[PATCH v5 15/24] landlock: Log scoped denials
From: Mickaël Salaün <mic@digikod.net>
Date: 2025-01-31 16:31:50
Also in:
lkml
Subsystem:
landlock security module, security subsystem, the rest · Maintainers:
Mickaël Salaün, Paul Moore, James Morris, "Serge E. Hallyn", Linus Torvalds
Add audit support for unix_stream_connect, unix_may_send, task_kill, and file_send_sigiotask hooks. The related blockers are: - scope.abstract_unix_socket - scope.signal Audit event sample for abstract unix socket: type=LANDLOCK_DENY msg=audit(1729738800.268:30): domain=195ba459b blockers=scope.abstract_unix_socket path=00666F6F Audit event sample for signal: type=LANDLOCK_DENY msg=audit(1729738800.291:31): domain=195ba459b blockers=scope.signal opid=1 ocomm="systemd" Cc: Günther Noack <gnoack@google.com> Cc: Tahera Fahimi <redacted> Signed-off-by: Mickaël Salaün <mic@digikod.net> Link: https://lore.kernel.org/r/20250131163059.1139617-16-mic@digikod.net (local) --- Changes since v4: - Rebase on top of the landlock_log_denial() and subject type changes. Changes since v3: - Cosmetic change to the "scope.*" blocker names. - Extend commit message. Changes since v1: - New patch. --- security/landlock/audit.c | 8 +++++ security/landlock/audit.h | 2 ++ security/landlock/task.c | 66 ++++++++++++++++++++++++++++++++++----- 3 files changed, 69 insertions(+), 7 deletions(-)
diff --git a/security/landlock/audit.c b/security/landlock/audit.c
index 9c856b31f9f6..fc4d1dfb5c25 100644
--- a/security/landlock/audit.c
+++ b/security/landlock/audit.c@@ -71,6 +71,14 @@ get_blocker(const enum landlock_request_type type, if (WARN_ON_ONCE(access_bit >= ARRAY_SIZE(net_access_strings))) return "unknown"; return net_access_strings[access_bit]; + + case LANDLOCK_REQUEST_SCOPE_ABSTRACT_UNIX_SOCKET: + WARN_ON_ONCE(access_bit != -1); + return "scope.abstract_unix_socket"; + + case LANDLOCK_REQUEST_SCOPE_SIGNAL: + WARN_ON_ONCE(access_bit != -1); + return "scope.signal"; } WARN_ON_ONCE(1);
diff --git a/security/landlock/audit.h b/security/landlock/audit.h
index eeff2c5bfa4f..aaf21b31baa8 100644
--- a/security/landlock/audit.h
+++ b/security/landlock/audit.h@@ -20,6 +20,8 @@ enum landlock_request_type { LANDLOCK_REQUEST_FS_CHANGE_LAYOUT, LANDLOCK_REQUEST_FS_ACCESS, LANDLOCK_REQUEST_NET_ACCESS, + LANDLOCK_REQUEST_SCOPE_ABSTRACT_UNIX_SOCKET, + LANDLOCK_REQUEST_SCOPE_SIGNAL, }; /*
diff --git a/security/landlock/task.c b/security/landlock/task.c
index 7b313a779de5..10bfba1994d0 100644
--- a/security/landlock/task.c
+++ b/security/landlock/task.c@@ -264,16 +264,31 @@ static int hook_unix_stream_connect(struct sock *const sock, struct sock *const other, struct sock *const newsk) { + size_t handle_layer; const struct landlock_cred_security *const subject = landlock_get_applicable_subject(current_cred(), unix_scope, - NULL); + &handle_layer); + struct lsm_network_audit audit_net = { + .sk = other, + }; + struct landlock_request request = { + .type = LANDLOCK_REQUEST_SCOPE_ABSTRACT_UNIX_SOCKET, + .audit = { + .type = LSM_AUDIT_DATA_NET, + .u.net = &audit_net, + }, + }; /* Quick return for non-landlocked tasks. */ if (!subject) return 0; - if (is_abstract_socket(other) && sock_is_scoped(other, subject->domain)) + if (is_abstract_socket(other) && + sock_is_scoped(other, subject->domain)) { + request.layer_plus_one = handle_layer + 1; + landlock_log_denial(subject, &request); return -EPERM; + } return 0; }
@@ -281,9 +296,20 @@ static int hook_unix_stream_connect(struct sock *const sock, static int hook_unix_may_send(struct socket *const sock, struct socket *const other) { + size_t handle_layer; const struct landlock_cred_security *const subject = landlock_get_applicable_subject(current_cred(), unix_scope, - NULL); + &handle_layer); + struct lsm_network_audit audit_net = { + .sk = other->sk, + }; + struct landlock_request request = { + .type = LANDLOCK_REQUEST_SCOPE_ABSTRACT_UNIX_SOCKET, + .audit = { + .type = LSM_AUDIT_DATA_NET, + .u.net = &audit_net, + }, + }; if (!subject) return 0;
@@ -296,8 +322,11 @@ static int hook_unix_may_send(struct socket *const sock, return 0; if (is_abstract_socket(other->sk) && - sock_is_scoped(other->sk, subject->domain)) + sock_is_scoped(other->sk, subject->domain)) { + request.layer_plus_one = handle_layer + 1; + landlock_log_denial(subject, &request); return -EPERM; + } return 0; }
@@ -311,13 +340,22 @@ static int hook_task_kill(struct task_struct *const p, const struct cred *cred) { bool is_scoped; + size_t handle_layer; const struct landlock_cred_security *subject; + struct landlock_request request = { + .type = LANDLOCK_REQUEST_SCOPE_SIGNAL, + .audit = { + .type = LSM_AUDIT_DATA_TASK, + .u.tsk = p, + }, + }; if (!cred) /* Not dealing with USB IO. */ cred = current_cred(); - subject = landlock_get_applicable_subject(cred, signal_scope, NULL); + subject = landlock_get_applicable_subject(cred, signal_scope, + &handle_layer); /* Quick return for non-landlocked tasks. */ if (!subject)
@@ -329,8 +367,11 @@ static int hook_task_kill(struct task_struct *const p, landlock_get_task_domain(p), signal_scope.scope); } - if (is_scoped) + if (is_scoped) { + request.layer_plus_one = handle_layer + 1; + landlock_log_denial(subject, &request); return -EPERM; + } return 0; }
@@ -338,7 +379,15 @@ static int hook_task_kill(struct task_struct *const p, static int hook_file_send_sigiotask(struct task_struct *tsk, struct fown_struct *fown, int signum) { + size_t handle_layer; const struct landlock_cred_security *subject; + struct landlock_request request = { + .type = LANDLOCK_REQUEST_SCOPE_SIGNAL, + .audit = { + .type = LSM_AUDIT_DATA_TASK, + .u.tsk = tsk, + }, + }; bool is_scoped = false; /* Lock already held by send_sigio() and send_sigurg(). */
@@ -361,8 +410,11 @@ static int hook_file_send_sigiotask(struct task_struct *tsk, landlock_get_task_domain(tsk), signal_scope.scope); } - if (is_scoped) + if (is_scoped) { + request.layer_plus_one = handle_layer + 1; + landlock_log_denial(subject, &request); return -EPERM; + } return 0; }
--
2.48.1