nvme: fix metadata handling in nvme-passthrough

On an NVMe namespace that does not support metadata, it is possible to
send an IO command with metadata through io-passthru. This allows issues
like [1] to trigger in the completion code path.
nvme_map_user_request() doesn't check if the namespace supports metadata
before sending it forward. It also allows admin commands with metadata to
be processed as it ignores metadata when bdev == NULL and may report
success.

Reject an IO command with metadata when the NVMe namespace doesn't
support it and reject an admin command if it has metadata.

[1] https://lore.kernel.org/all/mb61pcylvnym8.fsf@amazon.com/

Suggested-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Puranjay Mohan <pjy@amazon.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Anuj Gupta <anuj20.g@samsung.com>
Signed-off-by: Keith Busch <kbusch@kernel.org>

diff --git a/drivers/nvme/host/ioctl.c b/drivers/nvme/host/ioctl.c
index 850f81e08e7d81981b406bb867984f43bc060bde..1d769c842fbf53eab68b33e96099b1054319fa14 100644 (file)
--- a/drivers/nvme/host/ioctl.c
+++ b/drivers/nvme/host/ioctl.c
@@ -4,6 +4,7 @@
  * Copyright (c) 2017-2021 Christoph Hellwig.
  */
 #include <linux/bio-integrity.h>
+#include <linux/blk-integrity.h>
 #include <linux/ptrace.h>      /* for force_successful_syscall_return */
 #include <linux/nvme_ioctl.h>
 #include <linux/io_uring/cmd.h>
@@ -119,9 +120,14 @@ static int nvme_map_user_request(struct request *req, u64 ubuffer,
        struct request_queue *q = req->q;
        struct nvme_ns *ns = q->queuedata;
        struct block_device *bdev = ns ? ns->disk->part0 : NULL;
+       bool supports_metadata = bdev && blk_get_integrity(bdev->bd_disk);
+       bool has_metadata = meta_buffer && meta_len;
        struct bio *bio = NULL;
        int ret;
 
+       if (has_metadata && !supports_metadata)
+               return -EINVAL;
+
        if (ioucmd && (ioucmd->flags & IORING_URING_CMD_FIXED)) {
                struct iov_iter iter;
 
@@ -143,15 +149,15 @@ static int nvme_map_user_request(struct request *req, u64 ubuffer,
                goto out;
 
        bio = req->bio;
-       if (bdev) {
+       if (bdev)
                bio_set_dev(bio, bdev);
-               if (meta_buffer && meta_len) {
-                       ret = bio_integrity_map_user(bio, meta_buffer, meta_len,
-                                                    meta_seed);
-                       if (ret)
-                               goto out_unmap;
-                       req->cmd_flags |= REQ_INTEGRITY;
-               }
+
+       if (has_metadata) {
+               ret = bio_integrity_map_user(bio, meta_buffer, meta_len,
+                                            meta_seed);
+               if (ret)
+                       goto out_unmap;
+               req->cmd_flags |= REQ_INTEGRITY;
        }
 
        return ret;