nvmet: better data length validation

Currently the NVMe target stores the expexted data length in req->data_len
and uses that for data transfer decisions, but that does not take the
actual transfer length in the SGLs into account.  So this adds a new
transfer_len field, into which the transport drivers store the actual
transfer length.  We then check the two match before actually executing
the command.

The FC transport driver already had such a field, which is removed in
favour of the common one.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

drivers/nvme/target/core.c

@@ -501,6 +501,7 @@ bool nvmet_req_init(struct nvmet_req *req, struct nvmet_cq *cq,
 	req->ops = ops;
 	req->sg = NULL;
 	req->sg_cnt = 0;
+	req->transfer_len = 0;
 	req->rsp->status = 0;
 
 	/* no support for fused commands yet */
@@ -550,6 +551,15 @@ void nvmet_req_uninit(struct nvmet_req *req)
 }
 EXPORT_SYMBOL_GPL(nvmet_req_uninit);
 
+void nvmet_req_execute(struct nvmet_req *req)
+{
+	if (unlikely(req->data_len != req->transfer_len))
+		nvmet_req_complete(req, NVME_SC_SGL_INVALID_DATA | NVME_SC_DNR);
+	else
+		req->execute(req);
+}
+EXPORT_SYMBOL_GPL(nvmet_req_execute);
+
 static inline bool nvmet_cc_en(u32 cc)
 {
 	return (cc >> NVME_CC_EN_SHIFT) & 0x1;

drivers/nvme/target/fc.c

@@ -76,7 +76,6 @@ struct nvmet_fc_fcp_iod {
 	dma_addr_t			rspdma;
 	struct scatterlist		*data_sg;
 	int				data_sg_cnt;
-	u32				total_length;
 	u32				offset;
 	enum nvmet_fcp_datadir		io_dir;
 	bool				active;
@@ -1700,7 +1699,7 @@ nvmet_fc_alloc_tgt_pgs(struct nvmet_fc_fcp_iod *fod)
 	u32 page_len, length;
 	int i = 0;
 
-	length = fod->total_length;
+	length = fod->req.transfer_len;
 	nent = DIV_ROUND_UP(length, PAGE_SIZE);
 	sg = kmalloc_array(nent, sizeof(struct scatterlist), GFP_KERNEL);
 	if (!sg)
@@ -1789,7 +1788,7 @@ nvmet_fc_prep_fcp_rsp(struct nvmet_fc_tgtport *tgtport,
 	u32 rsn, rspcnt, xfr_length;
 
 	if (fod->fcpreq->op == NVMET_FCOP_READDATA_RSP)
-		xfr_length = fod->total_length;
+		xfr_length = fod->req.transfer_len;
 	else
 		xfr_length = fod->offset;
 
@@ -1815,7 +1814,7 @@ nvmet_fc_prep_fcp_rsp(struct nvmet_fc_tgtport *tgtport,
 	rspcnt = atomic_inc_return(&fod->queue->zrspcnt);
 	if (!(rspcnt % fod->queue->ersp_ratio) ||
 	    sqe->opcode == nvme_fabrics_command ||
-	    xfr_length != fod->total_length ||
+	    xfr_length != fod->req.transfer_len ||
 	    (le16_to_cpu(cqe->status) & 0xFFFE) || cqewd[0] || cqewd[1] ||
 	    (sqe->flags & (NVME_CMD_FUSE_FIRST | NVME_CMD_FUSE_SECOND)) ||
 	    queue_90percent_full(fod->queue, le16_to_cpu(cqe->sq_head)))
@@ -1892,7 +1891,7 @@ nvmet_fc_transfer_fcp_data(struct nvmet_fc_tgtport *tgtport,
 	fcpreq->timeout = NVME_FC_TGTOP_TIMEOUT_SEC;
 
 	tlen = min_t(u32, tgtport->max_sg_cnt * PAGE_SIZE,
-			(fod->total_length - fod->offset));
+			(fod->req.transfer_len - fod->offset));
 	fcpreq->transfer_length = tlen;
 	fcpreq->transferred_length = 0;
 	fcpreq->fcp_error = 0;
@@ -1906,7 +1905,7 @@ nvmet_fc_transfer_fcp_data(struct nvmet_fc_tgtport *tgtport,
 	 * combined xfr with response.
 	 */
 	if ((op == NVMET_FCOP_READDATA) &&
-	    ((fod->offset + fcpreq->transfer_length) == fod->total_length) &&
+	    ((fod->offset + fcpreq->transfer_length) == fod->req.transfer_len) &&
 	    (tgtport->ops->target_features & NVMET_FCTGTFEAT_READDATA_RSP)) {
 		fcpreq->op = NVMET_FCOP_READDATA_RSP;
 		nvmet_fc_prep_fcp_rsp(tgtport, fod);
@@ -1986,7 +1985,7 @@ nvmet_fc_fod_op_done(struct nvmet_fc_fcp_iod *fod)
 		}
 
 		fod->offset += fcpreq->transferred_length;
-		if (fod->offset != fod->total_length) {
+		if (fod->offset != fod->req.transfer_len) {
 			spin_lock_irqsave(&fod->flock, flags);
 			fod->writedataactive = true;
 			spin_unlock_irqrestore(&fod->flock, flags);
@@ -1998,9 +1997,7 @@ nvmet_fc_fod_op_done(struct nvmet_fc_fcp_iod *fod)
 		}
 
 		/* data transfer complete, resume with nvmet layer */
-
-		fod->req.execute(&fod->req);
-
+		nvmet_req_execute(&fod->req);
 		break;
 
 	case NVMET_FCOP_READDATA:
@@ -2023,7 +2020,7 @@ nvmet_fc_fod_op_done(struct nvmet_fc_fcp_iod *fod)
 		}
 
 		fod->offset += fcpreq->transferred_length;
-		if (fod->offset != fod->total_length) {
+		if (fod->offset != fod->req.transfer_len) {
 			/* transfer the next chunk */
 			nvmet_fc_transfer_fcp_data(tgtport, fod,
 						NVMET_FCOP_READDATA);
@@ -2160,7 +2157,7 @@ nvmet_fc_handle_fcp_rqst(struct nvmet_fc_tgtport *tgtport,
 
 	fod->fcpreq->done = nvmet_fc_xmt_fcp_op_done;
 
-	fod->total_length = be32_to_cpu(cmdiu->data_len);
+	fod->req.transfer_len = be32_to_cpu(cmdiu->data_len);
 	if (cmdiu->flags & FCNVME_CMD_FLAGS_WRITE) {
 		fod->io_dir = NVMET_FCP_WRITE;
 		if (!nvme_is_write(&cmdiu->sqe))
@@ -2171,7 +2168,7 @@ nvmet_fc_handle_fcp_rqst(struct nvmet_fc_tgtport *tgtport,
 			goto transport_error;
 	} else {
 		fod->io_dir = NVMET_FCP_NODATA;
-		if (fod->total_length)
+		if (fod->req.transfer_len)
 			goto transport_error;
 	}
 
@@ -2179,9 +2176,6 @@ nvmet_fc_handle_fcp_rqst(struct nvmet_fc_tgtport *tgtport,
 	fod->req.rsp = &fod->rspiubuf.cqe;
 	fod->req.port = fod->queue->port;
 
-	/* ensure nvmet handlers will set cmd handler callback */
-	fod->req.execute = NULL;
-
 	/* clear any response payload */
 	memset(&fod->rspiubuf, 0, sizeof(fod->rspiubuf));
 
@@ -2201,7 +2195,7 @@ nvmet_fc_handle_fcp_rqst(struct nvmet_fc_tgtport *tgtport,
 	/* keep a running counter of tail position */
 	atomic_inc(&fod->queue->sqtail);
 
-	if (fod->total_length) {
+	if (fod->req.transfer_len) {
 		ret = nvmet_fc_alloc_tgt_pgs(fod);
 		if (ret) {
 			nvmet_req_complete(&fod->req, ret);
@@ -2224,9 +2218,7 @@ nvmet_fc_handle_fcp_rqst(struct nvmet_fc_tgtport *tgtport,
 	 * can invoke the nvmet_layer now. If read data, cmd completion will
 	 * push the data
 	 */
-
-	fod->req.execute(&fod->req);
-
+	nvmet_req_execute(&fod->req);
 	return;
 
 transport_error:

drivers/nvme/target/loop.c

@@ -127,7 +127,7 @@ static void nvme_loop_execute_work(struct work_struct *work)
 	struct nvme_loop_iod *iod =
 		container_of(work, struct nvme_loop_iod, work);
 
-	iod->req.execute(&iod->req);
+	nvmet_req_execute(&iod->req);
 }
 
 static enum blk_eh_timer_return
@@ -176,6 +176,7 @@ static blk_status_t nvme_loop_queue_rq(struct blk_mq_hw_ctx *hctx,
 
 		iod->req.sg = iod->sg_table.sgl;
 		iod->req.sg_cnt = blk_rq_map_sg(req->q, req, iod->sg_table.sgl);
+		iod->req.transfer_len = blk_rq_bytes(req);
 	}
 
 	blk_mq_start_request(req);

drivers/nvme/target/nvmet.h

@@ -223,7 +223,10 @@ struct nvmet_req {
 	struct bio		inline_bio;
 	struct bio_vec		inline_bvec[NVMET_MAX_INLINE_BIOVEC];
 	int			sg_cnt;
+	/* data length as parsed from the command: */
 	size_t			data_len;
+	/* data length as parsed from the SGL descriptor: */
+	size_t			transfer_len;
 
 	struct nvmet_port	*port;
 
@@ -266,6 +269,7 @@ u16 nvmet_parse_fabrics_cmd(struct nvmet_req *req);
 bool nvmet_req_init(struct nvmet_req *req, struct nvmet_cq *cq,
 		struct nvmet_sq *sq, struct nvmet_fabrics_ops *ops);
 void nvmet_req_uninit(struct nvmet_req *req);
+void nvmet_req_execute(struct nvmet_req *req);
 void nvmet_req_complete(struct nvmet_req *req, u16 status);
 
 void nvmet_cq_setup(struct nvmet_ctrl *ctrl, struct nvmet_cq *cq, u16 qid,

drivers/nvme/target/rdma.c

@@ -148,14 +148,14 @@ static inline u32 get_unaligned_le24(const u8 *p)
 static inline bool nvmet_rdma_need_data_in(struct nvmet_rdma_rsp *rsp)
 {
 	return nvme_is_write(rsp->req.cmd) &&
-		rsp->req.data_len &&
+		rsp->req.transfer_len &&
 		!(rsp->flags & NVMET_RDMA_REQ_INLINE_DATA);
 }
 
 static inline bool nvmet_rdma_need_data_out(struct nvmet_rdma_rsp *rsp)
 {
 	return !nvme_is_write(rsp->req.cmd) &&
-		rsp->req.data_len &&
+		rsp->req.transfer_len &&
 		!rsp->req.rsp->status &&
 		!(rsp->flags & NVMET_RDMA_REQ_INLINE_DATA);
 }
@@ -577,7 +577,7 @@ static void nvmet_rdma_read_data_done(struct ib_cq *cq, struct ib_wc *wc)
 		return;
 	}
 
-	rsp->req.execute(&rsp->req);
+	nvmet_req_execute(&rsp->req);
 }
 
 static void nvmet_rdma_use_inline_sg(struct nvmet_rdma_rsp *rsp, u32 len,
@@ -609,6 +609,7 @@ static u16 nvmet_rdma_map_sgl_inline(struct nvmet_rdma_rsp *rsp)
 
 	nvmet_rdma_use_inline_sg(rsp, len, off);
 	rsp->flags |= NVMET_RDMA_REQ_INLINE_DATA;
+	rsp->req.transfer_len += len;
 	return 0;
 }
 
@@ -636,6 +637,7 @@ static u16 nvmet_rdma_map_sgl_keyed(struct nvmet_rdma_rsp *rsp,
 			nvmet_data_dir(&rsp->req));
 	if (ret < 0)
 		return NVME_SC_INTERNAL;
+	rsp->req.transfer_len += len;
 	rsp->n_rdma += ret;
 
 	if (invalidate) {
@@ -693,7 +695,7 @@ static bool nvmet_rdma_execute_command(struct nvmet_rdma_rsp *rsp)
 				queue->cm_id->port_num, &rsp->read_cqe, NULL))
 			nvmet_req_complete(&rsp->req, NVME_SC_DATA_XFER_ERROR);
 	} else {
-		rsp->req.execute(&rsp->req);
+		nvmet_req_execute(&rsp->req);
 	}
 
 	return true;