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([2001:41d0:303:db6b::]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-46c2279bc77sm18979840f8f.32.2026.06.25.16.53.36 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 25 Jun 2026 16:53:38 -0700 (PDT) From: Tristan Madani To: Paul Moore , Stephen Smalley Cc: Ondrej Mosnacek , Richard Haines , selinux@vger.kernel.org, stable@vger.kernel.org, linux-kernel@vger.kernel.org, tristan@talencesecurity.com Subject: [PATCH v3] selinux: avoid sk_socket dereference in selinux_sctp_bind_connect() Date: Thu, 25 Jun 2026 23:53:36 +0000 Message-ID: <20260625235336.3641828-1-tristmd@gmail.com> X-Mailer: git-send-email 2.47.3 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Tristan Madani selinux_sctp_bind_connect() dereferences sk->sk_socket to pass a struct socket * to selinux_socket_bind() and selinux_socket_connect_helper(). However, when the hook is invoked from the ASCONF softirq path (sctp_process_asconf), there is no file reference guaranteeing that sk->sk_socket is non-NULL. The setsockopt callers (bindx, connectx, set_primary, sendmsg connect) hold a file reference and are not affected. Both selinux_socket_bind() and selinux_socket_connect_helper() immediately resolve sock->sk, never using the struct socket * for anything else. Refactor the inner logic into helpers that take a struct sock * directly so that selinux_sctp_bind_connect() never needs to touch sk->sk_socket at all. Suggested-by: Stephen Smalley Fixes: d452930fd3b9 ("selinux: Add SCTP support") Cc: stable@vger.kernel.org Signed-off-by: Tristan Madani --- Changes in v3: - Keep comment describing IPv4/IPv6 address processing loop (Stephen Smalley). Changes in v2: - Refactor selinux_socket_bind() and selinux_socket_connect_helper() into sk-based inner helpers instead of adding a NULL check on sk->sk_socket (Stephen Smalley). security/selinux/hooks.c | 19 ++++++++++--------- 1 file changed, 10 insertions(+), 9 deletions(-) diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index fc926d3..1f202f6 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -4689,9 +4689,8 @@ static int selinux_socket_socketpair(struct socket *socka, Need to determine whether we should perform a name_bind permission check between the socket and the port number. */ -static int selinux_socket_bind(struct socket *sock, struct sockaddr *address, int addrlen) +static int __selinux_socket_bind(struct sock *sk, struct sockaddr *address, int addrlen) { - struct sock *sk = sock->sk; struct sk_security_struct *sksec = selinux_sock(sk); u16 family; int err; @@ -4825,13 +4824,17 @@ err_af: return -EAFNOSUPPORT; } +static int selinux_socket_bind(struct socket *sock, struct sockaddr *address, int addrlen) +{ + return __selinux_socket_bind(sock->sk, address, addrlen); +} + /* This supports connect(2) and SCTP connect services such as sctp_connectx(3) * and sctp_sendmsg(3) as described in Documentation/security/SCTP.rst */ -static int selinux_socket_connect_helper(struct socket *sock, +static int selinux_socket_connect_helper(struct sock *sk, struct sockaddr *address, int addrlen) { - struct sock *sk = sock->sk; struct sk_security_struct *sksec = selinux_sock(sk); int err; @@ -4924,7 +4927,7 @@ static int selinux_socket_connect(struct socket *sock, int err; struct sock *sk = sock->sk; - err = selinux_socket_connect_helper(sock, address, addrlen); + err = selinux_socket_connect_helper(sk, address, addrlen); if (err) return err; @@ -5409,13 +5412,11 @@ static int selinux_sctp_bind_connect(struct sock *sk, int optname, int len, err = 0, walk_size = 0; void *addr_buf; struct sockaddr *addr; - struct socket *sock; if (!selinux_policycap_extsockclass()) return 0; /* Process one or more addresses that may be IPv4 or IPv6 */ - sock = sk->sk_socket; addr_buf = address; while (walk_size < addrlen) { @@ -5444,14 +5445,14 @@ static int selinux_sctp_bind_connect(struct sock *sk, int optname, case SCTP_PRIMARY_ADDR: case SCTP_SET_PEER_PRIMARY_ADDR: case SCTP_SOCKOPT_BINDX_ADD: - err = selinux_socket_bind(sock, addr, len); + err = __selinux_socket_bind(sk, addr, len); break; /* Connect checks */ case SCTP_SOCKOPT_CONNECTX: case SCTP_PARAM_SET_PRIMARY: case SCTP_PARAM_ADD_IP: case SCTP_SENDMSG_CONNECT: - err = selinux_socket_connect_helper(sock, addr, len); + err = selinux_socket_connect_helper(sk, addr, len); if (err) return err; -- 2.47.3