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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+6b825a6494a04cc0e3f7@syzkaller.appspotmail.com,
	Jakub Kicinski <jakub.kicinski@netronome.com>,
	Sasha Levin <sashal@kernel.org>,
	netdev@vger.kernel.org
Subject: [PATCH AUTOSEL 5.3 08/33] llc: fix sk_buff leak in llc_conn_service()
Date: Fri, 25 Oct 2019 09:54:40 -0400	[thread overview]
Message-ID: <20191025135505.24762-8-sashal@kernel.org> (raw)
In-Reply-To: <20191025135505.24762-1-sashal@kernel.org>

From: Eric Biggers <ebiggers@google.com>

[ Upstream commit b74555de21acd791f12c4a1aeaf653dd7ac21133 ]

syzbot reported:

    BUG: memory leak
    unreferenced object 0xffff88811eb3de00 (size 224):
       comm "syz-executor559", pid 7315, jiffies 4294943019 (age 10.300s)
       hex dump (first 32 bytes):
         00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
         00 a0 38 24 81 88 ff ff 00 c0 f2 15 81 88 ff ff  ..8$............
       backtrace:
         [<000000008d1c66a1>] kmemleak_alloc_recursive  include/linux/kmemleak.h:55 [inline]
         [<000000008d1c66a1>] slab_post_alloc_hook mm/slab.h:439 [inline]
         [<000000008d1c66a1>] slab_alloc_node mm/slab.c:3269 [inline]
         [<000000008d1c66a1>] kmem_cache_alloc_node+0x153/0x2a0 mm/slab.c:3579
         [<00000000447d9496>] __alloc_skb+0x6e/0x210 net/core/skbuff.c:198
         [<000000000cdbf82f>] alloc_skb include/linux/skbuff.h:1058 [inline]
         [<000000000cdbf82f>] llc_alloc_frame+0x66/0x110 net/llc/llc_sap.c:54
         [<000000002418b52e>] llc_conn_ac_send_sabme_cmd_p_set_x+0x2f/0x140  net/llc/llc_c_ac.c:777
         [<000000001372ae17>] llc_exec_conn_trans_actions net/llc/llc_conn.c:475  [inline]
         [<000000001372ae17>] llc_conn_service net/llc/llc_conn.c:400 [inline]
         [<000000001372ae17>] llc_conn_state_process+0x1ac/0x640  net/llc/llc_conn.c:75
         [<00000000f27e53c1>] llc_establish_connection+0x110/0x170  net/llc/llc_if.c:109
         [<00000000291b2ca0>] llc_ui_connect+0x10e/0x370 net/llc/af_llc.c:477
         [<000000000f9c740b>] __sys_connect+0x11d/0x170 net/socket.c:1840
         [...]

The bug is that most callers of llc_conn_send_pdu() assume it consumes a
reference to the skb, when actually due to commit b85ab56c3f81 ("llc:
properly handle dev_queue_xmit() return value") it doesn't.

Revert most of that commit, and instead make the few places that need
llc_conn_send_pdu() to *not* consume a reference call skb_get() before.

Fixes: b85ab56c3f81 ("llc: properly handle dev_queue_xmit() return value")
Reported-by: syzbot+6b825a6494a04cc0e3f7@syzkaller.appspotmail.com
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>
---
 include/net/llc_conn.h |  2 +-
 net/llc/llc_c_ac.c     |  8 ++++++--
 net/llc/llc_conn.c     | 32 +++++++++-----------------------
 3 files changed, 16 insertions(+), 26 deletions(-)

diff --git a/include/net/llc_conn.h b/include/net/llc_conn.h
index df528a6235487..ea985aa7a6c5e 100644
--- a/include/net/llc_conn.h
+++ b/include/net/llc_conn.h
@@ -104,7 +104,7 @@ void llc_sk_reset(struct sock *sk);
 
 /* Access to a connection */
 int llc_conn_state_process(struct sock *sk, struct sk_buff *skb);
-int llc_conn_send_pdu(struct sock *sk, struct sk_buff *skb);
+void llc_conn_send_pdu(struct sock *sk, struct sk_buff *skb);
 void llc_conn_rtn_pdu(struct sock *sk, struct sk_buff *skb);
 void llc_conn_resend_i_pdu_as_cmd(struct sock *sk, u8 nr, u8 first_p_bit);
 void llc_conn_resend_i_pdu_as_rsp(struct sock *sk, u8 nr, u8 first_f_bit);
diff --git a/net/llc/llc_c_ac.c b/net/llc/llc_c_ac.c
index 4d78375f9872d..647c0554d04cd 100644
--- a/net/llc/llc_c_ac.c
+++ b/net/llc/llc_c_ac.c
@@ -372,6 +372,7 @@ int llc_conn_ac_send_i_cmd_p_set_1(struct sock *sk, struct sk_buff *skb)
 	llc_pdu_init_as_i_cmd(skb, 1, llc->vS, llc->vR);
 	rc = llc_mac_hdr_init(skb, llc->dev->dev_addr, llc->daddr.mac);
 	if (likely(!rc)) {
+		skb_get(skb);
 		llc_conn_send_pdu(sk, skb);
 		llc_conn_ac_inc_vs_by_1(sk, skb);
 	}
@@ -389,7 +390,8 @@ static int llc_conn_ac_send_i_cmd_p_set_0(struct sock *sk, struct sk_buff *skb)
 	llc_pdu_init_as_i_cmd(skb, 0, llc->vS, llc->vR);
 	rc = llc_mac_hdr_init(skb, llc->dev->dev_addr, llc->daddr.mac);
 	if (likely(!rc)) {
-		rc = llc_conn_send_pdu(sk, skb);
+		skb_get(skb);
+		llc_conn_send_pdu(sk, skb);
 		llc_conn_ac_inc_vs_by_1(sk, skb);
 	}
 	return rc;
@@ -406,6 +408,7 @@ int llc_conn_ac_send_i_xxx_x_set_0(struct sock *sk, struct sk_buff *skb)
 	llc_pdu_init_as_i_cmd(skb, 0, llc->vS, llc->vR);
 	rc = llc_mac_hdr_init(skb, llc->dev->dev_addr, llc->daddr.mac);
 	if (likely(!rc)) {
+		skb_get(skb);
 		llc_conn_send_pdu(sk, skb);
 		llc_conn_ac_inc_vs_by_1(sk, skb);
 	}
@@ -916,7 +919,8 @@ static int llc_conn_ac_send_i_rsp_f_set_ackpf(struct sock *sk,
 	llc_pdu_init_as_i_cmd(skb, llc->ack_pf, llc->vS, llc->vR);
 	rc = llc_mac_hdr_init(skb, llc->dev->dev_addr, llc->daddr.mac);
 	if (likely(!rc)) {
-		rc = llc_conn_send_pdu(sk, skb);
+		skb_get(skb);
+		llc_conn_send_pdu(sk, skb);
 		llc_conn_ac_inc_vs_by_1(sk, skb);
 	}
 	return rc;
diff --git a/net/llc/llc_conn.c b/net/llc/llc_conn.c
index 4ff89cb7c86f7..ed2aca12460ca 100644
--- a/net/llc/llc_conn.c
+++ b/net/llc/llc_conn.c
@@ -30,7 +30,7 @@
 #endif
 
 static int llc_find_offset(int state, int ev_type);
-static int llc_conn_send_pdus(struct sock *sk, struct sk_buff *skb);
+static void llc_conn_send_pdus(struct sock *sk);
 static int llc_conn_service(struct sock *sk, struct sk_buff *skb);
 static int llc_exec_conn_trans_actions(struct sock *sk,
 				       struct llc_conn_state_trans *trans,
@@ -193,11 +193,11 @@ int llc_conn_state_process(struct sock *sk, struct sk_buff *skb)
 	return rc;
 }
 
-int llc_conn_send_pdu(struct sock *sk, struct sk_buff *skb)
+void llc_conn_send_pdu(struct sock *sk, struct sk_buff *skb)
 {
 	/* queue PDU to send to MAC layer */
 	skb_queue_tail(&sk->sk_write_queue, skb);
-	return llc_conn_send_pdus(sk, skb);
+	llc_conn_send_pdus(sk);
 }
 
 /**
@@ -255,7 +255,7 @@ void llc_conn_resend_i_pdu_as_cmd(struct sock *sk, u8 nr, u8 first_p_bit)
 	if (howmany_resend > 0)
 		llc->vS = (llc->vS + 1) % LLC_2_SEQ_NBR_MODULO;
 	/* any PDUs to re-send are queued up; start sending to MAC */
-	llc_conn_send_pdus(sk, NULL);
+	llc_conn_send_pdus(sk);
 out:;
 }
 
@@ -296,7 +296,7 @@ void llc_conn_resend_i_pdu_as_rsp(struct sock *sk, u8 nr, u8 first_f_bit)
 	if (howmany_resend > 0)
 		llc->vS = (llc->vS + 1) % LLC_2_SEQ_NBR_MODULO;
 	/* any PDUs to re-send are queued up; start sending to MAC */
-	llc_conn_send_pdus(sk, NULL);
+	llc_conn_send_pdus(sk);
 out:;
 }
 
@@ -340,16 +340,12 @@ int llc_conn_remove_acked_pdus(struct sock *sk, u8 nr, u16 *how_many_unacked)
 /**
  *	llc_conn_send_pdus - Sends queued PDUs
  *	@sk: active connection
- *	@hold_skb: the skb held by caller, or NULL if does not care
  *
- *	Sends queued pdus to MAC layer for transmission. When @hold_skb is
- *	NULL, always return 0. Otherwise, return 0 if @hold_skb is sent
- *	successfully, or 1 for failure.
+ *	Sends queued pdus to MAC layer for transmission.
  */
-static int llc_conn_send_pdus(struct sock *sk, struct sk_buff *hold_skb)
+static void llc_conn_send_pdus(struct sock *sk)
 {
 	struct sk_buff *skb;
-	int ret = 0;
 
 	while ((skb = skb_dequeue(&sk->sk_write_queue)) != NULL) {
 		struct llc_pdu_sn *pdu = llc_pdu_sn_hdr(skb);
@@ -361,20 +357,10 @@ static int llc_conn_send_pdus(struct sock *sk, struct sk_buff *hold_skb)
 			skb_queue_tail(&llc_sk(sk)->pdu_unack_q, skb);
 			if (!skb2)
 				break;
-			dev_queue_xmit(skb2);
-		} else {
-			bool is_target = skb == hold_skb;
-			int rc;
-
-			if (is_target)
-				skb_get(skb);
-			rc = dev_queue_xmit(skb);
-			if (is_target)
-				ret = rc;
+			skb = skb2;
 		}
+		dev_queue_xmit(skb);
 	}
-
-	return ret;
 }
 
 /**
-- 
2.20.1


  parent reply	other threads:[~2019-10-25 13:55 UTC|newest]

Thread overview: 39+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-25 13:54 [PATCH AUTOSEL 5.3 01/33] net: ipv6: fix listify ip6_rcv_finish in case of forwarding Sasha Levin
2019-10-25 13:54 ` [PATCH AUTOSEL 5.3 02/33] sch_netem: fix rcu splat in netem_enqueue() Sasha Levin
2019-10-25 13:54 ` [PATCH AUTOSEL 5.3 03/33] net: sched: sch_sfb: don't call qdisc_put() while holding tree lock Sasha Levin
2019-10-25 13:54 ` [PATCH AUTOSEL 5.3 04/33] rxrpc: Fix call ref leak Sasha Levin
2019-10-25 13:54 ` [PATCH AUTOSEL 5.3 05/33] rxrpc: Fix trace-after-put looking at the put peer record Sasha Levin
2019-10-25 13:54 ` [PATCH AUTOSEL 5.3 06/33] rxrpc: rxrpc_peer needs to hold a ref on the rxrpc_local record Sasha Levin
2019-10-25 13:54 ` [PATCH AUTOSEL 5.3 07/33] llc: fix sk_buff leak in llc_sap_state_process() Sasha Levin
2019-10-25 13:54 ` Sasha Levin [this message]
2019-10-25 13:54 ` [PATCH AUTOSEL 5.3 09/33] NFC: pn533: fix use-after-free and memleaks Sasha Levin
2019-10-25 13:54 ` [PATCH AUTOSEL 5.3 10/33] bonding: fix potential NULL deref in bond_update_slave_arr Sasha Levin
2019-10-25 13:54 ` [PATCH AUTOSEL 5.3 11/33] netfilter: conntrack: avoid possible false sharing Sasha Levin
2019-10-25 13:54 ` [PATCH AUTOSEL 5.3 12/33] blackhole_netdev: fix syzkaller reported issue Sasha Levin
2019-10-25 15:49   ` Sasha Levin
2019-10-25 13:54 ` [PATCH AUTOSEL 5.3 13/33] net: usb: sr9800: fix uninitialized local variable Sasha Levin
2019-10-25 13:54 ` [PATCH AUTOSEL 5.3 14/33] scsi: qla2xxx: Fix different size DMA Alloc/Unmap Sasha Levin
2019-10-25 13:54 ` [PATCH AUTOSEL 5.3 15/33] jbd2: flush_descriptor(): Do not decrease buffer head's ref count Sasha Levin
2019-10-25 13:54 ` [PATCH AUTOSEL 5.3 16/33] netfilter: connlabels: prefer static lock initialiser Sasha Levin
2019-10-25 13:54 ` [PATCH AUTOSEL 5.3 17/33] usb: typec: fusb302: Call fusb302_debugfs_init earlier Sasha Levin
2019-10-25 13:54 ` [PATCH AUTOSEL 5.3 18/33] f2fs: fix to avoid discard command leak Sasha Levin
2019-10-25 13:54   ` [f2fs-dev] " Sasha Levin
2019-10-25 13:54 ` [PATCH AUTOSEL 5.3 19/33] net/rds: Whitelist rdma_cookie and rx_tstamp for usercopy Sasha Levin
2019-10-25 13:54 ` [PATCH AUTOSEL 5.3 20/33] scsi: qedf: Fix crash during sg_reset Sasha Levin
2019-10-25 13:54 ` [PATCH AUTOSEL 5.3 21/33] ath9k: dynack: fix possible deadlock in ath_dynack_node_{de}init Sasha Levin
2019-10-25 13:54 ` [PATCH AUTOSEL 5.3 22/33] Btrfs: fix hang when loading existing inode cache off disk Sasha Levin
2019-10-25 13:54 ` [PATCH AUTOSEL 5.3 23/33] Btrfs: fix inode cache block reserve leak on failure to allocate data space Sasha Levin
2019-10-25 13:54 ` [PATCH AUTOSEL 5.3 24/33] ubi: ubi_wl_get_peb: Increase the number of attempts while getting PEB Sasha Levin
2019-10-25 13:54   ` Sasha Levin
2019-10-25 13:54 ` [PATCH AUTOSEL 5.3 25/33] net: sched: sch_htb: don't call qdisc_put() while holding tree lock Sasha Levin
2019-10-25 13:54 ` [PATCH AUTOSEL 5.3 26/33] net: sched: multiq: " Sasha Levin
2019-10-25 13:54 ` [PATCH AUTOSEL 5.3 27/33] RDMA/siw: Fix serialization issue in write_space() Sasha Levin
2019-10-25 13:55 ` [PATCH AUTOSEL 5.3 28/33] RDMA/iwcm: Fix a lock inversion issue Sasha Levin
2019-10-25 13:55 ` [PATCH AUTOSEL 5.3 29/33] ipv6: Handle race in addrconf_dad_work Sasha Levin
2019-10-25 13:55 ` [PATCH AUTOSEL 5.3 30/33] bdi: Do not use freezable workqueue Sasha Levin
2019-10-25 13:55 ` [PATCH AUTOSEL 5.3 31/33] sctp: add chunks to sk_backlog when the newsk sk_socket is not set Sasha Levin
2019-10-25 13:55   ` Sasha Levin
2019-10-25 13:55 ` [PATCH AUTOSEL 5.3 32/33] ALSA: hda: Add codec on bus address table lately Sasha Levin
2019-10-25 14:09   ` Takashi Iwai
2019-10-25 13:55 ` [PATCH AUTOSEL 5.3 33/33] nvme: Add quirk for Kingston NVME SSD running FW E8FK11.T Sasha Levin
2019-10-25 13:55   ` Sasha Levin

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