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authorPaolo Abeni <pabeni@redhat.com>2023-04-20 19:17:13 +0200
committerPaul Moore <paul@paul-moore.com>2023-05-18 13:11:09 -0400
commite3d9387f002612093dbeaa272f7930ce5108033f (patch)
tree17040b845b29070d3bfadcf0525f503d03d8c126 /security
parentc52df19e3759055cf07d1c0030c46ea958163aa9 (diff)
security, lsm: Introduce security_mptcp_add_subflow()
MPTCP can create subflows in kernel context, and later indirectly expose them to user-space, via the owning MPTCP socket. As discussed in the reported link, the above causes unexpected failures for server, MPTCP-enabled applications. Let's introduce a new LSM hook to allow the security module to relabel the subflow according to the owning user-space process, via the MPTCP socket owning the subflow. Note that the new hook requires both the MPTCP socket and the new subflow. This could allow future extensions, e.g. explicitly validating the MPTCP <-> subflow linkage. Link: https://lore.kernel.org/mptcp/CAHC9VhTNh-YwiyTds=P1e3rixEDqbRTFj22bpya=+qJqfcaMfg@mail.gmail.com/ Signed-off-by: Paolo Abeni <pabeni@redhat.com> Acked-by: Matthieu Baerts <matthieu.baerts@tessares.net> Signed-off-by: Matthieu Baerts <matthieu.baerts@tessares.net> Signed-off-by: Paul Moore <paul@paul-moore.com>
Diffstat (limited to 'security')
-rw-r--r--security/security.c17
1 files changed, 17 insertions, 0 deletions
diff --git a/security/security.c b/security/security.c
index d5ff7ff45b77..0e7be1da0b3d 100644
--- a/security/security.c
+++ b/security/security.c
@@ -4667,6 +4667,23 @@ int security_sctp_assoc_established(struct sctp_association *asoc,
}
EXPORT_SYMBOL(security_sctp_assoc_established);
+/**
+ * security_mptcp_add_subflow() - Inherit the LSM label from the MPTCP socket
+ * @sk: the owning MPTCP socket
+ * @ssk: the new subflow
+ *
+ * Update the labeling for the given MPTCP subflow, to match the one of the
+ * owning MPTCP socket. This hook has to be called after the socket creation and
+ * initialization via the security_socket_create() and
+ * security_socket_post_create() LSM hooks.
+ *
+ * Return: Returns 0 on success or a negative error code on failure.
+ */
+int security_mptcp_add_subflow(struct sock *sk, struct sock *ssk)
+{
+ return call_int_hook(mptcp_add_subflow, 0, sk, ssk);
+}
+
#endif /* CONFIG_SECURITY_NETWORK */
#ifdef CONFIG_SECURITY_INFINIBAND