FAILED: patch "[PATCH] nvme: sanitize metadata bounce buffer for reads" failed to apply to 4.19-stable tree

[<gregkh@linuxfoundation.org>]

The patch below does not apply to the 4.19-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-4.19.y
git checkout FETCH_HEAD
git cherry-pick -x 2b32c76e2b0154b98b9322ae7546b8156cd703e6
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2023102146-postwar-smugly-830b@gregkh' --subject-prefix 'PATCH 4.19.y' HEAD^..

Possible dependencies:



thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 2b32c76e2b0154b98b9322ae7546b8156cd703e6 Mon Sep 17 00:00:00 2001
From: Keith Busch <kbusch@kernel.org>
Date: Mon, 16 Oct 2023 13:12:47 -0700
Subject: [PATCH] nvme: sanitize metadata bounce buffer for reads

User can request more metadata bytes than the device will write. Ensure
kernel buffer is initialized so we're not leaking unsanitized memory on
the copy-out.

Fixes: 0b7f1f26f95a51a ("nvme: use the block layer for userspace passthrough metadata")
Reviewed-by: Jens Axboe <axboe@kernel.dk>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Kanchan Joshi <joshi.k@samsung.com>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Signed-off-by: Keith Busch <kbusch@kernel.org>

diff --git a/drivers/nvme/host/ioctl.c b/drivers/nvme/host/ioctl.c
index d8ff796fd5f2..747c879e8982 100644
--- a/drivers/nvme/host/ioctl.c
+++ b/drivers/nvme/host/ioctl.c
@@ -108,9 +108,13 @@ static void *nvme_add_user_metadata(struct request *req, void __user *ubuf,
 	if (!buf)
 		goto out;
 
-	ret = -EFAULT;
-	if ((req_op(req) == REQ_OP_DRV_OUT) && copy_from_user(buf, ubuf, len))
-		goto out_free_meta;
+	if (req_op(req) == REQ_OP_DRV_OUT) {
+		ret = -EFAULT;
+		if (copy_from_user(buf, ubuf, len))
+			goto out_free_meta;
+	} else {
+		memset(buf, 0, len);
+	}
 
 	bip = bio_integrity_alloc(bio, GFP_KERNEL, 1);
 	if (IS_ERR(bip)) {