From 85c3222dddc6697dc7513623983a2ba748ba710e Mon Sep 17 00:00:00 2001 From: Paolo Abeni Date: Thu, 20 Apr 2023 19:17:14 +0200 Subject: [PATCH] selinux: Implement mptcp_add_subflow hook Newly added subflows should inherit the LSM label from the associated MPTCP socket regardless of the current context. This patch implements the above copying sid and class from the MPTCP socket context, deleting the existing subflow label, if any, and then re-creating the correct one. The new helper reuses the selinux_netlbl_sk_security_free() function, and the latter can end-up being called multiple times with the same argument; we additionally need to make it idempotent. Signed-off-by: Paolo Abeni Acked-by: Matthieu Baerts Signed-off-by: Matthieu Baerts Signed-off-by: Paul Moore --- security/selinux/hooks.c | 16 ++++++++++++++++ security/selinux/netlabel.c | 8 ++++++-- 2 files changed, 22 insertions(+), 2 deletions(-) diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index 99ded60a6b91..03660e551094 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -5379,6 +5379,21 @@ static void selinux_sctp_sk_clone(struct sctp_association *asoc, struct sock *sk selinux_netlbl_sctp_sk_clone(sk, newsk); } +static int selinux_mptcp_add_subflow(struct sock *sk, struct sock *ssk) +{ + struct sk_security_struct *ssksec = ssk->sk_security; + struct sk_security_struct *sksec = sk->sk_security; + + ssksec->sclass = sksec->sclass; + ssksec->sid = sksec->sid; + + /* replace the existing subflow label deleting the existing one + * and re-recreating a new label using the updated context + */ + selinux_netlbl_sk_security_free(ssksec); + return selinux_netlbl_socket_post_create(ssk, ssk->sk_family); +} + static int selinux_inet_conn_request(const struct sock *sk, struct sk_buff *skb, struct request_sock *req) { @@ -7074,6 +7089,7 @@ static struct security_hook_list selinux_hooks[] __ro_after_init = { LSM_HOOK_INIT(sctp_sk_clone, selinux_sctp_sk_clone), LSM_HOOK_INIT(sctp_bind_connect, selinux_sctp_bind_connect), LSM_HOOK_INIT(sctp_assoc_established, selinux_sctp_assoc_established), + LSM_HOOK_INIT(mptcp_add_subflow, selinux_mptcp_add_subflow), LSM_HOOK_INIT(inet_conn_request, selinux_inet_conn_request), LSM_HOOK_INIT(inet_csk_clone, selinux_inet_csk_clone), LSM_HOOK_INIT(inet_conn_established, selinux_inet_conn_established), diff --git a/security/selinux/netlabel.c b/security/selinux/netlabel.c index 767c670d33ea..528f5186e912 100644 --- a/security/selinux/netlabel.c +++ b/security/selinux/netlabel.c @@ -154,8 +154,12 @@ void selinux_netlbl_err(struct sk_buff *skb, u16 family, int error, int gateway) */ void selinux_netlbl_sk_security_free(struct sk_security_struct *sksec) { - if (sksec->nlbl_secattr != NULL) - netlbl_secattr_free(sksec->nlbl_secattr); + if (!sksec->nlbl_secattr) + return; + + netlbl_secattr_free(sksec->nlbl_secattr); + sksec->nlbl_secattr = NULL; + sksec->nlbl_state = NLBL_UNSET; } /**