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btrfs: convert btrfs_delayed_item.refs from atomic_t to refcount_t 

refcount_t type and corresponding API should be
used instead of atomic_t when the variable is used as
a reference counter. This allows to avoid accidental
refcounter overflows that might lead to use-after-free
situations.

Signed-off-by: Elena Reshetova <elena.reshetova@intel.com>
Signed-off-by: Hans Liljestrand <ishkamiel@gmail.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: David Windsor <dwindsor@gmail.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
Elena Reshetova 2017-03-03 10:55:17 +02:00 committed by David Sterba
parent 6de5f18e7b
commit 089e77e10d
2 changed files with 10 additions and 10 deletions
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18
fs/btrfs/delayed-inode.c
View File

@ -308,7 +308,7 @@ static struct btrfs_delayed_item *btrfs_alloc_delayed_item(u32 data_len)
item->ins_or_del = 0;
item->bytes_reserved = 0;
item->delayed_node = NULL;
atomic_set(&item->refs, 1);
refcount_set(&item->refs, 1);
}
return item;
}
@ -483,7 +483,7 @@ static void btrfs_release_delayed_item(struct btrfs_delayed_item *item)
{
if (item) {
__btrfs_remove_delayed_item(item);
if (atomic_dec_and_test(&item->refs))
if (refcount_dec_and_test(&item->refs))
kfree(item);
}
}
@ -1600,14 +1600,14 @@ bool btrfs_readdir_get_delayed_items(struct inode *inode,
mutex_lock(&delayed_node->mutex);
item = __btrfs_first_delayed_insertion_item(delayed_node);
while (item) {
atomic_inc(&item->refs);
refcount_inc(&item->refs);
list_add_tail(&item->readdir_list, ins_list);
item = __btrfs_next_delayed_item(item);
}
item = __btrfs_first_delayed_deletion_item(delayed_node);
while (item) {
atomic_inc(&item->refs);
refcount_inc(&item->refs);
list_add_tail(&item->readdir_list, del_list);
item = __btrfs_next_delayed_item(item);
}
@ -1634,13 +1634,13 @@ void btrfs_readdir_put_delayed_items(struct inode *inode,
list_for_each_entry_safe(curr, next, ins_list, readdir_list) {
list_del(&curr->readdir_list);
if (atomic_dec_and_test(&curr->refs))
if (refcount_dec_and_test(&curr->refs))
kfree(curr);
}
list_for_each_entry_safe(curr, next, del_list, readdir_list) {
list_del(&curr->readdir_list);
if (atomic_dec_and_test(&curr->refs))
if (refcount_dec_and_test(&curr->refs))
kfree(curr);
}
@ -1667,7 +1667,7 @@ int btrfs_should_delete_dir_index(struct list_head *del_list,
list_del(&curr->readdir_list);
ret = (curr->key.offset == index);
if (atomic_dec_and_test(&curr->refs))
if (refcount_dec_and_test(&curr->refs))
kfree(curr);
if (ret)
@ -1705,7 +1705,7 @@ int btrfs_readdir_delayed_dir_index(struct dir_context *ctx,
list_del(&curr->readdir_list);
if (curr->key.offset < ctx->pos) {
if (atomic_dec_and_test(&curr->refs))
if (refcount_dec_and_test(&curr->refs))
kfree(curr);
continue;
}
@ -1722,7 +1722,7 @@ int btrfs_readdir_delayed_dir_index(struct dir_context *ctx,
over = !dir_emit(ctx, name, name_len,
location.objectid, d_type);
if (atomic_dec_and_test(&curr->refs))
if (refcount_dec_and_test(&curr->refs))
kfree(curr);
if (over)

2
fs/btrfs/delayed-inode.h
View File

@ -80,7 +80,7 @@ struct btrfs_delayed_item {
struct list_head readdir_list; /* used for readdir items */
u64 bytes_reserved;
struct btrfs_delayed_node *delayed_node;
atomic_t refs;
refcount_t refs;
int ins_or_del;
u32 data_len;
char data[0];