vhost_scsi_handle_vq() moves pi_bytesout and pi_bytesin into the
protection sgl and subtracts them from exp_data_len. The length passed
to TCM is still exp_data_len + prot_bytes.
That sum matched an older target path which subtracted prot_length
again. sbc_check_prot() now replaces data_length from the CDB only
when the protect field is non-zero, and only for READ and WRITE.
target_cmd_size_check() leaves a write's data_length unchanged when the
CDB size is smaller.
MODE SELECT, SET TARGET PORT GROUPS and UNMAP then use data_length as
the size of t_data_sg. The PI bytes are not in that sgl. A parameter
list that ends on a page is followed by a read of the next physical
page.
Pass the data sgl length. Protected READ and WRITE still take their
length from the CDB.
KASAN reports:
BUG: KASAN: use-after-free in spc_emulate_modeselect+0x145/0x380
[target_core_mod]
Read of size 1
spc_emulate_modeselect
__target_execute_cmd
target_execute_cmd
vhost_scsi_write_pending
transport_generic_new_cmd
__target_submit
target_queued_submit_work
process_one_work
worker_thread
kthread
ret_from_fork
ret_from_fork_asm
Fixes: 9f977ef7b671 ("vhost-scsi: Include prot_bytes into expected data
transfer length")
Signed-off-by: Jia Jia <[email protected]>
---
diff --git a/drivers/vhost/scsi.c b/drivers/vhost/scsi.c
index 4f8c0260bc9e..4bd29c2ceed9 100644
--- a/drivers/vhost/scsi.c
+++ b/drivers/vhost/scsi.c
@@ -1534,9 +1534,13 @@ vhost_scsi_handle_vq(struct vhost_scsi *vs, struct
vhost_virtqueue *vq)
* vhost_scsi_queue_data_in() and vhost_scsi_queue_status()
*/
cmd->tvc_vq_desc = vc.head;
+ /*
+ * exp_data_len is the data sgl. prot_bytes already sit in
+ * the protection sgl. Protected READ and WRITE replace
+ * data_length from the CDB in sbc_check_prot().
+ */
vhost_scsi_target_queue_cmd(nexus, cmd, cdb, lun, task_attr,
- data_direction,
- exp_data_len + prot_bytes);
+ data_direction, exp_data_len);
ret = 0;
err:
/*
