Add support for the newly defined V4L2_CID_CAMERA_ORIENTATION
and V4L2_CID_CAMERA_SENSOR_ROTATION read-only controls used to report
the camera device mounting position and orientation respectively.
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Jacopo Mondi <jacopo@jmondi.org>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
While normal video/radio/vbi/swradio nodes have a proper QUERYCAP ioctl
that apps can call to determine that it is indeed a V4L2 device, there
is currently no equivalent for v4l-subdev nodes. Adding this ioctl will
solve that, and it will allow utilities like v4l2-compliance to be used
with these devices as well.
SUBDEV_QUERYCAP currently returns the version and capabilities of the
subdevice. Define a capability flag to report if the subdevice is
registered in read-only mode.
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Jacopo Mondi <jacopo@jmondi.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
The VIDIOC_ENUM_FMT ioctl enumerates all formats supported by a video
node. For MC-centric devices, its behaviour has always been ill-defined,
with drivers implementing one of the following behaviours:
- No support for VIDIOC_ENUM_FMT at all
- Enumerating all formats supported by the video node, regardless of the
configuration of the pipeline
- Enumerating formats supported by the video node for the active
configuration of the connected subdevice
The first behaviour is obviously useless for applications. The second
behaviour provides the most information, but doesn't offer a way to find
what formats are compatible with a given pipeline configuration. The
third behaviour fixes that, but with the drawback that applications
can't enumerate all supported formats anymore, and have to modify the
active configuration of the pipeline to enumerate formats.
The situation is messy as none of the implemented behaviours are ideal,
and userspace can't predict what will happen as the behaviour is
driver-specific.
To fix this, let's extend the VIDIOC_ENUM_FMT with a missing capability:
enumerating pixel formats for a given media bus code. The media bus code
is passed through the v4l2_fmtdesc structure in a new mbus_code field
(repurposed from the reserved fields). With this capability in place,
applications can enumerate pixel formats for a given media bus code
without modifying the active configuration of the device.
The current behaviour of the ioctl is preserved when the new mbus_code
field is set to 0, ensuring compatibility with existing userspace. The
API extension is documented as mandatory for MC-centric devices (as
advertised through the V4L2_CAP_IO_MC capability), allowing applications
and compliance tools to easily determine the availability of the
VIDIOC_ENUM_FMT extension.
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Pull flexible-array member conversion from Gustavo Silva:
"The current codebase makes use of the zero-length array language
extension to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array
member[1][2], introduced in C99:
struct foo {
int stuff;
struct boo array[];
};
By making use of the mechanism above, we will get a compiler warning
in case the flexible array does not occur last in the structure, which
will help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on.
Also, notice that, dynamic memory allocations won't be affected by
this change:
"Flexible array members have incomplete type, and so the sizeof
operator may not be applied. As a quirk of the original
implementation of zero-length arrays, sizeof evaluates to zero."[1]
sizeof(flexible-array-member) triggers a warning because flexible
array members have incomplete type[1]. There are some instances of
code in which the sizeof operator is being incorrectly/erroneously
applied to zero-length arrays and the result is zero. Such instances
may be hiding some bugs. So, this work (flexible-array member
convertions) will also help to get completely rid of those sorts of
issues.
Notice that all of these patches have been baking in linux-next for
quite a while now and, 238 more of these patches have already been
merged into 5.7-rc1.
There are a couple hundred more of these issues waiting to be
addressed in the whole codebase"
[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 7649773293 ("cxgb3/l2t: Fix undefined behaviour")
* tag 'flexible-array-member-5.7-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/gustavoars/linux: (28 commits)
xattr.h: Replace zero-length array with flexible-array member
uapi: linux: fiemap.h: Replace zero-length array with flexible-array member
uapi: linux: dlm_device.h: Replace zero-length array with flexible-array member
tpm_eventlog.h: Replace zero-length array with flexible-array member
ti_wilink_st.h: Replace zero-length array with flexible-array member
swap.h: Replace zero-length array with flexible-array member
skbuff.h: Replace zero-length array with flexible-array member
sched: topology.h: Replace zero-length array with flexible-array member
rslib.h: Replace zero-length array with flexible-array member
rio.h: Replace zero-length array with flexible-array member
posix_acl.h: Replace zero-length array with flexible-array member
platform_data: wilco-ec.h: Replace zero-length array with flexible-array member
memcontrol.h: Replace zero-length array with flexible-array member
list_lru.h: Replace zero-length array with flexible-array member
lib: cpu_rmap: Replace zero-length array with flexible-array member
irq.h: Replace zero-length array with flexible-array member
ihex.h: Replace zero-length array with flexible-array member
igmp.h: Replace zero-length array with flexible-array member
genalloc.h: Replace zero-length array with flexible-array member
ethtool.h: Replace zero-length array with flexible-array member
...
The current codebase makes use of the zero-length array language
extension to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:
struct foo {
int stuff;
struct boo array[];
};
By making use of the mechanism above, we will get a compiler warning
in case the flexible array does not occur last in the structure, which
will help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on.
Also, notice that, dynamic memory allocations won't be affected by
this change:
"Flexible array members have incomplete type, and so the sizeof operator
may not be applied. As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero."[1]
This issue was found with the help of Coccinelle.
[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 7649773293 ("cxgb3/l2t: Fix undefined behaviour")
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
The current codebase makes use of the zero-length array language
extension to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:
struct foo {
int stuff;
struct boo array[];
};
By making use of the mechanism above, we will get a compiler warning
in case the flexible array does not occur last in the structure, which
will help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on.
Also, notice that, dynamic memory allocations won't be affected by
this change:
"Flexible array members have incomplete type, and so the sizeof operator
may not be applied. As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero."[1]
This issue was found with the help of Coccinelle.
[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 7649773293 ("cxgb3/l2t: Fix undefined behaviour")
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Pull networking fixes from David Miller:
1) Disable RISCV BPF JIT builds when !MMU, from Björn Töpel.
2) nf_tables leaves dangling pointer after free, fix from Eric Dumazet.
3) Out of boundary write in __xsk_rcv_memcpy(), fix from Li RongQing.
4) Adjust icmp6 message source address selection when routes have a
preferred source address set, from Tim Stallard.
5) Be sure to validate HSR protocol version when creating new links,
from Taehee Yoo.
6) CAP_NET_ADMIN should be sufficient to manage l2tp tunnels even in
non-initial namespaces, from Michael Weiß.
7) Missing release firmware call in mlx5, from Eran Ben Elisha.
8) Fix variable type in macsec_changelink(), caught by KASAN. Fix from
Taehee Yoo.
9) Fix pause frame negotiation in marvell phy driver, from Clemens
Gruber.
10) Record RX queue early enough in tun packet paths such that XDP
programs will see the correct RX queue index, from Gilberto Bertin.
11) Fix double unlock in mptcp, from Florian Westphal.
12) Fix offset overflow in ARM bpf JIT, from Luke Nelson.
13) marvell10g needs to soft reset PHY when coming out of low power
mode, from Russell King.
14) Fix MTU setting regression in stmmac for some chip types, from
Florian Fainelli.
* git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (101 commits)
amd-xgbe: Use __napi_schedule() in BH context
mISDN: make dmril and dmrim static
net: stmmac: dwmac-sunxi: Provide TX and RX fifo sizes
net: dsa: mt7530: fix tagged frames pass-through in VLAN-unaware mode
tipc: fix incorrect increasing of link window
Documentation: Fix tcp_challenge_ack_limit default value
net: tulip: make early_486_chipsets static
dt-bindings: net: ethernet-phy: add desciption for ethernet-phy-id1234.d400
ipv6: remove redundant assignment to variable err
net/rds: Use ERR_PTR for rds_message_alloc_sgs()
net: mscc: ocelot: fix untagged packet drops when enslaving to vlan aware bridge
selftests/bpf: Check for correct program attach/detach in xdp_attach test
libbpf: Fix type of old_fd in bpf_xdp_set_link_opts
libbpf: Always specify expected_attach_type on program load if supported
xsk: Add missing check on user supplied headroom size
mac80211: fix channel switch trigger from unknown mesh peer
mac80211: fix race in ieee80211_register_hw()
net: marvell10g: soft-reset the PHY when coming out of low power
net: marvell10g: report firmware version
net/cxgb4: Check the return from t4_query_params properly
...
Pull btrfs fixes from David Sterba:
"We have a few regressions and one fix for stable:
- revert fsync optimization
- fix lost i_size update
- fix a space accounting leak
- build fix, add back definition of a deprecated ioctl flag
- fix search condition for old roots in relocation"
* tag 'for-5.7-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
btrfs: re-instantiate the removed BTRFS_SUBVOL_CREATE_ASYNC definition
btrfs: fix reclaim counter leak of space_info objects
btrfs: make full fsyncs always operate on the entire file again
btrfs: fix lost i_size update after cloning inline extent
btrfs: check commit root generation in should_ignore_root
The commit 9c1036fdb1 ("btrfs: Remove BTRFS_SUBVOL_CREATE_ASYNC
support") breaks strace build with the kernel headers from git:
btrfs.c: In function "btrfs_test_subvol_ioctls":
btrfs.c:531:23: error: "BTRFS_SUBVOL_CREATE_ASYNC" undeclared (first use
in this function)
vol_args_v2.flags = BTRFS_SUBVOL_CREATE_ASYNC;
Moreover, it is improper to break UAPI, strace uses the definitions to
decode ioctls that are considered part of public API.
Restore the macro definition and put it under "#ifndef __KERNEL__"
in order to prevent inadvertent in-kernel usage.
Fixes: 9c1036fdb1 ("btrfs: Remove BTRFS_SUBVOL_CREATE_ASYNC support")
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Eugene Syromiatnikov <esyr@redhat.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Pull iommu updates from Joerg Roedel:
- ARM-SMMU support for the TLB range invalidation command in SMMUv3.2
- ARM-SMMU introduction of command batching helpers to batch up CD and
ATC invalidation
- ARM-SMMU support for PCI PASID, along with necessary PCI symbol
exports
- Introduce a generic (actually rename an existing) IOMMU related
pointer in struct device and reduce the IOMMU related pointers
- Some fixes for the OMAP IOMMU driver to make it build on 64bit
architectures
- Various smaller fixes and improvements
* tag 'iommu-updates-v5.7' of git://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu: (39 commits)
iommu: Move fwspec->iommu_priv to struct dev_iommu
iommu/virtio: Use accessor functions for iommu private data
iommu/qcom: Use accessor functions for iommu private data
iommu/mediatek: Use accessor functions for iommu private data
iommu/renesas: Use accessor functions for iommu private data
iommu/arm-smmu: Use accessor functions for iommu private data
iommu/arm-smmu: Refactor master_cfg/fwspec usage
iommu/arm-smmu-v3: Use accessor functions for iommu private data
iommu: Introduce accessors for iommu private data
iommu/arm-smmu: Fix uninitilized variable warning
iommu: Move iommu_fwspec to struct dev_iommu
iommu: Rename struct iommu_param to dev_iommu
iommu/tegra-gart: Remove direct access of dev->iommu_fwspec
drm/msm/mdp5: Remove direct access of dev->iommu_fwspec
ACPI/IORT: Remove direct access of dev->iommu_fwspec
iommu: Define dev_iommu_fwspec_get() for !CONFIG_IOMMU_API
iommu/virtio: Reject IOMMU page granule larger than PAGE_SIZE
iommu/virtio: Fix freeing of incomplete domains
iommu/virtio: Fix sparse warning
iommu/vt-d: Add build dependency on IOASID
...
Pull virtio updates from Michael Tsirkin:
- Some bug fixes
- The new vdpa subsystem with two first drivers
* tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost:
virtio-balloon: Revert "virtio-balloon: Switch back to OOM handler for VIRTIO_BALLOON_F_DEFLATE_ON_OOM"
vdpa: move to drivers/vdpa
virtio: Intel IFC VF driver for VDPA
vdpasim: vDPA device simulator
vhost: introduce vDPA-based backend
virtio: introduce a vDPA based transport
vDPA: introduce vDPA bus
vringh: IOTLB support
vhost: factor out IOTLB
vhost: allow per device message handler
vhost: refine vhost and vringh kconfig
virtio-balloon: Switch back to OOM handler for VIRTIO_BALLOON_F_DEFLATE_ON_OOM
virtio-net: Introduce hash report feature
virtio-net: Introduce RSS receive steering feature
virtio-net: Introduce extended RSC feature
tools/virtio: option to build an out of tree module
Pull input updates from Dmitry Torokhov:
"An update to the Goodix touchscreen driver to enable it work properly
on various Bay Trail and Cherry Trail devices, and a few other
assorted changes"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input: (26 commits)
Input: update SPDX tag for input-event-codes.h
Input: i8042 - add Acer Aspire 5738z to nomux list
Input: goodix - fix compilation when ACPI support is disabled
dt-bindings: touchscreen: Convert edt-ft5x06 to json-schema
Input: of_touchscreen - explicitly choose axis
Input: goodix - support gt9147 touchpanel
dt-bindings: touchscreen: goodix: support of gt9147
Input: goodix - add support for Goodix GT917S
Input: goodix - use string-based chip ID
dt-bindings: input: touchscreen: add compatible string for Goodix GT917S
Input: goodix - add support for more then one touch-key
Input: goodix - fix spurious key release events
Input: goodix - try to reset the controller if the i2c-test fails
Input: goodix - restore config on resume if necessary
Input: goodix - make goodix_send_cfg() take a raw buffer as argument
Input: goodix - add minimum firmware size check
Input: goodix - save a copy of the config from goodix_read_config()
Input: goodix - move defines to above struct goodix_ts_data declaration
Input: goodix - add support for controlling the IRQ pin through ACPI methods
Input: goodix - add support for getting IRQ + reset GPIOs on Bay Trail devices
...
Pablo Neira Ayuso says:
====================
Netfilter fixes for net
The following patchset contains Netfilter fixes for net, they are:
1) Fix spurious overlap condition in the rbtree tree, from Stefano Brivio.
2) Fix possible uninitialized pointer dereference in nft_lookup.
3) IDLETIMER v1 target matches the Android layout, from
Maciej Zenczykowski.
4) Dangling pointer in nf_tables_set_alloc_name, from Eric Dumazet.
5) Fix RCU warning splat in ipset find_set_type(), from Amol Grover.
6) Report EOPNOTSUPP on unsupported set flags and object types in sets.
7) Add NFT_SET_CONCAT flag to provide consistent error reporting
when users defines set with ranges in concatenations in old kernels.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
Merge more updates from Andrew Morton:
- a lot more of MM, quite a bit more yet to come: (memcg, pagemap,
vmalloc, pagealloc, migration, thp, ksm, madvise, virtio,
userfaultfd, memory-hotplug, shmem, rmap, zswap, zsmalloc, cleanups)
- various other subsystems (procfs, misc, MAINTAINERS, bitops, lib,
checkpatch, epoll, binfmt, kallsyms, reiserfs, kmod, gcov, kconfig,
ubsan, fault-injection, ipc)
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (158 commits)
ipc/shm.c: make compat_ksys_shmctl() static
ipc/mqueue.c: fix a brace coding style issue
lib/Kconfig.debug: fix a typo "capabilitiy" -> "capability"
ubsan: include bug type in report header
kasan: unset panic_on_warn before calling panic()
ubsan: check panic_on_warn
drivers/misc/lkdtm/bugs.c: add arithmetic overflow and array bounds checks
ubsan: split "bounds" checker from other options
ubsan: add trap instrumentation option
init/Kconfig: clean up ANON_INODES and old IO schedulers options
kernel/gcov/fs.c: replace zero-length array with flexible-array member
gcov: gcc_3_4: replace zero-length array with flexible-array member
gcov: gcc_4_7: replace zero-length array with flexible-array member
kernel/kmod.c: fix a typo "assuems" -> "assumes"
reiserfs: clean up several indentation issues
kallsyms: unexport kallsyms_lookup_name() and kallsyms_on_each_symbol()
samples/hw_breakpoint: drop use of kallsyms_lookup_name()
samples/hw_breakpoint: drop HW_BREAKPOINT_R when reporting writes
fs/binfmt_elf.c: don't free interpreter's ELF pheaders on common path
fs/binfmt_elf.c: allocate less for static executable
...
Pull UML updates from Richard Weinberger:
- New mode for time travel, external via virtio
- Fixes for ubd to make sure no requests can get lost
- Fixes for vector networking
- Allow CONFIG_STATIC_LINK only when possible
- Minor cleanups and fixes
* tag 'for-linus-5.7-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rw/uml:
um: Remove some unnecessary NULL checks in vector_user.c
um: vector: Avoid NULL ptr deference if transport is unset
um: Make CONFIG_STATIC_LINK actually static
um: Implement cpu_relax() as ndelay(1) for time-travel
um: Implement ndelay/udelay in time-travel mode
um: Implement time-travel=ext
um: virtio: Implement VHOST_USER_PROTOCOL_F_INBAND_NOTIFICATIONS
um: time-travel: Rewrite as an event scheduler
um: Move timer-internal.h to non-shared
hostfs: Use kasprintf() instead of fixed buffer formatting
um: falloc.h needs to be directly included for older libc
um: ubd: Retry buffer read on any kind of error
um: ubd: Prevent buffer overrun on command completion
um: Fix overlapping ELF segments when statically linked
um: Delete never executed timer
um: Don't overwrite ethtool driver version
um: Fix len of file in create_pid_file
um: Don't use console_drivers directly
um: Cleanup CONFIG_IOSCHED_CFQ
Introduce the new uffd-wp APIs for userspace.
Firstly, we'll allow to do UFFDIO_REGISTER with write protection tracking
using the new UFFDIO_REGISTER_MODE_WP flag. Note that this flag can
co-exist with the existing UFFDIO_REGISTER_MODE_MISSING, in which case the
userspace program can not only resolve missing page faults, and at the
same time tracking page data changes along the way.
Secondly, we introduced the new UFFDIO_WRITEPROTECT API to do page level
write protection tracking. Note that we will need to register the memory
region with UFFDIO_REGISTER_MODE_WP before that.
[peterx@redhat.com: write up the commit message]
[peterx@redhat.com: remove useless block, write commit message, check against
VM_MAYWRITE rather than VM_WRITE when register]
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Jerome Glisse <jglisse@redhat.com>
Cc: Bobby Powers <bobbypowers@gmail.com>
Cc: Brian Geffon <bgeffon@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Denis Plotnikov <dplotnikov@virtuozzo.com>
Cc: "Dr . David Alan Gilbert" <dgilbert@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: "Kirill A . Shutemov" <kirill@shutemov.name>
Cc: Martin Cracauer <cracauer@cons.org>
Cc: Marty McFadden <mcfadden8@llnl.gov>
Cc: Maya Gokhale <gokhale2@llnl.gov>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Pavel Emelyanov <xemul@openvz.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Shaohua Li <shli@fb.com>
Link: http://lkml.kernel.org/r/20200220163112.11409-14-peterx@redhat.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Stefano originally proposed to introduce this flag, users hit EOPNOTSUPP
in new binaries with old kernels when defining a set with ranges in
a concatenation.
Fixes: f3a2181e16 ("netfilter: nf_tables: Support for sets with multiple ranged fields")
Reviewed-by: Stefano Brivio <sbrivio@redhat.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Pull fsnotify updates from Jan Kara:
"This implements the fanotify FAN_DIR_MODIFY event.
This event reports the name in a directory under which a change
happened and together with the directory filehandle and fstatat()
allows reliable and efficient implementation of directory
synchronization"
* tag 'fsnotify_for_v5.7-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs:
fanotify: Fix the checks in fanotify_fsid_equal
fanotify: report name info for FAN_DIR_MODIFY event
fanotify: record name info for FAN_DIR_MODIFY event
fanotify: Drop fanotify_event_has_fid()
fanotify: prepare to report both parent and child fid's
fanotify: send FAN_DIR_MODIFY event flavor with dir inode and name
fanotify: divorce fanotify_path_event and fanotify_fid_event
fanotify: Store fanotify handles differently
fanotify: Simplify create_fd()
fanotify: fix merging marks masks with FAN_ONDIR
fanotify: merge duplicate events on parent and child
fsnotify: replace inode pointer with an object id
fsnotify: simplify arguments passing to fsnotify_parent()
fsnotify: use helpers to access data by data_type
fsnotify: funnel all dirent events through fsnotify_name()
fsnotify: factor helpers fsnotify_dentry() and fsnotify_file()
fsnotify: tidy up FS_ and FAN_ constants
Android has long had an extension to IDLETIMER to send netlink
messages to userspace, see:
https://android.googlesource.com/kernel/common/+/refs/heads/android-mainline/include/uapi/linux/netfilter/xt_IDLETIMER.h#42
Note: this is idletimer target rev 1, there is no rev 0 in
the Android common kernel sources, see registration at:
https://android.googlesource.com/kernel/common/+/refs/heads/android-mainline/net/netfilter/xt_IDLETIMER.c#483
When we compare that to upstream's new idletimer target rev 1:
https://git.kernel.org/pub/scm/linux/kernel/git/pablo/nf-next.git/tree/include/uapi/linux/netfilter/xt_IDLETIMER.h#n46
We immediately notice that these two rev 1 structs are the
same size and layout, and that while timer_type and send_nl_msg
are differently named and serve a different purpose, they're
at the same offset.
This makes them impossible to tell apart - and thus one cannot
know in a mixed Android/vanilla environment whether one means
timer_type or send_nl_msg.
Since this is iptables/netfilter uapi it introduces a problem
between iptables (vanilla vs Android) userspace and kernel
(vanilla vs Android) if the two don't match each other.
Additionally when at some point in the future Android picks up
5.7+ it's not at all clear how to resolve the resulting merge
conflict.
Furthermore, since upgrading the kernel on old Android phones
is pretty much impossible there does not seem to be an easy way
out of this predicament.
The only thing I've been able to come up with is some super
disgusting kernel version >= 5.7 check in the iptables binary
to flip between different struct layouts.
By adding a dummy field to the vanilla Linux kernel header file
we can force the two structs to be compatible with each other.
Long term I think I would like to deprecate send_nl_msg out of
Android entirely, but I haven't quite been able to figure out
exactly how we depend on it. It seems to be very similar to
sysfs notifications but with some extra info.
Currently it's actually always enabled whenever Android uses
the IDLETIMER target, so we could also probably entirely
remove it from the uapi in favour of just always enabling it,
but again we can't upgrade old kernels already in the field.
(Also note that this doesn't change the structure's size,
as it is simply fitting into the pre-existing padding, and
that since 5.7 hasn't been released yet, there's still time
to make this uapi visible change)
Cc: Manoj Basapathi <manojbm@codeaurora.org>
Cc: Subash Abhinov Kasiviswanathan <subashab@codeaurora.org>
Signed-off-by: Maciej Żenczykowski <maze@google.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Jacopo Mondi
Hans Verkuil
Laurent Pinchart
Niklas Söderlund
Maheshwar Ajja
Linus Torvalds
Gustavo A. R. Silva
Eugene Syromiatnikov
David S. Miller
Shaohua Li
Andrea Arcangeli
Alexander Duyck
Pablo Neira Ayuso
Dmitry Torokhov
Maciej Żenczykowski