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authorKees Cook <kees+treewide@kernel.org>2026-09-02 15:31:14 -0700
committerKees Cook <kees@kernel.org>2026-09-04 21:37:00 -0700
commit3a2c4d55e32ad65efebdb6de44eef3bfa08bb49d (patch)
treec65086f9bdcd48c6360fb7cb4598bca084da1f32 /security/landlock/net.c
downloadlinux-stable-3a2c4d55e32ad65efebdb6de44eef3bfa08bb49d.tar.gz
linux-stable-3a2c4d55e32ad65efebdb6de44eef3bfa08bb49d.zip
treewide: refresh kmalloc_obj() conversionsgrafted
This is another run of the Coccinelle script for converting kmalloc() family of allocations to kmalloc_obj() via the existing rules in scripts/coccinelle/api/kmalloc_objs.cocci This catches both the set of kmalloc() uses added since the first kmalloc_obj() conversions in v7.0 and adds a large group missed in the first pass due to Coccinelle not interacting well with the cleanup.h scoped_...() family of macros[1]. I worked around this with spatch's "--macro-file" argument to a file with all the scoped_...() macros mapped to Coccinelle's YACFE_ITERATOR[2] as that was the closest viable control flow indicator I could find. Build tested allmodconfig on x86, arm64, arm, loongarch, mips, powerpc, riscv, and s390 with no new warnings. Link: https://lore.kernel.org/lkml/202609021314.8A9C0B8@keescook/ [1] Link: https://github.com/coccinelle/coccinelle/blob/master/standard.h [2] Signed-off-by: Kees Cook <kees+treewide@kernel.org>
Diffstat (limited to 'security/landlock/net.c')
-rw-r--r--security/landlock/net.c413
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);
+}