From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AIpwx4/LrGeWAovSN/6lpZOX+1LseXVGHEzVaV0ZcC1GqKbsrLPqW/Db7pxVR/G9Xy4ecS6t8IP8 ARC-Seal: i=1; a=rsa-sha256; t=1522346581; cv=none; d=google.com; s=arc-20160816; b=xOheK7MeOWrC/Wt4fxTpB9aE8xkrva0FViBJXCuVqPB9inSsREBsAxD9y+uhgbMw5N ZCQ/cUbrvRp/+RJlYsM/dlfdJeIliVdistR4YUJXuNpYFazaMYDHOdnhWonQryravNcX SV8Ei3YQ4lObs3YwOa+5AtuClHHwTDn08hvEeL/zOlJm/NUI5qofrjkeugex9Kq1Ai1x RJ2/gPs6jLpR6XVDScV7Omi3D9aroj/b0D799KyeEUdjZBRvO3Bl1e5URlx/eZv+qOA3 hBRT/8ogWk3LsQ9BXnpiKFdyxeB3ZonpyyZaqCgAvTtGTIkc6ZBjmAEW60uBYP+gjARG uSgA== 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=7mhFTWqtaU82dJPN0YZSGymGUzDwEOTxfuYBi6UnWHU=; b=gthgwVbsjSH5iGkbmDV8PNIAlA+8AJoW5GEiiqeCVXyVr1TN/iznh6IHURKExzB13M Dcsj7fIpe4mUtrVX1YTaBXH6hmz2CsKq3LgN+nJXqsWrBokNbRY6fzC2qiZQp9nfL4ns ZMpCXTrWKAynWEyt+cuH5RXn3vMN8NgIw/xSYJW8ANsofT0x6+JsEILOMhlpROnWRND8 uDzFBfbctbZdy1JDWbT12/rdWhh3ifUKkAW3O1v64OJZsjvkETJUy6lpkD/IZi1R/Rv5 yCPbz05Fir3+fkLKJZb3Lp9jUiIbjitkj+lLVcqZp3QLXVhDm/U4i6hZAsm2tEULHWB0 A+DQ== 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 4.15 35/47] dccp: check sk for closed state in dccp_sendmsg() Date: Thu, 29 Mar 2018 20:00:16 +0200 Message-Id: <20180329175732.210194134@linuxfoundation.org> X-Mailer: git-send-email 2.16.3 In-Reply-To: <20180329175729.225211114@linuxfoundation.org> References: <20180329175729.225211114@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?1596296089395383323?= X-GMAIL-MSGID: =?utf-8?q?1596296089395383323?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: 4.15-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 @@ -789,6 +789,11 @@ int dccp_sendmsg(struct sock *sk, struct 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_from_msg(skb_put(skb, len), msg, len); if (rc != 0)