From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AIpwx4/+LepnvpHiuITuiFsDy4tAuCqN494WGgVlFp1JjidfxdhMpI3Ar3SZsp/k2w+rZMvqGXX6 ARC-Seal: i=1; a=rsa-sha256; t=1522346825; cv=none; d=google.com; s=arc-20160816; b=I7hGTn6KYULaAGGA4yJmO1Z0af01SU0jAmmJb0wjxomujHIHdjKA514D9cNwL1seVG 3y+4vhdCxaSOQbvGEp7i42FwdEaiFKBzWgZF3BmgmAqsUBEfTgykMnAcea/i7grCKIDm QD/ncAoTJv9pYsKI/8W7N+S7TLxZvrs99Si5wkI/XqVkupd6a7k/4IRaHGwoM45pCSTL hza2QTfp9HWni/Kw5i0AWgQGuvobYSmxg63euCnaF8svvvkbl8B4WMBOaLExyKvkoWDY aJyvXtio4qnfOuOJG/603MPCisTIwufWbR01JN0pVhBpTKo1OZ5sXGUBPPbfZ0wMKAhp HjBQ== 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=ifwNW5B9NEMusyW6qfM8A4FRIFzG4osrg+3wOxie0yE=; b=DLQ4nLjIU6IdmXka+1TLwd9F4N5Ovl/xr+6BIucQlzYLFbeqZ7d+a7yyaEzImbX4+N b3I+txLJ2kYvedQ5fZkbS+27NGXI9Yps+jmXPf90+Atc/KLckbRD2VZUkOJzPEQYfsQc ktkQY633rahBDbzyiMinr6KYpGy7m+T2HTPI87jCmccsD+3iGajtSs1CQq/o3Eki+s/L sxkKnzAIDiJ2SbNKKxmdH/IWUrZ0959pkpQ+0lgkEUGf5C+MpuKM4GHp6nPlTYIK3Td0 xdI5bDBTAwtJI/WM+uk4M+vlyFMGNFwSOtLWvgGkFRFoAkHDhZhsigGtFyk9tXDxBsDp NNFQ== 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+ea75c0ffcd353d32515f064aaebefc5279e6161e@syzkaller.appspotmail.com, Tom Herbert , "David S. Miller" Subject: [PATCH 4.9 27/28] kcm: lock lower socket in kcm_attach Date: Thu, 29 Mar 2018 20:00:46 +0200 Message-Id: <20180329175736.687245659@linuxfoundation.org> X-Mailer: git-send-email 2.16.3 In-Reply-To: <20180329175733.447823703@linuxfoundation.org> References: <20180329175733.447823703@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?1596296045408642540?= X-GMAIL-MSGID: =?utf-8?q?1596296344981024550?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Tom Herbert [ Upstream commit 2cc683e88c0c993ac3721d9b702cb0630abe2879 ] Need to lock lower socket in order to provide mutual exclusion with kcm_unattach. v2: Add Reported-by for syzbot Fixes: ab7ac4eb9832e32a09f4e804 ("kcm: Kernel Connection Multiplexor module") Reported-by: syzbot+ea75c0ffcd353d32515f064aaebefc5279e6161e@syzkaller.appspotmail.com Signed-off-by: Tom Herbert Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/kcm/kcmsock.c | 33 +++++++++++++++++++++++---------- 1 file changed, 23 insertions(+), 10 deletions(-) --- a/net/kcm/kcmsock.c +++ b/net/kcm/kcmsock.c @@ -1375,24 +1375,32 @@ static int kcm_attach(struct socket *soc struct list_head *head; int index = 0; struct strp_callbacks cb; - int err; + int err = 0; csk = csock->sk; if (!csk) return -EINVAL; + lock_sock(csk); + /* Only allow TCP sockets to be attached for now */ if ((csk->sk_family != AF_INET && csk->sk_family != AF_INET6) || - csk->sk_protocol != IPPROTO_TCP) - return -EOPNOTSUPP; + csk->sk_protocol != IPPROTO_TCP) { + err = -EOPNOTSUPP; + goto out; + } /* Don't allow listeners or closed sockets */ - if (csk->sk_state == TCP_LISTEN || csk->sk_state == TCP_CLOSE) - return -EOPNOTSUPP; + if (csk->sk_state == TCP_LISTEN || csk->sk_state == TCP_CLOSE) { + err = -EOPNOTSUPP; + goto out; + } psock = kmem_cache_zalloc(kcm_psockp, GFP_KERNEL); - if (!psock) - return -ENOMEM; + if (!psock) { + err = -ENOMEM; + goto out; + } psock->mux = mux; psock->sk = csk; @@ -1406,7 +1414,7 @@ static int kcm_attach(struct socket *soc err = strp_init(&psock->strp, csk, &cb); if (err) { kmem_cache_free(kcm_psockp, psock); - return err; + goto out; } write_lock_bh(&csk->sk_callback_lock); @@ -1418,7 +1426,8 @@ static int kcm_attach(struct socket *soc write_unlock_bh(&csk->sk_callback_lock); strp_done(&psock->strp); kmem_cache_free(kcm_psockp, psock); - return -EALREADY; + err = -EALREADY; + goto out; } psock->save_data_ready = csk->sk_data_ready; @@ -1454,7 +1463,10 @@ static int kcm_attach(struct socket *soc /* Schedule RX work in case there are already bytes queued */ strp_check_rcv(&psock->strp); - return 0; +out: + release_sock(csk); + + return err; } static int kcm_attach_ioctl(struct socket *sock, struct kcm_attach *info) @@ -1506,6 +1518,7 @@ static void kcm_unattach(struct kcm_psoc if (WARN_ON(psock->rx_kcm)) { write_unlock_bh(&csk->sk_callback_lock); + release_sock(csk); return; }