[RFC 4/4] samples/landlock: Add support for LANDLOCK_ACCESS_FS_IOCTL

[Günther Noack]

Add ioctl support to the Landlock sample tool.

The ioctl right is grouped with the read-write rights in the sample
tool, as some ioctl requests provide features that mutate state.

Signed-off-by: Günther Noack <gnoack3000 at gmail.com>
---
 samples/landlock/sandboxer.c | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/samples/landlock/sandboxer.c b/samples/landlock/sandboxer.c
index e2056c8b902..c70d96d15c7 100644
--- a/samples/landlock/sandboxer.c
+++ b/samples/landlock/sandboxer.c
@@ -77,7 +77,8 @@ static int parse_path(char *env_path, const char ***const path_list)
 	LANDLOCK_ACCESS_FS_EXECUTE | \
 	LANDLOCK_ACCESS_FS_WRITE_FILE | \
 	LANDLOCK_ACCESS_FS_READ_FILE | \
-	LANDLOCK_ACCESS_FS_TRUNCATE)
+	LANDLOCK_ACCESS_FS_TRUNCATE | \
+	LANDLOCK_ACCESS_FS_IOCTL)
 
 /* clang-format on */
 
@@ -162,11 +163,12 @@ static int populate_ruleset(const char *const env_var, const int ruleset_fd,
 	LANDLOCK_ACCESS_FS_MAKE_BLOCK | \
 	LANDLOCK_ACCESS_FS_MAKE_SYM | \
 	LANDLOCK_ACCESS_FS_REFER | \
-	LANDLOCK_ACCESS_FS_TRUNCATE)
+	LANDLOCK_ACCESS_FS_TRUNCATE | \
+	LANDLOCK_ACCESS_FS_IOCTL)
 
 /* clang-format on */
 
-#define LANDLOCK_ABI_LAST 3
+#define LANDLOCK_ABI_LAST 4
 
 int main(const int argc, char *const argv[], char *const *const envp)
 {
@@ -255,6 +257,10 @@ int main(const int argc, char *const argv[], char *const *const envp)
 	case 2:
 		/* Removes LANDLOCK_ACCESS_FS_TRUNCATE for ABI < 3 */
 		ruleset_attr.handled_access_fs &= ~LANDLOCK_ACCESS_FS_TRUNCATE;
+		__attribute__((fallthrough));
+	case 3:
+		/* Removes LANDLOCK_ACCESS_FS_IOCTL for ABI < 4 */
+		ruleset_attr.handled_access_fs &= ~LANDLOCK_ACCESS_FS_IOCTL;
 
 		fprintf(stderr,
 			"Hint: You should update the running kernel "
-- 
2.40.1