[PATCH v2 1/3] ublk: Validate SQE128 flag before accessing the cmd

[Caleb Sander Mateos]

From: Govindarajulu Varadarajan <govind.varadar@xxxxxxxxx>

ublk_ctrl_cmd_dump() accesses (header *)sqe->cmd before
IO_URING_F_SQE128 flag check. This could cause out of boundary memory
access.

Move the SQE128 flag check earlier in ublk_ctrl_uring_cmd() to return
-EINVAL immediately if the flag is not set.

Fixes: 71f28f3136af ("ublk_drv: add io_uring based userspace block driver")
Signed-off-by: Govindarajulu Varadarajan <govind.varadar@xxxxxxxxx>
Reviewed-by: Caleb Sander Mateos <csander@xxxxxxxxxxxxxxx>
Reviewed-by: Ming Lei <ming.lei@xxxxxxxxxx>
---
 drivers/block/ublk_drv.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c
index 5efaf53261ce..01088194c8d3 100644
--- a/drivers/block/ublk_drv.c
+++ b/drivers/block/ublk_drv.c
@@ -5219,14 +5219,14 @@ static int ublk_ctrl_uring_cmd(struct io_uring_cmd *cmd,
 
 	if (ublk_ctrl_uring_cmd_may_sleep(cmd_op) &&
 	    issue_flags & IO_URING_F_NONBLOCK)
 		return -EAGAIN;
 
-	ublk_ctrl_cmd_dump(cmd);
-
 	if (!(issue_flags & IO_URING_F_SQE128))
-		goto out;
+		return -EINVAL;
+
+	ublk_ctrl_cmd_dump(cmd);
 
 	ret = ublk_check_cmd_op(cmd_op);
 	if (ret)
 		goto out;
 
-- 
2.45.2