[PATCH v12 8/9] samples/landlock: Add support for LANDLOCK_ACCESS_FS_IOCTL_DEV

[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 <gnoack at google.com>
---
 samples/landlock/sandboxer.c | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/samples/landlock/sandboxer.c b/samples/landlock/sandboxer.c
index 32e930c853bb..997f774e88ae 100644
--- a/samples/landlock/sandboxer.c
+++ b/samples/landlock/sandboxer.c
@@ -81,7 +81,8 @@ 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_DEV)
 
 /* clang-format on */
 
@@ -201,11 +202,12 @@ static int populate_ruleset_net(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_DEV)
 
 /* clang-format on */
 
-#define LANDLOCK_ABI_LAST 4
+#define LANDLOCK_ABI_LAST 5
 
 int main(const int argc, char *const argv[], char *const *const envp)
 {
@@ -319,6 +321,11 @@ int main(const int argc, char *const argv[], char *const *const envp)
 		ruleset_attr.handled_access_net &=
 			~(LANDLOCK_ACCESS_NET_BIND_TCP |
 			  LANDLOCK_ACCESS_NET_CONNECT_TCP);
+		__attribute__((fallthrough));
+	case 4:
+		/* Removes LANDLOCK_ACCESS_FS_IOCTL_DEV for ABI < 5 */
+		ruleset_attr.handled_access_fs &= ~LANDLOCK_ACCESS_FS_IOCTL_DEV;
+
 		fprintf(stderr,
 			"Hint: You should update the running kernel "
 			"to leverage Landlock features "
-- 
2.44.0.396.g6e790dbe36-goog