From patchwork Sun Oct 2 03:52:00 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tetsuo Handa X-Patchwork-Id: 12996732 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id BA8CDC433F5 for ; Sun, 2 Oct 2022 03:52:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229594AbiJBDwL (ORCPT ); Sat, 1 Oct 2022 23:52:11 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53322 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229537AbiJBDwH (ORCPT ); Sat, 1 Oct 2022 23:52:07 -0400 Received: from www262.sakura.ne.jp (www262.sakura.ne.jp [202.181.97.72]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 271A44E633 for ; Sat, 1 Oct 2022 20:52:05 -0700 (PDT) Received: from fsav117.sakura.ne.jp (fsav117.sakura.ne.jp [27.133.134.244]) by www262.sakura.ne.jp (8.15.2/8.15.2) with ESMTP id 2923q1A9059137; Sun, 2 Oct 2022 12:52:01 +0900 (JST) (envelope-from penguin-kernel@I-love.SAKURA.ne.jp) Received: from www262.sakura.ne.jp (202.181.97.72) by fsav117.sakura.ne.jp (F-Secure/fsigk_smtp/550/fsav117.sakura.ne.jp); Sun, 02 Oct 2022 12:52:01 +0900 (JST) X-Virus-Status: clean(F-Secure/fsigk_smtp/550/fsav117.sakura.ne.jp) Received: from [192.168.1.9] (M106072142033.v4.enabler.ne.jp [106.72.142.33]) (authenticated bits=0) by www262.sakura.ne.jp (8.15.2/8.15.2) with ESMTPSA id 2923q0og059130 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NO); Sun, 2 Oct 2022 12:52:01 +0900 (JST) (envelope-from penguin-kernel@I-love.SAKURA.ne.jp) Message-ID: Date: Sun, 2 Oct 2022 12:52:00 +0900 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 6.3; Win64; x64; rv:102.0) Gecko/20100101 Thunderbird/102.3.1 Subject: [PATCH v2] net/ieee802154: don't warn zero-sized raw_sendmsg() Content-Language: en-US From: Tetsuo Handa To: Alexander Aring , Stefan Schmidt , Zhengchao Shao , Alexei Starovoitov , Stanislav Fomichev , linux-wpan@vger.kernel.org Cc: syzbot , syzkaller-bugs@googlegroups.com, bpf@vger.kernel.org, netdev@vger.kernel.org References: <000000000000ac3b8305e4a6b766@google.com> <5e89b653-3fc6-25c5-324b-1b15909c0183@I-love.SAKURA.ne.jp> In-Reply-To: <5e89b653-3fc6-25c5-324b-1b15909c0183@I-love.SAKURA.ne.jp> Precedence: bulk List-ID: X-Mailing-List: linux-wpan@vger.kernel.org syzbot is hitting skb_assert_len() warning at __dev_queue_xmit() [1], for PF_IEEE802154 socket's zero-sized raw_sendmsg() request is hitting __dev_queue_xmit() with skb->len == 0. Since PF_IEEE802154 socket's zero-sized raw_sendmsg() request was able to return 0, don't call __dev_queue_xmit() if packet length is 0. ---------- #include #include int main(int argc, char *argv[]) { struct sockaddr_in addr = { .sin_family = AF_INET, .sin_addr.s_addr = htonl(INADDR_LOOPBACK) }; struct iovec iov = { }; struct msghdr hdr = { .msg_name = &addr, .msg_namelen = sizeof(addr), .msg_iov = &iov, .msg_iovlen = 1 }; sendmsg(socket(PF_IEEE802154, SOCK_RAW, 0), &hdr, 0); return 0; } ---------- Note that this might be a sign that commit fd1894224407c484 ("bpf: Don't redirect packets with invalid pkt_len") should be reverted, for skb->len == 0 was acceptable for at least PF_IEEE802154 socket. Link: https://syzkaller.appspot.com/bug?extid=5ea725c25d06fb9114c4 [1] Reported-by: syzbot Fixes: fd1894224407c484 ("bpf: Don't redirect packets with invalid pkt_len") Signed-off-by: Tetsuo Handa --- Changes in v2: Return 0 after checking -ENXIO case, for a test program shown above returns -ENXIO if dev was not found and returns 0 otherwise. net/ieee802154/socket.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/net/ieee802154/socket.c b/net/ieee802154/socket.c index 7889e1ef7fad..6e55fae4c686 100644 --- a/net/ieee802154/socket.c +++ b/net/ieee802154/socket.c @@ -272,6 +272,10 @@ static int raw_sendmsg(struct sock *sk, struct msghdr *msg, size_t size) err = -EMSGSIZE; goto out_dev; } + if (!size) { + err = 0; + goto out_dev; + } hlen = LL_RESERVED_SPACE(dev); tlen = dev->needed_tailroom;