[PATCH 3.18 00/13] 3.18.136-stable review

[PATCH 3.18 00/13] 3.18.136-stable review

[Greg Kroah-Hartman]

This is the start of the stable review cycle for the 3.18.136 release.
There are 13 patches in this series, all will be posted as a response
to this one.  If anyone has any issues with these being applied, please
let me know.

Responses should be made by Sat Feb 23 12:52:12 UTC 2019.
Anything received after that time might be too late.

The whole patch series can be found in one patch at:
	https://www.kernel.org/pub/linux/kernel/v3.x/stable-review/patch-3.18.136-rc1.gz
or in the git tree and branch at:
	git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git linux-3.18.y
and the diffstat can be found below.

thanks,

greg k-h

-------------
Pseudo-Shortlog of commits:

Greg Kroah-Hartman <gregkh@linuxfoundation.org>
    Linux 3.18.136-rc1

Eric Dumazet <edumazet@google.com>
    ax25: fix possible use-after-free

Eric Dumazet <edumazet@google.com>
    mISDN: fix a race in dev_expire_timer()

Eric Dumazet <edumazet@google.com>
    net/x25: do not hold the cpu too long in x25_new_lci()

Jann Horn <jannh@google.com>
    kvm: fix kvm_ioctl_create_device() reference counting (CVE-2019-6974)

Wei Yongjun <weiyongjun1@huawei.com>
    hwmon: (lm80) Fix missing unlock on error in set_fan_div()

Lorenzo Bianconi <lorenzo.bianconi@redhat.com>
    net: ipv4: use a dedicated counter for icmp_v4 redirect packets

Jose Abreu <jose.abreu@synopsys.com>
    net: stmmac: Fix a race in EEE enable callback

Paolo Abeni <pabeni@redhat.com>
    vsock: cope with memory allocation failure at socket creation time

Eric Dumazet <edumazet@google.com>
    vxlan: test dev->flags & IFF_UP before calling netif_rx()

Eric Dumazet <edumazet@google.com>
    tcp: clear icsk_backoff in tcp_write_queue_purge()

Eric Dumazet <edumazet@google.com>
    tcp: tcp_v4_err() should be more careful

Kai-Heng Feng <kai.heng.feng@canonical.com>
    sky2: Increase D3 delay again

Zhiqiang Liu <liuzhiqiang26@huawei.com>
    net: fix IPv6 prefix route residue


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

Diffstat:

 Makefile                                           |  4 ++--
 drivers/hwmon/lm80.c                               |  4 +++-
 drivers/isdn/mISDN/timerdev.c                      |  2 +-
 drivers/net/ethernet/marvell/sky2.c                |  2 +-
 .../net/ethernet/stmicro/stmmac/stmmac_ethtool.c   | 22 ++++++++++++----------
 drivers/net/vxlan.c                                | 13 +++++++++++--
 include/net/ax25.h                                 | 12 ++++++++++++
 include/net/inetpeer.h                             |  1 +
 include/net/tcp.h                                  |  1 +
 net/ax25/ax25_ip.c                                 |  4 ++--
 net/ax25/ax25_route.c                              | 19 ++++++++-----------
 net/ipv4/inetpeer.c                                |  1 +
 net/ipv4/route.c                                   |  7 +++++--
 net/ipv4/tcp.c                                     |  1 -
 net/ipv4/tcp_ipv4.c                                |  7 ++++---
 net/ipv6/addrconf.c                                |  3 ++-
 net/vmw_vsock/vmci_transport.c                     |  4 ++++
 net/x25/af_x25.c                                   |  6 ++----
 virt/kvm/kvm_main.c                                |  3 ++-
 19 files changed, 74 insertions(+), 42 deletions(-)

[PATCH 3.18 01/13] net: fix IPv6 prefix route residue

[Greg Kroah-Hartman]

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

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

[ Upstream commit e75913c93f7cd5f338ab373c34c93a655bd309cb ]

Follow those steps:
 # ip addr add 2001:123::1/32 dev eth0
 # ip addr add 2001:123:456::2/64 dev eth0
 # ip addr del 2001:123::1/32 dev eth0
 # ip addr del 2001:123:456::2/64 dev eth0
and then prefix route of 2001:123::1/32 will still exist.

This is because ipv6_prefix_equal in check_cleanup_prefix_route
func does not check whether two IPv6 addresses have the same
prefix length. If the prefix of one address starts with another
shorter address prefix, even though their prefix lengths are
different, the return value of ipv6_prefix_equal is true.

Here I add a check of whether two addresses have the same prefix
to decide whether their prefixes are equal.

Fixes: 5b84efecb7d9 ("ipv6 addrconf: don't cleanup prefix route for IFA_F_NOPREFIXROUTE")
Signed-off-by: Zhiqiang Liu <liuzhiqiang26@huawei.com>
Reported-by: Wenhao Zhang <zhangwenhao8@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 net/ipv6/addrconf.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -949,7 +949,8 @@ check_cleanup_prefix_route(struct inet6_
 	list_for_each_entry(ifa, &idev->addr_list, if_list) {
 		if (ifa == ifp)
 			continue;
-		if (!ipv6_prefix_equal(&ifa->addr, &ifp->addr,
+		if (ifa->prefix_len != ifp->prefix_len ||
+		    !ipv6_prefix_equal(&ifa->addr, &ifp->addr,
 				       ifp->prefix_len))
 			continue;
 		if (ifa->flags & (IFA_F_PERMANENT | IFA_F_NOPREFIXROUTE))

[PATCH 3.18 02/13] sky2: Increase D3 delay again

[Greg Kroah-Hartman]

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

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

From: Kai-Heng Feng <kai.heng.feng@canonical.com>

[ Upstream commit 1765f5dcd00963e33f1b8a4e0f34061fbc0e2f7f ]

Another platform requires even longer delay to make the device work
correctly after S3.

So increase the delay to 300ms.

BugLink: https://bugs.launchpad.net/bugs/1798921

Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/net/ethernet/marvell/sky2.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/net/ethernet/marvell/sky2.c
+++ b/drivers/net/ethernet/marvell/sky2.c
@@ -5069,7 +5069,7 @@ static int sky2_probe(struct pci_dev *pd
 	INIT_WORK(&hw->restart_work, sky2_restart);
 
 	pci_set_drvdata(pdev, hw);
-	pdev->d3_delay = 200;
+	pdev->d3_delay = 300;
 
 	return 0;
 

[PATCH 3.18 03/13] tcp: tcp_v4_err() should be more careful

[Greg Kroah-Hartman]

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

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

From: Eric Dumazet <edumazet@google.com>

[ Upstream commit 2c4cc9712364c051b1de2d175d5fbea6be948ebf ]

ICMP handlers are not very often stressed, we should
make them more resilient to bugs that might surface in
the future.

If there is no packet in retransmit queue, we should
avoid a NULL deref.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: soukjin bae <soukjin.bae@samsung.com>
Acked-by: Neal Cardwell <ncardwell@google.com>
Acked-by: Soheil Hassas Yeganeh <soheil@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 net/ipv4/tcp_ipv4.c |    7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -432,14 +432,15 @@ void tcp_v4_err(struct sk_buff *icmp_skb
 		if (sock_owned_by_user(sk))
 			break;
 
+		skb = tcp_write_queue_head(sk);
+		if (WARN_ON_ONCE(!skb))
+			break;
+
 		icsk->icsk_backoff--;
 		icsk->icsk_rto = tp->srtt_us ? __tcp_set_rto(tp) :
 					       TCP_TIMEOUT_INIT;
 		icsk->icsk_rto = inet_csk_rto_backoff(icsk, TCP_RTO_MAX);
 
-		skb = tcp_write_queue_head(sk);
-		BUG_ON(!skb);
-
 		remaining = icsk->icsk_rto -
 			    min(icsk->icsk_rto,
 				tcp_time_stamp - tcp_skb_timestamp(skb));

[PATCH 3.18 04/13] tcp: clear icsk_backoff in tcp_write_queue_purge()

[Greg Kroah-Hartman]

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

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

From: Eric Dumazet <edumazet@google.com>

[ Upstream commit 04c03114be82194d4a4858d41dba8e286ad1787c ]

soukjin bae reported a crash in tcp_v4_err() handling
ICMP_DEST_UNREACH after tcp_write_queue_head(sk)
returned a NULL pointer.

Current logic should have prevented this :

  if (seq != tp->snd_una  || !icsk->icsk_retransmits ||
      !icsk->icsk_backoff || fastopen)
      break;

Problem is the write queue might have been purged
and icsk_backoff has not been cleared.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: soukjin bae <soukjin.bae@samsung.com>
Acked-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 include/net/tcp.h |    1 +
 net/ipv4/tcp.c    |    1 -
 2 files changed, 1 insertion(+), 1 deletion(-)

--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -1379,6 +1379,7 @@ static inline void tcp_write_queue_purge
 		sk_wmem_free_skb(sk, skb);
 	sk_mem_reclaim(sk);
 	tcp_clear_all_retrans_hints(tcp_sk(sk));
+	inet_csk(sk)->icsk_backoff = 0;
 }
 
 static inline struct sk_buff *tcp_write_queue_head(const struct sock *sk)
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -2258,7 +2258,6 @@ int tcp_disconnect(struct sock *sk, int
 	tp->srtt_us = 0;
 	if ((tp->write_seq += tp->max_window + 2) == 0)
 		tp->write_seq = 1;
-	icsk->icsk_backoff = 0;
 	tp->snd_cwnd = 2;
 	icsk->icsk_probes_out = 0;
 	tp->packets_out = 0;

[PATCH 3.18 05/13] vxlan: test dev->flags & IFF_UP before calling netif_rx()

[Greg Kroah-Hartman]

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

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

From: Eric Dumazet <edumazet@google.com>

[ Upstream commit 4179cb5a4c924cd233eaadd081882425bc98f44e ]

netif_rx() must be called under a strict contract.

At device dismantle phase, core networking clears IFF_UP
and flush_all_backlogs() is called after rcu grace period
to make sure no incoming packet might be in a cpu backlog
and still referencing the device.

Most drivers call netif_rx() from their interrupt handler,
and since the interrupts are disabled at device dismantle,
netif_rx() does not have to check dev->flags & IFF_UP

Virtual drivers do not have this guarantee, and must
therefore make the check themselves.

Otherwise we risk use-after-free and/or crashes.

Note this patch also fixes a small issue that came
with commit ce6502a8f957 ("vxlan: fix a use after free
in vxlan_encap_bypass"), since the dev->stats.rx_dropped
change was done on the wrong device.

Fixes: d342894c5d2f ("vxlan: virtual extensible lan")
Fixes: ce6502a8f957 ("vxlan: fix a use after free in vxlan_encap_bypass")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Petr Machata <petrm@mellanox.com>
Cc: Ido Schimmel <idosch@mellanox.com>
Cc: Roopa Prabhu <roopa@cumulusnetworks.com>
Cc: Stefano Brivio <sbrivio@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/net/vxlan.c |   13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

--- a/drivers/net/vxlan.c
+++ b/drivers/net/vxlan.c
@@ -1665,7 +1665,7 @@ static void vxlan_encap_bypass(struct sk
 	struct pcpu_sw_netstats *tx_stats, *rx_stats;
 	union vxlan_addr loopback;
 	union vxlan_addr *remote_ip = &dst_vxlan->default_dst.remote_ip;
-	struct net_device *dev = skb->dev;
+	struct net_device *dev;
 	int len = skb->len;
 
 	tx_stats = this_cpu_ptr(src_vxlan->dev->tstats);
@@ -1685,8 +1685,15 @@ static void vxlan_encap_bypass(struct sk
 #endif
 	}
 
+	rcu_read_lock();
+	dev = skb->dev;
+	if (unlikely(!(dev->flags & IFF_UP))) {
+		kfree_skb(skb);
+		goto drop;
+	}
+
 	if (dst_vxlan->flags & VXLAN_F_LEARN)
-		vxlan_snoop(skb->dev, &loopback, eth_hdr(skb)->h_source);
+		vxlan_snoop(dev, &loopback, eth_hdr(skb)->h_source);
 
 	u64_stats_update_begin(&tx_stats->syncp);
 	tx_stats->tx_packets++;
@@ -1699,8 +1706,10 @@ static void vxlan_encap_bypass(struct sk
 		rx_stats->rx_bytes += len;
 		u64_stats_update_end(&rx_stats->syncp);
 	} else {
+drop:
 		dev->stats.rx_dropped++;
 	}
+	rcu_read_unlock();
 }
 
 static void vxlan_xmit_one(struct sk_buff *skb, struct net_device *dev,

[PATCH 3.18 06/13] vsock: cope with memory allocation failure at socket creation time

[Greg Kroah-Hartman]

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

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

From: Paolo Abeni <pabeni@redhat.com>

[ Upstream commit 225d9464268599a5b4d094d02ec17808e44c7553 ]

In the unlikely event that the kmalloc call in vmci_transport_socket_init()
fails, we end-up calling vmci_transport_destruct() with a NULL vmci_trans()
and oopsing.

This change addresses the above explicitly checking for zero vmci_trans()
at destruction time.

Reported-by: Xiumei Mu <xmu@redhat.com>
Fixes: d021c344051a ("VSOCK: Introduce VM Sockets")
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Reviewed-by: Jorgen Hansen <jhansen@vmware.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 net/vmw_vsock/vmci_transport.c |    4 ++++
 1 file changed, 4 insertions(+)

--- a/net/vmw_vsock/vmci_transport.c
+++ b/net/vmw_vsock/vmci_transport.c
@@ -1663,6 +1663,10 @@ static int vmci_transport_socket_init(st
 
 static void vmci_transport_destruct(struct vsock_sock *vsk)
 {
+	/* transport can be NULL if we hit a failure at init() time */
+	if (!vmci_trans(vsk))
+		return;
+
 	if (vmci_trans(vsk)->attach_sub_id != VMCI_INVALID_ID) {
 		vmci_event_unsubscribe(vmci_trans(vsk)->attach_sub_id);
 		vmci_trans(vsk)->attach_sub_id = VMCI_INVALID_ID;

[PATCH 3.18 07/13] net: stmmac: Fix a race in EEE enable callback

[Greg Kroah-Hartman]

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

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

From: Jose Abreu <jose.abreu@synopsys.com>

[ Upstream commit 8a7493e58ad688eb23b81e45461c5d314f4402f1 ]

We are saving the status of EEE even before we try to enable it. This
leads to a race with XMIT function that tries to arm EEE timer before we
set it up.

Fix this by only saving the EEE parameters after all operations are
performed with success.

Signed-off-by: Jose Abreu <joabreu@synopsys.com>
Fixes: d765955d2ae0 ("stmmac: add the Energy Efficient Ethernet support")
Cc: Joao Pinto <jpinto@synopsys.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Giuseppe Cavallaro <peppe.cavallaro@st.com>
Cc: Alexandre Torgue <alexandre.torgue@st.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/net/ethernet/stmicro/stmmac/stmmac_ethtool.c |   22 ++++++++++---------
 1 file changed, 12 insertions(+), 10 deletions(-)

--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_ethtool.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_ethtool.c
@@ -614,25 +614,27 @@ static int stmmac_ethtool_op_set_eee(str
 				     struct ethtool_eee *edata)
 {
 	struct stmmac_priv *priv = netdev_priv(dev);
+	int ret;
 
-	priv->eee_enabled = edata->eee_enabled;
-
-	if (!priv->eee_enabled)
+	if (!edata->eee_enabled) {
 		stmmac_disable_eee_mode(priv);
-	else {
+	} else {
 		/* We are asking for enabling the EEE but it is safe
 		 * to verify all by invoking the eee_init function.
 		 * In case of failure it will return an error.
 		 */
-		priv->eee_enabled = stmmac_eee_init(priv);
-		if (!priv->eee_enabled)
+		edata->eee_enabled = stmmac_eee_init(priv);
+		if (!edata->eee_enabled)
 			return -EOPNOTSUPP;
-
-		/* Do not change tx_lpi_timer in case of failure */
-		priv->tx_lpi_timer = edata->tx_lpi_timer;
 	}
 
-	return phy_ethtool_set_eee(priv->phydev, edata);
+	ret = phy_ethtool_set_eee(dev->phydev, edata);
+	if (ret)
+		return ret;
+
+	priv->eee_enabled = edata->eee_enabled;
+	priv->tx_lpi_timer = edata->tx_lpi_timer;
+	return 0;
 }
 
 static u32 stmmac_usec2riwt(u32 usec, struct stmmac_priv *priv)

[PATCH 3.18 08/13] net: ipv4: use a dedicated counter for icmp_v4 redirect packets

[Greg Kroah-Hartman]

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

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

From: Lorenzo Bianconi <lorenzo.bianconi@redhat.com>

[ Upstream commit c09551c6ff7fe16a79a42133bcecba5fc2fc3291 ]

According to the algorithm described in the comment block at the
beginning of ip_rt_send_redirect, the host should try to send
'ip_rt_redirect_number' ICMP redirect packets with an exponential
backoff and then stop sending them at all assuming that the destination
ignores redirects.
If the device has previously sent some ICMP error packets that are
rate-limited (e.g TTL expired) and continues to receive traffic,
the redirect packets will never be transmitted. This happens since
peer->rate_tokens will be typically greater than 'ip_rt_redirect_number'
and so it will never be reset even if the redirect silence timeout
(ip_rt_redirect_silence) has elapsed without receiving any packet
requiring redirects.

Fix it by using a dedicated counter for the number of ICMP redirect
packets that has been sent by the host

I have not been able to identify a given commit that introduced the
issue since ip_rt_send_redirect implements the same rate-limiting
algorithm from commit 1da177e4c3f4 ("Linux-2.6.12-rc2")

Signed-off-by: Lorenzo Bianconi <lorenzo.bianconi@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 include/net/inetpeer.h |    1 +
 net/ipv4/inetpeer.c    |    1 +
 net/ipv4/route.c       |    7 +++++--
 3 files changed, 7 insertions(+), 2 deletions(-)

--- a/include/net/inetpeer.h
+++ b/include/net/inetpeer.h
@@ -35,6 +35,7 @@ struct inet_peer {
 
 	u32			metrics[RTAX_MAX];
 	u32			rate_tokens;	/* rate limiting for ICMP */
+	u32			n_redirects;
 	unsigned long		rate_last;
 	union {
 		struct list_head	gc_list;
--- a/net/ipv4/inetpeer.c
+++ b/net/ipv4/inetpeer.c
@@ -464,6 +464,7 @@ relookup:
 		atomic_set(&p->rid, 0);
 		p->metrics[RTAX_LOCK-1] = INETPEER_METRICS_NEW;
 		p->rate_tokens = 0;
+		p->n_redirects = 0;
 		/* 60*HZ is arbitrary, but chosen enough high so that the first
 		 * calculation of tokens is at its maximum.
 		 */
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -864,13 +864,15 @@ void ip_rt_send_redirect(struct sk_buff
 	/* No redirected packets during ip_rt_redirect_silence;
 	 * reset the algorithm.
 	 */
-	if (time_after(jiffies, peer->rate_last + ip_rt_redirect_silence))
+	if (time_after(jiffies, peer->rate_last + ip_rt_redirect_silence)) {
 		peer->rate_tokens = 0;
+		peer->n_redirects = 0;
+	}
 
 	/* Too many ignored redirects; do not send anything
 	 * set dst.rate_last to the last seen redirected packet.
 	 */
-	if (peer->rate_tokens >= ip_rt_redirect_number) {
+	if (peer->n_redirects >= ip_rt_redirect_number) {
 		peer->rate_last = jiffies;
 		goto out_put_peer;
 	}
@@ -887,6 +889,7 @@ void ip_rt_send_redirect(struct sk_buff
 		icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST, gw);
 		peer->rate_last = jiffies;
 		++peer->rate_tokens;
+		++peer->n_redirects;
 #ifdef CONFIG_IP_ROUTE_VERBOSE
 		if (log_martians &&
 		    peer->rate_tokens == ip_rt_redirect_number)

[PATCH 3.18 09/13] hwmon: (lm80) Fix missing unlock on error in set_fan_div()

[Greg Kroah-Hartman]

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

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

From: Wei Yongjun <weiyongjun1@huawei.com>

commit 07bd14ccc3049f9c0147a91a4227a571f981601a upstream.

Add the missing unlock before return from function set_fan_div()
in the error handling case.

Fixes: c9c63915519b ("hwmon: (lm80) fix a missing check of the status of SMBus read")
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/hwmon/lm80.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

--- a/drivers/hwmon/lm80.c
+++ b/drivers/hwmon/lm80.c
@@ -393,8 +393,10 @@ static ssize_t set_fan_div(struct device
 	}
 
 	rv = lm80_read_value(client, LM80_REG_FANDIV);
-	if (rv < 0)
+	if (rv < 0) {
+		mutex_unlock(&data->update_lock);
 		return rv;
+	}
 	reg = (rv & ~(3 << (2 * (nr + 1))))
 	    | (data->fan_div[nr] << (2 * (nr + 1)));
 	lm80_write_value(client, LM80_REG_FANDIV, reg);

[PATCH 3.18 10/13] kvm: fix kvm_ioctl_create_device() reference counting (CVE-2019-6974)

[Greg Kroah-Hartman]

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

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

From: Jann Horn <jannh@google.com>

commit cfa39381173d5f969daf43582c95ad679189cbc9 upstream.

kvm_ioctl_create_device() does the following:

1. creates a device that holds a reference to the VM object (with a borrowed
   reference, the VM's refcount has not been bumped yet)
2. initializes the device
3. transfers the reference to the device to the caller's file descriptor table
4. calls kvm_get_kvm() to turn the borrowed reference to the VM into a real
   reference

The ownership transfer in step 3 must not happen before the reference to the VM
becomes a proper, non-borrowed reference, which only happens in step 4.
After step 3, an attacker can close the file descriptor and drop the borrowed
reference, which can cause the refcount of the kvm object to drop to zero.

This means that we need to grab a reference for the device before
anon_inode_getfd(), otherwise the VM can disappear from under us.

Fixes: 852b6d57dc7f ("kvm: add device control API")
Cc: stable@kernel.org
Signed-off-by: Jann Horn <jannh@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 virt/kvm/kvm_main.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -2398,14 +2398,15 @@ static int kvm_ioctl_create_device(struc
 		return ret;
 	}
 
+	kvm_get_kvm(kvm);
 	ret = anon_inode_getfd(ops->name, &kvm_device_fops, dev, O_RDWR | O_CLOEXEC);
 	if (ret < 0) {
+		kvm_put_kvm(kvm);
 		ops->destroy(dev);
 		return ret;
 	}
 
 	list_add(&dev->vm_node, &kvm->devices);
-	kvm_get_kvm(kvm);
 	cd->fd = ret;
 	return 0;
 }

[PATCH 3.18 11/13] net/x25: do not hold the cpu too long in x25_new_lci()

[Greg Kroah-Hartman]

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

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

From: Eric Dumazet <edumazet@google.com>

commit cf657d22ee1f0e887326a92169f2e28dc932fd10 upstream.

Due to quadratic behavior of x25_new_lci(), syzbot was able
to trigger an rcu stall.

Fix this by not blocking BH for the whole duration of
the function, and inserting a reschedule point when possible.

If we care enough, using a bitmap could get rid of the quadratic
behavior.

syzbot report :

rcu: INFO: rcu_preempt self-detected stall on CPU
rcu:    0-...!: (10500 ticks this GP) idle=4fa/1/0x4000000000000002 softirq=283376/283376 fqs=0
rcu:     (t=10501 jiffies g=383105 q=136)
rcu: rcu_preempt kthread starved for 10502 jiffies! g383105 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->cpu=0
rcu: RCU grace-period kthread stack dump:
rcu_preempt     I28928    10      2 0x80000000
Call Trace:
 context_switch kernel/sched/core.c:2844 [inline]
 __schedule+0x817/0x1cc0 kernel/sched/core.c:3485
 schedule+0x92/0x180 kernel/sched/core.c:3529
 schedule_timeout+0x4db/0xfd0 kernel/time/timer.c:1803
 rcu_gp_fqs_loop kernel/rcu/tree.c:1948 [inline]
 rcu_gp_kthread+0x956/0x17a0 kernel/rcu/tree.c:2105
 kthread+0x357/0x430 kernel/kthread.c:246
 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352
NMI backtrace for cpu 0
CPU: 0 PID: 8759 Comm: syz-executor2 Not tainted 5.0.0-rc4+ #51
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x172/0x1f0 lib/dump_stack.c:113
 nmi_cpu_backtrace.cold+0x63/0xa4 lib/nmi_backtrace.c:101
 nmi_trigger_cpumask_backtrace+0x1be/0x236 lib/nmi_backtrace.c:62
 arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38
 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline]
 rcu_dump_cpu_stacks+0x183/0x1cf kernel/rcu/tree.c:1211
 print_cpu_stall kernel/rcu/tree.c:1348 [inline]
 check_cpu_stall kernel/rcu/tree.c:1422 [inline]
 rcu_pending kernel/rcu/tree.c:3018 [inline]
 rcu_check_callbacks.cold+0x500/0xa4a kernel/rcu/tree.c:2521
 update_process_times+0x32/0x80 kernel/time/timer.c:1635
 tick_sched_handle+0xa2/0x190 kernel/time/tick-sched.c:161
 tick_sched_timer+0x47/0x130 kernel/time/tick-sched.c:1271
 __run_hrtimer kernel/time/hrtimer.c:1389 [inline]
 __hrtimer_run_queues+0x33e/0xde0 kernel/time/hrtimer.c:1451
 hrtimer_interrupt+0x314/0x770 kernel/time/hrtimer.c:1509
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1035 [inline]
 smp_apic_timer_interrupt+0x120/0x570 arch/x86/kernel/apic/apic.c:1060
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:807
 </IRQ>
RIP: 0010:__read_once_size include/linux/compiler.h:193 [inline]
RIP: 0010:queued_write_lock_slowpath+0x13e/0x290 kernel/locking/qrwlock.c:86
Code: 00 00 fc ff df 4c 8d 2c 01 41 83 c7 03 41 0f b6 45 00 41 38 c7 7c 08 84 c0 0f 85 0c 01 00 00 8b 03 3d 00 01 00 00 74 1a f3 90 <41> 0f b6 55 00 41 38 d7 7c eb 84 d2 74 e7 48 89 df e8 6c 0f 4f 00
RSP: 0018:ffff88805f117bd8 EFLAGS: 00000206 ORIG_RAX: ffffffffffffff13
RAX: 0000000000000300 RBX: ffffffff89413ba0 RCX: 1ffffffff1282774
RDX: 0000000000000000 RSI: 0000000000000004 RDI: ffffffff89413ba0
RBP: ffff88805f117c70 R08: 1ffffffff1282774 R09: fffffbfff1282775
R10: fffffbfff1282774 R11: ffffffff89413ba3 R12: 00000000000000ff
R13: fffffbfff1282774 R14: 1ffff1100be22f7d R15: 0000000000000003
 queued_write_lock include/asm-generic/qrwlock.h:104 [inline]
 do_raw_write_lock+0x1d6/0x290 kernel/locking/spinlock_debug.c:203
 __raw_write_lock_bh include/linux/rwlock_api_smp.h:204 [inline]
 _raw_write_lock_bh+0x3b/0x50 kernel/locking/spinlock.c:312
 x25_insert_socket+0x21/0xe0 net/x25/af_x25.c:267
 x25_bind+0x273/0x340 net/x25/af_x25.c:705
 __sys_bind+0x23f/0x290 net/socket.c:1505
 __do_sys_bind net/socket.c:1516 [inline]
 __se_sys_bind net/socket.c:1514 [inline]
 __x64_sys_bind+0x73/0xb0 net/socket.c:1514
 do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x457e39
Code: ad b8 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 7b b8 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fafccd0dc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000031
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000457e39
RDX: 0000000000000012 RSI: 0000000020000240 RDI: 0000000000000004
RBP: 000000000073bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fafccd0e6d4
R13: 00000000004bdf8b R14: 00000000004ce4b8 R15: 00000000ffffffff
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 8752 Comm: syz-executor4 Not tainted 5.0.0-rc4+ #51
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:__x25_find_socket+0x78/0x120 net/x25/af_x25.c:328
Code: 89 f8 48 c1 e8 03 80 3c 18 00 0f 85 a6 00 00 00 4d 8b 64 24 68 4d 85 e4 74 7f e8 03 97 3d fb 49 83 ec 68 74 74 e8 f8 96 3d fb <49> 8d bc 24 88 04 00 00 48 89 f8 48 c1 e8 03 0f b6 04 18 84 c0 74
RSP: 0018:ffff8880639efc58 EFLAGS: 00000246
RAX: 0000000000040000 RBX: dffffc0000000000 RCX: ffffc9000e677000
RDX: 0000000000040000 RSI: ffffffff863244b8 RDI: ffff88806a764628
RBP: ffff8880639efc80 R08: ffff8880a80d05c0 R09: fffffbfff1282775
R10: fffffbfff1282774 R11: ffffffff89413ba3 R12: ffff88806a7645c0
R13: 0000000000000001 R14: ffff88809f29ac00 R15: 0000000000000000
FS:  00007fe8d0c58700(0000) GS:ffff8880ae900000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b32823000 CR3: 00000000672eb000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 x25_new_lci net/x25/af_x25.c:357 [inline]
 x25_connect+0x374/0xdf0 net/x25/af_x25.c:786
 __sys_connect+0x266/0x330 net/socket.c:1686
 __do_sys_connect net/socket.c:1697 [inline]
 __se_sys_connect net/socket.c:1694 [inline]
 __x64_sys_connect+0x73/0xb0 net/socket.c:1694
 do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x457e39
Code: ad b8 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 7b b8 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fe8d0c57c78 EFLAGS: 00000246 ORIG_RAX: 000000000000002a
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000457e39
RDX: 0000000000000012 RSI: 0000000020000200 RDI: 0000000000000004
RBP: 000000000073bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fe8d0c586d4
R13: 00000000004be378 R14: 00000000004ceb00 R15: 00000000ffffffff

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Cc: Andrew Hendry <andrew.hendry@gmail.com>
Cc: linux-x25@vger.kernel.org
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 net/x25/af_x25.c |    6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

--- a/net/x25/af_x25.c
+++ b/net/x25/af_x25.c
@@ -352,17 +352,15 @@ static unsigned int x25_new_lci(struct x
 	unsigned int lci = 1;
 	struct sock *sk;
 
-	read_lock_bh(&x25_list_lock);
-
-	while ((sk = __x25_find_socket(lci, nb)) != NULL) {
+	while ((sk = x25_find_socket(lci, nb)) != NULL) {
 		sock_put(sk);
 		if (++lci == 4096) {
 			lci = 0;
 			break;
 		}
+		cond_resched();
 	}
 
-	read_unlock_bh(&x25_list_lock);
 	return lci;
 }
 

[PATCH 3.18 12/13] mISDN: fix a race in dev_expire_timer()

[Greg Kroah-Hartman]

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

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

From: Eric Dumazet <edumazet@google.com>

commit bdcc5bc25548ef6b08e2e43937148f907c212292 upstream.

Since mISDN_close() uses dev->pending to iterate over active
timers, there is a chance that one timer got removed from the
->pending list in dev_expire_timer() but that the thread
has not called yet wake_up_interruptible()

So mISDN_close() could miss this and free dev before
completion of at least one dev_expire_timer()

syzbot was able to catch this race :

BUG: KASAN: use-after-free in register_lock_class+0x140c/0x1bf0 kernel/locking/lockdep.c:827
Write of size 8 at addr ffff88809fc18948 by task syz-executor1/24769

CPU: 1 PID: 24769 Comm: syz-executor1 Not tainted 5.0.0-rc5 #60
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x172/0x1f0 lib/dump_stack.c:113
 print_address_description.cold+0x7c/0x20d mm/kasan/report.c:187
 kasan_report.cold+0x1b/0x40 mm/kasan/report.c:317
 __asan_report_store8_noabort+0x17/0x20 mm/kasan/generic_report.c:140
 register_lock_class+0x140c/0x1bf0 kernel/locking/lockdep.c:827
 __lock_acquire+0x11f/0x4700 kernel/locking/lockdep.c:3224
 lock_acquire+0x16f/0x3f0 kernel/locking/lockdep.c:3841
 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
 _raw_spin_lock_irqsave+0x95/0xcd kernel/locking/spinlock.c:152
 __wake_up_common_lock+0xc7/0x190 kernel/sched/wait.c:120
 __wake_up+0xe/0x10 kernel/sched/wait.c:145
 dev_expire_timer+0xe4/0x3b0 drivers/isdn/mISDN/timerdev.c:174
 call_timer_fn+0x190/0x720 kernel/time/timer.c:1325
protocol 88fb is buggy, dev hsr_slave_0
protocol 88fb is buggy, dev hsr_slave_1
 expire_timers kernel/time/timer.c:1362 [inline]
 __run_timers kernel/time/timer.c:1681 [inline]
 __run_timers kernel/time/timer.c:1649 [inline]
 run_timer_softirq+0x652/0x1700 kernel/time/timer.c:1694
 __do_softirq+0x266/0x95a kernel/softirq.c:292
 invoke_softirq kernel/softirq.c:373 [inline]
 irq_exit+0x180/0x1d0 kernel/softirq.c:413
 exiting_irq arch/x86/include/asm/apic.h:536 [inline]
 smp_apic_timer_interrupt+0x14a/0x570 arch/x86/kernel/apic/apic.c:1062
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:807
 </IRQ>
RIP: 0010:__sanitizer_cov_trace_pc+0x26/0x50 kernel/kcov.c:101
Code: 90 90 90 90 55 48 89 e5 48 8b 75 08 65 48 8b 04 25 40 ee 01 00 65 8b 15 98 12 92 7e 81 e2 00 01 1f 00 75 2b 8b 90 d8 12 00 00 <83> fa 02 75 20 48 8b 88 e0 12 00 00 8b 80 dc 12 00 00 48 8b 11 48
RSP: 0018:ffff8880589b7a60 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13
RAX: ffff888087ce25c0 RBX: 0000000000000001 RCX: ffffffff818f8ca3
RDX: 0000000000000000 RSI: ffffffff818f8b48 RDI: 0000000000000001
RBP: ffff8880589b7a60 R08: ffff888087ce25c0 R09: ffffed1015d25bd0
R10: ffffed1015d25bcf R11: ffff8880ae92de7b R12: ffffea0001ae4680
R13: ffffea0001ae4688 R14: 0000000000000000 R15: ffffea0001b41648
 PageIdle include/linux/page-flags.h:398 [inline]
 page_is_idle include/linux/page_idle.h:29 [inline]
 mark_page_accessed+0x618/0x1140 mm/swap.c:398
 touch_buffer fs/buffer.c:59 [inline]
 __find_get_block+0x312/0xcc0 fs/buffer.c:1298
 sb_find_get_block include/linux/buffer_head.h:338 [inline]
 recently_deleted fs/ext4/ialloc.c:682 [inline]
 find_inode_bit.isra.0+0x202/0x510 fs/ext4/ialloc.c:722
 __ext4_new_inode+0x14ad/0x52c0 fs/ext4/ialloc.c:914
 ext4_symlink+0x3f8/0xbe0 fs/ext4/namei.c:3096
 vfs_symlink fs/namei.c:4126 [inline]
 vfs_symlink+0x378/0x5d0 fs/namei.c:4112
 do_symlinkat+0x22b/0x290 fs/namei.c:4153
 __do_sys_symlink fs/namei.c:4172 [inline]
 __se_sys_symlink fs/namei.c:4170 [inline]
 __x64_sys_symlink+0x59/0x80 fs/namei.c:4170
 do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x457b67
Code: 0f 1f 00 b8 5c 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 6d bb fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 b8 58 00 00 00 0f 05 <48> 3d 01 f0 ff ff 0f 83 4d bb fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fff045ce0f8 EFLAGS: 00000202 ORIG_RAX: 0000000000000058
RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 0000000000457b67
RDX: 00007fff045ce173 RSI: 00000000004bd63f RDI: 00007fff045ce160
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000013
R10: 0000000000000075 R11: 0000000000000202 R12: 0000000000000000
R13: 0000000000000001 R14: 000000000000029b R15: 0000000000000001

Allocated by task 24763:
 save_stack+0x45/0xd0 mm/kasan/common.c:73
 set_track mm/kasan/common.c:85 [inline]
 __kasan_kmalloc mm/kasan/common.c:496 [inline]
 __kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:469
 kasan_kmalloc+0x9/0x10 mm/kasan/common.c:504
 kmem_cache_alloc_trace+0x151/0x760 mm/slab.c:3609
 kmalloc include/linux/slab.h:545 [inline]
 mISDN_open+0x9a/0x270 drivers/isdn/mISDN/timerdev.c:59
 misc_open+0x398/0x4c0 drivers/char/misc.c:141
 chrdev_open+0x247/0x6b0 fs/char_dev.c:417
 do_dentry_open+0x47d/0x1130 fs/open.c:771
 vfs_open+0xa0/0xd0 fs/open.c:880
 do_last fs/namei.c:3418 [inline]
 path_openat+0x10d7/0x4690 fs/namei.c:3534
 do_filp_open+0x1a1/0x280 fs/namei.c:3564
 do_sys_open+0x3fe/0x5d0 fs/open.c:1063
 __do_sys_openat fs/open.c:1090 [inline]
 __se_sys_openat fs/open.c:1084 [inline]
 __x64_sys_openat+0x9d/0x100 fs/open.c:1084
 do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 24762:
 save_stack+0x45/0xd0 mm/kasan/common.c:73
 set_track mm/kasan/common.c:85 [inline]
 __kasan_slab_free+0x102/0x150 mm/kasan/common.c:458
 kasan_slab_free+0xe/0x10 mm/kasan/common.c:466
 __cache_free mm/slab.c:3487 [inline]
 kfree+0xcf/0x230 mm/slab.c:3806
 mISDN_close+0x2a1/0x390 drivers/isdn/mISDN/timerdev.c:97
 __fput+0x2df/0x8d0 fs/file_table.c:278
 ____fput+0x16/0x20 fs/file_table.c:309
 task_work_run+0x14a/0x1c0 kernel/task_work.c:113
 tracehook_notify_resume include/linux/tracehook.h:188 [inline]
 exit_to_usermode_loop+0x273/0x2c0 arch/x86/entry/common.c:166
 prepare_exit_to_usermode arch/x86/entry/common.c:197 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:268 [inline]
 do_syscall_64+0x52d/0x610 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

The buggy address belongs to the object at ffff88809fc18900
 which belongs to the cache kmalloc-192 of size 192
The buggy address is located 72 bytes inside of
 192-byte region [ffff88809fc18900, ffff88809fc189c0)
The buggy address belongs to the page:
page:ffffea00027f0600 count:1 mapcount:0 mapping:ffff88812c3f0040 index:0xffff88809fc18000
flags: 0x1fffc0000000200(slab)
raw: 01fffc0000000200 ffffea000269f648 ffffea00029f7408 ffff88812c3f0040
raw: ffff88809fc18000 ffff88809fc18000 000000010000000b 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88809fc18800: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88809fc18880: 00 fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88809fc18900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                              ^
 ffff88809fc18980: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
 ffff88809fc18a00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00

Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Karsten Keil <isdn@linux-pingi.de>
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/isdn/mISDN/timerdev.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/isdn/mISDN/timerdev.c
+++ b/drivers/isdn/mISDN/timerdev.c
@@ -168,8 +168,8 @@ dev_expire_timer(unsigned long data)
 	spin_lock_irqsave(&timer->dev->lock, flags);
 	if (timer->id >= 0)
 		list_move_tail(&timer->list, &timer->dev->expired);
-	spin_unlock_irqrestore(&timer->dev->lock, flags);
 	wake_up_interruptible(&timer->dev->wait);
+	spin_unlock_irqrestore(&timer->dev->lock, flags);
 }
 
 static int

[PATCH 3.18 13/13] ax25: fix possible use-after-free

[Greg Kroah-Hartman]

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

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

From: Eric Dumazet <edumazet@google.com>

commit 63530aba7826a0f8e129874df9c4d264f9db3f9e upstream.

syzbot found that ax25 routes where not properly protected
against concurrent use [1].

In this particular report the bug happened while
copying ax25->digipeat.

Fix this problem by making sure we call ax25_get_route()
while ax25_route_lock is held, so that no modification
could happen while using the route.

The current two ax25_get_route() callers do not sleep,
so this change should be fine.

Once we do that, ax25_get_route() no longer needs to
grab a reference on the found route.

[1]
ax25_connect(): syz-executor0 uses autobind, please contact jreuter@yaina.de
BUG: KASAN: use-after-free in memcpy include/linux/string.h:352 [inline]
BUG: KASAN: use-after-free in kmemdup+0x42/0x60 mm/util.c:113
Read of size 66 at addr ffff888066641a80 by task syz-executor2/531

ax25_connect(): syz-executor0 uses autobind, please contact jreuter@yaina.de
CPU: 1 PID: 531 Comm: syz-executor2 Not tainted 5.0.0-rc2+ #10
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x1db/0x2d0 lib/dump_stack.c:113
 print_address_description.cold+0x7c/0x20d mm/kasan/report.c:187
 kasan_report.cold+0x1b/0x40 mm/kasan/report.c:317
 check_memory_region_inline mm/kasan/generic.c:185 [inline]
 check_memory_region+0x123/0x190 mm/kasan/generic.c:191
 memcpy+0x24/0x50 mm/kasan/common.c:130
 memcpy include/linux/string.h:352 [inline]
 kmemdup+0x42/0x60 mm/util.c:113
 kmemdup include/linux/string.h:425 [inline]
 ax25_rt_autobind+0x25d/0x750 net/ax25/ax25_route.c:424
 ax25_connect.cold+0x30/0xa4 net/ax25/af_ax25.c:1224
 __sys_connect+0x357/0x490 net/socket.c:1664
 __do_sys_connect net/socket.c:1675 [inline]
 __se_sys_connect net/socket.c:1672 [inline]
 __x64_sys_connect+0x73/0xb0 net/socket.c:1672
 do_syscall_64+0x1a3/0x800 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x458099
Code: 6d b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 3b b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f870ee22c78 EFLAGS: 00000246 ORIG_RAX: 000000000000002a
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000458099
RDX: 0000000000000048 RSI: 0000000020000080 RDI: 0000000000000005
RBP: 000000000073bf00 R08: 0000000000000000 R09: 0000000000000000
ax25_connect(): syz-executor4 uses autobind, please contact jreuter@yaina.de
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f870ee236d4
R13: 00000000004be48e R14: 00000000004ce9a8 R15: 00000000ffffffff

Allocated by task 526:
 save_stack+0x45/0xd0 mm/kasan/common.c:73
 set_track mm/kasan/common.c:85 [inline]
 __kasan_kmalloc mm/kasan/common.c:496 [inline]
 __kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:469
 kasan_kmalloc+0x9/0x10 mm/kasan/common.c:504
ax25_connect(): syz-executor5 uses autobind, please contact jreuter@yaina.de
 kmem_cache_alloc_trace+0x151/0x760 mm/slab.c:3609
 kmalloc include/linux/slab.h:545 [inline]
 ax25_rt_add net/ax25/ax25_route.c:95 [inline]
 ax25_rt_ioctl+0x3b9/0x1270 net/ax25/ax25_route.c:233
 ax25_ioctl+0x322/0x10b0 net/ax25/af_ax25.c:1763
 sock_do_ioctl+0xe2/0x400 net/socket.c:950
 sock_ioctl+0x32f/0x6c0 net/socket.c:1074
 vfs_ioctl fs/ioctl.c:46 [inline]
 file_ioctl fs/ioctl.c:509 [inline]
 do_vfs_ioctl+0x107b/0x17d0 fs/ioctl.c:696
 ksys_ioctl+0xab/0xd0 fs/ioctl.c:713
 __do_sys_ioctl fs/ioctl.c:720 [inline]
 __se_sys_ioctl fs/ioctl.c:718 [inline]
 __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:718
 do_syscall_64+0x1a3/0x800 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

ax25_connect(): syz-executor5 uses autobind, please contact jreuter@yaina.de
Freed by task 550:
 save_stack+0x45/0xd0 mm/kasan/common.c:73
 set_track mm/kasan/common.c:85 [inline]
 __kasan_slab_free+0x102/0x150 mm/kasan/common.c:458
 kasan_slab_free+0xe/0x10 mm/kasan/common.c:466
 __cache_free mm/slab.c:3487 [inline]
 kfree+0xcf/0x230 mm/slab.c:3806
 ax25_rt_add net/ax25/ax25_route.c:92 [inline]
 ax25_rt_ioctl+0x304/0x1270 net/ax25/ax25_route.c:233
 ax25_ioctl+0x322/0x10b0 net/ax25/af_ax25.c:1763
 sock_do_ioctl+0xe2/0x400 net/socket.c:950
 sock_ioctl+0x32f/0x6c0 net/socket.c:1074
 vfs_ioctl fs/ioctl.c:46 [inline]
 file_ioctl fs/ioctl.c:509 [inline]
 do_vfs_ioctl+0x107b/0x17d0 fs/ioctl.c:696
 ksys_ioctl+0xab/0xd0 fs/ioctl.c:713
 __do_sys_ioctl fs/ioctl.c:720 [inline]
 __se_sys_ioctl fs/ioctl.c:718 [inline]
 __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:718
 do_syscall_64+0x1a3/0x800 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

The buggy address belongs to the object at ffff888066641a80
 which belongs to the cache kmalloc-96 of size 96
The buggy address is located 0 bytes inside of
 96-byte region [ffff888066641a80, ffff888066641ae0)
The buggy address belongs to the page:
page:ffffea0001999040 count:1 mapcount:0 mapping:ffff88812c3f04c0 index:0x0
flags: 0x1fffc0000000200(slab)
ax25_connect(): syz-executor4 uses autobind, please contact jreuter@yaina.de
raw: 01fffc0000000200 ffffea0001817948 ffffea0002341dc8 ffff88812c3f04c0
raw: 0000000000000000 ffff888066641000 0000000100000020 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff888066641980: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc
 ffff888066641a00: 00 00 00 00 00 00 00 00 02 fc fc fc fc fc fc fc
>ffff888066641a80: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc
                   ^
 ffff888066641b00: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc
 ffff888066641b80: 00 00 00 00 00 00 00 00 00 00 00 00 fc fc fc fc

Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 include/net/ax25.h    |   12 ++++++++++++
 net/ax25/ax25_ip.c    |    4 ++--
 net/ax25/ax25_route.c |   19 ++++++++-----------
 3 files changed, 22 insertions(+), 13 deletions(-)

--- a/include/net/ax25.h
+++ b/include/net/ax25.h
@@ -197,6 +197,18 @@ static inline void ax25_hold_route(ax25_
 
 void __ax25_put_route(ax25_route *ax25_rt);
 
+extern rwlock_t ax25_route_lock;
+
+static inline void ax25_route_lock_use(void)
+{
+	read_lock(&ax25_route_lock);
+}
+
+static inline void ax25_route_lock_unuse(void)
+{
+	read_unlock(&ax25_route_lock);
+}
+
 static inline void ax25_put_route(ax25_route *ax25_rt)
 {
 	if (atomic_dec_and_test(&ax25_rt->refcount))
--- a/net/ax25/ax25_ip.c
+++ b/net/ax25/ax25_ip.c
@@ -118,6 +118,7 @@ int ax25_rebuild_header(struct sk_buff *
 	if (arp_find(bp + 1, skb))
 		return 1;
 
+	ax25_route_lock_use();
 	route = ax25_get_route(dst, NULL);
 	if (route) {
 		digipeat = route->digipeat;
@@ -209,9 +210,8 @@ int ax25_rebuild_header(struct sk_buff *
 	ax25_queue_xmit(skb, dev);
 
 put:
-	if (route)
-		ax25_put_route(route);
 
+	ax25_route_lock_unuse();
 	return 1;
 }
 
--- a/net/ax25/ax25_route.c
+++ b/net/ax25/ax25_route.c
@@ -40,7 +40,7 @@
 #include <linux/export.h>
 
 static ax25_route *ax25_route_list;
-static DEFINE_RWLOCK(ax25_route_lock);
+DEFINE_RWLOCK(ax25_route_lock);
 
 void ax25_rt_device_down(struct net_device *dev)
 {
@@ -349,6 +349,7 @@ const struct file_operations ax25_route_
  *	Find AX.25 route
  *
  *	Only routes with a reference count of zero can be destroyed.
+ *	Must be called with ax25_route_lock read locked.
  */
 ax25_route *ax25_get_route(ax25_address *addr, struct net_device *dev)
 {
@@ -356,7 +357,6 @@ ax25_route *ax25_get_route(ax25_address
 	ax25_route *ax25_def_rt = NULL;
 	ax25_route *ax25_rt;
 
-	read_lock(&ax25_route_lock);
 	/*
 	 *	Bind to the physical interface we heard them on, or the default
 	 *	route if none is found;
@@ -379,11 +379,6 @@ ax25_route *ax25_get_route(ax25_address
 	if (ax25_spe_rt != NULL)
 		ax25_rt = ax25_spe_rt;
 
-	if (ax25_rt != NULL)
-		ax25_hold_route(ax25_rt);
-
-	read_unlock(&ax25_route_lock);
-
 	return ax25_rt;
 }
 
@@ -414,9 +409,12 @@ int ax25_rt_autobind(ax25_cb *ax25, ax25
 	ax25_route *ax25_rt;
 	int err = 0;
 
-	if ((ax25_rt = ax25_get_route(addr, NULL)) == NULL)
+	ax25_route_lock_use();
+	ax25_rt = ax25_get_route(addr, NULL);
+	if (!ax25_rt) {
+		ax25_route_lock_unuse();
 		return -EHOSTUNREACH;
-
+	}
 	if ((ax25->ax25_dev = ax25_dev_ax25dev(ax25_rt->dev)) == NULL) {
 		err = -EHOSTUNREACH;
 		goto put;
@@ -451,8 +449,7 @@ int ax25_rt_autobind(ax25_cb *ax25, ax25
 	}
 
 put:
-	ax25_put_route(ax25_rt);
-
+	ax25_route_lock_unuse();
 	return err;
 }
 

Re: [PATCH 3.18 00/13] 3.18.136-stable review

[kernelci.org bot]

stable-rc/linux-3.18.y boot: 46 boots: 0 failed, 44 passed with 2 offline (v3.18.135-14-ge5aba7843b9c)

Full Boot Summary: https://kernelci.org/boot/all/job/stable-rc/branch/linux-3.18.y/kernel/v3.18.135-14-ge5aba7843b9c/
Full Build Summary: https://kernelci.org/build/stable-rc/branch/linux-3.18.y/kernel/v3.18.135-14-ge5aba7843b9c/

Tree: stable-rc
Branch: linux-3.18.y
Git Describe: v3.18.135-14-ge5aba7843b9c
Git Commit: e5aba7843b9cba24e3e4477fedc010b6801ebbc0
Git URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git
Tested: 18 unique boards, 11 SoC families, 11 builds out of 185

Offline Platforms:

arm:

    multi_v7_defconfig:
        gcc-7
            tegra20-iris-512: 1 offline lab

    tegra_defconfig:
        gcc-7
            tegra20-iris-512: 1 offline lab

---
For more info write to <info@kernelci.org>

Re: [PATCH 3.18 00/13] 3.18.136-stable review

[shuah]

On 2/21/19 7:35 AM, Greg Kroah-Hartman wrote:
> This is the start of the stable review cycle for the 3.18.136 release.
> There are 13 patches in this series, all will be posted as a response
> to this one.  If anyone has any issues with these being applied, please
> let me know.
> 
> Responses should be made by Sat Feb 23 12:52:12 UTC 2019.
> Anything received after that time might be too late.
> 
> The whole patch series can be found in one patch at:
> 	https://www.kernel.org/pub/linux/kernel/v3.x/stable-review/patch-3.18.136-rc1.gz
> or in the git tree and branch at:
> 	git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git linux-3.18.y
> and the diffstat can be found below.
> 
> thanks,
> 
> greg k-h
> 

Compiled and booted on my test system. No dmesg regressions.

thanks,
-- Shuah

Re: [PATCH 3.18 00/13] 3.18.136-stable review

[Guenter Roeck]

On Thu, Feb 21, 2019 at 03:35:31PM +0100, Greg Kroah-Hartman wrote:
> This is the start of the stable review cycle for the 3.18.136 release.
> There are 13 patches in this series, all will be posted as a response
> to this one.  If anyone has any issues with these being applied, please
> let me know.
> 
> Responses should be made by Sat Feb 23 12:52:12 UTC 2019.
> Anything received after that time might be too late.
> 
Build results:
	total: 155 pass: 155 fail: 0
Qemu test results:
	total: 226 pass: 226 fail: 0

Guenter