netdev - Re: [PATCH v1 net-next 14/15] af_unix: Remove sk_locked logic in unix_dgram

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <f2b838e4-1911-48c1-9a7e-fe476f763def@redhat.com>
Date: Tue, 10 Dec 2024 12:42:04 +0100
From: Paolo Abeni <pabeni@...hat.com>
To: Kuniyuki Iwashima <kuniyu@...zon.com>,
 "David S. Miller" <davem@...emloft.net>, Eric Dumazet <edumazet@...gle.com>,
 Jakub Kicinski <kuba@...nel.org>
Cc: Kuniyuki Iwashima <kuni1840@...il.com>, netdev@...r.kernel.org
Subject: Re: [PATCH v1 net-next 14/15] af_unix: Remove sk_locked logic in
 unix_dgram_sendmsg().

On 12/6/24 06:26, Kuniyuki Iwashima wrote:
> @@ -2136,27 +2133,21 @@ static int unix_dgram_sendmsg(struct socket *sock, struct msghdr *msg,
>  			goto restart;
>  		}
>  
> -		if (!sk_locked) {
> -			unix_state_unlock(other);
> -			unix_state_double_lock(sk, other);
> -		}
> +		unix_state_unlock(other);
> +		unix_state_double_lock(sk, other);
>  
>  		if (unix_peer(sk) != other ||
> -		    unix_dgram_peer_wake_me(sk, other)) {
> +		    unix_dgram_peer_wake_me(sk, other))
>  			err = -EAGAIN;
> -			sk_locked = 1;
> +
> +		unix_state_unlock(sk);
> +
> +		if (err)
>  			goto out_unlock;
> -		}
>  
> -		if (!sk_locked) {
> -			sk_locked = 1;
> -			goto restart_locked;
> -		}
> +		goto restart_locked;

I'm likely lost, but AFAICS the old code ensured that 'restart_locked'
was attempted at most once, while now there is no such constraint. Can
this loop forever under some not trivial condition?!?

Thanks!

Paolo