2019-03-25 21:38:35

by Aditya Pakki

Subject: [PATCH v3] nvdimm: btt_devs: fix a NULL pointer dereference

In case kmemdup fails, the fix releases resources and returns to
avoid the NULL pointer dereference.

Signed-off-by: Aditya Pakki <[email protected]>

---
v2: Replace incorrect kfree with ida_simple_remove, suggested by
Johannes Thumshirn
v1: Free nd_btt->id in case of failure and avoid double free, suggested
by Dan Williams
---
drivers/nvdimm/btt_devs.c | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/drivers/nvdimm/btt_devs.c b/drivers/nvdimm/btt_devs.c
index b72a303176c7..f73fb5fdc93f 100644
--- a/drivers/nvdimm/btt_devs.c
+++ b/drivers/nvdimm/btt_devs.c
@@ -204,8 +204,11 @@ static struct device *__nd_btt_create(struct nd_region *nd_region,
}

nd_btt->lbasize = lbasize;
- if (uuid)
+ if (uuid) {
uuid = kmemdup(uuid, 16, GFP_KERNEL);
+ if (!uuid)
+ goto out_put_id;
+ }
nd_btt->uuid = uuid;
dev = &nd_btt->dev;
dev_set_name(dev, "btt%d.%d", nd_region->id, nd_btt->id);
@@ -220,6 +223,11 @@ static struct device *__nd_btt_create(struct nd_region *nd_region,
return NULL;
}
return dev;
+
+out_put_id:
+ ida_simple_remove(&nd_region->btt_ida, nd_btt->id);
+ kfree(nd_btt);
+ return NULL;
}

struct device *nd_btt_create(struct nd_region *nd_region)
--
2.17.1

2019-03-25 21:45:25

by Dan Williams

Subject: Re: [PATCH v3] nvdimm: btt_devs: fix a NULL pointer dereference

On Mon, Mar 25, 2019 at 2:36 PM Aditya Pakki <[email protected]> wrote:
>
> In case kmemdup fails, the fix releases resources and returns to
> avoid the NULL pointer dereference.
>
> Signed-off-by: Aditya Pakki <[email protected]>
>
> ---
> v2: Replace incorrect kfree with ida_simple_remove, suggested by
> Johannes Thumshirn
> v1: Free nd_btt->id in case of failure and avoid double free, suggested
> by Dan Williams
> ---
> drivers/nvdimm/btt_devs.c | 10 +++++++++-
> 1 file changed, 9 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/nvdimm/btt_devs.c b/drivers/nvdimm/btt_devs.c
> index b72a303176c7..f73fb5fdc93f 100644
> --- a/drivers/nvdimm/btt_devs.c
> +++ b/drivers/nvdimm/btt_devs.c
> @@ -204,8 +204,11 @@ static struct device *__nd_btt_create(struct nd_region *nd_region,
> }
>
> nd_btt->lbasize = lbasize;
> - if (uuid)
> + if (uuid) {
> uuid = kmemdup(uuid, 16, GFP_KERNEL);
> + if (!uuid)
> + goto out_put_id;
> + }
> nd_btt->uuid = uuid;
> dev = &nd_btt->dev;
> dev_set_name(dev, "btt%d.%d", nd_region->id, nd_btt->id);
> @@ -220,6 +223,11 @@ static struct device *__nd_btt_create(struct nd_region *nd_region,
> return NULL;
> }
> return dev;
> +
> +out_put_id:
> + ida_simple_remove(&nd_region->btt_ida, nd_btt->id);
> + kfree(nd_btt);

There's still 2 calls to "kfree(nd_btt)" when only one is needed.
Please route them both to the same call.