nfc: Ensure presence of required attributes in the activate_target handler
commit a0323b979f81ad2deb2c8836eab506534891876a upstream.
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 <mjurczyk@google.com>
Acked-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/net/nfc/netlink.c b/net/nfc/netlink.c
index ea023b3..102c681 100644
--- a/net/nfc/netlink.c
+++ b/net/nfc/netlink.c
@@ -910,7 +910,9 @@
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]);