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Commit c1c20120 authored by Boaz Harrosh's avatar Boaz Harrosh Committed by Jens Axboe
Browse files

bsg: Fix sense buffer bug in SG_IO 



When submitting requests via SG_IO, which does a sync io, a
bsg_command is not allocated. So an in-Kernel sense_buffer was not
set. However when calling blk_execute_rq() with no sense buffer
one is provided from the stack. Now bsg at blk_complete_sgv4_hdr_rq()
would check if rq->sense_len and a sense was requested by sg_io_v4
the rq->sense was copy_user() back, but by now it is already mangled
stack memory.

I have fixed that by forcing a sense_buffer when calling bsg_map_hdr().
The bsg_command->sense is provided in the write/read path like before,
and on-the-stack buffer is provided when doing SG_IO.

I have also fixed a dprintk message to print rq->errors in hex because
of the scsi bit-field use of this member. For other block devices it
does not matter anyway.

Signed-off-by: default avatarBoaz Harrosh <bharrosh@panasas.com>
Acked-by: default avatarFUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: default avatarJens Axboe <jens.axboe@oracle.com>
parent 5955c7a2

block/bsg.c

+10 −7
Original line number Diff line number Diff line
@@ -244,7 +244,8 @@ bsg_validate_sgv4_hdr(struct request_queue *q, struct sg_io_v4 *hdr, int *rw) 
 * map sg_io_v4 to a request.

 */

static struct request *

bsg_map_hdr(struct bsg_device *bd, struct sg_io_v4 *hdr, fmode_t has_write_perm)

bsg_map_hdr(struct bsg_device *bd, struct sg_io_v4 *hdr, fmode_t has_write_perm,

	    u8 *sense)

{

	struct request_queue *q = bd->queue;

	struct request *rq, *next_rq = NULL;
@@ -306,6 +307,10 @@ bsg_map_hdr(struct bsg_device *bd, struct sg_io_v4 *hdr, fmode_t has_write_perm) 
		if (ret)

			goto out;

	}



	rq->sense = sense;

	rq->sense_len = 0;



	return rq;

out:

	if (rq->cmd != rq->__cmd)
@@ -348,9 +353,6 @@ static void bsg_rq_end_io(struct request *rq, int uptodate) 
static void bsg_add_command(struct bsg_device *bd, struct request_queue *q,

			    struct bsg_command *bc, struct request *rq)

{

	rq->sense = bc->sense;

	rq->sense_len = 0;



	/*

	 * add bc command to busy queue and submit rq for io

	 */
@@ -419,7 +421,7 @@ static int blk_complete_sgv4_hdr_rq(struct request *rq, struct sg_io_v4 *hdr, 
{

	int ret = 0;



	dprintk("rq %p bio %p %u\n", rq, bio, rq->errors);

	dprintk("rq %p bio %p 0x%x\n", rq, bio, rq->errors);

	/*

	 * fill in all the output members

	 */
@@ -635,7 +637,7 @@ static int __bsg_write(struct bsg_device *bd, const char __user *buf, 
		/*

		 * get a request, fill in the blanks, and add to request queue

		 */

		rq = bsg_map_hdr(bd, &bc->hdr, has_write_perm);

		rq = bsg_map_hdr(bd, &bc->hdr, has_write_perm, bc->sense);

		if (IS_ERR(rq)) {

			ret = PTR_ERR(rq);

			rq = NULL;
@@ -922,11 +924,12 @@ static long bsg_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 
		struct request *rq;

		struct bio *bio, *bidi_bio = NULL;

		struct sg_io_v4 hdr;

		u8 sense[SCSI_SENSE_BUFFERSIZE];



		if (copy_from_user(&hdr, uarg, sizeof(hdr)))

			return -EFAULT;



		rq = bsg_map_hdr(bd, &hdr, file->f_mode & FMODE_WRITE);

		rq = bsg_map_hdr(bd, &hdr, file->f_mode & FMODE_WRITE, sense);

		if (IS_ERR(rq))

			return PTR_ERR(rq);