nfc: Ensure presence of required attributes in the activate_target handler

Check that the NFC_ATTR_TARGET_INDEX and NFC_ATTR_PROTOCOLS 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: Mateusz Jurczyk <[email protected]>
Acked-by: Kees Cook <[email protected]>
Signed-off-by: Samuel Ortiz <[email protected]>
This commit is contained in:
Mateusz Jurczyk 2017-05-24 12:42:26 +02:00 • committed by Samuel Ortiz
commit a0323b979f

View file

@ -907,7 +907,9 @@ static int nfc_genl_activate_target(struct sk_buff *skb, struct genl_info *info)
u32 device_idx, target_idx, protocol;
int rc;
if (!info->attrs[NFC_ATTR_DEVICE_INDEX])
if (!info->attrs[NFC_ATTR_DEVICE_INDEX] ||
!info->attrs[NFC_ATTR_TARGET_INDEX] ||
!info->attrs[NFC_ATTR_PROTOCOLS])
return -EINVAL;
device_idx = nla_get_u32(info->attrs[NFC_ATTR_DEVICE_INDEX]);