Quoting Miklos Szeredi (miklos@xxxxxxxxxx):
> From: Miklos Szeredi <mszeredi@xxxxxxx>
>
> The PID and the TGID of the process tringgering the mount are sent to the
> daemon. Currently the global pid values are sent (ones valid in the initial pid
> namespace) but this is wrong if the autofs daemon itself is not running in the
> initial pid namespace.
>
> So send the pid values that are valid in the namespace of the autofs daemon.
>
> The namespace to use is taken from the oz_pgrp pid pointer, which was set at
> mount time to the mounting process' pid namespace.
>
> If the pid translation fails (the triggering process is in an unrelated pid
> namespace) then the automount fails with ENOENT.
>
> Cc: Serge E. Hallyn <serue@xxxxxxxxxx>
Makes sense.
Acked-by: Serge Hallyn <serge.hallyn@xxxxxxxxxxxxx>
Thanks, Miklos.
> Cc: Eric Biederman <ebiederm@xxxxxxxxxxxx>
> Signed-off-by: Miklos Szeredi <mszeredi@xxxxxxx>
> ---
> fs/autofs4/waitq.c | 16 ++++++++++++++--
> 1 file changed, 14 insertions(+), 2 deletions(-)
>
> --- a/fs/autofs4/waitq.c
> +++ b/fs/autofs4/waitq.c
> @@ -353,11 +353,23 @@ int autofs4_wait(struct autofs_sb_info *
> struct qstr qstr;
> char *name;
> int status, ret, type;
> + pid_t pid;
> + pid_t tgid;
>
> /* In catatonic mode, we don't wait for nobody */
> if (sbi->catatonic)
> return -ENOENT;
>
> + /*
> + * Try translating pids to the namespace of the daemon.
> + *
> + * Zero means failure: we are in an unrelated pid namespace.
> + */
> + pid = task_pid_nr_ns(current, ns_of_pid(sbi->oz_pgrp));
> + tgid = task_tgid_nr_ns(current, ns_of_pid(sbi->oz_pgrp));
> + if (pid == 0 || tgid == 0)
> + return -ENOENT;
> +
> if (!dentry->d_inode) {
> /*
> * A wait for a negative dentry is invalid for certain
> @@ -423,8 +435,8 @@ int autofs4_wait(struct autofs_sb_info *
> wq->ino = autofs4_get_ino(sbi);
> wq->uid = current_uid();
> wq->gid = current_gid();
> - wq->pid = current->pid;
> - wq->tgid = current->tgid;
> + wq->pid = pid;
> + wq->tgid = tgid;
> wq->status = -EINTR; /* Status return if interrupted */
> wq->wait_ctr = 2;
> mutex_unlock(&sbi->wq_mutex);
> --
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