diff options
Diffstat (limited to 'mm/slab_common.c')
| -rw-r--r-- | mm/slab_common.c | 20 |
1 files changed, 14 insertions, 6 deletions
diff --git a/mm/slab_common.c b/mm/slab_common.c index 4aedb8455352..88e833986332 100644 --- a/mm/slab_common.c +++ b/mm/slab_common.c @@ -1136,19 +1136,27 @@ static __always_inline void *__do_krealloc(const void *p, size_t new_size, void *ret; size_t ks; - if (likely(!ZERO_OR_NULL_PTR(p)) && !kasan_check_byte(p)) - return NULL; - - ks = ksize(p); + /* Don't use instrumented ksize to allow precise KASAN poisoning. */ + if (likely(!ZERO_OR_NULL_PTR(p))) { + if (!kasan_check_byte(p)) + return NULL; + ks = kfence_ksize(p) ?: __ksize(p); + } else + ks = 0; + /* If the object still fits, repoison it precisely. */ if (ks >= new_size) { p = kasan_krealloc((void *)p, new_size, flags); return (void *)p; } ret = kmalloc_track_caller(new_size, flags); - if (ret && p) - memcpy(ret, p, ks); + if (ret && p) { + /* Disable KASAN checks as the object's redzone is accessed. */ + kasan_disable_current(); + memcpy(ret, kasan_reset_tag(p), ks); + kasan_enable_current(); + } return ret; } |