diff options
| -rw-r--r-- | drivers/block/ublk_drv.c | 55 |
1 files changed, 43 insertions, 12 deletions
diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c index a725a236a38f..c932e9ea5a0f 100644 --- a/drivers/block/ublk_drv.c +++ b/drivers/block/ublk_drv.c @@ -377,8 +377,50 @@ static void ublk_free_disk(struct gendisk *disk) put_device(&ub->cdev_dev); } +static void ublk_store_owner_uid_gid(unsigned int *owner_uid, + unsigned int *owner_gid) +{ + kuid_t uid; + kgid_t gid; + + current_uid_gid(&uid, &gid); + + *owner_uid = from_kuid(&init_user_ns, uid); + *owner_gid = from_kgid(&init_user_ns, gid); +} + +static int ublk_open(struct block_device *bdev, fmode_t mode) +{ + struct ublk_device *ub = bdev->bd_disk->private_data; + + if (capable(CAP_SYS_ADMIN)) + return 0; + + /* + * If it is one unprivileged device, only owner can open + * the disk. Otherwise it could be one trap made by one + * evil user who grants this disk's privileges to other + * users deliberately. + * + * This way is reasonable too given anyone can create + * unprivileged device, and no need other's grant. + */ + if (ub->dev_info.flags & UBLK_F_UNPRIVILEGED_DEV) { + unsigned int curr_uid, curr_gid; + + ublk_store_owner_uid_gid(&curr_uid, &curr_gid); + + if (curr_uid != ub->dev_info.owner_uid || curr_gid != + ub->dev_info.owner_gid) + return -EPERM; + } + + return 0; +} + static const struct block_device_operations ub_fops = { .owner = THIS_MODULE, + .open = ublk_open, .free_disk = ublk_free_disk, }; @@ -1620,17 +1662,6 @@ out_free_cpumask: return ret; } -static void ublk_store_owner_uid_gid(struct ublksrv_ctrl_dev_info *info) -{ - kuid_t uid; - kgid_t gid; - - current_uid_gid(&uid, &gid); - - info->owner_uid = from_kuid(&init_user_ns, uid); - info->owner_gid = from_kgid(&init_user_ns, gid); -} - static inline void ublk_dump_dev_info(struct ublksrv_ctrl_dev_info *info) { pr_devel("%s: dev id %d flags %llx\n", __func__, @@ -1664,7 +1695,7 @@ static int ublk_ctrl_add_dev(struct io_uring_cmd *cmd) return -EPERM; /* the created device is always owned by current user */ - ublk_store_owner_uid_gid(&info); + ublk_store_owner_uid_gid(&info.owner_uid, &info.owner_gid); if (header->dev_id != info.dev_id) { pr_warn("%s: dev id not match %u %u\n", |