[PATCH v2 06/10] af_unix: record the pid of the connecting thread
COOLING10d
From: Christian Brauner <brauner@kernel.org>
Date: 2026-09-09 10:43:34
Also in:
linux-fsdevel, lkml
Subsystem:
networking [general], networking [unix sockets], the rest · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Kuniyuki Iwashima, Linus Torvalds
Currently only the struct pid of the thread-group leader is recorded. The identity of the actual thread that connected to a given socket cannot be retrieved. Add the plumbing to make it possible to retrieve a pidfd for the connecting thread. Nothing uses the thread-specific struct pid yet. No functional changes. Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org> --- net/unix/af_unix.c | 30 +++++++++++++----------------- 1 file changed, 13 insertions(+), 17 deletions(-)
diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c
index 335abd23c9bf..d01ee76c8026 100644
--- a/net/unix/af_unix.c
+++ b/net/unix/af_unix.c@@ -743,51 +743,47 @@ struct unix_peercred { static inline int prepare_peercred(struct unix_peercred *peercred) { - struct pid *pid; int err; - pid = task_tgid(current); - err = pidfs_register_pid(pid); - if (likely(!err)) { - peercred->peer_pid[PIDTYPE_TGID] = get_pid(pid); - peercred->peer_cred = get_current_cred(); + get_task_pids(peercred->peer_pid, current); + err = pidfs_register_pids(peercred->peer_pid); + if (unlikely(err)) { + put_pids(peercred->peer_pid); + return err; } - return err; + + peercred->peer_cred = get_current_cred(); + return 0; } static void drop_peercred(struct unix_peercred *peercred) { const struct cred *cred = NULL; - struct pid *pid = NULL; might_sleep(); - swap(peercred->peer_pid[PIDTYPE_TGID], pid); + put_pids(peercred->peer_pid); swap(peercred->peer_cred, cred); - - put_pid(pid); put_cred(cred); } static inline void init_peercred(struct sock *sk, const struct unix_peercred *peercred) { - sk->sk_peer_pid[PIDTYPE_TGID] = peercred->peer_pid[PIDTYPE_TGID]; + memcpy(sk->sk_peer_pid, peercred->peer_pid, sizeof(sk->sk_peer_pid)); sk->sk_peer_cred = peercred->peer_cred; } static void update_peercred(struct sock *sk, struct unix_peercred *peercred) { const struct cred *old_cred; - struct pid *old_pid; spin_lock(&sk->sk_peer_lock); - old_pid = sk->sk_peer_pid[PIDTYPE_TGID]; + swap_pids(sk->sk_peer_pid, peercred->peer_pid); old_cred = sk->sk_peer_cred; - init_peercred(sk, peercred); + sk->sk_peer_cred = peercred->peer_cred; spin_unlock(&sk->sk_peer_lock); - peercred->peer_pid[PIDTYPE_TGID] = old_pid; peercred->peer_cred = old_cred; }
@@ -796,7 +792,7 @@ static void copy_peercred(struct sock *sk, struct sock *peersk) lockdep_assert_held(&unix_sk(peersk)->lock); spin_lock(&sk->sk_peer_lock); - sk->sk_peer_pid[PIDTYPE_TGID] = get_pid(peersk->sk_peer_pid[PIDTYPE_TGID]); + get_pids(sk->sk_peer_pid, peersk->sk_peer_pid); sk->sk_peer_cred = get_cred(peersk->sk_peer_cred); spin_unlock(&sk->sk_peer_lock); }
--
2.53.0