nfc: Ensure presence of required attributes in the deactivate_target handler

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@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Young Xiao 2019-06-14 15:13:02 +08:00 committed by David S. Miller
parent b8003cef2e
commit 385097a367

View File

@ -911,7 +911,8 @@ static int nfc_genl_deactivate_target(struct sk_buff *skb,
u32 device_idx, target_idx; u32 device_idx, target_idx;
int rc; int rc;
if (!info->attrs[NFC_ATTR_DEVICE_INDEX]) if (!info->attrs[NFC_ATTR_DEVICE_INDEX] ||
!info->attrs[NFC_ATTR_TARGET_INDEX])
return -EINVAL; return -EINVAL;
device_idx = nla_get_u32(info->attrs[NFC_ATTR_DEVICE_INDEX]); device_idx = nla_get_u32(info->attrs[NFC_ATTR_DEVICE_INDEX]);