[PATCH 04/10] sock: add sock_swap_peercred
From: Marc-André Lureau <hidden>
Date: 2021-10-21 12:37:48
Also in:
lkml
Subsystem:
networking [general], networking [sockets], the rest · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Kuniyuki Iwashima, Willem de Bruijn, Linus Torvalds
Signed-off-by: Marc-André Lureau <redacted> --- include/net/sock.h | 3 +++ net/core/sock.c | 24 ++++++++++++++++++++++++ 2 files changed, 27 insertions(+)
diff --git a/include/net/sock.h b/include/net/sock.h
index d6877df26200..635d270c3a65 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h@@ -1822,6 +1822,9 @@ void sock_init_peercred(struct sock *sk); /* Copy peer credentials from peersk */ void sock_copy_peercred(struct sock *sk, struct sock *peersk); +/* Swap socket credentials */ +void sock_swap_peercred(struct sock *sk, struct sock *peersk); + /* * Socket reference counting postulates. *
diff --git a/net/core/sock.c b/net/core/sock.c
index f6b2662824df..365b63afa915 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c@@ -3239,6 +3239,30 @@ void sock_copy_peercred(struct sock *sk, struct sock *peersk) } EXPORT_SYMBOL(sock_copy_peercred); +void sock_swap_peercred(struct sock *sk, struct sock *peersk) +{ + const struct cred *old_cred; + struct pid *old_pid; + + if (sk < peersk) { + spin_lock(&sk->sk_peer_lock); + spin_lock_nested(&peersk->sk_peer_lock, SINGLE_DEPTH_NESTING); + } else { + spin_lock(&peersk->sk_peer_lock); + spin_lock_nested(&sk->sk_peer_lock, SINGLE_DEPTH_NESTING); + } + old_pid = sk->sk_peer_pid; + old_cred = sk->sk_peer_cred; + sk->sk_peer_pid = peersk->sk_peer_pid; + sk->sk_peer_cred = peersk->sk_peer_cred; + peersk->sk_peer_pid = old_pid; + peersk->sk_peer_cred = old_cred; + + spin_unlock(&sk->sk_peer_lock); + spin_unlock(&peersk->sk_peer_lock); +} +EXPORT_SYMBOL(sock_swap_peercred); + void lock_sock_nested(struct sock *sk, int subclass) { /* The sk_lock has mutex_lock() semantics here. */
--
2.33.0.721.g106298f7f9