diff options
Diffstat (limited to 'kernel/seccomp.c')
| -rw-r--r-- | kernel/seccomp.c | 44 |
1 files changed, 41 insertions, 3 deletions
diff --git a/kernel/seccomp.c b/kernel/seccomp.c index b5ac87f6dbd4..e9852d1b4a5e 100644 --- a/kernel/seccomp.c +++ b/kernel/seccomp.c @@ -200,6 +200,8 @@ static inline void seccomp_cache_prepare(struct seccomp_filter *sfilter) * the filter can be freed. * @cache: cache of arch/syscall mappings to actions * @log: true if all actions except for SECCOMP_RET_ALLOW should be logged + * @wait_killable_recv: Put notifying process in killable state once the + * notification is received by the userspace listener. * @prev: points to a previously installed, or inherited, filter * @prog: the BPF program to evaluate * @notif: the struct that holds all notification related information @@ -220,6 +222,7 @@ struct seccomp_filter { refcount_t refs; refcount_t users; bool log; + bool wait_killable_recv; struct action_cache cache; struct seccomp_filter *prev; struct bpf_prog *prog; @@ -893,6 +896,10 @@ static long seccomp_attach_filter(unsigned int flags, if (flags & SECCOMP_FILTER_FLAG_LOG) filter->log = true; + /* Set wait killable flag, if present. */ + if (flags & SECCOMP_FILTER_FLAG_WAIT_KILLABLE_RECV) + filter->wait_killable_recv = true; + /* * If there is an existing filter, make it the prev and don't drop its * task reference. @@ -1080,6 +1087,12 @@ static void seccomp_handle_addfd(struct seccomp_kaddfd *addfd, struct seccomp_kn complete(&addfd->completion); } +static bool should_sleep_killable(struct seccomp_filter *match, + struct seccomp_knotif *n) +{ + return match->wait_killable_recv && n->state == SECCOMP_NOTIFY_SENT; +} + static int seccomp_do_user_notification(int this_syscall, struct seccomp_filter *match, const struct seccomp_data *sd) @@ -1100,7 +1113,7 @@ static int seccomp_do_user_notification(int this_syscall, n.data = sd; n.id = seccomp_next_notify_id(match); init_completion(&n.ready); - list_add(&n.list, &match->notif->notifications); + list_add_tail(&n.list, &match->notif->notifications); INIT_LIST_HEAD(&n.addfd); up(&match->notif->request); @@ -1110,11 +1123,25 @@ static int seccomp_do_user_notification(int this_syscall, * This is where we wait for a reply from userspace. */ do { + bool wait_killable = should_sleep_killable(match, &n); + mutex_unlock(&match->notify_lock); - err = wait_for_completion_interruptible(&n.ready); + if (wait_killable) + err = wait_for_completion_killable(&n.ready); + else + err = wait_for_completion_interruptible(&n.ready); mutex_lock(&match->notify_lock); - if (err != 0) + + if (err != 0) { + /* + * Check to see if the notifcation got picked up and + * whether we should switch to wait killable. + */ + if (!wait_killable && should_sleep_killable(match, &n)) + continue; + goto interrupted; + } addfd = list_first_entry_or_null(&n.addfd, struct seccomp_kaddfd, list); @@ -1484,6 +1511,9 @@ out: mutex_lock(&filter->notify_lock); knotif = find_notification(filter, unotif.id); if (knotif) { + /* Reset the process to make sure it's not stuck */ + if (should_sleep_killable(filter, knotif)) + complete(&knotif->ready); knotif->state = SECCOMP_NOTIFY_INIT; up(&filter->notif->request); } @@ -1829,6 +1859,14 @@ static long seccomp_set_mode_filter(unsigned int flags, ((flags & SECCOMP_FILTER_FLAG_TSYNC_ESRCH) == 0)) return -EINVAL; + /* + * The SECCOMP_FILTER_FLAG_WAIT_KILLABLE_SENT flag doesn't make sense + * without the SECCOMP_FILTER_FLAG_NEW_LISTENER flag. + */ + if ((flags & SECCOMP_FILTER_FLAG_WAIT_KILLABLE_RECV) && + ((flags & SECCOMP_FILTER_FLAG_NEW_LISTENER) == 0)) + return -EINVAL; + /* Prepare the new filter before holding any locks. */ prepared = seccomp_prepare_user_filter(filter); if (IS_ERR(prepared)) |