Chuck Lever 25fb53e43e handshake: Require admin permission for DONE command ...

[ Upstream commit 81246a6530 ]

ACCEPT and DONE are the two downcalls of the handshake genl
family, both intended for use by the trusted handshake agent
(tlshd). ACCEPT already requires GENL_ADMIN_PERM; DONE has
no privilege check at all.

The fd-lookup in handshake_nl_done_doit() only confirms that
some pending handshake request exists for the supplied sockfd;
it does not authenticate the sender. An unprivileged process
that guesses or observes a valid sockfd can therefore submit
a DONE with HANDSHAKE_A_DONE_STATUS == 0, leaving the kernel
consumer to proceed as if the handshake succeeded. A non-zero
status on a forged DONE tears down a legitimate in-flight
handshake before tlshd can report its real result.

Fixes: 3b3009ea8a ("net/handshake: Create a NETLINK service for handling handshake requests")
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Hannes Reinecke <hare@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Link: https://patch.msgid.link/20260609141831.90694-1-cel@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

2026-07-24 16:03:12 +02:00

..

specs

handshake: Require admin permission for DONE command

2026-07-24 16:03:12 +02:00

genetlink-c.yaml

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genetlink-legacy.yaml

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genetlink.yaml

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netlink-raw.yaml

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