From mboxrd@z Thu Jan 1 00:00:00 1970 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 0B4E7C7618A for ; Wed, 15 Mar 2023 12:38:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232860AbjCOMib (ORCPT ); Wed, 15 Mar 2023 08:38:31 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53692 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232947AbjCOMiP (ORCPT ); Wed, 15 Mar 2023 08:38:15 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CE1659AFDB for ; Wed, 15 Mar 2023 05:37:18 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 3B723B81E00 for ; Wed, 15 Mar 2023 12:37:18 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 895FDC433D2; Wed, 15 Mar 2023 12:37:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1678883836; bh=R63HPpZq8h7gdUMFQmD6fmDT7vOIDou4F1fXXxV7wgE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=h/UKaqL0j5ZEjpF5g59KLi2p1Q5fu8M4/gQmzzgfDmD6gcOClI0gj2zfufChnVP/l dGO8D64FjxNQJ8OBlqJIy/WewU7dON6ji65CIVEn7voXxnSfKneIAwI8Sdk2jyd+32 8E0KD2aFG08HhO69QQRd3DY9jF1UC86PNNnpJvQk= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, syzbot+7699d9e5635c10253a27@syzkaller.appspotmail.com, Eric Dumazet , Rao Shoaib , Kuniyuki Iwashima , Jakub Kicinski , Sasha Levin Subject: [PATCH 6.1 110/143] af_unix: fix struct pid leaks in OOB support Date: Wed, 15 Mar 2023 13:13:16 +0100 Message-Id: <20230315115743.838907537@linuxfoundation.org> X-Mailer: git-send-email 2.40.0 In-Reply-To: <20230315115740.429574234@linuxfoundation.org> References: <20230315115740.429574234@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Eric Dumazet [ Upstream commit 2aab4b96900272885bc157f8b236abf1cdc02e08 ] syzbot reported struct pid leak [1]. Issue is that queue_oob() calls maybe_add_creds() which potentially holds a reference on a pid. But skb->destructor is not set (either directly or by calling unix_scm_to_skb()) This means that subsequent kfree_skb() or consume_skb() would leak this reference. In this fix, I chose to fully support scm even for the OOB message. [1] BUG: memory leak unreferenced object 0xffff8881053e7f80 (size 128): comm "syz-executor242", pid 5066, jiffies 4294946079 (age 13.220s) hex dump (first 32 bytes): 01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ backtrace: [] alloc_pid+0x6a/0x560 kernel/pid.c:180 [] copy_process+0x169f/0x26c0 kernel/fork.c:2285 [] kernel_clone+0xf7/0x610 kernel/fork.c:2684 [] __do_sys_clone+0x7c/0xb0 kernel/fork.c:2825 [] do_syscall_x64 arch/x86/entry/common.c:50 [inline] [] do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80 [] entry_SYSCALL_64_after_hwframe+0x63/0xcd Fixes: 314001f0bf92 ("af_unix: Add OOB support") Reported-by: syzbot+7699d9e5635c10253a27@syzkaller.appspotmail.com Signed-off-by: Eric Dumazet Cc: Rao Shoaib Reviewed-by: Kuniyuki Iwashima Link: https://lore.kernel.org/r/20230307164530.771896-1-edumazet@google.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- net/unix/af_unix.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c index f0c2293f1d3b8..7d17601ceee79 100644 --- a/net/unix/af_unix.c +++ b/net/unix/af_unix.c @@ -2104,7 +2104,8 @@ static int unix_dgram_sendmsg(struct socket *sock, struct msghdr *msg, #define UNIX_SKB_FRAGS_SZ (PAGE_SIZE << get_order(32768)) #if IS_ENABLED(CONFIG_AF_UNIX_OOB) -static int queue_oob(struct socket *sock, struct msghdr *msg, struct sock *other) +static int queue_oob(struct socket *sock, struct msghdr *msg, struct sock *other, + struct scm_cookie *scm, bool fds_sent) { struct unix_sock *ousk = unix_sk(other); struct sk_buff *skb; @@ -2115,6 +2116,11 @@ static int queue_oob(struct socket *sock, struct msghdr *msg, struct sock *other if (!skb) return err; + err = unix_scm_to_skb(scm, skb, !fds_sent); + if (err < 0) { + kfree_skb(skb); + return err; + } skb_put(skb, 1); err = skb_copy_datagram_from_iter(skb, 0, &msg->msg_iter, 1); @@ -2242,7 +2248,7 @@ static int unix_stream_sendmsg(struct socket *sock, struct msghdr *msg, #if IS_ENABLED(CONFIG_AF_UNIX_OOB) if (msg->msg_flags & MSG_OOB) { - err = queue_oob(sock, msg, other); + err = queue_oob(sock, msg, other, &scm, fds_sent); if (err) goto out_err; sent++; -- 2.39.2