[PATCH net 1/2] ieee802154: admin-gate legacy LLSEC dump operations

[Michael Bommarito <michael.bommarito@gmail.com>]

In net/ieee802154/netlink.c, the legacy IEEE802154_NL family ops table
builds the LLSEC dump entries (LLSEC_LIST_KEY, LLSEC_LIST_DEV,
LLSEC_LIST_DEVKEY, LLSEC_LIST_SECLEVEL) with IEEE802154_DUMP() which
sets no .flags, so generic netlink runs them ungated. The modern
nl802154 family admin-gates the equivalent reads via
NL802154_CMD_GET_SEC_KEY and friends with .flags = GENL_ADMIN_PERM.

Any local uid that can open AF_NETLINK / NETLINK_GENERIC can resolve
the "802.15.4 MAC" family and dump LLSEC_LIST_KEY on any wpan netdev
that has an LLSEC key installed; the dump handler writes the raw
16-byte AES-128 key bytes (IEEE802154_ATTR_LLSEC_KEY_BYTES, copied
verbatim from struct ieee802154_llsec_key.key) into the reply.
Recovering the AES key compromises 802.15.4 LLSEC link confidentiality
and authenticity, since LLSEC uses CCM* and the same key authenticates
and encrypts frames.

Impact: any local uid with no capabilities can read the raw 16-byte
AES-128 LLSEC key from the kernel keytable on any wpan netdev that has
an administrator-installed LLSEC key, by issuing an LLSEC_LIST_KEY
dump on the legacy IEEE802154_NL generic-netlink family.

Introduce IEEE802154_DUMP_PRIV() mirroring IEEE802154_DUMP() but
setting .flags = GENL_ADMIN_PERM, and use it for the four LLSEC dump
entries. LIST_PHY and LIST_IFACE retain IEEE802154_DUMP() because the
modern nl802154 family exposes their equivalents to unprivileged
readers by design (NL802154_CMD_GET_WPAN_PHY and
NL802154_CMD_GET_INTERFACE carry "can be retrieved by unprivileged
users" annotations).

Fixes: 3e9c156e2c21 ("ieee802154: add netlink interfaces for llsec")
Cc: stable@vger.kernel.org
Assisted-by: Claude:claude-opus-4-7
Signed-off-by: Michael Bommarito <michael.bommarito@gmail.com>
---
 net/ieee802154/ieee802154.h |  8 ++++++++
 net/ieee802154/netlink.c    | 16 ++++++++--------
 2 files changed, 16 insertions(+), 8 deletions(-)

diff --git a/net/ieee802154/ieee802154.h b/net/ieee802154/ieee802154.h
index c5d91f78301ad..fd9778f705503 100644
--- a/net/ieee802154/ieee802154.h
+++ b/net/ieee802154/ieee802154.h
@@ -23,6 +23,14 @@ void ieee802154_nl_exit(void);
 		.dumpit	= _dump,			\
 	}
 
+#define IEEE802154_DUMP_PRIV(_cmd, _func, _dump)	\
+	{						\
+		.cmd	= _cmd,				\
+		.doit	= _func,			\
+		.dumpit	= _dump,			\
+		.flags	= GENL_ADMIN_PERM,		\
+	}
+
 struct genl_info;
 
 struct sk_buff *ieee802154_nl_create(int flags, u8 req);
diff --git a/net/ieee802154/netlink.c b/net/ieee802154/netlink.c
index 7d2de4ee6992b..9c9fd14d0ca8b 100644
--- a/net/ieee802154/netlink.c
+++ b/net/ieee802154/netlink.c
@@ -98,20 +98,20 @@ static const struct genl_small_ops ieee802154_ops[] = {
 	IEEE802154_OP(IEEE802154_SET_MACPARAMS, ieee802154_set_macparams),
 	IEEE802154_OP(IEEE802154_LLSEC_GETPARAMS, ieee802154_llsec_getparams),
 	IEEE802154_OP(IEEE802154_LLSEC_SETPARAMS, ieee802154_llsec_setparams),
-	IEEE802154_DUMP(IEEE802154_LLSEC_LIST_KEY, NULL,
-			ieee802154_llsec_dump_keys),
+	IEEE802154_DUMP_PRIV(IEEE802154_LLSEC_LIST_KEY, NULL,
+			     ieee802154_llsec_dump_keys),
 	IEEE802154_OP(IEEE802154_LLSEC_ADD_KEY, ieee802154_llsec_add_key),
 	IEEE802154_OP(IEEE802154_LLSEC_DEL_KEY, ieee802154_llsec_del_key),
-	IEEE802154_DUMP(IEEE802154_LLSEC_LIST_DEV, NULL,
-			ieee802154_llsec_dump_devs),
+	IEEE802154_DUMP_PRIV(IEEE802154_LLSEC_LIST_DEV, NULL,
+			     ieee802154_llsec_dump_devs),
 	IEEE802154_OP(IEEE802154_LLSEC_ADD_DEV, ieee802154_llsec_add_dev),
 	IEEE802154_OP(IEEE802154_LLSEC_DEL_DEV, ieee802154_llsec_del_dev),
-	IEEE802154_DUMP(IEEE802154_LLSEC_LIST_DEVKEY, NULL,
-			ieee802154_llsec_dump_devkeys),
+	IEEE802154_DUMP_PRIV(IEEE802154_LLSEC_LIST_DEVKEY, NULL,
+			     ieee802154_llsec_dump_devkeys),
 	IEEE802154_OP(IEEE802154_LLSEC_ADD_DEVKEY, ieee802154_llsec_add_devkey),
 	IEEE802154_OP(IEEE802154_LLSEC_DEL_DEVKEY, ieee802154_llsec_del_devkey),
-	IEEE802154_DUMP(IEEE802154_LLSEC_LIST_SECLEVEL, NULL,
-			ieee802154_llsec_dump_seclevels),
+	IEEE802154_DUMP_PRIV(IEEE802154_LLSEC_LIST_SECLEVEL, NULL,
+			     ieee802154_llsec_dump_seclevels),
 	IEEE802154_OP(IEEE802154_LLSEC_ADD_SECLEVEL,
 		      ieee802154_llsec_add_seclevel),
 	IEEE802154_OP(IEEE802154_LLSEC_DEL_SECLEVEL,
-- 
2.53.0