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[144.76.156.219]) by smtp.gmail.com with ESMTPSA id h18-20020a5d6892000000b002f9bfac5baesm2450752wru.47.2023.04.20.10.17.32 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 20 Apr 2023 10:17:32 -0700 (PDT) From: Matthieu Baerts Date: Thu, 20 Apr 2023 19:17:14 +0200 Subject: [PATCH LSM v2 2/2] selinux: Implement mptcp_add_subflow hook MIME-Version: 1.0 Message-Id: <20230419-upstream-lsm-next-20230419-mptcp-sublows-user-ctx-v2-2-e7a3c8c15676@tessares.net> References: <20230419-upstream-lsm-next-20230419-mptcp-sublows-user-ctx-v2-0-e7a3c8c15676@tessares.net> In-Reply-To: <20230419-upstream-lsm-next-20230419-mptcp-sublows-user-ctx-v2-0-e7a3c8c15676@tessares.net> To: Paul Moore , James Morris , "Serge E. Hallyn" , Stephen Smalley , Eric Paris Cc: Paolo Abeni , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Ondrej Mosnacek , mptcp@lists.linux.dev, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, linux-security-module@vger.kernel.org, selinux@vger.kernel.org, Matthieu Baerts X-Mailer: b4 0.12.2 X-Developer-Signature: v=1; a=openpgp-sha256; l=3129; i=matthieu.baerts@tessares.net; h=from:subject:message-id; bh=WLhdu7VM8rRQHFyxZs5IsD7KrHV+7/B+Pjyz5LAXc28=; b=owEBbQKS/ZANAwAIAfa3gk9CaaBzAcsmYgBkQXOpmi1k2/KgRY8NOtTX9iCZ7MkaYNHhEgOGn ii8nlJrcKCJAjMEAAEIAB0WIQToy4X3aHcFem4n93r2t4JPQmmgcwUCZEFzqQAKCRD2t4JPQmmg czKpEADSd17bfsUVbQ+uwJhsBgw8gyj6F3CtxsSF5KcOpGnw3lyvx9DHDX3ZY0GpnEx6uEm8Hc3 TNVAFrZsnmASC8q2zSQmdzynSgXyktDuWkGJvFyQupfT4LRGVgiSj7/j/d2l3X9xfjhRwROizxA KZ7ptNIATPin22KviVmh9csEgsLTEgHmazsEI88uXKHTiKYQik0xYGxhJSM+FnDF3MaPSKP5oIV dXtzacqLcPJvvLRnMXxmoYW/XtTSOB3S7cnknl/gP4Bzl4k6AsZsvyZJpQLBYIbY3kyK9CxKO/U trvZGfaJMCgOyAeLjJIoF1tPjwG92qQIG78maTIRG4G2WF1iVufCf0zPR/lpnNPYhbVtUS+a8Q7 Pb1xpbh3+bJ4pJ2pMImtO6S+YClntJq2rgxJ23gnQXiRzJhUHUdPwZINwkbYBBN+dNcTvXmu752 6hp81pkoLZ9RP7vFt0I3fCH31NiTBsr3l8NOhpLlqXIQqpQIquubMPFVaIgvWlXLsANN4E1kLE5 oRHd4w+ASJI9zkmMdhEbkmpptsmHNiCScdbWgePbEhV8ObL7Zh2IbDsx0Rd1YIKbZaZ3SPcB5kd CFve8+sUXHE394KCAMiiMogopfITRpL7JyGtny7xhDB/nU65Q/3IvEw8VhbGGLtBCxr4XAa/KWN YgTynBW3b4sRIgg== X-Developer-Key: i=matthieu.baerts@tessares.net; a=openpgp; fpr=E8CB85F76877057A6E27F77AF6B7824F4269A073 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Paolo Abeni 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 --- v2: - Address Paul's comments: - use "MPTCP socket" instead of "msk" in the commit message - "updated" context instead of "current" one in the comment --- 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 9a5bdfc21314..67e6cd18ad59 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -5476,6 +5476,21 @@ 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) { @@ -7216,6 +7231,7 @@ static struct security_hook_list selinux_hooks[] __lsm_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 1321f15799e2..33187e38def7 100644 --- a/security/selinux/netlabel.c +++ b/security/selinux/netlabel.c @@ -155,8 +155,12 @@ 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; } /**