From: Kuniyuki Iwashima <kuniyu@amazon.com>
To: <rao.shoaib@oracle.com>
Cc: <davem@davemloft.net>, <edumazet@google.com>, <kuba@kernel.org>,
<kuniyu@amazon.com>, <netdev@vger.kernel.org>,
<pabeni@redhat.com>
Subject: Re: [PATCH net] af_unix: Read with MSG_PEEK loops if the first unread byte is OOB
Date: Fri, 19 Apr 2024 17:36:13 -0700 [thread overview]
Message-ID: <20240420003613.35749-1-kuniyu@amazon.com> (raw)
In-Reply-To: <CH3PR10MB683386BD63824096BF86BA9DEF0D2@CH3PR10MB6833.namprd10.prod.outlook.com>
From: Rao Shoaib <rao.shoaib@oracle.com>
Date: Fri, 19 Apr 2024 04:46:32 +0000
> Read with MSG_PEEK flag loops if the first byte to read is an OOB byte.
> commit 22dd70eb2c3d ("af_unix: Don't peek OOB data without MSG_OOB.")
> addresses the loop issue but does not address the issue that no data
> beyond OOB byte can be read.
>
> >>> from socket import *
> >>> c1, c2 = socketpair(AF_UNIX, SOCK_STREAM)
> >>> c1.send(b'a', MSG_OOB)
> 1
> >>> c1.send(b'b')
> 1
> >>> c2.recv(1, MSG_PEEK | MSG_DONTWAIT)
> b'b'
>
> Fixes: 314001f0bf92 ("af_unix: Add OOB support")
> Signed-off-by: Rao Shoaib <Rao.Shoaib@oracle.com>
> ---
> net/unix/af_unix.c | 25 ++++++++++++++-----------
> 1 file changed, 14 insertions(+), 11 deletions(-)
>
> diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c
> index 9a6ad5974dff..8928f1f496f4 100644
> --- a/net/unix/af_unix.c
> +++ b/net/unix/af_unix.c
> @@ -2658,19 +2658,20 @@ static struct sk_buff *manage_oob(struct sk_buff *skb, struct sock *sk,
> if (skb == u->oob_skb) {
> if (copied) {
> skb = NULL;
> - } else if (sock_flag(sk, SOCK_URGINLINE)) {
The patch does not apply cleanly on net.git probably because tab was
replaced by spaces ?
Could you check your mail client config and repost v2 to make patchwork
happy ?
https://patchwork.kernel.org/project/netdevbpf/patch/CH3PR10MB683386BD63824096BF86BA9DEF0D2@CH3PR10MB6833.namprd10.prod.outlook.com/
> - if (!(flags & MSG_PEEK)) {
> + } else if (!(flags & MSG_PEEK)) {
> + if (sock_flag(sk, SOCK_URGINLINE)) {
> WRITE_ONCE(u->oob_skb, NULL);
> consume_skb(skb);
> + } else {
> + skb_unlink(skb, &sk->sk_receive_queue);
> + WRITE_ONCE(u->oob_skb, NULL);
> + if (!WARN_ON_ONCE(skb_unref(skb)))
> + kfree_skb(skb);
> + skb = skb_peek(&sk->sk_receive_queue);
> }
> - } else if (flags & MSG_PEEK) {
> - skb = NULL;
> } else {
> - skb_unlink(skb, &sk->sk_receive_queue);
> - WRITE_ONCE(u->oob_skb, NULL);
> - if (!WARN_ON_ONCE(skb_unref(skb)))
> - kfree_skb(skb);
> - skb = skb_peek(&sk->sk_receive_queue);
> + if (!sock_flag(sk, SOCK_URGINLINE))
This can be `else if` to avoid another nesting here.
> + skb = skb_peek_next(skb, &sk->sk_receive_queue);
> }
> }
> }
> @@ -2747,9 +2748,11 @@ static int unix_stream_read_generic(struct unix_stream_read_state *state,
> #if IS_ENABLED(CONFIG_AF_UNIX_OOB)
> if (skb) {
> skb = manage_oob(skb, sk, flags, copied);
> - if (!skb && copied) {
> + if (!skb) {
> unix_state_unlock(sk);
> - break;
> + if (copied || (flags & MSG_PEEK))
> + break;
> + goto redo;
> }
> }
> #endif
> --
> 2.39.3
prev parent reply other threads:[~2024-04-20 0:36 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-19 4:46 [PATCH net] af_unix: Read with MSG_PEEK loops if the first unread byte is OOB Rao Shoaib
2024-04-20 0:36 ` Kuniyuki Iwashima [this message]
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