diff options
Diffstat (limited to 'fs/namespace.c')
| -rw-r--r-- | fs/namespace.c | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/fs/namespace.c b/fs/namespace.c index 56c1dcffb4dc..8e3603558e59 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -70,7 +70,8 @@ static DEFINE_IDA(mnt_id_ida); static DEFINE_IDA(mnt_group_ida); /* Don't allow confusion with old 32bit mount ID */ -static atomic64_t mnt_id_ctr = ATOMIC64_INIT(1ULL << 32); +#define MNT_UNIQUE_ID_OFFSET (1ULL << 32) +static atomic64_t mnt_id_ctr = ATOMIC64_INIT(MNT_UNIQUE_ID_OFFSET); static struct hlist_head *mount_hashtable __ro_after_init; static struct hlist_head *mountpoint_hashtable __ro_after_init; @@ -5241,6 +5242,9 @@ static int copy_mnt_id_req(const struct mnt_id_req __user *req, return ret; if (kreq->spare != 0) return -EINVAL; + /* The first valid unique mount id is MNT_UNIQUE_ID_OFFSET + 1. */ + if (kreq->mnt_id <= MNT_UNIQUE_ID_OFFSET) + return -EINVAL; return 0; } |