samples/landlock: Extend sample tool to support LANDLOCK_ACCESS_FS_TRUNCATE

Update the sandboxer sample to restrict truncate actions. This is
automatically enabled by default if the running kernel supports
LANDLOCK_ACCESS_FS_TRUNCATE, except for the paths listed in the
LL_FS_RW environment variable.

Signed-off-by: Günther Noack <gnoack3000@gmail.com>
Link: https://lore.kernel.org/r/20221018182216.301684-11-gnoack3000@gmail.com
Signed-off-by: Mickaël Salaün <mic@digikod.net>
This commit is contained in:
Günther Noack 2022-10-18 20:22:15 +02:00 committed by Mickaël Salaün
parent 0d8c658be2
commit faeb919766
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View file

@ -76,7 +76,8 @@ static int parse_path(char *env_path, const char ***const path_list)
#define ACCESS_FILE ( \
LANDLOCK_ACCESS_FS_EXECUTE | \
LANDLOCK_ACCESS_FS_WRITE_FILE | \
LANDLOCK_ACCESS_FS_READ_FILE)
LANDLOCK_ACCESS_FS_READ_FILE | \
LANDLOCK_ACCESS_FS_TRUNCATE)
/* clang-format on */
@ -160,11 +161,12 @@ out_free_name:
LANDLOCK_ACCESS_FS_MAKE_FIFO | \
LANDLOCK_ACCESS_FS_MAKE_BLOCK | \
LANDLOCK_ACCESS_FS_MAKE_SYM | \
LANDLOCK_ACCESS_FS_REFER)
LANDLOCK_ACCESS_FS_REFER | \
LANDLOCK_ACCESS_FS_TRUNCATE)
/* clang-format on */
#define LANDLOCK_ABI_LAST 2
#define LANDLOCK_ABI_LAST 3
int main(const int argc, char *const argv[], char *const *const envp)
{
@ -234,6 +236,10 @@ int main(const int argc, char *const argv[], char *const *const envp)
case 1:
/* Removes LANDLOCK_ACCESS_FS_REFER for ABI < 2 */
ruleset_attr.handled_access_fs &= ~LANDLOCK_ACCESS_FS_REFER;
__attribute__((fallthrough));
case 2:
/* Removes LANDLOCK_ACCESS_FS_TRUNCATE for ABI < 3 */
ruleset_attr.handled_access_fs &= ~LANDLOCK_ACCESS_FS_TRUNCATE;
fprintf(stderr,
"Hint: You should update the running kernel "