ftrace: Synchronize the initialization of ftrace_opsgrafted

There's some internal state that ftrace_ops needs to have set, but since
it can be declared outside of the ftrace.c code, it calls
ftrace_ops_init() on the ops in every global function. The issue is that
if two tasks call it on the same ops at the same time it is possible to
have the initialization of one corrupt the initialization of the other
call.

Create a ops_mutex to use to synchronize every initialization of the
ftrace_ops. The mutex is taken within checking the ftrace_ops flag that
states it was initializied but the flag is checked again after the mutex
has been taken. Checking first outside the mutex allows it to shortcut
having to take the mutex. But then the check needs to be done again after
the mute is taken in case of races.

Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260902095501.6b59af20@gandalf.local.home
Fixes: f04f24fb7e48d ("ftrace, kprobes: Fix a deadlock on ftrace_regex_lock")
Reported-by: sashiko-bot@kernel.org
Close: https://lore.kernel.org/all/20260829025528.49A831F000E9@smtp.kernel.org/
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

1 files changed, 413 insertions, 0 deletions

diff --git a/security/landlock/net.c b/security/landlock/net.c
new file mode 100644
index 000000000..8f2aaac54
--- /dev/null
+++ b/security/landlock/net.c
@@ -0,0 +1,413 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Landlock - Network management and hooks
+ *
+ * Copyright © 2022-2023 Huawei Tech. Co., Ltd.
+ * Copyright © 2022-2025 Microsoft Corporation
+ */
+
+#include <linux/in.h>
+#include <linux/lsm_audit.h>
+#include <linux/net.h>
+#include <linux/socket.h>
+#include <net/ipv6.h>
+
+#include "common.h"
+#include "cred.h"
+#include "domain.h"
+#include "limits.h"
+#include "log.h"
+#include "net.h"
+#include "ruleset.h"
+
+#include <trace/events/landlock.h>
+
+int landlock_append_net_rule(struct landlock_ruleset *const ruleset,
+			     const u16 port, access_mask_t access_rights,
+			     const u32 flags)
+{
+	int err;
+	const struct landlock_id id = {
+		.key.data = (__force uintptr_t)htons(port),
+		.type = LANDLOCK_KEY_NET_PORT,
+	};
+
+	BUILD_BUG_ON(sizeof(port) > sizeof(id.key.data));
+
+	/* Transforms relative access rights to absolute ones. */
+	access_rights |= LANDLOCK_MASK_ACCESS_NET & ~ruleset->handled_masks.net;
+
+	mutex_lock(&ruleset->lock);
+	err = landlock_insert_rule(ruleset, id, access_rights, flags);
+
+	/*
+	 * Emit after the rule insertion succeeds, so every event corresponds to
+	 * a rule that is actually in the ruleset.  The ruleset lock is still
+	 * held for BTF consistency (enforced by lockdep_assert_held in
+	 * TP_fast_assign).
+	 */
+	if (!err)
+		trace_landlock_add_rule_net(ruleset, access_rights, port);
+	mutex_unlock(&ruleset->lock);
+
+	return err;
+}
+
+static bool unmask_layers_net(const struct landlock_domain *const domain,
+			      const struct landlock_id id,
+			      struct layer_masks *masks,
+			      access_mask_t access_request)
+{
+	const struct landlock_rule *rule = NULL;
+	bool ret;
+
+	ret = landlock_unmask_layers(domain, id, masks, &rule);
+	if (rule)
+		trace_landlock_check_rule_net(
+			domain, rule, access_request,
+			ntohs((__force __be16)id.key.data));
+	return ret;
+}
+
+static int current_check_access_socket(struct socket *const sock,
+				       struct sockaddr *const address,
+				       const int addrlen,
+				       access_mask_t access_request,
+				       bool connecting)
+{
+	unsigned short sock_family;
+	__be16 port;
+	struct layer_masks layer_masks = {};
+	struct landlock_id id = {
+		.type = LANDLOCK_KEY_NET_PORT,
+	};
+	const struct access_masks masks = {
+		.net = access_request,
+	};
+	const struct landlock_cred_security *const subject =
+		landlock_get_applicable_subject(current_cred(), masks, NULL);
+	struct lsm_network_audit audit_net = {};
+
+	if (!subject)
+		return 0;
+
+	/* Checks for minimal header length to safely read sa_family. */
+	if (addrlen < offsetofend(typeof(*address), sa_family))
+		return -EINVAL;
+
+	/*
+	 * The socket is not locked, so sk_family can change concurrently due to
+	 * e.g. setsockopt(IPV6_ADDRFORM).
+	 */
+	sock_family = READ_ONCE(sock->sk->sk_family);
+
+	switch (address->sa_family) {
+	case AF_UNSPEC:
+		if (access_request == LANDLOCK_ACCESS_NET_CONNECT_TCP ||
+		    (access_request == LANDLOCK_ACCESS_NET_CONNECT_SEND_UDP &&
+		     connecting)) {
+			/*
+			 * Connecting to an address with AF_UNSPEC dissolves the
+			 * remote association while retaining the socket object
+			 * (i.e., the file descriptor). For TCP, it has the same
+			 * effect as closing the connection. For UDP, it removes
+			 * any preset remote address. As for dropping
+			 * privileges, these actions are always allowed.  Let
+			 * the network stack handle potential inconsistencies
+			 * and return -EINVAL if needed.
+			 */
+			return 0;
+		} else if (access_request ==
+			   LANDLOCK_ACCESS_NET_CONNECT_SEND_UDP) {
+			if (sock_family == AF_INET6) {
+				/*
+				 * We cannot allow sending UDP datagrams to an
+				 * explicit AF_UNSPEC address on IPv6 sockets,
+				 * even if AF_UNSPEC is treated as "no address"
+				 * on such sockets (so it should always be
+				 * allowed).  That's because the socket's family
+				 * can change under our feet (if another thread
+				 * calls setsockopt(IPV6_ADDRFORM)) to IPv4,
+				 * which would then treat AF_UNSPEC as AF_INET.
+				 */
+				audit_net.family = AF_UNSPEC;
+				audit_net.sk = sock->sk;
+				landlock_init_layer_masks(
+					subject->domain, access_request,
+					&layer_masks, LANDLOCK_KEY_NET_PORT);
+				landlock_log_denial(
+					subject,
+					&(struct landlock_request){
+						.type = LANDLOCK_REQUEST_NET_ACCESS,
+						.audit.type =
+							LSM_AUDIT_DATA_NET,
+						.audit.u.net = &audit_net,
+						.access = access_request,
+						.layer_masks = &layer_masks,
+					});
+				return -EACCES;
+			}
+		} else if (access_request == LANDLOCK_ACCESS_NET_BIND_TCP ||
+			   access_request == LANDLOCK_ACCESS_NET_BIND_UDP) {
+			/*
+			 * Binding to an AF_UNSPEC address is treated
+			 * differently by IPv4 and IPv6 sockets. The socket's
+			 * family may change under our feet due to
+			 * setsockopt(IPV6_ADDRFORM), but that's ok: we either
+			 * reject entirely for IPv6 or require
+			 * %LANDLOCK_ACCESS_NET_BIND_TCP or
+			 * %LANDLOCK_ACCESS_NET_BIND_UDP for IPv4, so it cannot
+			 * be used to bypass the policy.
+			 *
+			 * IPv4 sockets map AF_UNSPEC to AF_INET for
+			 * retrocompatibility for bind accesses, only if the
+			 * address is INADDR_ANY (cf. __inet_bind). IPv6
+			 * sockets always reject it.
+			 *
+			 * Checking the address is required to not wrongfully
+			 * return -EACCES instead of -EAFNOSUPPORT or -EINVAL.
+			 * We could return 0 and let the network stack handle
+			 * these checks, but it is safer to return a proper
+			 * error and test consistency thanks to kselftest.
+			 */
+			if (sock_family == AF_INET) {
+				const struct sockaddr_in *const sockaddr =
+					(struct sockaddr_in *)address;
+
+				if (addrlen < sizeof(struct sockaddr_in))
+					return -EINVAL;
+
+				if (sockaddr->sin_addr.s_addr !=
+				    htonl(INADDR_ANY))
+					return -EAFNOSUPPORT;
+			} else {
+				if (addrlen < SIN6_LEN_RFC2133)
+					return -EINVAL;
+				else
+					return -EAFNOSUPPORT;
+			}
+		} else {
+			WARN_ON_ONCE(1);
+		}
+		/*
+		 * AF_UNSPEC is treated as AF_INET only in
+		 * bind(AF_UNSPEC+INADDR_ANY) on IPv4 sockets and when sending
+		 * to AF_UNSPEC addresses on IPv4 sockets.
+		 */
+		fallthrough;
+	case AF_INET: {
+		const struct sockaddr_in *addr4;
+
+		if (addrlen < sizeof(struct sockaddr_in))
+			return -EINVAL;
+
+		addr4 = (struct sockaddr_in *)address;
+		port = addr4->sin_port;
+
+		if (access_request == LANDLOCK_ACCESS_NET_CONNECT_TCP ||
+		    access_request == LANDLOCK_ACCESS_NET_CONNECT_SEND_UDP) {
+			audit_net.dport = port;
+			audit_net.v4info.daddr = addr4->sin_addr.s_addr;
+		} else if (access_request == LANDLOCK_ACCESS_NET_BIND_TCP ||
+			   access_request == LANDLOCK_ACCESS_NET_BIND_UDP) {
+			audit_net.sport = port;
+			audit_net.v4info.saddr = addr4->sin_addr.s_addr;
+		} else {
+			WARN_ON_ONCE(1);
+		}
+		break;
+	}
+
+#if IS_ENABLED(CONFIG_IPV6)
+	case AF_INET6: {
+		const struct sockaddr_in6 *addr6;
+
+		if (addrlen < SIN6_LEN_RFC2133)
+			return -EINVAL;
+
+		addr6 = (struct sockaddr_in6 *)address;
+		port = addr6->sin6_port;
+
+		if (access_request == LANDLOCK_ACCESS_NET_CONNECT_TCP ||
+		    access_request == LANDLOCK_ACCESS_NET_CONNECT_SEND_UDP) {
+			audit_net.dport = port;
+			audit_net.v6info.daddr = addr6->sin6_addr;
+		} else if (access_request == LANDLOCK_ACCESS_NET_BIND_TCP ||
+			   access_request == LANDLOCK_ACCESS_NET_BIND_UDP) {
+			audit_net.sport = port;
+			audit_net.v6info.saddr = addr6->sin6_addr;
+		} else {
+			WARN_ON_ONCE(1);
+		}
+		break;
+	}
+#endif /* IS_ENABLED(CONFIG_IPV6) */
+
+	default:
+		return 0;
+	}
+
+	/*
+	 * Checks sa_family consistency to not wrongfully return
+	 * -EACCES instead of -EINVAL.  Valid sa_family changes are
+	 * only (from AF_INET or AF_INET6) to AF_UNSPEC.
+	 *
+	 * We could return 0 and let the network stack handle this
+	 * check, but it is safer to return a proper error and test
+	 * consistency thanks to kselftest.
+	 */
+	if (address->sa_family != sock_family &&
+	    address->sa_family != AF_UNSPEC)
+		return -EINVAL;
+
+	id.key.data = (__force uintptr_t)port;
+	BUILD_BUG_ON(sizeof(port) > sizeof(id.key.data));
+
+	access_request = landlock_init_layer_masks(subject->domain,
+						   access_request, &layer_masks,
+						   LANDLOCK_KEY_NET_PORT);
+	if (!access_request)
+		return 0;
+
+	if (unmask_layers_net(subject->domain, id, &layer_masks,
+			      access_request))
+		return 0;
+
+	audit_net.family = address->sa_family;
+	audit_net.sk = sock->sk;
+	landlock_log_denial(subject,
+			    &(struct landlock_request){
+				    .type = LANDLOCK_REQUEST_NET_ACCESS,
+				    .audit.type = LSM_AUDIT_DATA_NET,
+				    .audit.u.net = &audit_net,
+				    .access = access_request,
+				    .layer_masks = &layer_masks,
+			    });
+	return -EACCES;
+}
+
+static int current_check_autobind_udp_socket(struct socket *const sock)
+{
+	const struct access_masks bind_udp = {
+		.net = LANDLOCK_ACCESS_NET_BIND_UDP,
+	};
+	struct sockaddr_storage port0 = {};
+	unsigned short num;
+	bool slow;
+
+	/* Quick return for non-Landlocked tasks. */
+	if (!landlock_get_applicable_subject(current_cred(), bind_udp, NULL))
+		return 0;
+
+	/*
+	 * On UDP sockets, if a local port has not already been bound, calling
+	 * connect() or sending a first datagram has the side effect of
+	 * autobinding an ephemeral port: we also have to check that the process
+	 * would have had the right to bind(0) explicitly.  Hold the socket lock
+	 * around the inet_num read to exclude udp_lib_get_port()'s transient
+	 * inet_num = snum write that is reverted to 0 on a failing reuseport
+	 * bind.
+	 */
+	slow = lock_sock_fast(sock->sk);
+	num = inet_sk(sock->sk)->inet_num;
+	unlock_sock_fast(sock->sk, slow);
+	if (num != 0)
+		return 0;
+
+	/*
+	 * Construct a struct sockaddr* with port 0 to pretend the process tried
+	 * to bind() on that address.
+	 */
+	port0.ss_family = READ_ONCE(sock->sk->sk_family);
+
+	return current_check_access_socket(sock, (struct sockaddr *)&port0,
+					   sizeof(port0), bind_udp.net, false);
+}
+
+static int hook_socket_bind(struct socket *const sock,
+			    struct sockaddr *const address, const int addrlen)
+{
+	access_mask_t access_request;
+
+	if (sk_is_tcp(sock->sk))
+		access_request = LANDLOCK_ACCESS_NET_BIND_TCP;
+	else if (sk_is_udp(sock->sk))
+		access_request = LANDLOCK_ACCESS_NET_BIND_UDP;
+	else
+		return 0;
+
+	return current_check_access_socket(sock, address, addrlen,
+					   access_request, false);
+}
+
+static int hook_socket_connect(struct socket *const sock,
+			       struct sockaddr *const address,
+			       const int addrlen)
+{
+	access_mask_t access_request;
+	int ret = 0;
+
+	if (sk_is_tcp(sock->sk))
+		access_request = LANDLOCK_ACCESS_NET_CONNECT_TCP;
+	else if (sk_is_udp(sock->sk))
+		access_request = LANDLOCK_ACCESS_NET_CONNECT_SEND_UDP;
+	else
+		return 0;
+
+	ret = current_check_access_socket(sock, address, addrlen,
+					  access_request, true);
+
+	/*
+	 * connect()ing to an AF_UNSPEC address does not trigger an autobind and
+	 * should never be restricted.
+	 */
+	if (ret == 0 && sk_is_udp(sock->sk) &&
+	    addrlen >= offsetofend(typeof(*address), sa_family) &&
+	    address->sa_family != AF_UNSPEC)
+		ret = current_check_autobind_udp_socket(sock);
+
+	return ret;
+}
+
+static int hook_socket_sendmsg(struct socket *const sock,
+			       struct msghdr *const msg, const int size)
+{
+	struct sockaddr *const address = msg->msg_name;
+	const int addrlen = msg->msg_namelen;
+	access_mask_t access_request;
+	int ret = 0;
+
+	if ((msg->msg_flags & MSG_FASTOPEN) && address && sk_is_tcp(sock->sk)) {
+		ret = current_check_access_socket(
+			sock, address, addrlen, LANDLOCK_ACCESS_NET_CONNECT_TCP,
+			true);
+		if (ret != 0)
+			return ret;
+	}
+
+	if (sk_is_udp(sock->sk))
+		access_request = LANDLOCK_ACCESS_NET_CONNECT_SEND_UDP;
+	else
+		return 0;
+
+	if (address != NULL)
+		ret = current_check_access_socket(sock, address, addrlen,
+						  access_request, false);
+
+	if (ret == 0)
+		ret = current_check_autobind_udp_socket(sock);
+
+	return ret;
+}
+
+static struct security_hook_list landlock_hooks[] __ro_after_init = {
+	LSM_HOOK_INIT(socket_bind, hook_socket_bind),
+	LSM_HOOK_INIT(socket_connect, hook_socket_connect),
+	LSM_HOOK_INIT(socket_sendmsg, hook_socket_sendmsg),
+};
+
+__init void landlock_add_net_hooks(void)
+{
+	security_add_hooks(landlock_hooks, ARRAY_SIZE(landlock_hooks),
+			   &landlock_lsmid);
+}