LKML Archive on lore.kernel.org
help / color / mirror / Atom feed
From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	stable@vger.kernel.org, Guillaume Nault <g.nault@alphalink.fr>,
	"David S. Miller" <davem@davemloft.net>
Subject: [PATCH 4.16 41/81] l2tp: hold reference on tunnels in netlink dumps
Date: Fri, 27 Apr 2018 15:58:43 +0200	[thread overview]
Message-ID: <20180427135745.475083315@linuxfoundation.org> (raw)
In-Reply-To: <20180427135743.216853156@linuxfoundation.org>

4.16-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Guillaume Nault <g.nault@alphalink.fr>


[ Upstream commit 5846c131c39b6d0add36ec19dc8650700690f930 ]

l2tp_tunnel_find_nth() is unsafe: no reference is held on the returned
tunnel, therefore it can be freed whenever the caller uses it.
This patch defines l2tp_tunnel_get_nth() which works similarly, but
also takes a reference on the returned tunnel. The caller then has to
drop it after it stops using the tunnel.

Convert netlink dumps to make them safe against concurrent tunnel
deletion.

Fixes: 309795f4bec2 ("l2tp: Add netlink control API for L2TP")
Signed-off-by: Guillaume Nault <g.nault@alphalink.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 net/l2tp/l2tp_core.c    |   20 ++++++++++++++++++++
 net/l2tp/l2tp_core.h    |    2 ++
 net/l2tp/l2tp_netlink.c |   11 ++++++++---
 3 files changed, 30 insertions(+), 3 deletions(-)

--- a/net/l2tp/l2tp_core.c
+++ b/net/l2tp/l2tp_core.c
@@ -183,6 +183,26 @@ struct l2tp_tunnel *l2tp_tunnel_get(cons
 }
 EXPORT_SYMBOL_GPL(l2tp_tunnel_get);
 
+struct l2tp_tunnel *l2tp_tunnel_get_nth(const struct net *net, int nth)
+{
+	const struct l2tp_net *pn = l2tp_pernet(net);
+	struct l2tp_tunnel *tunnel;
+	int count = 0;
+
+	rcu_read_lock_bh();
+	list_for_each_entry_rcu(tunnel, &pn->l2tp_tunnel_list, list) {
+		if (++count > nth) {
+			l2tp_tunnel_inc_refcount(tunnel);
+			rcu_read_unlock_bh();
+			return tunnel;
+		}
+	}
+	rcu_read_unlock_bh();
+
+	return NULL;
+}
+EXPORT_SYMBOL_GPL(l2tp_tunnel_get_nth);
+
 /* Lookup a session. A new reference is held on the returned session. */
 struct l2tp_session *l2tp_session_get(const struct net *net,
 				      struct l2tp_tunnel *tunnel,
--- a/net/l2tp/l2tp_core.h
+++ b/net/l2tp/l2tp_core.h
@@ -212,6 +212,8 @@ static inline void *l2tp_session_priv(st
 }
 
 struct l2tp_tunnel *l2tp_tunnel_get(const struct net *net, u32 tunnel_id);
+struct l2tp_tunnel *l2tp_tunnel_get_nth(const struct net *net, int nth);
+
 void l2tp_tunnel_free(struct l2tp_tunnel *tunnel);
 
 struct l2tp_session *l2tp_session_get(const struct net *net,
--- a/net/l2tp/l2tp_netlink.c
+++ b/net/l2tp/l2tp_netlink.c
@@ -487,14 +487,17 @@ static int l2tp_nl_cmd_tunnel_dump(struc
 	struct net *net = sock_net(skb->sk);
 
 	for (;;) {
-		tunnel = l2tp_tunnel_find_nth(net, ti);
+		tunnel = l2tp_tunnel_get_nth(net, ti);
 		if (tunnel == NULL)
 			goto out;
 
 		if (l2tp_nl_tunnel_send(skb, NETLINK_CB(cb->skb).portid,
 					cb->nlh->nlmsg_seq, NLM_F_MULTI,
-					tunnel, L2TP_CMD_TUNNEL_GET) < 0)
+					tunnel, L2TP_CMD_TUNNEL_GET) < 0) {
+			l2tp_tunnel_dec_refcount(tunnel);
 			goto out;
+		}
+		l2tp_tunnel_dec_refcount(tunnel);
 
 		ti++;
 	}
@@ -848,7 +851,7 @@ static int l2tp_nl_cmd_session_dump(stru
 
 	for (;;) {
 		if (tunnel == NULL) {
-			tunnel = l2tp_tunnel_find_nth(net, ti);
+			tunnel = l2tp_tunnel_get_nth(net, ti);
 			if (tunnel == NULL)
 				goto out;
 		}
@@ -856,6 +859,7 @@ static int l2tp_nl_cmd_session_dump(stru
 		session = l2tp_session_get_nth(tunnel, si);
 		if (session == NULL) {
 			ti++;
+			l2tp_tunnel_dec_refcount(tunnel);
 			tunnel = NULL;
 			si = 0;
 			continue;
@@ -865,6 +869,7 @@ static int l2tp_nl_cmd_session_dump(stru
 					 cb->nlh->nlmsg_seq, NLM_F_MULTI,
 					 session, L2TP_CMD_SESSION_GET) < 0) {
 			l2tp_session_dec_refcount(session);
+			l2tp_tunnel_dec_refcount(tunnel);
 			break;
 		}
 		l2tp_session_dec_refcount(session);

  parent reply	other threads:[~2018-04-27 13:58 UTC|newest]

Thread overview: 88+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-04-27 13:58 [PATCH 4.16 00/81] 4.16.6-stable review Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.16 01/81] Revert "pinctrl: intel: Initialize GPIO properly when used through irqchip" Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.16 02/81] drm: bridge: dw-hdmi: Fix overflow workaround for Amlogic Meson GX SoCs Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.16 03/81] i40e: Fix attach VF to VM issue Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.16 04/81] tpm: cmd_ready command can be issued only after granting locality Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.16 05/81] tpm: tpm-interface: fix tpm_transmit/_cmd kdoc Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.16 06/81] tpm: add retry logic Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.16 07/81] Revert "ath10k: send (re)assoc peer command when NSS changed" Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.16 08/81] bonding: do not set slave_dev npinfo before slave_enable_netpoll in bond_enslave Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.16 09/81] docs: ip-sysctl.txt: fix name of some ipv6 variables Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.16 10/81] ipv6: add RTA_TABLE and RTA_PREFSRC to rtm_ipv6_policy Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.16 11/81] ipv6: sr: fix NULL pointer dereference in seg6_do_srh_encap()- v4 pkts Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.16 12/81] KEYS: DNS: limit the length of option strings Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.16 13/81] l2tp: check sockaddr length in pppol2tp_connect() Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.16 14/81] llc: delete timers synchronously in llc_sk_free() Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.16 15/81] net: af_packet: fix race in PACKET_{R|T}X_RING Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.16 16/81] net: fix deadlock while clearing neighbor proxy table Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.16 17/81] net: mvpp2: Fix DMA address mask size Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.16 18/81] net: qmi_wwan: add Wistron Neweb D19Q1 Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.16 19/81] net/smc: fix shutdown in state SMC_LISTEN Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.16 20/81] net: stmmac: Disable ACS Feature for GMAC >= 4 Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.16 21/81] packet: fix bitfield update race Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.16 22/81] pppoe: check sockaddr length in pppoe_connect() Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.16 23/81] Revert "macsec: missing dev_put() on error in macsec_newlink()" Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.16 24/81] sctp: do not check port in sctp_inet6_cmp_addr Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.16 25/81] strparser: Do not call mod_delayed_work with a timeout of LONG_MAX Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.16 26/81] strparser: Fix incorrect strp->need_bytes value Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.16 27/81] tcp: clear tp->packets_out when purging write queue Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.16 28/81] tcp: dont read out-of-bounds opsize Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.16 29/81] tcp: md5: reject TCP_MD5SIG or TCP_MD5SIG_EXT on established sockets Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.16 30/81] team: avoid adding twice the same option to the event list Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.16 31/81] team: fix netconsole setup over team Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.16 32/81] tipc: add policy for TIPC_NLA_NET_ADDR Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.16 33/81] vlan: Fix reading memory beyond skb->tail in skb_vlan_tagged_multi Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.16 34/81] vmxnet3: fix incorrect dereference when rxvlan is disabled Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.16 35/81] amd-xgbe: Add pre/post auto-negotiation phy hooks Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.16 36/81] amd-xgbe: Improve KR auto-negotiation and training Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.16 37/81] amd-xgbe: Only use the SFP supported transceiver signals Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.16 38/81] net: sched: ife: signal not finding metaid Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.16 39/81] net: sched: ife: handle malformed tlv length Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.16 40/81] net: sched: ife: check on metadata length Greg Kroah-Hartman
2018-04-27 13:58 ` Greg Kroah-Hartman [this message]
2018-04-27 13:58 ` [PATCH 4.16 42/81] l2tp: hold reference on tunnels printed in pppol2tp proc file Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.16 43/81] l2tp: hold reference on tunnels printed in l2tp/tunnels debugfs file Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.16 44/81] l2tp: fix {pppol2tp, l2tp_dfs}_seq_stop() in case of seq_file overflow Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.16 45/81] llc: hold llc_sap before release_sock() Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.16 46/81] llc: fix NULL pointer deref for SOCK_ZAPPED Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.16 47/81] s390/qeth: fix error handling in adapter command callbacks Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.16 48/81] s390/qeth: avoid control IO completion stalls Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.16 49/81] s390/qeth: handle failure on workqueue creation Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.16 50/81] net: ethernet: ti: cpsw: fix tx vlan priority mapping Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.16 51/81] net: validate attribute sizes in neigh_dump_table() Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.16 52/81] bnxt_en: Fix memory fault in bnxt_ethtool_init() Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.16 53/81] virtio-net: add missing virtqueue kick when flushing packets Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.16 54/81] VSOCK: make af_vsock.ko removable again Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.16 55/81] net: aquantia: Regression on reset with 1.x firmware Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.16 56/81] tun: fix vlan packet truncation Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.16 57/81] net: aquantia: oops when shutdown on already stopped device Greg Kroah-Hartman
2018-04-27 13:59 ` [PATCH 4.16 58/81] virtio_net: split out ctrl buffer Greg Kroah-Hartman
2018-04-27 13:59 ` [PATCH 4.16 59/81] virtio_net: fix adding vids on big-endian Greg Kroah-Hartman
2018-04-27 13:59 ` [PATCH 4.16 60/81] Revert "mm/hmm: fix header file if/else/endif maze" Greg Kroah-Hartman
2018-04-27 13:59 ` [PATCH 4.16 61/81] commoncap: Handle memory allocation failure Greg Kroah-Hartman
2018-04-27 13:59 ` [PATCH 4.16 62/81] scsi: mptsas: Disable WRITE SAME Greg Kroah-Hartman
2018-04-27 13:59 ` [PATCH 4.16 63/81] cdrom: information leak in cdrom_ioctl_media_changed() Greg Kroah-Hartman
2018-04-27 13:59 ` [PATCH 4.16 64/81] fsnotify: Fix fsnotify_mark_connector race Greg Kroah-Hartman
2018-04-27 13:59 ` [PATCH 4.16 65/81] m68k/mac: Dont remap SWIM MMIO region Greg Kroah-Hartman
2018-04-27 13:59 ` [PATCH 4.16 66/81] block/swim: Check drive type Greg Kroah-Hartman
2018-04-27 13:59 ` [PATCH 4.16 67/81] block/swim: Dont log an error message for an invalid ioctl Greg Kroah-Hartman
2018-04-27 13:59 ` [PATCH 4.16 68/81] block/swim: Remove extra put_disk() call from error path Greg Kroah-Hartman
2018-04-27 13:59 ` [PATCH 4.16 69/81] block/swim: Rename macros to avoid inconsistent inverted logic Greg Kroah-Hartman
2018-04-27 13:59 ` [PATCH 4.16 70/81] block/swim: Select appropriate drive on device open Greg Kroah-Hartman
2018-04-27 13:59 ` [PATCH 4.16 71/81] block/swim: Fix array bounds check Greg Kroah-Hartman
2018-04-27 13:59 ` [PATCH 4.16 72/81] block/swim: Fix IO error at end of medium Greg Kroah-Hartman
2018-04-27 13:59 ` [PATCH 4.16 73/81] tracing: Fix missing tab for hwlat_detector print format Greg Kroah-Hartman
2018-04-27 13:59 ` [PATCH 4.16 74/81] hwmon: (k10temp) Add temperature offset for Ryzen 2700X Greg Kroah-Hartman
2018-04-27 13:59 ` [PATCH 4.16 75/81] hwmon: (k10temp) Add support for AMD Ryzen w/ Vega graphics Greg Kroah-Hartman
2018-04-27 13:59 ` [PATCH 4.16 76/81] s390/cio: update chpid descriptor after resource accessibility event Greg Kroah-Hartman
2018-04-27 13:59 ` [PATCH 4.16 77/81] s390/dasd: fix IO error for newly defined devices Greg Kroah-Hartman
2018-04-27 13:59 ` [PATCH 4.16 78/81] s390/uprobes: implement arch_uretprobe_is_alive() Greg Kroah-Hartman
2018-04-27 13:59 ` [PATCH 4.16 79/81] s390/cpum_cf: rename IBM z13/z14 counter names Greg Kroah-Hartman
2018-04-27 13:59 ` [PATCH 4.16 80/81] kprobes: Fix random address output of blacklist file Greg Kroah-Hartman
2018-04-27 13:59 ` [PATCH 4.16 81/81] ACPI / video: Only default only_lcd to true on Win8-ready _desktops_ Greg Kroah-Hartman
2018-04-27 18:15 ` [PATCH 4.16 00/81] 4.16.6-stable review Shuah Khan
2018-04-27 20:41 ` Dan Rue
2018-04-28  5:50   ` Greg Kroah-Hartman
2018-04-27 20:44 ` kernelci.org bot
2018-04-28 14:32 ` Guenter Roeck
2018-04-28 15:52   ` Greg Kroah-Hartman

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20180427135745.475083315@linuxfoundation.org \
    --to=gregkh@linuxfoundation.org \
    --cc=davem@davemloft.net \
    --cc=g.nault@alphalink.fr \
    --cc=linux-kernel@vger.kernel.org \
    --cc=stable@vger.kernel.org \
    --subject='Re: [PATCH 4.16 41/81] l2tp: hold reference on tunnels in netlink dumps' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).