nvmet: fixup crash on NULL device path

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>
This commit is contained in:
Hannes Reinecke 2018-07-25 08:35:17 +02:00 committed by Christoph Hellwig
parent 6cdefc6e2a
commit 5613d31214

View file

@ -282,6 +282,7 @@ 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);
@ -289,10 +290,14 @@ 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;