linux-stable.git/net, branch v4.4.97 Linux kernel stable tree KEYS: Fix race between updating and finding a negative key 2017-10-27T08:23:18+00:00 David Howells dhowells@redhat.com 2017-10-04T15:43:25+00:00 8a004caec12bf241e567e3640401256cc9bc2e45 commit 363b02dab09b3226f3bd1420dad9c72b79a42a76 upstream. Consolidate KEY_FLAG_INSTANTIATED, KEY_FLAG_NEGATIVE and the rejection error into one field such that: (1) The instantiation state can be modified/read atomically. (2) The error can be accessed atomically with the state. (3) The error isn't stored unioned with the payload pointers. This deals with the problem that the state is spread over three different objects (two bits and a separate variable) and reading or updating them atomically isn't practical, given that not only can uninstantiated keys change into instantiated or rejected keys, but rejected keys can also turn into instantiated keys - and someone accessing the key might not be using any locking. The main side effect of this problem is that what was held in the payload may change, depending on the state. For instance, you might observe the key to be in the rejected state. You then read the cached error, but if the key semaphore wasn't locked, the key might've become instantiated between the two reads - and you might now have something in hand that isn't actually an error code. The state is now KEY_IS_UNINSTANTIATED, KEY_IS_POSITIVE or a negative error code if the key is negatively instantiated. The key_is_instantiated() function is replaced with key_is_positive() to avoid confusion as negative keys are also 'instantiated'. Additionally, barriering is included: (1) Order payload-set before state-set during instantiation. (2) Order state-read before payload-read when using the key. Further separate barriering is necessary if RCU is being used to access the payload content after reading the payload pointers. Fixes: 146aa8b1453b ("KEYS: Merge the type-specific data with the payload data") Reported-by: Eric Biggers <ebiggers@google.com> Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 363b02dab09b3226f3bd1420dad9c72b79a42a76 upstream.

Consolidate KEY_FLAG_INSTANTIATED, KEY_FLAG_NEGATIVE and the rejection
error into one field such that:

 (1) The instantiation state can be modified/read atomically.

 (2) The error can be accessed atomically with the state.

 (3) The error isn't stored unioned with the payload pointers.

This deals with the problem that the state is spread over three different
objects (two bits and a separate variable) and reading or updating them
atomically isn't practical, given that not only can uninstantiated keys
change into instantiated or rejected keys, but rejected keys can also turn
into instantiated keys - and someone accessing the key might not be using
any locking.

The main side effect of this problem is that what was held in the payload
may change, depending on the state.  For instance, you might observe the
key to be in the rejected state.  You then read the cached error, but if
the key semaphore wasn't locked, the key might've become instantiated
between the two reads - and you might now have something in hand that isn't
actually an error code.

The state is now KEY_IS_UNINSTANTIATED, KEY_IS_POSITIVE or a negative error
code if the key is negatively instantiated.  The key_is_instantiated()
function is replaced with key_is_positive() to avoid confusion as negative
keys are also 'instantiated'.

Additionally, barriering is included:

 (1) Order payload-set before state-set during instantiation.

 (2) Order state-read before payload-read when using the key.

Further separate barriering is necessary if RCU is being used to access the
payload content after reading the payload pointers.

Fixes: 146aa8b1453b ("KEYS: Merge the type-specific data with the payload data")
Reported-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
netfilter: nf_ct_expect: Change __nf_ct_expect_check() return value. 2017-10-21T15:09:04+00:00 Jarno Rajahalme jarno@ovn.org 2017-02-24T01:08:54+00:00 5c65ed5c07d742138902c94e6c4b685b4b5d25fb [ Upstream commit 4b86c459c7bee3acaf92f0e2b4c6ac803eaa1a58 ] Commit 4dee62b1b9b4 ("netfilter: nf_ct_expect: nf_ct_expect_insert() returns void") inadvertently changed the successful return value of nf_ct_expect_related_report() from 0 to 1 due to __nf_ct_expect_check() returning 1 on success. Prevent this regression in the future by changing the return value of __nf_ct_expect_check() to 0 on success. Signed-off-by: Jarno Rajahalme <jarno@ovn.org> Acked-by: Joe Stringer <joe@ovn.org> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org> Signed-off-by: Sasha Levin <alexander.levin@verizon.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
[ Upstream commit 4b86c459c7bee3acaf92f0e2b4c6ac803eaa1a58 ]

Commit 4dee62b1b9b4 ("netfilter: nf_ct_expect: nf_ct_expect_insert()
returns void") inadvertently changed the successful return value of
nf_ct_expect_related_report() from 0 to 1 due to
__nf_ct_expect_check() returning 1 on success.  Prevent this
regression in the future by changing the return value of
__nf_ct_expect_check() to 0 on success.

Signed-off-by: Jarno Rajahalme <jarno@ovn.org>
Acked-by: Joe Stringer <joe@ovn.org>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
mac80211: fix power saving clients handling in iwlwifi 2017-10-21T15:09:04+00:00 Emmanuel Grumbach emmanuel.grumbach@intel.com 2017-02-20T13:24:36+00:00 7ed668eeb85143c7ae6fbbaf72dae467ef5620c0 [ Upstream commit d98937f4ea713d21e0fcc345919f86c877dd8d6f ] iwlwifi now supports RSS and can't let mac80211 track the PS state based on the Rx frames since they can come out of order. iwlwifi is now advertising AP_LINK_PS, and uses explicit notifications to teach mac80211 about the PS state of the stations and the PS poll / uAPSD trigger frames coming our way from the peers. Because of that, the TIM stopped being maintained in mac80211. I tried to fix this in commit c68df2e7be0c ("mac80211: allow using AP_LINK_PS with mac80211-generated TIM IE") but that was later reverted by Felix in commit 6c18a6b4e799 ("Revert "mac80211: allow using AP_LINK_PS with mac80211-generated TIM IE") since it broke drivers that do not implement set_tim. Since none of the drivers that set AP_LINK_PS have the set_tim() handler set besides iwlwifi, I can bail out in __sta_info_recalc_tim if AP_LINK_PS AND .set_tim is not implemented. Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com> Signed-off-by: Johannes Berg <johannes.berg@intel.com> Signed-off-by: Sasha Levin <alexander.levin@verizon.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
[ Upstream commit d98937f4ea713d21e0fcc345919f86c877dd8d6f ]

iwlwifi now supports RSS and can't let mac80211 track the
PS state based on the Rx frames since they can come out of
order. iwlwifi is now advertising AP_LINK_PS, and uses
explicit notifications to teach mac80211 about the PS state
of the stations and the PS poll / uAPSD trigger frames
coming our way from the peers.

Because of that, the TIM stopped being maintained in
mac80211. I tried to fix this in commit c68df2e7be0c
("mac80211: allow using AP_LINK_PS with mac80211-generated TIM IE")
but that was later reverted by Felix in commit 6c18a6b4e799
("Revert "mac80211: allow using AP_LINK_PS with mac80211-generated TIM IE")
since it broke drivers that do not implement set_tim.

Since none of the drivers that set AP_LINK_PS have the
set_tim() handler set besides iwlwifi, I can bail out in
__sta_info_recalc_tim if AP_LINK_PS AND .set_tim is not
implemented.

Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
tipc: use only positive error codes in messages 2017-10-21T15:09:03+00:00 Parthasarathy Bhuvaragan parthasarathy.bhuvaragan@ericsson.com 2017-09-29T08:02:54+00:00 01e3e6315171641d040cdaf1818b7ec10fc8dd72 [ Upstream commit aad06212d36cf34859428a0a279e5c14ee5c9e26 ] In commit e3a77561e7d32 ("tipc: split up function tipc_msg_eval()"), we have updated the function tipc_msg_lookup_dest() to set the error codes to negative values at destination lookup failures. Thus when the function sets the error code to -TIPC_ERR_NO_NAME, its inserted into the 4 bit error field of the message header as 0xf instead of TIPC_ERR_NO_NAME (1). The value 0xf is an unknown error code. In this commit, we set only positive error code. Fixes: e3a77561e7d32 ("tipc: split up function tipc_msg_eval()") Signed-off-by: Parthasarathy Bhuvaragan <parthasarathy.bhuvaragan@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
[ Upstream commit aad06212d36cf34859428a0a279e5c14ee5c9e26 ]

In commit e3a77561e7d32 ("tipc: split up function tipc_msg_eval()"),
we have updated the function tipc_msg_lookup_dest() to set the error
codes to negative values at destination lookup failures. Thus when
the function sets the error code to -TIPC_ERR_NO_NAME, its inserted
into the 4 bit error field of the message header as 0xf instead of
TIPC_ERR_NO_NAME (1). The value 0xf is an unknown error code.

In this commit, we set only positive error code.

Fixes: e3a77561e7d32 ("tipc: split up function tipc_msg_eval()")
Signed-off-by: Parthasarathy Bhuvaragan <parthasarathy.bhuvaragan@ericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
net: Set sk_prot_creator when cloning sockets to the right proto 2017-10-21T15:09:03+00:00 Christoph Paasch cpaasch@apple.com 2017-09-27T00:38:50+00:00 685699703a0a39896ba0af91e6d2a80103fe4966 [ Upstream commit 9d538fa60bad4f7b23193c89e843797a1cf71ef3 ] sk->sk_prot and sk->sk_prot_creator can differ when the app uses IPV6_ADDRFORM (transforming an IPv6-socket to an IPv4-one). Which is why sk_prot_creator is there to make sure that sk_prot_free() does the kmem_cache_free() on the right kmem_cache slab. Now, if such a socket gets transformed back to a listening socket (using connect() with AF_UNSPEC) we will allocate an IPv4 tcp_sock through sk_clone_lock() when a new connection comes in. But sk_prot_creator will still point to the IPv6 kmem_cache (as everything got copied in sk_clone_lock()). When freeing, we will thus put this memory back into the IPv6 kmem_cache although it was allocated in the IPv4 cache. I have seen memory corruption happening because of this. With slub-debugging and MEMCG_KMEM enabled this gives the warning "cache_from_obj: Wrong slab cache. TCPv6 but object is from TCP" A C-program to trigger this: void main(void) { int fd = socket(AF_INET6, SOCK_STREAM, IPPROTO_TCP); int new_fd, newest_fd, client_fd; struct sockaddr_in6 bind_addr; struct sockaddr_in bind_addr4, client_addr1, client_addr2; struct sockaddr unsp; int val; memset(&bind_addr, 0, sizeof(bind_addr)); bind_addr.sin6_family = AF_INET6; bind_addr.sin6_port = ntohs(42424); memset(&client_addr1, 0, sizeof(client_addr1)); client_addr1.sin_family = AF_INET; client_addr1.sin_port = ntohs(42424); client_addr1.sin_addr.s_addr = inet_addr("127.0.0.1"); memset(&client_addr2, 0, sizeof(client_addr2)); client_addr2.sin_family = AF_INET; client_addr2.sin_port = ntohs(42421); client_addr2.sin_addr.s_addr = inet_addr("127.0.0.1"); memset(&unsp, 0, sizeof(unsp)); unsp.sa_family = AF_UNSPEC; bind(fd, (struct sockaddr *)&bind_addr, sizeof(bind_addr)); listen(fd, 5); client_fd = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP); connect(client_fd, (struct sockaddr *)&client_addr1, sizeof(client_addr1)); new_fd = accept(fd, NULL, NULL); close(fd); val = AF_INET; setsockopt(new_fd, SOL_IPV6, IPV6_ADDRFORM, &val, sizeof(val)); connect(new_fd, &unsp, sizeof(unsp)); memset(&bind_addr4, 0, sizeof(bind_addr4)); bind_addr4.sin_family = AF_INET; bind_addr4.sin_port = ntohs(42421); bind(new_fd, (struct sockaddr *)&bind_addr4, sizeof(bind_addr4)); listen(new_fd, 5); client_fd = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP); connect(client_fd, (struct sockaddr *)&client_addr2, sizeof(client_addr2)); newest_fd = accept(new_fd, NULL, NULL); close(new_fd); close(client_fd); close(new_fd); } As far as I can see, this bug has been there since the beginning of the git-days. Signed-off-by: Christoph Paasch <cpaasch@apple.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
[ Upstream commit 9d538fa60bad4f7b23193c89e843797a1cf71ef3 ]

sk->sk_prot and sk->sk_prot_creator can differ when the app uses
IPV6_ADDRFORM (transforming an IPv6-socket to an IPv4-one).
Which is why sk_prot_creator is there to make sure that sk_prot_free()
does the kmem_cache_free() on the right kmem_cache slab.

Now, if such a socket gets transformed back to a listening socket (using
connect() with AF_UNSPEC) we will allocate an IPv4 tcp_sock through
sk_clone_lock() when a new connection comes in. But sk_prot_creator will
still point to the IPv6 kmem_cache (as everything got copied in
sk_clone_lock()). When freeing, we will thus put this
memory back into the IPv6 kmem_cache although it was allocated in the
IPv4 cache. I have seen memory corruption happening because of this.

With slub-debugging and MEMCG_KMEM enabled this gives the warning
	"cache_from_obj: Wrong slab cache. TCPv6 but object is from TCP"

A C-program to trigger this:

void main(void)
{
        int fd = socket(AF_INET6, SOCK_STREAM, IPPROTO_TCP);
        int new_fd, newest_fd, client_fd;
        struct sockaddr_in6 bind_addr;
        struct sockaddr_in bind_addr4, client_addr1, client_addr2;
        struct sockaddr unsp;
        int val;

        memset(&bind_addr, 0, sizeof(bind_addr));
        bind_addr.sin6_family = AF_INET6;
        bind_addr.sin6_port = ntohs(42424);

        memset(&client_addr1, 0, sizeof(client_addr1));
        client_addr1.sin_family = AF_INET;
        client_addr1.sin_port = ntohs(42424);
        client_addr1.sin_addr.s_addr = inet_addr("127.0.0.1");

        memset(&client_addr2, 0, sizeof(client_addr2));
        client_addr2.sin_family = AF_INET;
        client_addr2.sin_port = ntohs(42421);
        client_addr2.sin_addr.s_addr = inet_addr("127.0.0.1");

        memset(&unsp, 0, sizeof(unsp));
        unsp.sa_family = AF_UNSPEC;

        bind(fd, (struct sockaddr *)&bind_addr, sizeof(bind_addr));

        listen(fd, 5);

        client_fd = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
        connect(client_fd, (struct sockaddr *)&client_addr1, sizeof(client_addr1));
        new_fd = accept(fd, NULL, NULL);
        close(fd);

        val = AF_INET;
        setsockopt(new_fd, SOL_IPV6, IPV6_ADDRFORM, &val, sizeof(val));

        connect(new_fd, &unsp, sizeof(unsp));

        memset(&bind_addr4, 0, sizeof(bind_addr4));
        bind_addr4.sin_family = AF_INET;
        bind_addr4.sin_port = ntohs(42421);
        bind(new_fd, (struct sockaddr *)&bind_addr4, sizeof(bind_addr4));

        listen(new_fd, 5);

        client_fd = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
        connect(client_fd, (struct sockaddr *)&client_addr2, sizeof(client_addr2));

        newest_fd = accept(new_fd, NULL, NULL);
        close(new_fd);

        close(client_fd);
        close(new_fd);
}

As far as I can see, this bug has been there since the beginning of the
git-days.

Signed-off-by: Christoph Paasch <cpaasch@apple.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
packet: only test po->has_vnet_hdr once in packet_snd 2017-10-21T15:09:03+00:00 Willem de Bruijn willemb@google.com 2017-09-26T16:20:17+00:00 1299f7e17e9e442be49a9b6011f6fe5259960ebb [ Upstream commit da7c9561015e93d10fe6aab73e9288e0d09d65a6 ] Packet socket option po->has_vnet_hdr can be updated concurrently with other operations if no ring is attached. Do not test the option twice in packet_snd, as the value may change in between calls. A race on setsockopt disable may cause a packet > mtu to be sent without having GSO options set. Fixes: bfd5f4a3d605 ("packet: Add GSO/csum offload support.") Signed-off-by: Willem de Bruijn <willemb@google.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
[ Upstream commit da7c9561015e93d10fe6aab73e9288e0d09d65a6 ]

Packet socket option po->has_vnet_hdr can be updated concurrently with
other operations if no ring is attached.

Do not test the option twice in packet_snd, as the value may change in
between calls. A race on setsockopt disable may cause a packet > mtu
to be sent without having GSO options set.

Fixes: bfd5f4a3d605 ("packet: Add GSO/csum offload support.")
Signed-off-by: Willem de Bruijn <willemb@google.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
packet: in packet_do_bind, test fanout with bind_lock held 2017-10-21T15:09:03+00:00 Willem de Bruijn willemb@google.com 2017-09-26T16:19:37+00:00 1b6c80e797eeadf643861f8340ed5791d813d80c [ Upstream commit 4971613c1639d8e5f102c4e797c3bf8f83a5a69e ] Once a socket has po->fanout set, it remains a member of the group until it is destroyed. The prot_hook must be constant and identical across sockets in the group. If fanout_add races with packet_do_bind between the test of po->fanout and taking the lock, the bind call may make type or dev inconsistent with that of the fanout group. Hold po->bind_lock when testing po->fanout to avoid this race. I had to introduce artificial delay (local_bh_enable) to actually observe the race. Fixes: dc99f600698d ("packet: Add fanout support.") Signed-off-by: Willem de Bruijn <willemb@google.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
[ Upstream commit 4971613c1639d8e5f102c4e797c3bf8f83a5a69e ]

Once a socket has po->fanout set, it remains a member of the group
until it is destroyed. The prot_hook must be constant and identical
across sockets in the group.

If fanout_add races with packet_do_bind between the test of po->fanout
and taking the lock, the bind call may make type or dev inconsistent
with that of the fanout group.

Hold po->bind_lock when testing po->fanout to avoid this race.

I had to introduce artificial delay (local_bh_enable) to actually
observe the race.

Fixes: dc99f600698d ("packet: Add fanout support.")
Signed-off-by: Willem de Bruijn <willemb@google.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
l2tp: fix race condition in l2tp_tunnel_delete 2017-10-21T15:09:03+00:00 Sabrina Dubroca sd@queasysnail.net 2017-09-26T14:16:43+00:00 b5f689d94bc3bbcaf25142f43bd31712d10adb44 [ Upstream commit 62b982eeb4589b2e6d7c01a90590e3a4c2b2ca19 ] If we try to delete the same tunnel twice, the first delete operation does a lookup (l2tp_tunnel_get), finds the tunnel, calls l2tp_tunnel_delete, which queues it for deletion by l2tp_tunnel_del_work. The second delete operation also finds the tunnel and calls l2tp_tunnel_delete. If the workqueue has already fired and started running l2tp_tunnel_del_work, then l2tp_tunnel_delete will queue the same tunnel a second time, and try to free the socket again. Add a dead flag to prevent firing the workqueue twice. Then we can remove the check of queue_work's result that was meant to prevent that race but doesn't. Reproducer: ip l2tp add tunnel tunnel_id 3000 peer_tunnel_id 4000 local 192.168.0.2 remote 192.168.0.1 encap udp udp_sport 5000 udp_dport 6000 ip l2tp add session name l2tp1 tunnel_id 3000 session_id 1000 peer_session_id 2000 ip link set l2tp1 up ip l2tp del tunnel tunnel_id 3000 ip l2tp del tunnel tunnel_id 3000 Fixes: f8ccac0e4493 ("l2tp: put tunnel socket release on a workqueue") Reported-by: Jianlin Shi <jishi@redhat.com> Signed-off-by: Sabrina Dubroca <sd@queasysnail.net> Acked-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> 
[ Upstream commit 62b982eeb4589b2e6d7c01a90590e3a4c2b2ca19 ]

If we try to delete the same tunnel twice, the first delete operation
does a lookup (l2tp_tunnel_get), finds the tunnel, calls
l2tp_tunnel_delete, which queues it for deletion by
l2tp_tunnel_del_work.

The second delete operation also finds the tunnel and calls
l2tp_tunnel_delete. If the workqueue has already fired and started
running l2tp_tunnel_del_work, then l2tp_tunnel_delete will queue the
same tunnel a second time, and try to free the socket again.

Add a dead flag to prevent firing the workqueue twice. Then we can
remove the check of queue_work's result that was meant to prevent that
race but doesn't.

Reproducer:

    ip l2tp add tunnel tunnel_id 3000 peer_tunnel_id 4000 local 192.168.0.2 remote 192.168.0.1 encap udp udp_sport 5000 udp_dport 6000
    ip l2tp add session name l2tp1 tunnel_id 3000 session_id 1000 peer_session_id 2000
    ip link set l2tp1 up
    ip l2tp del tunnel tunnel_id 3000
    ip l2tp del tunnel tunnel_id 3000

Fixes: f8ccac0e4493 ("l2tp: put tunnel socket release on a workqueue")
Reported-by: Jianlin Shi <jishi@redhat.com>
Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>
Acked-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>
l2tp: Avoid schedule while atomic in exit_net 2017-10-21T15:09:03+00:00 Ridge Kennedy ridge.kennedy@alliedtelesis.co.nz 2017-02-22T01:59:49+00:00 110cf3dd4bcc0838a86efc9eb86ac31583b4b578 [ Upstream commit 12d656af4e3d2781b9b9f52538593e1717e7c979 ] While destroying a network namespace that contains a L2TP tunnel a "BUG: scheduling while atomic" can be observed. Enabling lockdep shows that this is happening because l2tp_exit_net() is calling l2tp_tunnel_closeall() (via l2tp_tunnel_delete()) from within an RCU critical section. l2tp_exit_net() takes rcu_read_lock_bh() << list_for_each_entry_rcu() >> l2tp_tunnel_delete() l2tp_tunnel_closeall() __l2tp_session_unhash() synchronize_rcu() << Illegal inside RCU critical section >> BUG: sleeping function called from invalid context in_atomic(): 1, irqs_disabled(): 0, pid: 86, name: kworker/u16:2 INFO: lockdep is turned off. CPU: 2 PID: 86 Comm: kworker/u16:2 Tainted: G W O 4.4.6-at1 #2 Hardware name: Xen HVM domU, BIOS 4.6.1-xs125300 05/09/2016 Workqueue: netns cleanup_net 0000000000000000 ffff880202417b90 ffffffff812b0013 ffff880202410ac0 ffffffff81870de8 ffff880202417bb8 ffffffff8107aee8 ffffffff81870de8 0000000000000c51 0000000000000000 ffff880202417be0 ffffffff8107b024 Call Trace: [<ffffffff812b0013>] dump_stack+0x85/0xc2 [<ffffffff8107aee8>] ___might_sleep+0x148/0x240 [<ffffffff8107b024>] __might_sleep+0x44/0x80 [<ffffffff810b21bd>] synchronize_sched+0x2d/0xe0 [<ffffffff8109be6d>] ? trace_hardirqs_on+0xd/0x10 [<ffffffff8105c7bb>] ? __local_bh_enable_ip+0x6b/0xc0 [<ffffffff816a1b00>] ? _raw_spin_unlock_bh+0x30/0x40 [<ffffffff81667482>] __l2tp_session_unhash+0x172/0x220 [<ffffffff81667397>] ? __l2tp_session_unhash+0x87/0x220 [<ffffffff8166888b>] l2tp_tunnel_closeall+0x9b/0x140 [<ffffffff81668c74>] l2tp_tunnel_delete+0x14/0x60 [<ffffffff81668dd0>] l2tp_exit_net+0x110/0x270 [<ffffffff81668d5c>] ? l2tp_exit_net+0x9c/0x270 [<ffffffff815001c3>] ops_exit_list.isra.6+0x33/0x60 [<ffffffff81501166>] cleanup_net+0x1b6/0x280 ... This bug can easily be reproduced with a few steps: $ sudo unshare -n bash # Create a shell in a new namespace # ip link set lo up # ip addr add 127.0.0.1 dev lo # ip l2tp add tunnel remote 127.0.0.1 local 127.0.0.1 tunnel_id 1 \ peer_tunnel_id 1 udp_sport 50000 udp_dport 50000 # ip l2tp add session name foo tunnel_id 1 session_id 1 \ peer_session_id 1 # ip link set foo up # exit # Exit the shell, in turn exiting the namespace $ dmesg ... [942121.089216] BUG: scheduling while atomic: kworker/u16:3/13872/0x00000200 ... To fix this, move the call to l2tp_tunnel_closeall() out of the RCU critical section, and instead call it from l2tp_tunnel_del_work(), which is running from the l2tp_wq workqueue. Fixes: 2b551c6e7d5b ("l2tp: close sessions before initiating tunnel delete") Signed-off-by: Ridge Kennedy <ridge.kennedy@alliedtelesis.co.nz> Acked-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> 
[ Upstream commit 12d656af4e3d2781b9b9f52538593e1717e7c979 ]

While destroying a network namespace that contains a L2TP tunnel a
"BUG: scheduling while atomic" can be observed.

Enabling lockdep shows that this is happening because l2tp_exit_net()
is calling l2tp_tunnel_closeall() (via l2tp_tunnel_delete()) from
within an RCU critical section.

l2tp_exit_net() takes rcu_read_lock_bh()
  << list_for_each_entry_rcu() >>
  l2tp_tunnel_delete()
    l2tp_tunnel_closeall()
      __l2tp_session_unhash()
        synchronize_rcu() << Illegal inside RCU critical section >>

BUG: sleeping function called from invalid context
in_atomic(): 1, irqs_disabled(): 0, pid: 86, name: kworker/u16:2
INFO: lockdep is turned off.
CPU: 2 PID: 86 Comm: kworker/u16:2 Tainted: G        W  O    4.4.6-at1 #2
Hardware name: Xen HVM domU, BIOS 4.6.1-xs125300 05/09/2016
Workqueue: netns cleanup_net
 0000000000000000 ffff880202417b90 ffffffff812b0013 ffff880202410ac0
 ffffffff81870de8 ffff880202417bb8 ffffffff8107aee8 ffffffff81870de8
 0000000000000c51 0000000000000000 ffff880202417be0 ffffffff8107b024
Call Trace:
 [<ffffffff812b0013>] dump_stack+0x85/0xc2
 [<ffffffff8107aee8>] ___might_sleep+0x148/0x240
 [<ffffffff8107b024>] __might_sleep+0x44/0x80
 [<ffffffff810b21bd>] synchronize_sched+0x2d/0xe0
 [<ffffffff8109be6d>] ? trace_hardirqs_on+0xd/0x10
 [<ffffffff8105c7bb>] ? __local_bh_enable_ip+0x6b/0xc0
 [<ffffffff816a1b00>] ? _raw_spin_unlock_bh+0x30/0x40
 [<ffffffff81667482>] __l2tp_session_unhash+0x172/0x220
 [<ffffffff81667397>] ? __l2tp_session_unhash+0x87/0x220
 [<ffffffff8166888b>] l2tp_tunnel_closeall+0x9b/0x140
 [<ffffffff81668c74>] l2tp_tunnel_delete+0x14/0x60
 [<ffffffff81668dd0>] l2tp_exit_net+0x110/0x270
 [<ffffffff81668d5c>] ? l2tp_exit_net+0x9c/0x270
 [<ffffffff815001c3>] ops_exit_list.isra.6+0x33/0x60
 [<ffffffff81501166>] cleanup_net+0x1b6/0x280
 ...

This bug can easily be reproduced with a few steps:

 $ sudo unshare -n bash  # Create a shell in a new namespace
 # ip link set lo up
 # ip addr add 127.0.0.1 dev lo
 # ip l2tp add tunnel remote 127.0.0.1 local 127.0.0.1 tunnel_id 1 \
    peer_tunnel_id 1 udp_sport 50000 udp_dport 50000
 # ip l2tp add session name foo tunnel_id 1 session_id 1 \
    peer_session_id 1
 # ip link set foo up
 # exit  # Exit the shell, in turn exiting the namespace
 $ dmesg
 ...
 [942121.089216] BUG: scheduling while atomic: kworker/u16:3/13872/0x00000200
 ...

To fix this, move the call to l2tp_tunnel_closeall() out of the RCU
critical section, and instead call it from l2tp_tunnel_del_work(), which
is running from the l2tp_wq workqueue.

Fixes: 2b551c6e7d5b ("l2tp: close sessions before initiating tunnel delete")
Signed-off-by: Ridge Kennedy <ridge.kennedy@alliedtelesis.co.nz>
Acked-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>
vti: fix use after free in vti_tunnel_xmit/vti6_tnl_xmit 2017-10-21T15:09:02+00:00 Alexey Kodanev alexey.kodanev@oracle.com 2017-09-26T12:14:29+00:00 93040aa17862c1647f493f2c482d5b5f288f212f [ Upstream commit 36f6ee22d2d66046e369757ec6bbe1c482957ba6 ] When running LTP IPsec tests, KASan might report: BUG: KASAN: use-after-free in vti_tunnel_xmit+0xeee/0xff0 [ip_vti] Read of size 4 at addr ffff880dc6ad1980 by task swapper/0/0 ... Call Trace: <IRQ> dump_stack+0x63/0x89 print_address_description+0x7c/0x290 kasan_report+0x28d/0x370 ? vti_tunnel_xmit+0xeee/0xff0 [ip_vti] __asan_report_load4_noabort+0x19/0x20 vti_tunnel_xmit+0xeee/0xff0 [ip_vti] ? vti_init_net+0x190/0x190 [ip_vti] ? save_stack_trace+0x1b/0x20 ? save_stack+0x46/0xd0 dev_hard_start_xmit+0x147/0x510 ? icmp_echo.part.24+0x1f0/0x210 __dev_queue_xmit+0x1394/0x1c60 ... Freed by task 0: save_stack_trace+0x1b/0x20 save_stack+0x46/0xd0 kasan_slab_free+0x70/0xc0 kmem_cache_free+0x81/0x1e0 kfree_skbmem+0xb1/0xe0 kfree_skb+0x75/0x170 kfree_skb_list+0x3e/0x60 __dev_queue_xmit+0x1298/0x1c60 dev_queue_xmit+0x10/0x20 neigh_resolve_output+0x3a8/0x740 ip_finish_output2+0x5c0/0xe70 ip_finish_output+0x4ba/0x680 ip_output+0x1c1/0x3a0 xfrm_output_resume+0xc65/0x13d0 xfrm_output+0x1e4/0x380 xfrm4_output_finish+0x5c/0x70 Can be fixed if we get skb->len before dst_output(). Fixes: b9959fd3b0fa ("vti: switch to new ip tunnel code") Fixes: 22e1b23dafa8 ("vti6: Support inter address family tunneling.") Signed-off-by: Alexey Kodanev <alexey.kodanev@oracle.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
[ Upstream commit 36f6ee22d2d66046e369757ec6bbe1c482957ba6 ]

When running LTP IPsec tests, KASan might report:

BUG: KASAN: use-after-free in vti_tunnel_xmit+0xeee/0xff0 [ip_vti]
Read of size 4 at addr ffff880dc6ad1980 by task swapper/0/0
...
Call Trace:
  <IRQ>
  dump_stack+0x63/0x89
  print_address_description+0x7c/0x290
  kasan_report+0x28d/0x370
  ? vti_tunnel_xmit+0xeee/0xff0 [ip_vti]
  __asan_report_load4_noabort+0x19/0x20
  vti_tunnel_xmit+0xeee/0xff0 [ip_vti]
  ? vti_init_net+0x190/0x190 [ip_vti]
  ? save_stack_trace+0x1b/0x20
  ? save_stack+0x46/0xd0
  dev_hard_start_xmit+0x147/0x510
  ? icmp_echo.part.24+0x1f0/0x210
  __dev_queue_xmit+0x1394/0x1c60
...
Freed by task 0:
  save_stack_trace+0x1b/0x20
  save_stack+0x46/0xd0
  kasan_slab_free+0x70/0xc0
  kmem_cache_free+0x81/0x1e0
  kfree_skbmem+0xb1/0xe0
  kfree_skb+0x75/0x170
  kfree_skb_list+0x3e/0x60
  __dev_queue_xmit+0x1298/0x1c60
  dev_queue_xmit+0x10/0x20
  neigh_resolve_output+0x3a8/0x740
  ip_finish_output2+0x5c0/0xe70
  ip_finish_output+0x4ba/0x680
  ip_output+0x1c1/0x3a0
  xfrm_output_resume+0xc65/0x13d0
  xfrm_output+0x1e4/0x380
  xfrm4_output_finish+0x5c/0x70

Can be fixed if we get skb->len before dst_output().

Fixes: b9959fd3b0fa ("vti: switch to new ip tunnel code")
Fixes: 22e1b23dafa8 ("vti6: Support inter address family tunneling.")
Signed-off-by: Alexey Kodanev <alexey.kodanev@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>