netdev - [PATCH v5 06/15] landlock: user space API network support

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Message-ID: <20220516152038.39594-7-konstantin.meskhidze@huawei.com>
Date:   Mon, 16 May 2022 23:20:29 +0800
From:   Konstantin Meskhidze <konstantin.meskhidze@...wei.com>
To:     <mic@...ikod.net>
CC:     <willemdebruijn.kernel@...il.com>,
        <linux-security-module@...r.kernel.org>, <netdev@...r.kernel.org>,
        <netfilter-devel@...r.kernel.org>, <yusongping@...wei.com>,
        <anton.sirazetdinov@...wei.com>
Subject: [PATCH v5 06/15] landlock: user space API network support

User space API was refactored to support
network actions. New network access flags,
network rule and network attributes were
added.

Signed-off-by: Konstantin Meskhidze <konstantin.meskhidze@...wei.com>
---

Changes since v3:
* Split commit.
* Refactoring User API for network rule type.

Changes since v4:
* None

---
 include/uapi/linux/landlock.h | 48 +++++++++++++++++++++++++++++++++++
 security/landlock/syscalls.c  |  3 ++-
 2 files changed, 50 insertions(+), 1 deletion(-)

diff --git a/include/uapi/linux/landlock.h b/include/uapi/linux/landlock.h
index 23df4e0e8ace..91d6cb359bf8 100644
--- a/include/uapi/linux/landlock.h
+++ b/include/uapi/linux/landlock.h
@@ -31,6 +31,13 @@ struct landlock_ruleset_attr {
 	 * this access right.
 	 */
 	__u64 handled_access_fs;
+
+	/**
+	 * @handled_access_net: Bitmask of actions (cf. `Network flags`_)
+	 * that is handled by this ruleset and should then be forbidden if no
+	 * rule explicitly allow them.
+	 */
+	__u64 handled_access_net;
 };

 /*
@@ -54,6 +61,11 @@ enum landlock_rule_type {
 	 * landlock_path_beneath_attr .
 	 */
 	LANDLOCK_RULE_PATH_BENEATH = 1,
+	/**
+	 * @LANDLOCK_RULE_NET_SERVICE: Type of a &struct
+	 * landlock_net_service_attr .
+	 */
+	LANDLOCK_RULE_NET_SERVICE = 2,
 };

 /**
@@ -79,6 +91,24 @@ struct landlock_path_beneath_attr {
 	 */
 } __attribute__((packed));

+/**
+ * struct landlock_net_service_attr - TCP subnet definition
+ *
+ * Argument of sys_landlock_add_rule().
+ */
+struct landlock_net_service_attr {
+	/**
+	 * @allowed_access: Bitmask of allowed access network for services
+	 * (cf. `Network flags`_).
+	 */
+	__u64 allowed_access;
+	/**
+	 * @port: Network port
+	 */
+	__u16 port;
+
+} __attribute__((packed));
+
 /**
  * DOC: fs_access
  *
@@ -162,4 +192,22 @@ struct landlock_path_beneath_attr {
 #define LANDLOCK_ACCESS_FS_REFER			(1ULL << 13)
 /* clang-format on */

+/**
+ * DOC: net_access
+ *
+ * Network flags
+ * ~~~~~~~~~~~~~~~~
+ *
+ * These flags enable to restrict a sandboxed process to a set of network
+ * actions.
+ *
+ * TCP sockets with allowed actions:
+ *
+ * - %LANDLOCK_ACCESS_NET_BIND_TCP: Bind a TCP socket to a local port.
+ * - %LANDLOCK_ACCESS_NET_CONNECT_TCP: Connect an active TCP socket to
+ *   a remote port.
+ */
+#define LANDLOCK_ACCESS_NET_BIND_TCP			(1ULL << 0)
+#define LANDLOCK_ACCESS_NET_CONNECT_TCP			(1ULL << 1)
+
 #endif /* _UAPI_LINUX_LANDLOCK_H */
diff --git a/security/landlock/syscalls.c b/security/landlock/syscalls.c
index 412ced6c512f..31f9facec123 100644
--- a/security/landlock/syscalls.c
+++ b/security/landlock/syscalls.c
@@ -82,8 +82,9 @@ static void build_check_abi(void)
 	 * struct size.
 	 */
 	ruleset_size = sizeof(ruleset_attr.handled_access_fs);
+	ruleset_size += sizeof(ruleset_attr.handled_access_net);
 	BUILD_BUG_ON(sizeof(ruleset_attr) != ruleset_size);
-	BUILD_BUG_ON(sizeof(ruleset_attr) != 8);
+	BUILD_BUG_ON(sizeof(ruleset_attr) != 16);

 	path_beneath_size = sizeof(path_beneath_attr.allowed_access);
 	path_beneath_size += sizeof(path_beneath_attr.parent_fd);
--
2.25.1