linux-stable.git/lib/kobject_uevent.c, branch v4.17.2 Linux kernel stable tree net: Drop pernet_operations::async 2018-03-27T17:18:09+00:00 Kirill Tkhai ktkhai@virtuozzo.com 2018-03-27T15:02:13+00:00 2f635ceeb22ba13c307236d69795fbb29cfa3e7c Synchronous pernet_operations are not allowed anymore. All are asynchronous. So, drop the structure member. Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com> Signed-off-by: David S. Miller <davem@davemloft.net> 
Synchronous pernet_operations are not allowed anymore.
All are asynchronous. So, drop the structure member.

Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
netns: send uevent messages 2018-03-22T15:16:43+00:00 Christian Brauner christian.brauner@ubuntu.com 2018-03-19T12:17:31+00:00 692ec06d7c92af8ca841a6367648b9b3045344fd This patch adds a receive method to NETLINK_KOBJECT_UEVENT netlink sockets to allow sending uevent messages into the network namespace the socket belongs to. Currently non-initial network namespaces are already isolated and don't receive uevents. There are a number of cases where it is beneficial for a sufficiently privileged userspace process to send a uevent into a network namespace. One such use case would be debugging and fuzzing of a piece of software which listens and reacts to uevents. By running a copy of that software inside a network namespace, specific uevents could then be presented to it. More concretely, this would allow for easy testing of udevd/ueventd. This will also allow some piece of software to run components inside a separate network namespace and then effectively filter what that software can receive. Some examples of software that do directly listen to uevents and that we have in the past attempted to run inside a network namespace are rbd (CEPH client) or the X server. Implementation: The implementation has been kept as simple as possible from the kernel's perspective. Specifically, a simple input method uevent_net_rcv() is added to NETLINK_KOBJECT_UEVENT sockets which completely reuses existing af_netlink infrastructure and does neither add an additional netlink family nor requires any user-visible changes. For example, by using netlink_rcv_skb() we can make use of existing netlink infrastructure to report back informative error messages to userspace. Furthermore, this implementation does not introduce any overhead for existing uevent generating codepaths. The struct netns got a new uevent socket member that records the uevent socket associated with that network namespace including its position in the uevent socket list. Since we record the uevent socket for each network namespace in struct net we don't have to walk the whole uevent socket list. Instead we can directly retrieve the relevant uevent socket and send the message. At exit time we can now also trivially remove the uevent socket from the uevent socket list. This keeps the codepath very performant without introducing needless overhead and even makes older codepaths faster. Uevent sequence numbers are kept global. When a uevent message is sent to another network namespace the implementation will simply increment the global uevent sequence number and append it to the received uevent. This has the advantage that the kernel will never need to parse the received uevent message to replace any existing uevent sequence numbers. Instead it is up to the userspace process to remove any existing uevent sequence numbers in case the uevent message to be sent contains any. Security: In order for a caller to send uevent messages to a target network namespace the caller must have CAP_SYS_ADMIN in the owning user namespace of the target network namespace. Additionally, any received uevent message is verified to not exceed size UEVENT_BUFFER_SIZE. This includes the space needed to append the uevent sequence number. Testing: This patch has been tested and verified to work with the following udev implementations: 1. CentOS 6 with udevd version 147 2. Debian Sid with systemd-udevd version 237 3. Android 7.1.1 with ueventd Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com> Signed-off-by: David S. Miller <davem@davemloft.net> 
This patch adds a receive method to NETLINK_KOBJECT_UEVENT netlink sockets
to allow sending uevent messages into the network namespace the socket
belongs to.

Currently non-initial network namespaces are already isolated and don't
receive uevents. There are a number of cases where it is beneficial for a
sufficiently privileged userspace process to send a uevent into a network
namespace.

One such use case would be debugging and fuzzing of a piece of software
which listens and reacts to uevents. By running a copy of that software
inside a network namespace, specific uevents could then be presented to it.
More concretely, this would allow for easy testing of udevd/ueventd.

This will also allow some piece of software to run components inside a
separate network namespace and then effectively filter what that software
can receive. Some examples of software that do directly listen to uevents
and that we have in the past attempted to run inside a network namespace
are rbd (CEPH client) or the X server.

Implementation:
The implementation has been kept as simple as possible from the kernel's
perspective. Specifically, a simple input method uevent_net_rcv() is added
to NETLINK_KOBJECT_UEVENT sockets which completely reuses existing
af_netlink infrastructure and does neither add an additional netlink family
nor requires any user-visible changes.

For example, by using netlink_rcv_skb() we can make use of existing netlink
infrastructure to report back informative error messages to userspace.

Furthermore, this implementation does not introduce any overhead for
existing uevent generating codepaths. The struct netns got a new uevent
socket member that records the uevent socket associated with that network
namespace including its position in the uevent socket list. Since we record
the uevent socket for each network namespace in struct net we don't have to
walk the whole uevent socket list. Instead we can directly retrieve the
relevant uevent socket and send the message. At exit time we can now also
trivially remove the uevent socket from the uevent socket list. This keeps
the codepath very performant without introducing needless overhead and even
makes older codepaths faster.

Uevent sequence numbers are kept global. When a uevent message is sent to
another network namespace the implementation will simply increment the
global uevent sequence number and append it to the received uevent. This
has the advantage that the kernel will never need to parse the received
uevent message to replace any existing uevent sequence numbers. Instead it
is up to the userspace process to remove any existing uevent sequence
numbers in case the uevent message to be sent contains any.

Security:
In order for a caller to send uevent messages to a target network namespace
the caller must have CAP_SYS_ADMIN in the owning user namespace of the
target network namespace. Additionally, any received uevent message is
verified to not exceed size UEVENT_BUFFER_SIZE. This includes the space
needed to append the uevent sequence number.

Testing:
This patch has been tested and verified to work with the following udev
implementations:
1. CentOS 6 with udevd version 147
2. Debian Sid with systemd-udevd version 237
3. Android 7.1.1 with ueventd

Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
net: add uevent socket member 2018-03-22T15:16:42+00:00 Christian Brauner christian.brauner@ubuntu.com 2018-03-19T12:17:30+00:00 94e5e3087a67c765be98592b36d8d187566478d5 This commit adds struct uevent_sock to struct net. Since struct uevent_sock records the position of the uevent socket in the uevent socket list we can trivially remove it from the uevent socket list during cleanup. This speeds up the old removal codepath. Note, list_del() will hit __list_del_entry_valid() in its call chain which will validate that the element is a member of the list. If it isn't it will take care that the list is not modified. Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com> Signed-off-by: David S. Miller <davem@davemloft.net> 
This commit adds struct uevent_sock to struct net. Since struct uevent_sock
records the position of the uevent socket in the uevent socket list we can
trivially remove it from the uevent socket list during cleanup. This speeds
up the old removal codepath.
Note, list_del() will hit __list_del_entry_valid() in its call chain which
will validate that the element is a member of the list. If it isn't it will
take care that the list is not modified.

Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
net: Convert uevent_net_ops 2018-02-13T15:36:07+00:00 Kirill Tkhai ktkhai@virtuozzo.com 2018-02-13T09:28:33+00:00 15898a011b3d0390869f31167c4403835bc04954 uevent_net_init() and uevent_net_exit() create and destroy netlink socket, and these actions serialized in netlink code. Parallel execution with other pernet_operations makes the socket disappear earlier from uevent_sock_list on ->exit. As userspace can't be interested in broadcast messages of dying net, and, as I see, no one in kernel listen them, we may safely make uevent_net_ops async. Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com> Acked-by: Andrei Vagin <avagin@virtuozzo.com> Signed-off-by: David S. Miller <davem@davemloft.net> 
uevent_net_init() and uevent_net_exit() create and
destroy netlink socket, and these actions serialized
in netlink code.

Parallel execution with other pernet_operations
makes the socket disappear earlier from uevent_sock_list
on ->exit. As userspace can't be interested in broadcast
messages of dying net, and, as I see, no one in kernel
listen them, we may safely make uevent_net_ops async.

Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Acked-by: Andrei Vagin <avagin@virtuozzo.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Merge 4.15-rc6 into driver-core-next 2018-01-02T13:56:51+00:00 Greg Kroah-Hartman gregkh@linuxfoundation.org 2018-01-02T13:56:51+00:00 8c9076b07c99c2a37a96b9f5265e4def47823c86 We want the fixes in here as well. Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
We want the fixes in here as well.

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
kobject: fix suppressing modalias in uevents delivered over netlink 2017-12-21T10:10:33+00:00 Dmitry Torokhov dmitry.torokhov@gmail.com 2017-12-13T23:21:22+00:00 9b3fa47d4a76b1d606a396455f9bbeee083ef008 The commit 4a336a23d619 ("kobject: copy env blob in one go") optimized constructing uevent data for delivery over netlink by using the raw environment buffer, instead of reconstructing it from individual environment pointers. Unfortunately in doing so it broke suppressing MODALIAS attribute for KOBJ_UNBIND events, as the code that suppressed this attribute only adjusted the environment pointers, but left the buffer itself alone. Let's fix it by making sure the offending attribute is obliterated form the buffer as well. Reported-by: Tariq Toukan <tariqt@mellanox.com> Reported-by: Casey Leedom <leedom@chelsio.com> Fixes: 4a336a23d619 ("kobject: copy env blob in one go") Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
The commit 4a336a23d619 ("kobject: copy env blob in one go") optimized
constructing uevent data for delivery over netlink by using the raw
environment buffer, instead of reconstructing it from individual
environment pointers. Unfortunately in doing so it broke suppressing
MODALIAS attribute for KOBJ_UNBIND events, as the code that suppressed this
attribute only adjusted the environment pointers, but left the buffer
itself alone. Let's fix it by making sure the offending attribute is
obliterated form the buffer as well.

Reported-by: Tariq Toukan <tariqt@mellanox.com>
Reported-by: Casey Leedom <leedom@chelsio.com>
Fixes: 4a336a23d619 ("kobject: copy env blob in one go")
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
kobject: Remove redundant license text 2017-12-07T17:36:43+00:00 Greg Kroah-Hartman gregkh@linuxfoundation.org 2017-11-07T16:30:06+00:00 045c5f75b77177ad19fe747e33aae2249a12e827 Now that the SPDX tag is in all kobject files, that identifies the license in a specific and legally-defined manner. So the extra GPL text wording can be removed as it is no longer needed at all. This is done on a quest to remove the 700+ different ways that files in the kernel describe the GPL license text. And there's unneeded stuff like the address (sometimes incorrect) for the FSF which is never needed. No copyright headers or other non-license-description text was removed. Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
Now that the SPDX tag is in all kobject files, that identifies the
license in a specific and legally-defined manner.  So the extra GPL text
wording can be removed as it is no longer needed at all.

This is done on a quest to remove the 700+ different ways that files in
the kernel describe the GPL license text.  And there's unneeded stuff
like the address (sometimes incorrect) for the FSF which is never
needed.

No copyright headers or other non-license-description text was removed.

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
kobject: add SPDX identifiers to all kobject files 2017-12-07T17:36:43+00:00 Greg Kroah-Hartman gregkh@linuxfoundation.org 2017-11-07T16:30:05+00:00 d9d16e16a3f82e88fec99222c9c7e26563b05688 It's good to have SPDX identifiers in all files to make it easier to audit the kernel tree for correct licenses. Update the kobject files files with the correct SPDX license identifier based on the license text in the file itself. The SPDX identifier is a legally binding shorthand, which can be used instead of the full boiler plate text. This work is based on a script and data from Thomas Gleixner, Philippe Ombredanne, and Kate Stewart. Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Kate Stewart <kstewart@linuxfoundation.org> Cc: Philippe Ombredanne <pombredanne@nexb.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
It's good to have SPDX identifiers in all files to make it easier to
audit the kernel tree for correct licenses.

Update the kobject files files with the correct SPDX license identifier
based on the license text in the file itself.  The SPDX identifier is a
legally binding shorthand, which can be used instead of the full boiler
plate text.

This work is based on a script and data from Thomas Gleixner, Philippe
Ombredanne, and Kate Stewart.

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Kate Stewart <kstewart@linuxfoundation.org>
Cc: Philippe Ombredanne <pombredanne@nexb.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-10-06T01:19:22+00:00 David S. Miller davem@davemloft.net 2017-10-06T00:57:03+00:00 53954cf8c5d205624167a2bfd117cc0c1a5f3c6d Just simple overlapping changes. Signed-off-by: David S. Miller <davem@davemloft.net> 
Just simple overlapping changes.

Signed-off-by: David S. Miller <davem@davemloft.net>
kobject: factorize skb setup in kobject_uevent_net_broadcast() 2017-09-19T23:32:23+00:00 Eric Dumazet edumazet@google.com 2017-09-19T23:27:05+00:00 d464e84eed02993d40ad55fdc19f4523e4deee5b We can build one skb and let it be cloned in netlink. This is much faster, and use less memory (all clones will share the same skb->head) Tested: time perf record (for f in `seq 1 3000` ; do ip netns add tast$f; done) [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 4.110 MB perf.data (~179584 samples) ] real 0m24.227s # instead of 0m52.554s user 0m0.329s sys 0m23.753s # instead of 0m51.375s 14.77% ip [kernel.kallsyms] [k] __ip6addrlbl_add 14.56% ip [kernel.kallsyms] [k] netlink_broadcast_filtered 11.65% ip [kernel.kallsyms] [k] netlink_has_listeners 6.19% ip [kernel.kallsyms] [k] _raw_spin_lock_irqsave 5.66% ip [kernel.kallsyms] [k] kobject_uevent_env 4.97% ip [kernel.kallsyms] [k] memset_erms 4.67% ip [kernel.kallsyms] [k] refcount_sub_and_test 4.41% ip [kernel.kallsyms] [k] _raw_read_lock 3.59% ip [kernel.kallsyms] [k] refcount_inc_not_zero 3.13% ip [kernel.kallsyms] [k] _raw_spin_unlock_irqrestore 1.55% ip [kernel.kallsyms] [k] __wake_up 1.20% ip [kernel.kallsyms] [k] strlen 1.03% ip [kernel.kallsyms] [k] __wake_up_common 0.93% ip [kernel.kallsyms] [k] consume_skb 0.92% ip [kernel.kallsyms] [k] netlink_trim 0.87% ip [kernel.kallsyms] [k] insert_header 0.63% ip [kernel.kallsyms] [k] unmap_page_range Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> 
We can build one skb and let it be cloned in netlink.

This is much faster, and use less memory (all clones will
share the same skb->head)

Tested:

time perf record (for f in `seq 1 3000` ; do ip netns add tast$f; done)
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 4.110 MB perf.data (~179584 samples) ]

real    0m24.227s # instead of 0m52.554s
user    0m0.329s
sys 0m23.753s # instead of 0m51.375s

    14.77%       ip  [kernel.kallsyms]  [k] __ip6addrlbl_add
    14.56%       ip  [kernel.kallsyms]  [k] netlink_broadcast_filtered
    11.65%       ip  [kernel.kallsyms]  [k] netlink_has_listeners
     6.19%       ip  [kernel.kallsyms]  [k] _raw_spin_lock_irqsave
     5.66%       ip  [kernel.kallsyms]  [k] kobject_uevent_env
     4.97%       ip  [kernel.kallsyms]  [k] memset_erms
     4.67%       ip  [kernel.kallsyms]  [k] refcount_sub_and_test
     4.41%       ip  [kernel.kallsyms]  [k] _raw_read_lock
     3.59%       ip  [kernel.kallsyms]  [k] refcount_inc_not_zero
     3.13%       ip  [kernel.kallsyms]  [k] _raw_spin_unlock_irqrestore
     1.55%       ip  [kernel.kallsyms]  [k] __wake_up
     1.20%       ip  [kernel.kallsyms]  [k] strlen
     1.03%       ip  [kernel.kallsyms]  [k] __wake_up_common
     0.93%       ip  [kernel.kallsyms]  [k] consume_skb
     0.92%       ip  [kernel.kallsyms]  [k] netlink_trim
     0.87%       ip  [kernel.kallsyms]  [k] insert_header
     0.63%       ip  [kernel.kallsyms]  [k] unmap_page_range

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>