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af_unix: Move SOCK_PASS{CRED,PIDFD,SEC} to struct sock.

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As explained in the next patch, SO_PASSRIGHTS would have a problem
if we assigned a corresponding bit to socket->flags, so it must be
managed in struct sock.

Mixing socket->flags and sk->sk_flags for similar options will look
confusing, and sk->sk_flags does not have enough space on 32bit system.

Also, as mentioned in commit 16e5726269 ("af_unix: dont send
SCM_CREDENTIALS by default"), SOCK_PASSCRED and SOCK_PASSPID handling
is known to be slow, and managing the flags in struct socket cannot
avoid that for embryo sockets.

Let's move SOCK_PASS{CRED,PIDFD,SEC} to struct sock.

While at it, other SOCK_XXX flags in net.h are grouped as enum.

Note that assign_bit() was atomic, so the writer side is moved down
after lock_sock() in setsockopt(), but the bit is only read once
in sendmsg() and recvmsg(), so lock_sock() is not needed there.

Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Kuniyuki Iwashima
2025-05-19 13:57:57 -07:00
committed by David S. Miller
parent 7d8d93fdde
commit 0e81cfd971
5 changed files with 61 additions and 61 deletions
Download Patch File Download Diff File Expand all files Collapse all files

18
net/unix/af_unix.c
View File

@@ -767,10 +767,7 @@ static void copy_peercred(struct sock *sk, struct sock *peersk)
static bool unix_may_passcred(const struct sock *sk)
{
struct socket *sock = sk->sk_socket;
return test_bit(SOCK_PASSCRED, &sock->flags) ||
test_bit(SOCK_PASSPIDFD, &sock->flags);
return sk->sk_scm_credentials || sk->sk_scm_pidfd;
}
static int unix_listen(struct socket *sock, int backlog)
@@ -1713,17 +1710,6 @@ static int unix_socketpair(struct socket *socka, struct socket *sockb)
return 0;
}
static void unix_sock_inherit_flags(const struct socket *old,
struct socket *new)
{
if (test_bit(SOCK_PASSCRED, &old->flags))
set_bit(SOCK_PASSCRED, &new->flags);
if (test_bit(SOCK_PASSPIDFD, &old->flags))
set_bit(SOCK_PASSPIDFD, &new->flags);
if (test_bit(SOCK_PASSSEC, &old->flags))
set_bit(SOCK_PASSSEC, &new->flags);
}
static int unix_accept(struct socket *sock, struct socket *newsock,
struct proto_accept_arg *arg)
{
@@ -1760,7 +1746,7 @@ static int unix_accept(struct socket *sock, struct socket *newsock,
unix_state_lock(tsk);
unix_update_edges(unix_sk(tsk));
newsock->state = SS_CONNECTED;
unix_sock_inherit_flags(sock, newsock);
tsk->sk_scm_recv_flags = READ_ONCE(sk->sk_scm_recv_flags);
sock_graft(tsk, newsock);
unix_state_unlock(tsk);
return 0;