[PATCH 5.4] nvme: fix metadata handling in nvme-passthrough

[PATCH 5.4] nvme: fix metadata handling in nvme-passthrough

[Hagar Hemdan]

From: Puranjay Mohan <pjy@amazon.com>

[ Upstream commit 7c2fd76048e95dd267055b5f5e0a48e6e7c81fd9 ]

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>
[ Move the changes from nvme_map_user_request() to nvme_submit_user_cmd()
  to make it work on 5.4 ]
Signed-off-by: Hagar Hemdan <hagarhem@amazon.com>
---
 drivers/nvme/host/core.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index 0676637e1eab..a841fd4929ad 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -921,11 +921,16 @@ static int nvme_submit_user_cmd(struct request_queue *q,
 	bool write = nvme_is_write(cmd);
 	struct nvme_ns *ns = q->queuedata;
 	struct gendisk *disk = ns ? ns->disk : NULL;
+	bool supports_metadata = disk && blk_get_integrity(disk);
+	bool has_metadata = meta_buffer && meta_len;
 	struct request *req;
 	struct bio *bio = NULL;
 	void *meta = NULL;
 	int ret;
 
+	if (has_metadata && !supports_metadata)
+		return -EINVAL;
+
 	req = nvme_alloc_request(q, cmd, 0, NVME_QID_ANY);
 	if (IS_ERR(req))
 		return PTR_ERR(req);
@@ -940,7 +945,7 @@ static int nvme_submit_user_cmd(struct request_queue *q,
 			goto out;
 		bio = req->bio;
 		bio->bi_disk = disk;
-		if (disk && meta_buffer && meta_len) {
+		if (has_metadata) {
 			meta = nvme_add_user_metadata(bio, meta_buffer, meta_len,
 					meta_seed, write);
 			if (IS_ERR(meta)) {
-- 
2.40.1

Re: [PATCH 5.4] nvme: fix metadata handling in nvme-passthrough

[Sasha Levin]

[ Sasha's backport helper bot ]

Hi,

The upstream commit SHA1 provided is correct: 7c2fd76048e95dd267055b5f5e0a48e6e7c81fd9

WARNING: Author mismatch between patch and upstream commit:
Backport author: Hagar Hemdan <hagarhem@amazon.com>
Commit author: Puranjay Mohan <pjy@amazon.com>


Status in newer kernel trees:
6.12.y | Present (exact SHA1)
6.11.y | Present (different SHA1: dc522d2bc1d0)
6.6.y | Not found
6.1.y | Not found
5.15.y | Not found
5.10.y | Not found
5.4.y | Not found

Note: The patch differs from the upstream commit:
---
--- -	2024-11-25 10:29:11.090159886 -0500
+++ /tmp/tmp.n0e8JIvoqt	2024-11-25 10:29:11.084066265 -0500
@@ -1,3 +1,5 @@
+[ Upstream commit 7c2fd76048e95dd267055b5f5e0a48e6e7c81fd9 ]
+
 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.
@@ -17,58 +19,43 @@
 Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
 Reviewed-by: Anuj Gupta <anuj20.g@samsung.com>
 Signed-off-by: Keith Busch <kbusch@kernel.org>
+[ Move the changes from nvme_map_user_request() to nvme_submit_user_cmd()
+  to make it work on 5.4 ]
+Signed-off-by: Hagar Hemdan <hagarhem@amazon.com>
 ---
- drivers/nvme/host/ioctl.c | 22 ++++++++++++++--------
- 1 file changed, 14 insertions(+), 8 deletions(-)
+ drivers/nvme/host/core.c | 7 ++++++-
+ 1 file changed, 6 insertions(+), 1 deletion(-)
 
-diff --git a/drivers/nvme/host/ioctl.c b/drivers/nvme/host/ioctl.c
-index 850f81e08e7d8..1d769c842fbf5 100644
---- 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;
+diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
+index 0676637e1eab..a841fd4929ad 100644
+--- a/drivers/nvme/host/core.c
++++ b/drivers/nvme/host/core.c
+@@ -921,11 +921,16 @@ static int nvme_submit_user_cmd(struct request_queue *q,
+ 	bool write = nvme_is_write(cmd);
  	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);
+ 	struct gendisk *disk = ns ? ns->disk : NULL;
++	bool supports_metadata = disk && blk_get_integrity(disk);
 +	bool has_metadata = meta_buffer && meta_len;
+ 	struct request *req;
  	struct bio *bio = NULL;
+ 	void *meta = 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;
+ 	req = nvme_alloc_request(q, cmd, 0, NVME_QID_ANY);
+ 	if (IS_ERR(req))
+ 		return PTR_ERR(req);
+@@ -940,7 +945,7 @@ static int nvme_submit_user_cmd(struct request_queue *q,
+ 			goto out;
+ 		bio = req->bio;
+ 		bio->bi_disk = disk;
+-		if (disk && meta_buffer && meta_len) {
++		if (has_metadata) {
+ 			meta = nvme_add_user_metadata(bio, meta_buffer, meta_len,
+ 					meta_seed, write);
+ 			if (IS_ERR(meta)) {
+-- 
+2.40.1
+
---

Results of testing on various branches:

| Branch                    | Patch Apply | Build Test |
|---------------------------|-------------|------------|
| stable/linux-5.4.y        |  Success    |  Success   |