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>

1 files changed, 10 insertions, 0 deletions

diff --git a/drivers/nvme/target/core.c b/drivers/nvme/target/core.c
index da088293eafc..22a2a2bb40f9 100644
--- a/drivers/nvme/target/core.c
+++ b/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;