Re: [PATCH] nfc: Fix potential resource leaks

Krzysztof Kozlowski
2022-12-21T09:45:44Z

On 20/12/2022 14:46, Miaoqian Lin wrote:
> nfc_get_device() take reference for the device, add missing
> nfc_put_device() to release it when not need anymore.
> Also fix the style warnning by use error EOPNOTSUPP instead of
> ENOTSUPP.
>
> Fixes: 5ce3f32b5264 ("NFC: netlink: SE API implementation")
> Fixes: 29e76924cf08 ("nfc: netlink: Add capability to reply to vendor_cmd with data")
> Signed-off-by: Miaoqian Lin <linmq006@gmail.com>
> ---
> net/nfc/netlink.c | 51 ++++++++++++++++++++++++++++++++++-------------
> 1 file changed, 37 insertions(+), 14 deletions(-)
>
> diff --git a/net/nfc/netlink.c b/net/nfc/netlink.c
> index 9d91087b9399..d081beaf4828 100644
> --- a/net/nfc/netlink.c
> +++ b/net/nfc/netlink.c
> @@ -1497,6 +1497,7 @@ static int nfc_genl_se_io(struct sk_buff *skb, struct genl_info *info)
> u32 dev_idx, se_idx;
> u8 *apdu;
> size_t apdu_len;
> + int error;

Let's don't introduce the third or fourth style. Existing code calls it
"rc".

>
> if (!info->attrs[NFC_ATTR_DEVICE_INDEX] ||
> !info->attrs[NFC_ATTR_SE_INDEX] ||
> @@ -1510,25 +1511,37 @@ static int nfc_genl_se_io(struct sk_buff *skb, struct genl_info *info)
> if (!dev)
> return -ENODEV;
>
> - if (!dev->ops || !dev->ops->se_io)
> - return -ENOTSUPP;
> + if (!dev->ops || !dev->ops->se_io) {
> + error = -EOPNOTSUPP;
> + goto put_dev;
> + }
>
> apdu_len = nla_len(info->attrs[NFC_ATTR_SE_APDU]);
> - if (apdu_len == 0)
> - return -EINVAL;
> + if (apdu_len == 0) {
> + error = -EINVAL;
> + goto put_dev;
> + }
>
> apdu = nla_data(info->attrs[NFC_ATTR_SE_APDU]);
> - if (!apdu)
> - return -EINVAL;
> + if (!apdu) {
> + error = -EINVAL;
> + goto put_dev;
> + }
>
> ctx = kzalloc(sizeof(struct se_io_ctx), GFP_KERNEL);
> - if (!ctx)
> - return -ENOMEM;
> + if (!ctx) {
> + error = -ENOMEM;
> + goto put_dev;
> + }
>
> ctx->dev_idx = dev_idx;
> ctx->se_idx = se_idx;
>
> - return nfc_se_io(dev, se_idx, apdu, apdu_len, se_io_cb, ctx);
> + error = nfc_se_io(dev, se_idx, apdu, apdu_len, se_io_cb, ctx);
> +
> +put_dev:
> + nfc_put_device(dev);
> + return error;
> }
>
> static int nfc_genl_vendor_cmd(struct sk_buff *skb,
> @@ -1551,14 +1564,20 @@ static int nfc_genl_vendor_cmd(struct sk_buff *skb,
> subcmd = nla_get_u32(info->attrs[NFC_ATTR_VENDOR_SUBCMD]);
>
> dev = nfc_get_device(dev_idx);
> - if (!dev || !dev->vendor_cmds || !dev->n_vendor_cmds)
> + if (!dev)
> return -ENODEV;

Blank line

> + if (!dev->vendor_cmds || !dev->n_vendor_cmds) {
> + err = -ENODEV;
> + goto put_dev;
> + }
>
> if (info->attrs[NFC_ATTR_VENDOR_DATA]) {
> data = nla_data(info->attrs[NFC_ATTR_VENDOR_DATA]);
> data_len = nla_len(info->attrs[NFC_ATTR_VENDOR_DATA]);
> - if (data_len == 0)
> - return -EINVAL;
> + if (data_len == 0) {
> + err = -EINVAL;
> + goto put_dev;
> + }
> } else {
> data = NULL;
> data_len = 0;
> @@ -1573,10 +1592,14 @@ static int nfc_genl_vendor_cmd(struct sk_buff *skb,
> dev->cur_cmd_info = info;
> err = cmd->doit(dev, data, data_len);
> dev->cur_cmd_info = NULL;
> - return err;
> + goto put_dev;
> }
>
> - return -EOPNOTSUPP;
> + err = -EOPNOTSUPP;
> +
> +put_dev:
> + nfc_put_device(dev);
> + return err;
> }
>
> /* message building helper */

Best regards,
Krzysztof