From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AIpwx49EqQACOLmjZYOUe00k3S67ggCcV59O0xaCHT4YRYGtQtrL7h0O9qL0GkQdxe6Gfv4E8qs9 ARC-Seal: i=1; a=rsa-sha256; t=1522346736; cv=none; d=google.com; s=arc-20160816; b=oALkXIgKNEdGOtXqveXSGLvgcoK4GArS3YH1hyMkoRi84C+2785NabrCBN0iQvjWLa /aY9Vb7ktIxMau0CY/q2hurIw6zeh5CEFMjwvba+8YpGbxrik21y6D3S2ZMdGDbPtOeH Co3URZwoYD/49jCenyXKE+lANR9vU8Tj6fbiyqGn4axDE7c/EilxXsi4y0Zi46Ghecnt /QrEsA4hR4a/aaFFNt7WZzfcFd0Z6fUp5gm0ZLaKW4OrWyDCLQ3C/Ehre31RgT8dqbfR V6SdhyQ5hATqbBgaMPJ3JwOa9vrI7w2cD11t7FpLIWyCMNzhQRU2yxEUOsbDnr/z6/lM OTXQ== 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=2ptrj1DOgifx9IfBvHPnnG6KZJeZ5FshLrPKl1jurJM=; b=Mh8qoc+C7xSYrfsBVmQQaCYoI+asJFPJPrpOqw+QzrRE51HM2XPkonzkKHRfLiEe97 pOrkMT+FJJ5iv7w+A6JJPgMpk1shpq+pPtI0RyIKZI4ms6VamKKkjUovHK2PplaMLX/0 fS7PsS+FdmacDI5SISDfkGt0775Z7yhVg2e050AQoulKvMIKK33NAnAisq52U/JxuCJ9 nC2NgPMsTJ/uIx72xm9c8tMMk1TkgMf2ODfko2BoMock5z0uAdOlKMz0YPSV6HEjX0bY l6wbC04yyV2+JACxLv8bMjvmr+lnBZ3tfcA5xZAy9+PGq8Isn28LJEyh3Ecq1O+EHL8p 4jwg== 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 4.14 22/43] dccp: check sk for closed state in dccp_sendmsg() Date: Thu, 29 Mar 2018 20:00:17 +0200 Message-Id: <20180329175732.432357056@linuxfoundation.org> X-Mailer: git-send-email 2.16.3 In-Reply-To: <20180329175730.190353692@linuxfoundation.org> References: <20180329175730.190353692@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?1596296250824182738?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: 4.14-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)