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bcache: fix variable length array abuse in btree_iter

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btree_iter is used in two ways: either allocated on the stack with a
fixed size MAX_BSETS, or from a mempool with a dynamic size based on the
specific cache set. Previously, the struct had a fixed-length array of
size MAX_BSETS which was indexed out-of-bounds for the dynamically-sized
iterators, which causes UBSAN to complain.

This patch uses the same approach as in bcachefs's sort_iter and splits
the iterator into a btree_iter with a flexible array member and a
btree_iter_stack which embeds a btree_iter as well as a fixed-length
data array.

Cc: stable@vger.kernel.org
Closes: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/2039368
Signed-off-by: Matthew Mirvish <matthew@mm12.xyz>
Signed-off-by: Coly Li <colyli@suse.de>
Link: https://lore.kernel.org/r/20240509011117.2697-3-colyli@suse.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Matthew Mirvish 2024-05-09 09:11:17 +08:00 committed by Jens Axboe
parent 2abd9a197d
commit 3a861560cc
6 changed files with 70 additions and 59 deletions
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44
drivers/md/bcache/bset.c
View file

@ -54,7 +54,7 @@ void bch_dump_bucket(struct btree_keys *b)
int __bch_count_data(struct btree_keys *b)
{
unsigned int ret = 0;
struct btree_iter iter;
struct btree_iter_stack iter;
struct bkey *k;
if (b->ops->is_extents)
@ -67,7 +67,7 @@ void __bch_check_keys(struct btree_keys *b, const char *fmt, ...)
{
va_list args;
struct bkey *k, *p = NULL;
struct btree_iter iter;
struct btree_iter_stack iter;
const char *err;
for_each_key(b, k, &iter) {
@ -879,7 +879,7 @@ unsigned int bch_btree_insert_key(struct btree_keys *b, struct bkey *k,
unsigned int status = BTREE_INSERT_STATUS_NO_INSERT;
struct bset *i = bset_tree_last(b)->data;
struct bkey *m, *prev = NULL;
struct btree_iter iter;
struct btree_iter_stack iter;
struct bkey preceding_key_on_stack = ZERO_KEY;
struct bkey *preceding_key_p = &preceding_key_on_stack;
@ -895,9 +895,9 @@ unsigned int bch_btree_insert_key(struct btree_keys *b, struct bkey *k,
else
preceding_key(k, &preceding_key_p);
m = bch_btree_iter_init(b, &iter, preceding_key_p);
m = bch_btree_iter_stack_init(b, &iter, preceding_key_p);
if (b->ops->insert_fixup(b, k, &iter, replace_key))
if (b->ops->insert_fixup(b, k, &iter.iter, replace_key))
return status;
status = BTREE_INSERT_STATUS_INSERT;
@ -1100,33 +1100,33 @@ void bch_btree_iter_push(struct btree_iter *iter, struct bkey *k,
btree_iter_cmp));
}
static struct bkey *__bch_btree_iter_init(struct btree_keys *b,
struct btree_iter *iter,
struct bkey *search,
struct bset_tree *start)
static struct bkey *__bch_btree_iter_stack_init(struct btree_keys *b,
struct btree_iter_stack *iter,
struct bkey *search,
struct bset_tree *start)
{
struct bkey *ret = NULL;
iter->size = ARRAY_SIZE(iter->data);
iter->used = 0;
iter->iter.size = ARRAY_SIZE(iter->stack_data);
iter->iter.used = 0;
#ifdef CONFIG_BCACHE_DEBUG
iter->b = b;
iter->iter.b = b;
#endif
for (; start <= bset_tree_last(b); start++) {
ret = bch_bset_search(b, start, search);
bch_btree_iter_push(iter, ret, bset_bkey_last(start->data));
bch_btree_iter_push(&iter->iter, ret, bset_bkey_last(start->data));
}
return ret;
}
struct bkey *bch_btree_iter_init(struct btree_keys *b,
struct btree_iter *iter,
struct bkey *bch_btree_iter_stack_init(struct btree_keys *b,
struct btree_iter_stack *iter,
struct bkey *search)
{
return __bch_btree_iter_init(b, iter, search, b->set);
return __bch_btree_iter_stack_init(b, iter, search, b->set);
}
static inline struct bkey *__bch_btree_iter_next(struct btree_iter *iter,
@ -1293,10 +1293,10 @@ void bch_btree_sort_partial(struct btree_keys *b, unsigned int start,
struct bset_sort_state *state)
{
size_t order = b->page_order, keys = 0;
struct btree_iter iter;
struct btree_iter_stack iter;
int oldsize = bch_count_data(b);
__bch_btree_iter_init(b, &iter, NULL, &b->set[start]);
__bch_btree_iter_stack_init(b, &iter, NULL, &b->set[start]);
if (start) {
unsigned int i;
@ -1307,7 +1307,7 @@ void bch_btree_sort_partial(struct btree_keys *b, unsigned int start,
order = get_order(__set_bytes(b->set->data, keys));
}
__btree_sort(b, &iter, start, order, false, state);
__btree_sort(b, &iter.iter, start, order, false, state);
EBUG_ON(oldsize >= 0 && bch_count_data(b) != oldsize);
}
@ -1323,11 +1323,11 @@ void bch_btree_sort_into(struct btree_keys *b, struct btree_keys *new,
struct bset_sort_state *state)
{
uint64_t start_time = local_clock();
struct btree_iter iter;
struct btree_iter_stack iter;
bch_btree_iter_init(b, &iter, NULL);
bch_btree_iter_stack_init(b, &iter, NULL);
btree_mergesort(b, new->set->data, &iter, false, true);
btree_mergesort(b, new->set->data, &iter.iter, false, true);
bch_time_stats_update(&state->time, start_time);

28
drivers/md/bcache/bset.h
View file

@ -321,7 +321,14 @@ struct btree_iter {
#endif
struct btree_iter_set {
struct bkey *k, *end;
} data[MAX_BSETS];
} data[];
};
/* Fixed-size btree_iter that can be allocated on the stack */
struct btree_iter_stack {
struct btree_iter iter;
struct btree_iter_set stack_data[MAX_BSETS];
};
typedef bool (*ptr_filter_fn)(struct btree_keys *b, const struct bkey *k);
@ -333,9 +340,9 @@ struct bkey *bch_btree_iter_next_filter(struct btree_iter *iter,
void bch_btree_iter_push(struct btree_iter *iter, struct bkey *k,
struct bkey *end);
struct bkey *bch_btree_iter_init(struct btree_keys *b,
struct btree_iter *iter,
struct bkey *search);
struct bkey *bch_btree_iter_stack_init(struct btree_keys *b,
struct btree_iter_stack *iter,
struct bkey *search);
struct bkey *__bch_bset_search(struct btree_keys *b, struct bset_tree *t,
const struct bkey *search);
@ -350,13 +357,14 @@ static inline struct bkey *bch_bset_search(struct btree_keys *b,
return search ? __bch_bset_search(b, t, search) : t->data->start;
}
#define for_each_key_filter(b, k, iter, filter) \
for (bch_btree_iter_init((b), (iter), NULL); \
((k) = bch_btree_iter_next_filter((iter), (b), filter));)
#define for_each_key_filter(b, k, stack_iter, filter) \
for (bch_btree_iter_stack_init((b), (stack_iter), NULL); \
((k) = bch_btree_iter_next_filter(&((stack_iter)->iter), (b), \
filter));)
#define for_each_key(b, k, iter) \
for (bch_btree_iter_init((b), (iter), NULL); \
((k) = bch_btree_iter_next(iter));)
#define for_each_key(b, k, stack_iter) \
for (bch_btree_iter_stack_init((b), (stack_iter), NULL); \
((k) = bch_btree_iter_next(&((stack_iter)->iter)));)
/* Sorting */

40
drivers/md/bcache/btree.c
View file

@ -1309,7 +1309,7 @@ static bool btree_gc_mark_node(struct btree *b, struct gc_stat *gc)
uint8_t stale = 0;
unsigned int keys = 0, good_keys = 0;
struct bkey *k;
struct btree_iter iter;
struct btree_iter_stack iter;
struct bset_tree *t;
gc->nodes++;
@ -1570,7 +1570,7 @@ static int btree_gc_rewrite_node(struct btree *b, struct btree_op *op,
static unsigned int btree_gc_count_keys(struct btree *b)
{
struct bkey *k;
struct btree_iter iter;
struct btree_iter_stack iter;
unsigned int ret = 0;
for_each_key_filter(&b->keys, k, &iter, bch_ptr_bad)
@ -1611,17 +1611,18 @@ static int btree_gc_recurse(struct btree *b, struct btree_op *op,
int ret = 0;
bool should_rewrite;
struct bkey *k;
struct btree_iter iter;
struct btree_iter_stack iter;
struct gc_merge_info r[GC_MERGE_NODES];
struct gc_merge_info *i, *last = r + ARRAY_SIZE(r) - 1;
bch_btree_iter_init(&b->keys, &iter, &b->c->gc_done);
bch_btree_iter_stack_init(&b->keys, &iter, &b->c->gc_done);
for (i = r; i < r + ARRAY_SIZE(r); i++)
i->b = ERR_PTR(-EINTR);
while (1) {
k = bch_btree_iter_next_filter(&iter, &b->keys, bch_ptr_bad);
k = bch_btree_iter_next_filter(&iter.iter, &b->keys,
bch_ptr_bad);
if (k) {
r->b = bch_btree_node_get(b->c, op, k, b->level - 1,
true, b);
@ -1911,7 +1912,7 @@ static int bch_btree_check_recurse(struct btree *b, struct btree_op *op)
{
int ret = 0;
struct bkey *k, *p = NULL;
struct btree_iter iter;
struct btree_iter_stack iter;
for_each_key_filter(&b->keys, k, &iter, bch_ptr_invalid)
bch_initial_mark_key(b->c, b->level, k);
@ -1919,10 +1920,10 @@ static int bch_btree_check_recurse(struct btree *b, struct btree_op *op)
bch_initial_mark_key(b->c, b->level + 1, &b->key);
if (b->level) {
bch_btree_iter_init(&b->keys, &iter, NULL);
bch_btree_iter_stack_init(&b->keys, &iter, NULL);
do {
k = bch_btree_iter_next_filter(&iter, &b->keys,
k = bch_btree_iter_next_filter(&iter.iter, &b->keys,
bch_ptr_bad);
if (k) {
btree_node_prefetch(b, k);
@ -1950,7 +1951,7 @@ static int bch_btree_check_thread(void *arg)
struct btree_check_info *info = arg;
struct btree_check_state *check_state = info->state;
struct cache_set *c = check_state->c;
struct btree_iter iter;
struct btree_iter_stack iter;
struct bkey *k, *p;
int cur_idx, prev_idx, skip_nr;
@ -1959,8 +1960,8 @@ static int bch_btree_check_thread(void *arg)
ret = 0;
/* root node keys are checked before thread created */
bch_btree_iter_init(&c->root->keys, &iter, NULL);
k = bch_btree_iter_next_filter(&iter, &c->root->keys, bch_ptr_bad);
bch_btree_iter_stack_init(&c->root->keys, &iter, NULL);
k = bch_btree_iter_next_filter(&iter.iter, &c->root->keys, bch_ptr_bad);
BUG_ON(!k);
p = k;
@ -1978,7 +1979,7 @@ static int bch_btree_check_thread(void *arg)
skip_nr = cur_idx - prev_idx;
while (skip_nr) {
k = bch_btree_iter_next_filter(&iter,
k = bch_btree_iter_next_filter(&iter.iter,
&c->root->keys,
bch_ptr_bad);
if (k)
@ -2051,7 +2052,7 @@ int bch_btree_check(struct cache_set *c)
int ret = 0;
int i;
struct bkey *k = NULL;
struct btree_iter iter;
struct btree_iter_stack iter;
struct btree_check_state check_state;
/* check and mark root node keys */
@ -2547,11 +2548,11 @@ static int bch_btree_map_nodes_recurse(struct btree *b, struct btree_op *op,
if (b->level) {
struct bkey *k;
struct btree_iter iter;
struct btree_iter_stack iter;
bch_btree_iter_init(&b->keys, &iter, from);
bch_btree_iter_stack_init(&b->keys, &iter, from);
while ((k = bch_btree_iter_next_filter(&iter, &b->keys,
while ((k = bch_btree_iter_next_filter(&iter.iter, &b->keys,
bch_ptr_bad))) {
ret = bcache_btree(map_nodes_recurse, k, b,
op, from, fn, flags);
@ -2580,11 +2581,12 @@ int bch_btree_map_keys_recurse(struct btree *b, struct btree_op *op,
{
int ret = MAP_CONTINUE;
struct bkey *k;
struct btree_iter iter;
struct btree_iter_stack iter;
bch_btree_iter_init(&b->keys, &iter, from);
bch_btree_iter_stack_init(&b->keys, &iter, from);
while ((k = bch_btree_iter_next_filter(&iter, &b->keys, bch_ptr_bad))) {
while ((k = bch_btree_iter_next_filter(&iter.iter, &b->keys,
bch_ptr_bad))) {
ret = !b->level
? fn(op, b, k)
: bcache_btree(map_keys_recurse, k,

5
drivers/md/bcache/super.c
View file

@ -1914,8 +1914,9 @@ struct cache_set *bch_cache_set_alloc(struct cache_sb *sb)
INIT_LIST_HEAD(&c->btree_cache_freed);
INIT_LIST_HEAD(&c->data_buckets);
iter_size = ((meta_bucket_pages(sb) * PAGE_SECTORS) / sb->block_size + 1) *
sizeof(struct btree_iter_set);
iter_size = sizeof(struct btree_iter) +
((meta_bucket_pages(sb) * PAGE_SECTORS) / sb->block_size) *
sizeof(struct btree_iter_set);
c->devices = kcalloc(c->nr_uuids, sizeof(void *), GFP_KERNEL);
if (!c->devices)

2
drivers/md/bcache/sysfs.c
View file

@ -660,7 +660,7 @@ static unsigned int bch_root_usage(struct cache_set *c)
unsigned int bytes = 0;
struct bkey *k;
struct btree *b;
struct btree_iter iter;
struct btree_iter_stack iter;
goto lock_root;

10
drivers/md/bcache/writeback.c
View file

@ -908,15 +908,15 @@ static int bch_dirty_init_thread(void *arg)
struct dirty_init_thrd_info *info = arg;
struct bch_dirty_init_state *state = info->state;
struct cache_set *c = state->c;
struct btree_iter iter;
struct btree_iter_stack iter;
struct bkey *k, *p;
int cur_idx, prev_idx, skip_nr;
k = p = NULL;
prev_idx = 0;
bch_btree_iter_init(&c->root->keys, &iter, NULL);
k = bch_btree_iter_next_filter(&iter, &c->root->keys, bch_ptr_bad);
bch_btree_iter_stack_init(&c->root->keys, &iter, NULL);
k = bch_btree_iter_next_filter(&iter.iter, &c->root->keys, bch_ptr_bad);
BUG_ON(!k);
p = k;
@ -930,7 +930,7 @@ static int bch_dirty_init_thread(void *arg)
skip_nr = cur_idx - prev_idx;
while (skip_nr) {
k = bch_btree_iter_next_filter(&iter,
k = bch_btree_iter_next_filter(&iter.iter,
&c->root->keys,
bch_ptr_bad);
if (k)
@ -979,7 +979,7 @@ void bch_sectors_dirty_init(struct bcache_device *d)
int i;
struct btree *b = NULL;
struct bkey *k = NULL;
struct btree_iter iter;
struct btree_iter_stack iter;
struct sectors_dirty_init op;
struct cache_set *c = d->c;
struct bch_dirty_init_state state;