ACK: [PATCH 1/1] nfc: Ensure presence of required attributes in the deactivate_target handler

[Connor Kuehl]

On 7/9/19 11:12 PM, Tyler Hicks wrote:
> From: Young Xiao <92siuyang at gmail.com>
> 
> Check that the NFC_ATTR_TARGET_INDEX attributes (in addition to
> NFC_ATTR_DEVICE_INDEX) are provided by the netlink client prior to
> accessing them. This prevents potential unhandled NULL pointer dereference
> exceptions which can be triggered by malicious user-mode programs,
> if they omit one or both of these attributes.
> 
> Signed-off-by: Young Xiao <92siuyang at gmail.com>
> Signed-off-by: David S. Miller <davem at davemloft.net>
> 
> CVE-2019-12984
> 
> (cherry picked from commit 385097a3675749cbc9e97c085c0e5dfe4269ca51)
> Signed-off-by: Tyler Hicks <tyhicks at canonical.com>

Acked-by: Connor Kuehl <connor.kuehl at canonical.com>

> ---
>  net/nfc/netlink.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/net/nfc/netlink.c b/net/nfc/netlink.c
> index 376181cc1def..9f2875efb4ac 100644
> --- a/net/nfc/netlink.c
> +++ b/net/nfc/netlink.c
> @@ -922,7 +922,8 @@ static int nfc_genl_deactivate_target(struct sk_buff *skb,
>  	u32 device_idx, target_idx;
>  	int rc;
>  
> -	if (!info->attrs[NFC_ATTR_DEVICE_INDEX])
> +	if (!info->attrs[NFC_ATTR_DEVICE_INDEX] ||
> +	    !info->attrs[NFC_ATTR_TARGET_INDEX])
>  		return -EINVAL;
>  
>  	device_idx = nla_get_u32(info->attrs[NFC_ATTR_DEVICE_INDEX]);
>