From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AIpwx494xuBuoFWYGOvBSgUjypn/RmDMq7kk/l9zi3W9CEMaYsUsBvVLaAdoJyfSN3seV0//SMz9 ARC-Seal: i=1; a=rsa-sha256; t=1522346870; cv=none; d=google.com; s=arc-20160816; b=i7nYO+W/hIpU3crx0fMeNEWKC2J2JslfRzXew7AUfr891a9ttzmvGWBDgknVx/ToGC 8LiQsrTDFYYCa9+uZUnmYunsDqf0R8JPwR3ttF5mnODsQq7qjfOLSDa7iXhqBNyxJkXa Eo8yXKtfXxEd5eKpU9orp495cj1iWf/BAyPDJkiBXFSmePasMS6lJKJFjQ+Sr7EW9gGC FgEDPOB6D6ICTDEjIea1hGvUzM3O0bEmcEFoHHuXy/AxfsOCN2By9sirNS1JhLMITvwc F7tR2G1dwgsSLOVUS0UJcnvw0MPiLJMcC3BY/1ac/jupHJihNymC5taW40Xz1E16NQ25 nZWA== 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=kjOpv0O0B9EzIXyv3Ugr2fnykhoOMnIhVqnMPC/xISc=; b=ZWHS1z4HWRikvRcrOJPtzvpqg2+lBp/e/G9PGhT2oFJCGQuJX8LV20iZbNcNDmhDsn rgUYbmxJs5h8bODwGP1Bt+yAkX5waoN1/wL3zg6qisDQYu7qffR5y/EcgxZDhWjBN6Rn ELlkFi5gNZQ/8Z3x0aWLn66/cwcqet1QSiB1f+H5AJMRBMpw0VNlEh5N4jh9e6Dd98RM 2ltKYV7WjMTahvdbENyuNvPJzyTMSJyqeiaSDyAnNvrycuqqeHdi7+2NSy6WPvASY7Gp qTuQNegkZhPa+ON29LupSmZZr6dObEMmwKv6YfGLHZwtooqFnu3ajiZR/riU6Cy92Pdj wobA== 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 4.4 04/20] dccp: check sk for closed state in dccp_sendmsg() Date: Thu, 29 Mar 2018 20:00:40 +0200 Message-Id: <20180329175742.066392990@linuxfoundation.org> X-Mailer: git-send-email 2.16.3 In-Reply-To: <20180329175741.886181131@linuxfoundation.org> References: <20180329175741.886181131@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?1596296392155362805?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: 4.4-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)