diff options
| author | Mehul Rao <mehulrao@gmail.com> | 2026-03-05 14:31:46 -0500 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2026-03-06 04:25:44 -0700 |
| commit | 25966fc097691e5c925ad080f64a2f19c5fd940a (patch) | |
| tree | 30faa8e480014ca6436b5bf8c2479e70704d20c9 /drivers/block | |
| parent | ce8ee8583ed83122405eabaa8fb351be4d9dc65c (diff) | |
ublk: fix NULL pointer dereference in ublk_ctrl_set_size()
ublk_ctrl_set_size() unconditionally dereferences ub->ub_disk via
set_capacity_and_notify() without checking if it is NULL.
ub->ub_disk is NULL before UBLK_CMD_START_DEV completes (it is only
assigned in ublk_ctrl_start_dev()) and after UBLK_CMD_STOP_DEV runs
(ublk_detach_disk() sets it to NULL). Since the UBLK_CMD_UPDATE_SIZE
handler performs no state validation, a user can trigger a NULL pointer
dereference by sending UPDATE_SIZE to a device that has been added but
not yet started, or one that has been stopped.
Fix this by checking ub->ub_disk under ub->mutex before dereferencing
it, and returning -ENODEV if the disk is not available.
Fixes: 98b995660bff ("ublk: Add UBLK_U_CMD_UPDATE_SIZE")
Cc: stable@vger.kernel.org
Signed-off-by: Mehul Rao <mehulrao@gmail.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'drivers/block')
| -rw-r--r-- | drivers/block/ublk_drv.c | 12 |
1 files changed, 9 insertions, 3 deletions
diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c index c13cda58a7c6..03edabdf8977 100644 --- a/drivers/block/ublk_drv.c +++ b/drivers/block/ublk_drv.c @@ -5003,15 +5003,22 @@ static int ublk_ctrl_get_features(const struct ublksrv_ctrl_cmd *header) return 0; } -static void ublk_ctrl_set_size(struct ublk_device *ub, const struct ublksrv_ctrl_cmd *header) +static int ublk_ctrl_set_size(struct ublk_device *ub, const struct ublksrv_ctrl_cmd *header) { struct ublk_param_basic *p = &ub->params.basic; u64 new_size = header->data[0]; + int ret = 0; mutex_lock(&ub->mutex); + if (!ub->ub_disk) { + ret = -ENODEV; + goto out; + } p->dev_sectors = new_size; set_capacity_and_notify(ub->ub_disk, p->dev_sectors); +out: mutex_unlock(&ub->mutex); + return ret; } struct count_busy { @@ -5331,8 +5338,7 @@ static int ublk_ctrl_uring_cmd(struct io_uring_cmd *cmd, ret = ublk_ctrl_end_recovery(ub, &header); break; case UBLK_CMD_UPDATE_SIZE: - ublk_ctrl_set_size(ub, &header); - ret = 0; + ret = ublk_ctrl_set_size(ub, &header); break; case UBLK_CMD_QUIESCE_DEV: ret = ublk_ctrl_quiesce_dev(ub, &header); |