From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=209.85.210.198 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793547527; b=l/3zuJckxErFoqwBDSFiEi6/Xis9ZMSYWM/ht3JK4j8WX4BZaLLiSGoV0F23V1DTBN4K rOqGVlEzsOqrd1bKC7GrNLRnay9pa0Rh3wcMQa/eJGfIv5nzCraSbnFHdZc3DwtgJHUOP xnjEE0tBd9GVN/asPJpjPaUVrIPJfGvVKM2RUOJWDtw+scX+JCok+kCoQ6t8prChJOF/E f4Ij7mqzP7hCNqYcxPaecVeBlJpMlr/7RyKoCh4JbHj9HbRhPR5AT6IQwD7hXkDhffwRk 7o0fRWVMk5DAT3TA/RgJeu57rTgfFJZrdAd59CEvie0wMSuf8Eq5KBObYzJQ3Rb6fuw== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793547527; h=DMARC-Filter:Received:DKIM-Signature:X-Google-DKIM-Signature: X-Forwarded-Encrypted:X-Gm-Message-State:X-Received:Date:In-Reply-To: Mime-Version:References:Message-ID:Subject:From:To:Cc:Content-Type; bh=y4TC5oAYHs7m0oof9CZGtZfqTYpKndLI+6fmGJ2s+hM=; b=MUZ8yROAqpgZ1Mk+LJBcYN4f1/lyB6Z0kwM/kjjy3Nb8Jp8jet0PPd/kOIoO4V7UvVf9 PqSPZ4H5VzwlqAIAc7yNQqKIkd5RX9z7fll+KkBjGXHiwVOQnxC9auBBBmdXz16cg/i/t TtuDW7/5YRDvC1l8+oQEUJNhR14lmbUZQBqEcNIWcr3qdtoVJnvHe2iOssh1EN+2+Ox0G swwS9GTggTSuoXNRjLtj5GJkHdDRrSjSchcP02XuJ6+jjGD8AX3Iy22A3qwvTtDph9fzI wrCx1cR/ViPaubaihU1eZMWd7WFLg4ZjYW+z6PnKANzeDo9P281C2de0WiIjZKsGiWQ== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass header.from=google.com; spf=pass smtp.mailfrom=flex--kuniyu.bounces.google.com; dkim=pass header.d=google.com header.i=@google.com header.a=rsa-sha256 header.s=20260707 header.b=IXDSYuIt; arc=none smtp.remote-ip=209.85.210.198 Received: from mail-pf1-f198.google.com (mail-pf1-f198.google.com [209.85.210.198]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 434EE606A324 for ; Sun, 1 Nov 2026 15:38:47 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org 434EE606A324 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--kuniyu.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=google.com header.i=@google.com header.a=rsa-sha256 header.s=20260707 header.b=IXDSYuIt Received: by mail-pf1-f198.google.com with SMTP id d2e1a72fcca58-8a086f5d91aso2981373b3a.1 for ; Sun, 01 Nov 2026 07:38:47 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20260707; t=1793547526; x=1794152326; darn=vger.kernel.org; h=content-type:cc:to:from:subject:message-id:references:mime-version :in-reply-to:date:from:to:cc:subject:date:message-id:reply-to :content-type; bh=y4TC5oAYHs7m0oof9CZGtZfqTYpKndLI+6fmGJ2s+hM=; b=IXDSYuItLSaxnqoVKukX0g47XLtbVnvRRKeef741LJLA3gTWZekxiQWzrut+TAsEhI hnaY320n0OSq8F5KtdsNBqWfI6pkeIuWA9XZuH9j6wlhUKNXAM3ibQXXXF7a+i938pXA XfWjw1L+BXduRDlWdKhHhW7MUUfpF76l4/Vvv5HethbpMxIlX9MC0t+8Snn1pv83VhOW jCAB0lePRXG9MfCOiq63h+bJo+UzzeCob17be2J86uFN8TyUbJrBZCVdL4fNtqbfxPIZ Z87yveRZw24RXbb1jSaXFAtWiZSlDr/S8gy/8WtV6TvrBjYQcHtr5jd6+1nH88Jazsag OdpQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20260707; t=1793547526; x=1794152326; h=content-type:cc:to:from:subject:message-id:references:mime-version :in-reply-to:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to:content-type; bh=y4TC5oAYHs7m0oof9CZGtZfqTYpKndLI+6fmGJ2s+hM=; b=g44h6YNXxuhvEHsFoENtYZWaSNSvhz+YN9unYRw6WgTRrpQeXEhY2x/xm860W443OR XP2aK+TiQm2kcymGiXdUQ+tV+73AqW6qip7clFF4rVzoib7CBFVvr117JTN+nRTWBe6N DY/46DUy0chSvmgrIw8Pr+hdUHw/QIUEgA5W5aLJYXv/YfAk+d9mqmsV8yDJ+QbSx9hT 5zp6VV3XyLYgJx5pj6F43yl4vEyqLFn4PwTisxQhvwatNV2g6PRSRG10sdowAOIzbQUR 6nMHjDO93xAuFcf2RoBjyIjv04SYc2rymj9V6AwP/Y1PMxkHSmGyk1s7g5uIWyfq7eZs yWIw== X-Forwarded-Encrypted: i=1; AKwUvBwy4DyS2weOGV3xk8tsOM7Rpp8r2q9Yg1CvhN7XEOh3Jg0p8hCvhWxA5IoqO79LUSZnOexAuPQL7D9P0QI=@vger.kernel.org X-Gm-Message-State: AFq9FYLqxbNq4EEhFp9KM1XslrTov1GmXgi1Nlew7/TJOL4LsaCbppRW jmKkTibI+zGY/zUydMRU4PI6lQ2a9bDmyawb/dK+GrKQ/SzHswwwu3LsrR6YwApqa2RD2cqKFhB cSYirBg== X-Received: from pfnj8.prod.google.com ([2002:aa7:83c8:0:b0:8a6:c8f0:ec6d]) (user=kuniyu job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6a00:2e8f:b0:8a0:1c79:b442 with SMTP id d2e1a72fcca58-8a9b69872fbmr7076112b3a.0.1793547526202; Sun, 01 Nov 2026 07:38:46 -0800 (PST) Date: Sun, 1 Nov 2026 15:38:45 +0000 In-Reply-To: <0b1a91e7fa0de128c6e2bd3ae2f5c960a5c0f883.1793444262.git.thnkslprpt@gmail.com> X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list Mime-Version: 1.0 References: <0b1a91e7fa0de128c6e2bd3ae2f5c960a5c0f883.1793444262.git.thnkslprpt@gmail.com> Message-ID: Subject: Re: [PATCH net 1/2] net: check the sendmsg LSM hook for every batched message From: Kuniyuki Iwashima To: Avi Weiss Cc: netdev@vger.kernel.org, edumazet@kernel.org, pabeni@redhat.com, willemb@google.com, davem@davemloft.net, kuba@kernel.org, horms@kernel.org, linux-kernel@vger.kernel.org Content-Type: text/plain; charset="us-ascii" On Sat, 31 Oct 2026 13:08:40 +0200, Avi Weiss wrote: > sendmmsg() skips security_socket_sendmsg() when two consecutive > messages have the same explicit destination address. The comparison > does not account for the message size, so a BPF LSM policy that denies > large sends can be bypassed by placing an allowed message first. What is the real use case ? or is this something just flagged by AI ? > > Use __sock_sendmsg() for the cached-destination case as well, so that > every message undergoes the LSM check. Keep the remainder of the > address-caching logic unchanged in this minimal correction. > > Fixes: 228e548e6020 ("net: Add sendmmsg socket system call") This is net-next material. > Signed-off-by: Avi Weiss > --- > net/socket.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/net/socket.c b/net/socket.c > index 2e3b5737c481..c2a85224ab55 100644 > --- a/net/socket.c > +++ b/net/socket.c > @@ -2709,7 +2709,7 @@ static int ____sys_sendmsg(struct socket *sock, struct msghdr *msg_sys, /* * If this is sendmmsg() and current destination address is same as * previously succeeded address, omit asking LSM's decision. * used_address->name_len is initialized to UINT_MAX so that the first * destination address never matches. */ The comment here is stale. if (used_address && msg_sys->msg_name && > used_address->name_len == msg_sys->msg_namelen && > !memcmp(&used_address->name, msg_sys->msg_name, > used_address->name_len)) { Also, used_address, etc is no longer needed. > - err = sock_sendmsg_nosec(sock, msg_sys); > + err = __sock_sendmsg(sock, msg_sys); > goto out_freectl; > } > err = __sock_sendmsg(sock, msg_sys); > -- > 2.43.0 >