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From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Eric Biggers <ebiggers@google.com>,
	syzbot+6bf095f9becf5efef645@syzkaller.appspotmail.com,
	syzbot+31c16aa4202dace3812e@syzkaller.appspotmail.com,
	Jakub Kicinski <jakub.kicinski@netronome.com>,
	Sasha Levin <sashal@kernel.org>,
	netdev@vger.kernel.org
Subject: [PATCH AUTOSEL 5.3 25/99] llc: fix sk_buff leak in llc_sap_state_process()
Date: Sat, 26 Oct 2019 09:14:46 -0400	[thread overview]
Message-ID: <20191026131600.2507-25-sashal@kernel.org> (raw)
In-Reply-To: <20191026131600.2507-1-sashal@kernel.org>

From: Eric Biggers <ebiggers@google.com>

[ Upstream commit c6ee11c39fcc1fb55130748990a8f199e76263b4 ]

syzbot reported:

    BUG: memory leak
    unreferenced object 0xffff888116270800 (size 224):
       comm "syz-executor641", pid 7047, jiffies 4294947360 (age 13.860s)
       hex dump (first 32 bytes):
         00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
         00 20 e1 2a 81 88 ff ff 00 40 3d 2a 81 88 ff ff  . .*.....@=*....
       backtrace:
         [<000000004d41b4cc>] kmemleak_alloc_recursive  include/linux/kmemleak.h:55 [inline]
         [<000000004d41b4cc>] slab_post_alloc_hook mm/slab.h:439 [inline]
         [<000000004d41b4cc>] slab_alloc_node mm/slab.c:3269 [inline]
         [<000000004d41b4cc>] kmem_cache_alloc_node+0x153/0x2a0 mm/slab.c:3579
         [<00000000506a5965>] __alloc_skb+0x6e/0x210 net/core/skbuff.c:198
         [<000000001ba5a161>] alloc_skb include/linux/skbuff.h:1058 [inline]
         [<000000001ba5a161>] alloc_skb_with_frags+0x5f/0x250  net/core/skbuff.c:5327
         [<0000000047d9c78b>] sock_alloc_send_pskb+0x269/0x2a0  net/core/sock.c:2225
         [<000000003828fe54>] sock_alloc_send_skb+0x32/0x40 net/core/sock.c:2242
         [<00000000e34d94f9>] llc_ui_sendmsg+0x10a/0x540 net/llc/af_llc.c:933
         [<00000000de2de3fb>] sock_sendmsg_nosec net/socket.c:652 [inline]
         [<00000000de2de3fb>] sock_sendmsg+0x54/0x70 net/socket.c:671
         [<000000008fe16e7a>] __sys_sendto+0x148/0x1f0 net/socket.c:1964
	 [...]

The bug is that llc_sap_state_process() always takes an extra reference
to the skb, but sometimes neither llc_sap_next_state() nor
llc_sap_state_process() itself drops this reference.

Fix it by changing llc_sap_next_state() to never consume a reference to
the skb, rather than sometimes do so and sometimes not.  Then remove the
extra skb_get() and kfree_skb() from llc_sap_state_process().

Reported-by: syzbot+6bf095f9becf5efef645@syzkaller.appspotmail.com
Reported-by: syzbot+31c16aa4202dace3812e@syzkaller.appspotmail.com
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 net/llc/llc_s_ac.c | 12 +++++++++---
 net/llc/llc_sap.c  | 23 ++++++++---------------
 2 files changed, 17 insertions(+), 18 deletions(-)

diff --git a/net/llc/llc_s_ac.c b/net/llc/llc_s_ac.c
index a94bd56bcac6f..7ae4cc684d3ab 100644
--- a/net/llc/llc_s_ac.c
+++ b/net/llc/llc_s_ac.c
@@ -58,8 +58,10 @@ int llc_sap_action_send_ui(struct llc_sap *sap, struct sk_buff *skb)
 			    ev->daddr.lsap, LLC_PDU_CMD);
 	llc_pdu_init_as_ui_cmd(skb);
 	rc = llc_mac_hdr_init(skb, ev->saddr.mac, ev->daddr.mac);
-	if (likely(!rc))
+	if (likely(!rc)) {
+		skb_get(skb);
 		rc = dev_queue_xmit(skb);
+	}
 	return rc;
 }
 
@@ -81,8 +83,10 @@ int llc_sap_action_send_xid_c(struct llc_sap *sap, struct sk_buff *skb)
 			    ev->daddr.lsap, LLC_PDU_CMD);
 	llc_pdu_init_as_xid_cmd(skb, LLC_XID_NULL_CLASS_2, 0);
 	rc = llc_mac_hdr_init(skb, ev->saddr.mac, ev->daddr.mac);
-	if (likely(!rc))
+	if (likely(!rc)) {
+		skb_get(skb);
 		rc = dev_queue_xmit(skb);
+	}
 	return rc;
 }
 
@@ -135,8 +139,10 @@ int llc_sap_action_send_test_c(struct llc_sap *sap, struct sk_buff *skb)
 			    ev->daddr.lsap, LLC_PDU_CMD);
 	llc_pdu_init_as_test_cmd(skb);
 	rc = llc_mac_hdr_init(skb, ev->saddr.mac, ev->daddr.mac);
-	if (likely(!rc))
+	if (likely(!rc)) {
+		skb_get(skb);
 		rc = dev_queue_xmit(skb);
+	}
 	return rc;
 }
 
diff --git a/net/llc/llc_sap.c b/net/llc/llc_sap.c
index a7f7b8ff47292..be419062e19a6 100644
--- a/net/llc/llc_sap.c
+++ b/net/llc/llc_sap.c
@@ -197,29 +197,22 @@ static int llc_sap_next_state(struct llc_sap *sap, struct sk_buff *skb)
  *	After executing actions of the event, upper layer will be indicated
  *	if needed(on receiving an UI frame). sk can be null for the
  *	datalink_proto case.
+ *
+ *	This function always consumes a reference to the skb.
  */
 static void llc_sap_state_process(struct llc_sap *sap, struct sk_buff *skb)
 {
 	struct llc_sap_state_ev *ev = llc_sap_ev(skb);
 
-	/*
-	 * We have to hold the skb, because llc_sap_next_state
-	 * will kfree it in the sending path and we need to
-	 * look at the skb->cb, where we encode llc_sap_state_ev.
-	 */
-	skb_get(skb);
 	ev->ind_cfm_flag = 0;
 	llc_sap_next_state(sap, skb);
-	if (ev->ind_cfm_flag == LLC_IND) {
-		if (skb->sk->sk_state == TCP_LISTEN)
-			kfree_skb(skb);
-		else {
-			llc_save_primitive(skb->sk, skb, ev->prim);
 
-			/* queue skb to the user. */
-			if (sock_queue_rcv_skb(skb->sk, skb))
-				kfree_skb(skb);
-		}
+	if (ev->ind_cfm_flag == LLC_IND && skb->sk->sk_state != TCP_LISTEN) {
+		llc_save_primitive(skb->sk, skb, ev->prim);
+
+		/* queue skb to the user. */
+		if (sock_queue_rcv_skb(skb->sk, skb) == 0)
+			return;
 	}
 	kfree_skb(skb);
 }
-- 
2.20.1


  parent reply	other threads:[~2019-10-26 13:16 UTC|newest]

Thread overview: 66+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-26 13:14 [PATCH AUTOSEL 5.3 01/99] tools: bpf: Use !building_out_of_srctree to determine srctree Sasha Levin
2019-10-26 13:14 ` [PATCH AUTOSEL 5.3 05/99] rt2x00: initialize last_reset Sasha Levin
2019-10-26 13:14 ` [PATCH AUTOSEL 5.3 07/99] mac80211_hwsim: fix incorrect dev_alloc_name failure goto Sasha Levin
2019-10-26 13:14 ` [PATCH AUTOSEL 5.3 10/99] net: dsa: b53: Do not clear existing mirrored port mask Sasha Levin
2019-10-26 13:14 ` [PATCH AUTOSEL 5.3 11/99] net: stmmac: selftests: Check if filtering is available before running Sasha Levin
2019-10-26 13:14 ` [PATCH AUTOSEL 5.3 12/99] net: stmmac: gmac4+: Not all Unicast addresses may be available Sasha Levin
2019-10-26 13:14 ` [PATCH AUTOSEL 5.3 13/99] net: stmmac: selftests: Fix L2 Hash Filter test Sasha Levin
2019-10-26 13:14 ` [PATCH AUTOSEL 5.3 16/99] rxrpc: Fix call ref leak Sasha Levin
2019-10-26 13:14 ` [PATCH AUTOSEL 5.3 17/99] rxrpc: Fix trace-after-put looking at the put peer record Sasha Levin
2019-10-26 13:14 ` [PATCH AUTOSEL 5.3 18/99] rxrpc: Fix trace-after-put looking at the put connection record Sasha Levin
2019-10-26 13:14 ` [PATCH AUTOSEL 5.3 19/99] rxrpc: Fix trace-after-put looking at the put call record Sasha Levin
2019-10-26 13:14 ` [PATCH AUTOSEL 5.3 20/99] rxrpc: rxrpc_peer needs to hold a ref on the rxrpc_local record Sasha Levin
2019-10-26 13:14 ` [PATCH AUTOSEL 5.3 21/99] nl80211: fix memory leak in nl80211_get_ftm_responder_stats Sasha Levin
2019-10-26 13:14 ` [PATCH AUTOSEL 5.3 22/99] cfg80211: fix a bunch of RCU issues in multi-bssid code Sasha Levin
2019-10-26 13:14 ` [PATCH AUTOSEL 5.3 23/99] mac80211: accept deauth frames in IBSS mode Sasha Levin
2019-10-26 13:14 ` [PATCH AUTOSEL 5.3 24/99] mac80211: fix scan when operating on DFS channels in ETSI domains Sasha Levin
2019-10-26 13:14 ` Sasha Levin [this message]
2019-10-26 13:14 ` [PATCH AUTOSEL 5.3 26/99] llc: fix sk_buff leak in llc_conn_service() Sasha Levin
2019-10-26 13:14 ` [PATCH AUTOSEL 5.3 27/99] llc: fix another potential sk_buff leak in llc_ui_sendmsg() Sasha Levin
2019-10-26 13:14 ` [PATCH AUTOSEL 5.3 28/99] llc: fix sk_buff refcounting in llc_conn_state_process() Sasha Levin
2019-10-26 13:14 ` [PATCH AUTOSEL 5.3 29/99] selftests/bpf: Set rp_filter in test_flow_dissector Sasha Levin
2019-10-26 13:14 ` [PATCH AUTOSEL 5.3 30/99] selftests/bpf: More compatible nc options in test_lwt_ip_encap Sasha Levin
2019-10-26 13:14 ` [PATCH AUTOSEL 5.3 31/99] net_sched: fix backward compatibility for TCA_KIND Sasha Levin
2019-10-26 13:14 ` [PATCH AUTOSEL 5.3 32/99] net_sched: fix backward compatibility for TCA_ACT_KIND Sasha Levin
2019-10-26 13:14 ` [PATCH AUTOSEL 5.3 33/99] NFC: pn533: fix use-after-free and memleaks Sasha Levin
2019-10-26 13:14 ` [PATCH AUTOSEL 5.3 34/99] ip6erspan: remove the incorrect mtu limit for ip6erspan Sasha Levin
2019-10-26 13:14 ` [PATCH AUTOSEL 5.3 35/99] iwlwifi: mvm: fix race in sync rx queue notification Sasha Levin
2019-10-26 13:14 ` [PATCH AUTOSEL 5.3 36/99] iwlwifi: dbg_ini: fix memory leak in alloc_sgtable Sasha Levin
2019-10-26 13:14 ` [PATCH AUTOSEL 5.3 37/99] iwlwifi: pcie: fix memory leaks in iwl_pcie_ctxt_info_gen3_init Sasha Levin
2019-10-26 13:14 ` [PATCH AUTOSEL 5.3 38/99] iwlwifi: exclude GEO SAR support for 3168 Sasha Levin
2019-10-26 13:15 ` [PATCH AUTOSEL 5.3 40/99] net: stmmac: fix length of PTP clock's name string Sasha Levin
2019-10-26 13:15 ` [PATCH AUTOSEL 5.3 41/99] net: stmmac: fix disabling flexible PPS output Sasha Levin
2019-10-26 13:15 ` [PATCH AUTOSEL 5.3 42/99] bonding: fix potential NULL deref in bond_update_slave_arr Sasha Levin
2019-10-26 13:15 ` [PATCH AUTOSEL 5.3 43/99] sctp: add chunks to sk_backlog when the newsk sk_socket is not set Sasha Levin
2019-10-26 13:15 ` [PATCH AUTOSEL 5.3 46/99] act_mirred: Fix mirred_init_module error handling Sasha Levin
2019-10-26 13:15 ` [PATCH AUTOSEL 5.3 47/99] net: usb: qmi_wwan: add Telit 0x1050 composition Sasha Levin
2019-10-26 13:15 ` [PATCH AUTOSEL 5.3 48/99] netns: fix NLM_F_ECHO mechanism for RTM_NEWNSID Sasha Levin
2019-10-26 13:15 ` [PATCH AUTOSEL 5.3 49/99] netfilter: conntrack: avoid possible false sharing Sasha Levin
2019-10-26 13:15 ` [PATCH AUTOSEL 5.3 50/99] tun: remove possible false sharing in tun_flow_update() Sasha Levin
2019-10-26 13:15 ` [PATCH AUTOSEL 5.3 51/99] net: avoid possible false sharing in sk_leave_memory_pressure() Sasha Levin
2019-10-26 13:15 ` [PATCH AUTOSEL 5.3 52/99] net: add {READ|WRITE}_ONCE() annotations on ->rskq_accept_head Sasha Levin
2019-10-26 13:15 ` [PATCH AUTOSEL 5.3 53/99] net/smc: fix SMCD link group creation with VLAN id Sasha Levin
2019-10-26 13:15 ` [PATCH AUTOSEL 5.3 54/99] net/smc: receive returns without data Sasha Levin
2019-10-26 13:15 ` [PATCH AUTOSEL 5.3 55/99] net/smc: receive pending data after RCV_SHUTDOWN Sasha Levin
2019-10-26 13:15 ` [PATCH AUTOSEL 5.3 57/99] vhost/test: stop device before reset Sasha Levin
2019-10-26 13:15 ` [PATCH AUTOSEL 5.3 58/99] net/ibmvnic: Fix EOI when running in XIVE mode Sasha Levin
2019-10-26 13:15 ` [PATCH AUTOSEL 5.3 59/99] netdevsim: Fix error handling in nsim_fib_init and nsim_fib_exit Sasha Levin
2019-10-26 13:15 ` [PATCH AUTOSEL 5.3 60/99] ath10k: fix latency issue for QCA988x Sasha Levin
2019-10-26 13:15 ` [PATCH AUTOSEL 5.3 69/99] net: aquantia: temperature retrieval fix Sasha Levin
2019-10-26 13:15 ` [PATCH AUTOSEL 5.3 70/99] net: aquantia: do not pass lro session with invalid tcp checksum Sasha Levin
2019-10-26 13:15 ` [PATCH AUTOSEL 5.3 71/99] net: aquantia: correctly handle macvlan and multicast coexistence Sasha Levin
2019-10-26 13:15 ` [PATCH AUTOSEL 5.3 78/99] net: i82596: fix dma_alloc_attr for sni_82596 Sasha Levin
2019-10-26 13:15 ` [PATCH AUTOSEL 5.3 79/99] net: bcmgenet: Fix RGMII_MODE_EN value for GENET v1/2/3 Sasha Levin
2019-10-26 13:15 ` [PATCH AUTOSEL 5.3 80/99] net: usb: sr9800: fix uninitialized local variable Sasha Levin
2019-10-26 13:15 ` [PATCH AUTOSEL 5.3 82/99] net: stmmac: disable/enable ptp_ref_clk in suspend/resume flow Sasha Levin
2019-10-26 13:15 ` [PATCH AUTOSEL 5.3 84/99] usb: hso: obey DMA rules in tiocmget Sasha Levin
2019-10-26 13:15 ` [PATCH AUTOSEL 5.3 85/99] dpaa2-eth: add irq for the dpmac connect/disconnect event Sasha Levin
2019-10-26 13:15 ` [PATCH AUTOSEL 5.3 86/99] net: stmmac: fix argument to stmmac_pcs_ctrl_ane() Sasha Levin
2019-10-26 13:15 ` [PATCH AUTOSEL 5.3 87/99] net: phy: micrel: Discern KSZ8051 and KSZ8795 PHYs Sasha Levin
2019-10-26 13:15 ` [PATCH AUTOSEL 5.3 88/99] net: phy: micrel: Update KSZ87xx PHY name Sasha Levin
2019-10-26 13:15 ` [PATCH AUTOSEL 5.3 90/99] net: bcmgenet: don't set phydev->link from MAC Sasha Levin
2019-10-26 13:15 ` [PATCH AUTOSEL 5.3 91/99] net: phy: bcm7xxx: define soft_reset for 40nm EPHY Sasha Levin
2019-10-26 13:15 ` [PATCH AUTOSEL 5.3 92/99] net: bcmgenet: reset 40nm EPHY on energy detect Sasha Levin
2019-10-26 13:15 ` [PATCH AUTOSEL 5.3 93/99] net: usb: lan78xx: Connect PHY before registering MAC Sasha Levin
2019-10-26 13:15 ` [PATCH AUTOSEL 5.3 98/99] net: hns3: fix mis-counting IRQ vector numbers issue Sasha Levin
2019-10-26 13:16 ` [PATCH AUTOSEL 5.3 99/99] net: aquantia: add an error handling in aq_nic_set_multicast_list Sasha Levin

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