadow for low canonical addresses, we 5442f004eeaSJann Horn * can still be pretty sure - that shadow region is a fairly narrow 5452f004eeaSJann Horn * chunk of the non-canonical address space. 5462f004eeaSJann Horn * But faults that look like shadow for non-canonical addresses are a 5472f004eeaSJann Horn * really large chunk of the address space. In that case, we still 5482f004eeaSJann Horn * print the decoded address, but make it clear that this is not 5492f004eeaSJann Horn * necessarily what's actually going on. 5502f004eeaSJann Horn */ 5512f004eeaSJann Horn if (orig_addr < PAGE_SIZE) 5522f004eeaSJann Horn bug_type = "null-ptr-deref"; 5532f004eeaSJann Horn else if (orig_addr < TASK_SIZE) 5542f004eeaSJann Horn bug_type = "probably user-memory-access"; 5552f004eeaSJann Horn else 5562f004eeaSJann Horn bug_type = "maybe wild-memory-access"; 5572f004eeaSJann Horn pr_alert("KASAN: %s in range [0x%016lx-0x%016lx]\n", bug_type, 5581f600626SAndrey Konovalov orig_addr, orig_addr + KASAN_GRANULE_SIZE - 1); 5592f004eeaSJann Horn } 5602f004eeaSJann Horn #endif 561