From: Hannes Reinecke <hare@suse.de>
Date: Wed, 25 Jul 2018 08:35:17 +0200
Subject: [PATCH] nvmet: fixup crash on NULL device path
Git-commit: 5613d31214eb4c5c04cdfce4966bb661c8b43191
Patch-Mainline: v4.18-rc7
References: bsc#1054245
When writing an empty string into the device_path attribute the kernel
will crash with
nvmet: failed to open block device (null): (-22)
BUG: unable to handle kernel NULL pointer dereference at 0000000000000000
This patch sanitizes the error handling for invalid device path settings.
Fixes: a07b4970 ("nvmet: add a generic NVMe target")
Signed-off-by: Hannes Reinecke <hare@suse.com>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
---
drivers/nvme/target/configfs.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)
diff --git a/drivers/nvme/target/configfs.c b/drivers/nvme/target/configfs.c
index 2360f4d65b4c..fce77db0d2f7 100644
--- a/drivers/nvme/target/configfs.c
+++ b/drivers/nvme/target/configfs.c
@@ -285,6 +285,7 @@ static ssize_t nvmet_ns_device_path_store(struct config_item *item,
{
struct nvmet_ns *ns = to_nvmet_ns(item);
struct nvmet_subsys *subsys = ns->subsys;
+ size_t len;
int ret;
mutex_lock(&subsys->lock);
@@ -292,10 +293,14 @@ static ssize_t nvmet_ns_device_path_store(struct config_item *item,
if (ns->enabled)
goto out_unlock;
- kfree(ns->device_path);
+ ret = -EINVAL;
+ len = strcspn(page, "\n");
+ if (!len)
+ goto out_unlock;
+ kfree(ns->device_path);
ret = -ENOMEM;
- ns->device_path = kstrndup(page, strcspn(page, "\n"), GFP_KERNEL);
+ ns->device_path = kstrndup(page, len, GFP_KERNEL);
if (!ns->device_path)
goto out_unlock;
--
2.12.3