diff options
| -rw-r--r-- | include/linux/poison.h | 3 | ||||
| -rw-r--r-- | lib/flex_array.c | 15 |
2 files changed, 10 insertions, 8 deletions
diff --git a/include/linux/poison.h b/include/linux/poison.h index 6729f7dcd60..7fc194aef8c 100644 --- a/include/linux/poison.h +++ b/include/linux/poison.h @@ -65,6 +65,9 @@ #define MUTEX_DEBUG_INIT 0x11 #define MUTEX_DEBUG_FREE 0x22 +/********** lib/flex_array.c **********/ +#define FLEX_ARRAY_FREE 0x6c /* for use-after-free poisoning */ + /********** security/ **********/ #define KEY_DESTROY 0xbd diff --git a/lib/flex_array.c b/lib/flex_array.c index b68f99be408..e22d0e9776a 100644 --- a/lib/flex_array.c +++ b/lib/flex_array.c @@ -113,6 +113,8 @@ struct flex_array *flex_array_alloc(int element_size, unsigned int total, return NULL; ret->element_size = element_size; ret->total_nr_elements = total; + if (elements_fit_in_base(ret) && !(flags & __GFP_ZERO)) + memset(ret->parts[0], FLEX_ARRAY_FREE, bytes_left_in_base()); return ret; } @@ -159,15 +161,12 @@ __fa_get_part(struct flex_array *fa, int part_nr, gfp_t flags) { struct flex_array_part *part = fa->parts[part_nr]; if (!part) { - /* - * This leaves the part pages uninitialized - * and with potentially random data, just - * as if the user had kmalloc()'d the whole. - * __GFP_ZERO can be used to zero it. - */ - part = kmalloc(FLEX_ARRAY_PART_SIZE, flags); + part = kmalloc(sizeof(struct flex_array_part), flags); if (!part) return NULL; + if (!(flags & __GFP_ZERO)) + memset(part, FLEX_ARRAY_FREE, + sizeof(struct flex_array_part)); fa->parts[part_nr] = part; } return part; @@ -228,7 +227,7 @@ int flex_array_clear(struct flex_array *fa, unsigned int element_nr) return -EINVAL; } dst = &part->elements[index_inside_part(fa, element_nr)]; - memset(dst, 0, fa->element_size); + memset(dst, FLEX_ARRAY_FREE, fa->element_size); return 0; } |