diff options
Diffstat (limited to 'security/landlock/fs.c')
| -rw-r--r-- | security/landlock/fs.c | 39 |
1 files changed, 33 insertions, 6 deletions
diff --git a/security/landlock/fs.c b/security/landlock/fs.c index 71b9dc331aae..c19aab87c4d2 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> @@ -1628,21 +1630,46 @@ 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); } |