diff options
Diffstat (limited to 'security/landlock/fs.c')
| -rw-r--r-- | security/landlock/fs.c | 50 |
1 files changed, 38 insertions, 12 deletions
diff --git a/security/landlock/fs.c b/security/landlock/fs.c index e31b97a9f175..511e6ae8b79c 100644 --- a/security/landlock/fs.c +++ b/security/landlock/fs.c @@ -27,7 +27,9 @@ #include <linux/mount.h> #include <linux/namei.h> #include <linux/path.h> +#include <linux/pid.h> #include <linux/rcupdate.h> +#include <linux/sched/signal.h> #include <linux/spinlock.h> #include <linux/stat.h> #include <linux/types.h> @@ -937,10 +939,6 @@ static access_mask_t get_mode_access(const umode_t mode) switch (mode & S_IFMT) { case S_IFLNK: return LANDLOCK_ACCESS_FS_MAKE_SYM; - case 0: - /* A zero mode translates to S_IFREG. */ - case S_IFREG: - return LANDLOCK_ACCESS_FS_MAKE_REG; case S_IFDIR: return LANDLOCK_ACCESS_FS_MAKE_DIR; case S_IFCHR: @@ -951,9 +949,12 @@ static access_mask_t get_mode_access(const umode_t mode) return LANDLOCK_ACCESS_FS_MAKE_FIFO; case S_IFSOCK: return LANDLOCK_ACCESS_FS_MAKE_SOCK; + case S_IFREG: + case 0: + /* A zero mode translates to S_IFREG. */ default: - WARN_ON_ONCE(1); - return 0; + /* Treats weird files as regular files. */ + return LANDLOCK_ACCESS_FS_MAKE_REG; } } @@ -1624,21 +1625,46 @@ static int hook_file_ioctl_compat(struct file *file, unsigned int cmd, return -EACCES; } -static void hook_file_set_fowner(struct file *file) +/* + * Always allow sending signals between threads of the same process. This + * ensures consistency with hook_task_kill(). + */ +static bool control_current_fowner(struct fown_struct *const fown) { - struct landlock_ruleset *new_dom, *prev_dom; + struct task_struct *p; /* * Lock already held by __f_setown(), see commit 26f204380a3c ("fs: Fix * file_set_fowner LSM hook inconsistencies"). */ - lockdep_assert_held(&file_f_owner(file)->lock); - new_dom = landlock_get_current_domain(); - landlock_get_ruleset(new_dom); + lockdep_assert_held(&fown->lock); + + /* + * Some callers (e.g. fcntl_dirnotify) may not be in an RCU read-side + * critical section. + */ + guard(rcu)(); + p = pid_task(fown->pid, fown->pid_type); + if (!p) + return true; + + return !same_thread_group(p, current); +} + +static void hook_file_set_fowner(struct file *file) +{ + struct landlock_ruleset *prev_dom; + struct landlock_ruleset *new_dom = NULL; + + if (control_current_fowner(file_f_owner(file))) { + new_dom = landlock_get_current_domain(); + landlock_get_ruleset(new_dom); + } + prev_dom = landlock_file(file)->fown_domain; landlock_file(file)->fown_domain = new_dom; - /* Called in an RCU read-side critical section. */ + /* May be called in an RCU read-side critical section. */ landlock_put_ruleset_deferred(prev_dom); } |