diff options
Diffstat (limited to 'mm/kasan/report.c')
| -rw-r--r-- | mm/kasan/report.c | 40 |
1 files changed, 40 insertions, 0 deletions
diff --git a/mm/kasan/report.c b/mm/kasan/report.c index 621782100eaa..5ef9f24f566b 100644 --- a/mm/kasan/report.c +++ b/mm/kasan/report.c @@ -512,3 +512,43 @@ void __kasan_report(unsigned long addr, size_t size, bool is_write, unsigned lon end_report(&flags); } + +#ifdef CONFIG_KASAN_INLINE +/* + * With CONFIG_KASAN_INLINE, accesses to bogus pointers (outside the high + * canonical half of the address space) cause out-of-bounds shadow memory reads + * before the actual access. For addresses in the low canonical half of the + * address space, as well as most non-canonical addresses, that out-of-bounds + * shadow memory access lands in the non-canonical part of the address space. + * Help the user figure out what the original bogus pointer was. + */ +void kasan_non_canonical_hook(unsigned long addr) +{ + unsigned long orig_addr; + const char *bug_type; + + if (addr < KASAN_SHADOW_OFFSET) + return; + + orig_addr = (addr - KASAN_SHADOW_OFFSET) << KASAN_SHADOW_SCALE_SHIFT; + /* + * For faults near the shadow address for NULL, we can be fairly certain + * that this is a KASAN shadow memory access. + * For faults that correspond to shadow for low canonical addresses, we + * can still be pretty sure - that shadow region is a fairly narrow + * chunk of the non-canonical address space. + * But faults that look like shadow for non-canonical addresses are a + * really large chunk of the address space. In that case, we still + * print the decoded address, but make it clear that this is not + * necessarily what's actually going on. + */ + if (orig_addr < PAGE_SIZE) + bug_type = "null-ptr-deref"; + else if (orig_addr < TASK_SIZE) + bug_type = "probably user-memory-access"; + else + bug_type = "maybe wild-memory-access"; + pr_alert("KASAN: %s in range [0x%016lx-0x%016lx]\n", bug_type, + orig_addr, orig_addr + KASAN_SHADOW_MASK); +} +#endif |