[PATCH 5/6] samples/landlock: Support POSIX message queue scoping

[Oxana Kharitonova <oxana@cloudflare.com>]

Teach the sandboxer sample to request LANDLOCK_SCOPE_POSIX_MSG_QUEUE
through LL_SCOPED.

Add the "q" scope selector for POSIX message queues and document it in
the sample help text. Also allow POSIX message queue denials to be
quieted with "posix_msg_queue" through LL_QUIET_ACCESS.

Signed-off-by: Oxana Kharitonova <oxana@cloudflare.com>
---
 samples/landlock/sandboxer.c | 16 ++++++++++++++--
 1 file changed, 14 insertions(+), 2 deletions(-)

diff --git a/samples/landlock/sandboxer.c b/samples/landlock/sandboxer.c
index ac71019e6212..59024ca53398 100644
--- a/samples/landlock/sandboxer.c
+++ b/samples/landlock/sandboxer.c
@@ -240,10 +240,12 @@ static bool check_ruleset_scope(const char *const env_var,
 	bool error = false;
 	bool abstract_scoping = false;
 	bool signal_scoping = false;
+	bool posix_mqueue_scoping = false;
 
 	/* Scoping is not supported by Landlock ABI */
 	if (!(ruleset_attr->scoped &
-	      (LANDLOCK_SCOPE_ABSTRACT_UNIX_SOCKET | LANDLOCK_SCOPE_SIGNAL)))
+	      (LANDLOCK_SCOPE_ABSTRACT_UNIX_SOCKET | LANDLOCK_SCOPE_SIGNAL |
+	       LANDLOCK_SCOPE_POSIX_MSG_QUEUE)))
 		goto out_unset;
 
 	env_type_scope = getenv(env_var);
@@ -260,6 +262,9 @@ static bool check_ruleset_scope(const char *const env_var,
 		} else if (strcmp("s", ipc_scoping_name) == 0 &&
 			   !signal_scoping) {
 			signal_scoping = true;
+		} else if (strcmp("q", ipc_scoping_name) == 0 &&
+			   !posix_mqueue_scoping) {
+			posix_mqueue_scoping = true;
 		} else {
 			fprintf(stderr, "Unknown or duplicate scope \"%s\"\n",
 				ipc_scoping_name);
@@ -276,6 +281,8 @@ static bool check_ruleset_scope(const char *const env_var,
 		ruleset_attr->scoped &= ~LANDLOCK_SCOPE_ABSTRACT_UNIX_SOCKET;
 	if (!signal_scoping)
 		ruleset_attr->scoped &= ~LANDLOCK_SCOPE_SIGNAL;
+	if (!posix_mqueue_scoping)
+		ruleset_attr->scoped &= ~LANDLOCK_SCOPE_POSIX_MSG_QUEUE;
 
 	unsetenv(env_var);
 	return error;
@@ -354,6 +361,9 @@ static int add_quiet_access(const char *const env_var,
 				LANDLOCK_SCOPE_ABSTRACT_UNIX_SOCKET;
 		else if (strcmp(str_access, "signal") == 0)
 			ruleset_attr->quiet_scoped |= LANDLOCK_SCOPE_SIGNAL;
+		else if (strcmp(str_access, "posix_msg_queue") == 0)
+			ruleset_attr->quiet_scoped |=
+				LANDLOCK_SCOPE_POSIX_MSG_QUEUE;
 		else {
 			fprintf(stderr, "Unknown quiet access \"%s\"\n",
 				str_access);
@@ -400,6 +410,7 @@ static const char help[] =
 	"* " ENV_SCOPED_NAME ": actions denied on the outside of the landlock domain\n"
 	"  - \"a\" to restrict opening abstract unix sockets\n"
 	"  - \"s\" to restrict sending signals\n"
+	"  - \"q\" to restrict opening POSIX message queues\n"
 	"\n"
 	"A sandboxer should not log denied access requests to avoid spamming logs, "
 	"but to test audit we can set " ENV_FORCE_LOG_NAME "=1\n"
@@ -416,6 +427,7 @@ static const char help[] =
 	"  - \"udp_connect\" to quiet udp connect / send denials\n"
 	"  - \"abstract_unix_socket\" to quiet abstract unix socket denials\n"
 	"  - \"signal\" to quiet signal denials\n"
+	"  - \"posix_msg_queue\" to quiet POSIX message queue denials\n"
 	"\n"
 	"Example:\n"
 	ENV_FS_RO_NAME "=\"${PATH}:/lib:/usr:/proc:/etc:/dev/urandom\" "
@@ -423,7 +435,7 @@ static const char help[] =
 	ENV_TCP_BIND_NAME "=\"9418\" "
 	ENV_TCP_CONNECT_NAME "=\"80:443\" "
 	ENV_UDP_CONNECT_SEND_NAME "=\"53\" "
-	ENV_SCOPED_NAME "=\"a:s\" "
+	ENV_SCOPED_NAME "=\"a:s:q\" "
 	"%1$s bash -i\n"
 	"\n"
 	"This sandboxer can use Landlock features up to ABI version "
-- 
2.50.1 (Apple Git-155)