Some time ago blk_execute_rq() was modified such that it no longer
allocates a sense buffer. Make sg_io() allocate and use a sense buffer.
This patch avoids that the following bug is triggered when running the
libiscsi tests against the scsi_debug driver:
usercopy: Kernel memory exposure attempt detected from null address (offset 0, size 18)!
------------[ cut here ]------------
kernel BUG at mm/usercopy.c:102!
CPU: 5 PID: 693 Comm: iscsi-test-cu Not tainted 5.0.0-rc3-dbg+ #3
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1 04/01/2014
RIP: 0010:usercopy_abort+0x7a/0x7c
Call Trace:
__check_object_size.cold.1+0x37/0x3d
sg_io+0x5a2/0x700
scsi_cmd_ioctl+0x4d4/0x540
scsi_cmd_blk_ioctl+0x7b/0x8b
sd_ioctl+0xba/0x150
blkdev_ioctl+0x6e1/0xea0
block_ioctl+0x79/0x90
do_vfs_ioctl+0x12b/0x9b0
ksys_ioctl+0x41/0x80
__x64_sys_ioctl+0x43/0x50
do_syscall_64+0x71/0x210
entry_SYSCALL_64_after_hwframe+0x49/0xbe
Cc: Christoph Hellwig <hch@xxxxxx>
Cc: Martin K. Petersen <martin.petersen@xxxxxxxxxx>
Cc: Douglas Gilbert <dgilbert@xxxxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx> # v4.11+
Fixes: 82ed4db499b8 ("block: split scsi_request out of struct request")
Signed-off-by: Bart Van Assche <bvanassche@xxxxxxx>
---
block/scsi_ioctl.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/block/scsi_ioctl.c b/block/scsi_ioctl.c
index 533f4aee8567..066929ec0d61 100644
--- a/block/scsi_ioctl.c
+++ b/block/scsi_ioctl.c
@@ -299,6 +299,7 @@ static int sg_io(struct request_queue *q, struct gendisk *bd_disk,
struct request *rq;
struct scsi_request *req;
struct bio *bio;
+ u8 sense[SCSI_SENSE_BUFFERSIZE];
if (hdr->interface_id != 'S')
return -EINVAL;
@@ -361,6 +362,7 @@ static int sg_io(struct request_queue *q, struct gendisk *bd_disk,
bio = rq->bio;
req->retries = 0;
+ req->sense = sense;
start_time = jiffies;
--
2.20.1.321.g9e740568ce-goog
