Merge tag 'landlock-6.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/mic/linux

Pull landlock updates from Mickaël Salaün:
 "This brings two main changes to Landlock:

   - A signal scoping fix with a new interface for user space to know if
     it is compatible with the running kernel.

   - Audit support to give visibility on why access requests are denied,
     including the origin of the security policy, missing access rights,
     and description of object(s). This was designed to limit log spam
     as much as possible while still alerting about unexpected blocked
     access.

  With these changes come new and improved documentation, and a lot of
  new tests"

* tag 'landlock-6.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/mic/linux: (36 commits)
  landlock: Add audit documentation
  selftests/landlock: Add audit tests for network
  selftests/landlock: Add audit tests for filesystem
  selftests/landlock: Add audit tests for abstract UNIX socket scoping
  selftests/landlock: Add audit tests for ptrace
  selftests/landlock: Test audit with restrict flags
  selftests/landlock: Add tests for audit flags and domain IDs
  selftests/landlock: Extend tests for landlock_restrict_self(2)'s flags
  selftests/landlock: Add test for invalid ruleset file descriptor
  samples/landlock: Enable users to log sandbox denials
  landlock: Add LANDLOCK_RESTRICT_SELF_LOG_SUBDOMAINS_OFF
  landlock: Add LANDLOCK_RESTRICT_SELF_LOG_*_EXEC_* flags
  landlock: Log scoped denials
  landlock: Log TCP bind and connect denials
  landlock: Log truncate and IOCTL denials
  landlock: Factor out IOCTL hooks
  landlock: Log file-related denials
  landlock: Log mount-related denials
  landlock: Add AUDIT_LANDLOCK_DOMAIN and log domain status
  landlock: Add AUDIT_LANDLOCK_ACCESS and log ptrace denials
  ...

1 files changed, 59 insertions, 19 deletions

diff --git a/security/landlock/net.c b/security/landlock/net.c
index 104b6c01fe50..1f3915a90a80 100644
--- a/security/landlock/net.c
+++ b/security/landlock/net.c
@@ -1,16 +1,18 @@
 // SPDX-License-Identifier: GPL-2.0-only
 /*
- * Landlock LSM - Network management and hooks
+ * Landlock - Network management and hooks
  *
  * Copyright © 2022-2023 Huawei Tech. Co., Ltd.
- * Copyright © 2022-2023 Microsoft Corporation
+ * 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 "audit.h"
 #include "common.h"
 #include "cred.h"
 #include "limits.h"
@@ -39,10 +41,6 @@ int landlock_append_net_rule(struct landlock_ruleset *const ruleset,
 	return err;
 }
 
-static const struct access_masks any_net = {
-	.net = ~0,
-};
-
 static int current_check_access_socket(struct socket *const sock,
 				       struct sockaddr *const address,
 				       const int addrlen,
@@ -54,14 +52,15 @@ static int current_check_access_socket(struct socket *const sock,
 	struct landlock_id id = {
 		.type = LANDLOCK_KEY_NET_PORT,
 	};
-	const struct landlock_ruleset *const dom =
-		landlock_get_applicable_domain(landlock_get_current_domain(),
-					       any_net);
+	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 (!dom)
+	if (!subject)
 		return 0;
-	if (WARN_ON_ONCE(dom->num_layers < 1))
-		return -EACCES;
 
 	if (!sk_is_tcp(sock->sk))
 		return 0;
@@ -72,18 +71,48 @@ static int current_check_access_socket(struct socket *const sock,
 
 	switch (address->sa_family) {
 	case AF_UNSPEC:
-	case AF_INET:
+	case AF_INET: {
+		const struct sockaddr_in *addr4;
+
 		if (addrlen < sizeof(struct sockaddr_in))
 			return -EINVAL;
-		port = ((struct sockaddr_in *)address)->sin_port;
+
+		addr4 = (struct sockaddr_in *)address;
+		port = addr4->sin_port;
+
+		if (access_request == LANDLOCK_ACCESS_NET_CONNECT_TCP) {
+			audit_net.dport = port;
+			audit_net.v4info.daddr = addr4->sin_addr.s_addr;
+		} else if (access_request == LANDLOCK_ACCESS_NET_BIND_TCP) {
+			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:
+	case AF_INET6: {
+		const struct sockaddr_in6 *addr6;
+
 		if (addrlen < SIN6_LEN_RFC2133)
 			return -EINVAL;
-		port = ((struct sockaddr_in6 *)address)->sin6_port;
+
+		addr6 = (struct sockaddr_in6 *)address;
+		port = addr6->sin6_port;
+
+		if (access_request == LANDLOCK_ACCESS_NET_CONNECT_TCP) {
+			audit_net.dport = port;
+			audit_net.v6info.daddr = addr6->sin6_addr;
+		} else if (access_request == LANDLOCK_ACCESS_NET_BIND_TCP) {
+			audit_net.sport = port;
+			audit_net.v6info.saddr = addr6->sin6_addr;
+		} else {
+			WARN_ON_ONCE(1);
+		}
 		break;
+	}
 #endif /* IS_ENABLED(CONFIG_IPV6) */
 
 	default:
@@ -145,13 +174,24 @@ static int current_check_access_socket(struct socket *const sock,
 	id.key.data = (__force uintptr_t)port;
 	BUILD_BUG_ON(sizeof(port) > sizeof(id.key.data));
 
-	rule = landlock_find_rule(dom, id);
-	access_request = landlock_init_layer_masks(
-		dom, access_request, &layer_masks, LANDLOCK_KEY_NET_PORT);
+	rule = landlock_find_rule(subject->domain, id);
+	access_request = landlock_init_layer_masks(subject->domain,
+						   access_request, &layer_masks,
+						   LANDLOCK_KEY_NET_PORT);
 	if (landlock_unmask_layers(rule, access_request, &layer_masks,
 				   ARRAY_SIZE(layer_masks)))
 		return 0;
 
+	audit_net.family = address->sa_family;
+	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,
+				    .layer_masks_size = ARRAY_SIZE(layer_masks),
+			    });
 	return -EACCES;
 }