From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AIpwx4/KnfIuUcZr/dG4P37djYdZ0o49iXry8TGanRsIPsvCobZXMYGrUH9E2mRVtZgiJ6zBA0Or ARC-Seal: i=1; a=rsa-sha256; t=1523021142; cv=none; d=google.com; s=arc-20160816; b=w3VUas3+t1kKXqEpg0l2vA1k7x5VQK/abQC/mgF0H7KO3B5cjUh5LcS+0HoJctKBsk od9MIJEtQGEAXxPXNLvO0vHXYJ/oL7o7eYykF4t3pzeklPVgmyWxU40h0d8X8luby7Bh 1bFkxnohgrqMv+JY3RJtXod76yFlHqGUW8rK8VOklyQ0XtdsjCkUANb2zzquqZBXIsRR YgEaKJUMvqAoPhRkVygGnu76QFI2EqpKHjYAAx2XsP2XEOAE4+uaYBAqBx3crq2OD85j xe31n0/VEHvtKEx64dkxAGMzscf9u8P6Dq3llZ+E48q0SprTp068oxGJM5m236Yu3Krw d9zA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=mime-version:user-agent:references:in-reply-to:message-id:date :subject:cc:to:from:arc-authentication-results; bh=Mb0kGQV59F62kzWT2jjQyoPhjCXsSTRxyTu5uCChm1U=; b=cSYb93TwHdrq7vQ5zekRZrQyD/jS26bRzYFX+PlGpEfrsgGEaCMEBAaH907hCAxoeH xIuzr358yVM9cryTHd5GPH+gzz7wJzfxltWuZCX66k3Vdzz0gzMVcxB5/udGqXyyN3UO qUWJBJEBSJ9znSyvk6qDuA7MwIJRgw+mQbKBOWvj68sxnhimjmQD7MJAbsa3Ok/8SeIy MHaIqPUj41Dyv4FNpvv0hiLIM5BWbFk9DKt8AeNS5NYoIA/Zr05J6rqoZ2cLQYTjlyxr 7PO15/N79jhZqgu5ujNKk3tu+Q4uVGHWaoDWiI4+WQqiOiOdjVKFSkY7Md3OglzQ++b7 hIaA== ARC-Authentication-Results: i=1; mx.google.com; spf=softfail (google.com: domain of transitioning gregkh@linuxfoundation.org does not designate 90.92.61.202 as permitted sender) smtp.mailfrom=gregkh@linuxfoundation.org Authentication-Results: mx.google.com; spf=softfail (google.com: domain of transitioning gregkh@linuxfoundation.org does not designate 90.92.61.202 as permitted sender) smtp.mailfrom=gregkh@linuxfoundation.org From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, syzbot+f99ab3887ab65d70f816@syzkaller.appspotmail.com, Alexey Kodanev , "David S. Miller" Subject: [PATCH 3.18 23/93] dccp: check sk for closed state in dccp_sendmsg() Date: Fri, 6 Apr 2018 15:22:52 +0200 Message-Id: <20180406084225.977167807@linuxfoundation.org> X-Mailer: git-send-email 2.17.0 In-Reply-To: <20180406084224.918716300@linuxfoundation.org> References: <20180406084224.918716300@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-LABELS: =?utf-8?b?IlxcU2VudCI=?= X-GMAIL-THRID: =?utf-8?q?1597003418083901287?= X-GMAIL-MSGID: =?utf-8?q?1597003418083901287?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: 3.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Alexey Kodanev [ Upstream commit 67f93df79aeefc3add4e4b31a752600f834236e2 ] dccp_disconnect() sets 'dp->dccps_hc_tx_ccid' tx handler to NULL, therefore if DCCP socket is disconnected and dccp_sendmsg() is called after it, it will cause a NULL pointer dereference in dccp_write_xmit(). This crash and the reproducer was reported by syzbot. Looks like it is reproduced if commit 69c64866ce07 ("dccp: CVE-2017-8824: use-after-free in DCCP code") is applied. Reported-by: syzbot+f99ab3887ab65d70f816@syzkaller.appspotmail.com Signed-off-by: Alexey Kodanev Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/dccp/proto.c | 5 +++++ 1 file changed, 5 insertions(+) --- a/net/dccp/proto.c +++ b/net/dccp/proto.c @@ -792,6 +792,11 @@ int dccp_sendmsg(struct kiocb *iocb, str if (skb == NULL) goto out_release; + if (sk->sk_state == DCCP_CLOSED) { + rc = -ENOTCONN; + goto out_discard; + } + skb_reserve(skb, sk->sk_prot->max_header); rc = memcpy_fromiovec(skb_put(skb, len), msg->msg_iov, len); if (rc != 0)