123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225226227228229230231232233234235236237238239240241242243244245246247248249250251252253254255256257258259260261262263264265266267268269270271272273274275276277278279280281282283284285286287288289290291292293294295296297298299300301302303304305306307308309310311312313314315316317318319320321322323324325326327328329330331332333334335336337338339340341342343344345346347348349350351352353354355356357358359360361362363364365366367368369370371372373374375376377378379380381382383384385386387388389390391392393394395396397398399400401402403404405406407408409410411412413414415416417418419420421422423424425426427428429430431432433434435436437438439440441442443444445446447448449450451452453454455 |
- #include <linux/bitops.h>
- #include <linux/ftrace.h>
- #include <linux/init.h>
- #include <linux/kernel.h>
- #include <linux/mm.h>
- #include <linux/printk.h>
- #include <linux/sched.h>
- #include <linux/slab.h>
- #include <linux/stackdepot.h>
- #include <linux/stacktrace.h>
- #include <linux/string.h>
- #include <linux/types.h>
- #include <linux/kasan.h>
- #include <linux/module.h>
- #include <asm/sections.h>
- #include "kasan.h"
- #include "../slab.h"
- #define SHADOW_BYTES_PER_BLOCK 1
- #define SHADOW_BLOCKS_PER_ROW 16
- #define SHADOW_BYTES_PER_ROW (SHADOW_BLOCKS_PER_ROW * SHADOW_BYTES_PER_BLOCK)
- #define SHADOW_ROWS_AROUND_ADDR 2
- static const void *find_first_bad_addr(const void *addr, size_t size)
- {
- u8 shadow_val = *(u8 *)kasan_mem_to_shadow(addr);
- const void *first_bad_addr = addr;
- while (!shadow_val && first_bad_addr < addr + size) {
- first_bad_addr += KASAN_SHADOW_SCALE_SIZE;
- shadow_val = *(u8 *)kasan_mem_to_shadow(first_bad_addr);
- }
- return first_bad_addr;
- }
- static bool addr_has_shadow(struct kasan_access_info *info)
- {
- return (info->access_addr >=
- kasan_shadow_to_mem((void *)KASAN_SHADOW_START));
- }
- static const char *get_shadow_bug_type(struct kasan_access_info *info)
- {
- const char *bug_type = "unknown-crash";
- u8 *shadow_addr;
- info->first_bad_addr = find_first_bad_addr(info->access_addr,
- info->access_size);
- shadow_addr = (u8 *)kasan_mem_to_shadow(info->first_bad_addr);
-
- if (*shadow_addr > 0 && *shadow_addr <= KASAN_SHADOW_SCALE_SIZE - 1)
- shadow_addr++;
- switch (*shadow_addr) {
- case 0 ... KASAN_SHADOW_SCALE_SIZE - 1:
-
- bug_type = "out-of-bounds";
- break;
- case KASAN_PAGE_REDZONE:
- case KASAN_KMALLOC_REDZONE:
- bug_type = "slab-out-of-bounds";
- break;
- case KASAN_GLOBAL_REDZONE:
- bug_type = "global-out-of-bounds";
- break;
- case KASAN_STACK_LEFT:
- case KASAN_STACK_MID:
- case KASAN_STACK_RIGHT:
- case KASAN_STACK_PARTIAL:
- bug_type = "stack-out-of-bounds";
- break;
- case KASAN_FREE_PAGE:
- case KASAN_KMALLOC_FREE:
- bug_type = "use-after-free";
- break;
- case KASAN_USE_AFTER_SCOPE:
- bug_type = "use-after-scope";
- break;
- case KASAN_ALLOCA_LEFT:
- case KASAN_ALLOCA_RIGHT:
- bug_type = "alloca-out-of-bounds";
- break;
- }
- return bug_type;
- }
- static const char *get_wild_bug_type(struct kasan_access_info *info)
- {
- const char *bug_type = "unknown-crash";
- if ((unsigned long)info->access_addr < PAGE_SIZE)
- bug_type = "null-ptr-deref";
- else if ((unsigned long)info->access_addr < TASK_SIZE)
- bug_type = "user-memory-access";
- else
- bug_type = "wild-memory-access";
- return bug_type;
- }
- static const char *get_bug_type(struct kasan_access_info *info)
- {
- if (addr_has_shadow(info))
- return get_shadow_bug_type(info);
- return get_wild_bug_type(info);
- }
- static void print_error_description(struct kasan_access_info *info)
- {
- const char *bug_type = get_bug_type(info);
- pr_err("BUG: KASAN: %s in %pS\n",
- bug_type, (void *)info->ip);
- pr_err("%s of size %zu at addr %px by task %s/%d\n",
- info->is_write ? "Write" : "Read", info->access_size,
- info->access_addr, current->comm, task_pid_nr(current));
- }
- static inline bool kernel_or_module_addr(const void *addr)
- {
- if (addr >= (void *)_stext && addr < (void *)_end)
- return true;
- if (is_module_address((unsigned long)addr))
- return true;
- return false;
- }
- static inline bool init_task_stack_addr(const void *addr)
- {
- return addr >= (void *)&init_thread_union.stack &&
- (addr <= (void *)&init_thread_union.stack +
- sizeof(init_thread_union.stack));
- }
- static DEFINE_SPINLOCK(report_lock);
- static void kasan_start_report(unsigned long *flags)
- {
-
- kasan_disable_current();
- spin_lock_irqsave(&report_lock, *flags);
- pr_err("==================================================================\n");
- }
- static void kasan_end_report(unsigned long *flags)
- {
- pr_err("==================================================================\n");
- add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE);
- spin_unlock_irqrestore(&report_lock, *flags);
- #ifndef CONFIG_KASAN_PANIC_ON_WARN
- if (panic_on_warn)
- #endif
- panic("panic_on_warn set ...\n");
- kasan_enable_current();
- }
- static void print_track(struct kasan_track *track, const char *prefix)
- {
- pr_err("%s by task %u:\n", prefix, track->pid);
- if (track->stack) {
- struct stack_trace trace;
- depot_fetch_stack(track->stack, &trace);
- print_stack_trace(&trace, 0);
- } else {
- pr_err("(stack is not available)\n");
- }
- }
- static struct page *addr_to_page(const void *addr)
- {
- if ((addr >= (void *)PAGE_OFFSET) &&
- (addr < high_memory))
- return virt_to_head_page(addr);
- return NULL;
- }
- static void describe_object_addr(struct kmem_cache *cache, void *object,
- const void *addr)
- {
- unsigned long access_addr = (unsigned long)addr;
- unsigned long object_addr = (unsigned long)object;
- const char *rel_type;
- int rel_bytes;
- pr_err("The buggy address belongs to the object at %px\n"
- " which belongs to the cache %s of size %d\n",
- object, cache->name, cache->object_size);
- if (!addr)
- return;
- if (access_addr < object_addr) {
- rel_type = "to the left";
- rel_bytes = object_addr - access_addr;
- } else if (access_addr >= object_addr + cache->object_size) {
- rel_type = "to the right";
- rel_bytes = access_addr - (object_addr + cache->object_size);
- } else {
- rel_type = "inside";
- rel_bytes = access_addr - object_addr;
- }
- pr_err("The buggy address is located %d bytes %s of\n"
- " %d-byte region [%px, %px)\n",
- rel_bytes, rel_type, cache->object_size, (void *)object_addr,
- (void *)(object_addr + cache->object_size));
- }
- static void describe_object(struct kmem_cache *cache, void *object,
- const void *addr)
- {
- struct kasan_alloc_meta *alloc_info = get_alloc_info(cache, object);
- if (cache->flags & SLAB_KASAN) {
- print_track(&alloc_info->alloc_track, "Allocated");
- pr_err("\n");
- print_track(&alloc_info->free_track, "Freed");
- pr_err("\n");
- }
- describe_object_addr(cache, object, addr);
- }
- static void print_address_description(void *addr)
- {
- struct page *page = addr_to_page(addr);
- dump_stack();
- pr_err("\n");
- if (page && PageSlab(page)) {
- struct kmem_cache *cache = page->slab_cache;
- void *object = nearest_obj(cache, page, addr);
- describe_object(cache, object, addr);
- }
- if (kernel_or_module_addr(addr) && !init_task_stack_addr(addr)) {
- pr_err("The buggy address belongs to the variable:\n");
- pr_err(" %pS\n", addr);
- }
- if (page) {
- pr_err("The buggy address belongs to the page:\n");
- dump_page(page, "kasan: bad access detected");
- }
- }
- static bool row_is_guilty(const void *row, const void *guilty)
- {
- return (row <= guilty) && (guilty < row + SHADOW_BYTES_PER_ROW);
- }
- static int shadow_pointer_offset(const void *row, const void *shadow)
- {
-
- return 3 + (BITS_PER_LONG/8)*2 + (shadow - row)*2 +
- (shadow - row) / SHADOW_BYTES_PER_BLOCK + 1;
- }
- static void print_shadow_for_address(const void *addr)
- {
- int i;
- const void *shadow = kasan_mem_to_shadow(addr);
- const void *shadow_row;
- shadow_row = (void *)round_down((unsigned long)shadow,
- SHADOW_BYTES_PER_ROW)
- - SHADOW_ROWS_AROUND_ADDR * SHADOW_BYTES_PER_ROW;
- pr_err("Memory state around the buggy address:\n");
- for (i = -SHADOW_ROWS_AROUND_ADDR; i <= SHADOW_ROWS_AROUND_ADDR; i++) {
- const void *kaddr = kasan_shadow_to_mem(shadow_row);
- char buffer[4 + (BITS_PER_LONG/8)*2];
- char shadow_buf[SHADOW_BYTES_PER_ROW];
- snprintf(buffer, sizeof(buffer),
- (i == 0) ? ">%px: " : " %px: ", kaddr);
-
- memcpy(shadow_buf, shadow_row, SHADOW_BYTES_PER_ROW);
- print_hex_dump(KERN_ERR, buffer,
- DUMP_PREFIX_NONE, SHADOW_BYTES_PER_ROW, 1,
- shadow_buf, SHADOW_BYTES_PER_ROW, 0);
- if (row_is_guilty(shadow_row, shadow))
- pr_err("%*c\n",
- shadow_pointer_offset(shadow_row, shadow),
- '^');
- shadow_row += SHADOW_BYTES_PER_ROW;
- }
- }
- void kasan_report_double_free(struct kmem_cache *cache, void *object,
- void *ip)
- {
- unsigned long flags;
- kasan_start_report(&flags);
- pr_err("BUG: KASAN: double-free or invalid-free in %pS\n", ip);
- pr_err("\n");
- print_address_description(object);
- pr_err("\n");
- print_shadow_for_address(object);
- kasan_end_report(&flags);
- }
- static void kasan_report_error(struct kasan_access_info *info)
- {
- unsigned long flags;
- kasan_start_report(&flags);
- print_error_description(info);
- pr_err("\n");
- if (!addr_has_shadow(info)) {
- dump_stack();
- } else {
- print_address_description((void *)info->access_addr);
- pr_err("\n");
- print_shadow_for_address(info->first_bad_addr);
- }
- kasan_end_report(&flags);
- }
- static unsigned long kasan_flags;
- #define KASAN_BIT_REPORTED 0
- #define KASAN_BIT_MULTI_SHOT 1
- bool kasan_save_enable_multi_shot(void)
- {
- return test_and_set_bit(KASAN_BIT_MULTI_SHOT, &kasan_flags);
- }
- EXPORT_SYMBOL_GPL(kasan_save_enable_multi_shot);
- void kasan_restore_multi_shot(bool enabled)
- {
- if (!enabled)
- clear_bit(KASAN_BIT_MULTI_SHOT, &kasan_flags);
- }
- EXPORT_SYMBOL_GPL(kasan_restore_multi_shot);
- static int __init kasan_set_multi_shot(char *str)
- {
- set_bit(KASAN_BIT_MULTI_SHOT, &kasan_flags);
- return 1;
- }
- __setup("kasan_multi_shot", kasan_set_multi_shot);
- static inline bool kasan_report_enabled(void)
- {
- if (current->kasan_depth)
- return false;
- if (test_bit(KASAN_BIT_MULTI_SHOT, &kasan_flags))
- return true;
- return !test_and_set_bit(KASAN_BIT_REPORTED, &kasan_flags);
- }
- void kasan_report(unsigned long addr, size_t size,
- bool is_write, unsigned long ip)
- {
- struct kasan_access_info info;
- if (likely(!kasan_report_enabled()))
- return;
- disable_trace_on_warning();
- info.access_addr = (void *)addr;
- info.first_bad_addr = (void *)addr;
- info.access_size = size;
- info.is_write = is_write;
- info.ip = ip;
- info.first_bad_addr = NULL;
- kasan_report_error(&info);
- }
- #define DEFINE_ASAN_REPORT_LOAD(size) \
- void __asan_report_load##size##_noabort(unsigned long addr) \
- { \
- kasan_report(addr, size, false, _RET_IP_); \
- } \
- EXPORT_SYMBOL(__asan_report_load##size##_noabort)
- #define DEFINE_ASAN_REPORT_STORE(size) \
- void __asan_report_store##size##_noabort(unsigned long addr) \
- { \
- kasan_report(addr, size, true, _RET_IP_); \
- } \
- EXPORT_SYMBOL(__asan_report_store##size##_noabort)
- DEFINE_ASAN_REPORT_LOAD(1);
- DEFINE_ASAN_REPORT_LOAD(2);
- DEFINE_ASAN_REPORT_LOAD(4);
- DEFINE_ASAN_REPORT_LOAD(8);
- DEFINE_ASAN_REPORT_LOAD(16);
- DEFINE_ASAN_REPORT_STORE(1);
- DEFINE_ASAN_REPORT_STORE(2);
- DEFINE_ASAN_REPORT_STORE(4);
- DEFINE_ASAN_REPORT_STORE(8);
- DEFINE_ASAN_REPORT_STORE(16);
- void __asan_report_load_n_noabort(unsigned long addr, size_t size)
- {
- kasan_report(addr, size, false, _RET_IP_);
- }
- EXPORT_SYMBOL(__asan_report_load_n_noabort);
- void __asan_report_store_n_noabort(unsigned long addr, size_t size)
- {
- kasan_report(addr, size, true, _RET_IP_);
- }
- EXPORT_SYMBOL(__asan_report_store_n_noabort);
|