linux-snapdragon: wcn36xx: mac address generation on boot

[Paolo Pisati]

Impact:

The wcn36xx driver in Xenial/linux-snapdragon had an ability to autogenerate its MAC address upon boot, or read it from a file (/lib/firmware/wlan/macaddr0). The linux-snapdragon kernel in Bionic doesn't have this feature.

While by itself not a bug (Xenial used a QCOM provided custom driver, while Bionic uses the upstream wcn36xx driver), it can be easily work-arounded by specifying the hw address in /etc/network/interfaces, or set using ifconfig on the command line, but it turned out to be a real problem on ubuntu core:

1) upon boot, with no MAC address assigned, the wcn36xx assigns itself the
dummy address "00:00:00:00:00" and that prevents the network interface from working at all, until a valid address is set

2) the ubuntu core installer doesn't have any knowledge about this behaviour, it simply tries to bring up the interface and on failure, it marks it as 'not working'

On top of that, ubuntu core ships a small script in initramfs, that generates the /lib/firmware/wlan/macaddr0 file starting from the android boot serial, effectively generating a unique MAC address per board: clearly, without driver support, this ubuntu core feature doesn't work.

Fix:

Import back the MAC generation mechanism from Xenial: the pseudo random
generation and the parsing of /lib/firmware/wlan/macaddr0 - see the attached patch.

How to test:

Unpon boot, if no /lib/firmware/wlan/macaddr0 is present, the kernel will print:

[ 10.612701] wcn36xx a204000.wcnss:smd-edge:wcnss:wifi: Direct firmware load for wlan/macaddr0 failed with error -2
[ 10.612713] wcn36xx a204000.wcnss:smd-edge:wcnss:wifi: Failed (-2) to read macaddressfile wlan/macaddr0, using a random address instead

ubuntu@dragon410c:~$ ifconfig wlan0
wlan0: flags=4098<BROADCAST,MULTICAST> mtu 1500
        ether 00:0a:f5:d5:54:d7 txqueuelen 1000 (Ethernet)
        RX packets 0 bytes 0 (0.0 B)
        RX errors 0 dropped 0 overruns 0 frame 0
        TX packets 0 bytes 0 (0.0 B)
        TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0

else, if /lib/firmware/wlan/macaddr0 is present, its content will be used to generate wlan0 MAC address:

ubuntu@dragon410c:~$ cat /lib/firmware/wlan/macaddr0
fe:1a:19:77:d9:88

ubuntu@dragon410c:~$ ifconfig wlan0
wlan0: flags=4098<BROADCAST,MULTICAST> mtu 1500
        ether fe:1a:19:77:d9:88 txqueuelen 1000 (Ethernet)
        RX packets 0 bytes 0 (0.0 B)
        RX errors 0 dropped 0 overruns 0 frame 0
        TX packets 0 bytes 0 (0.0 B)
        TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0

Regression potential:

Low - the patch is small and the code is wrapped in a Kconfig option
(WCN36XX_SNAPDRAGON_HACKS) that only affects the linux-snapdragon flavour,
leaving the generic kernel untouched.

---

[Ubuntu Kernel Bot (ubuntu-kernel-bot)]

This bug is missing log files that will aid in diagnosing the problem. While running an Ubuntu kernel (not a mainline or third-party kernel) please enter the following command in a terminal window:

apport-collect 1776491

and then change the status of the bug to 'Confirmed'.

If, due to the nature of the issue you have encountered, you are unable to run this command, please add a comment stating that fact and change the bug status to 'Confirmed'.

This change has been made by an automated script, maintained by the Ubuntu Kernel Team.

[Launchpad Janitor (janitor)]

This bug was fixed in the package linux - 4.17.0-6.7

---------------
linux (4.17.0-6.7) cosmic; urgency=medium

  * linux: 4.17.0-6.7 -proposed tracker (LP: #1783396)

  * [Regression] EXT4-fs error (device sda2): ext4_validate_block_bitmap:383:
    comm stress-ng: bg 4705: bad block bitmap checksum (LP: #1781709)
    - SAUCE: Revert "UBUNTU: SAUCE: ext4: fix ext4_validate_inode_bitmap: comm
      stress-ng: Corrupt inode bitmap"
    - SAUCE: ext4: check for allocation block validity with block group locked

  * Cosmic update to 4.17.9 stable release (LP: #1783201)
    - userfaultfd: hugetlbfs: fix userfaultfd_huge_must_wait() pte access
    - mm: hugetlb: yield when prepping struct pages
    - mm: teach dump_page() to correctly output poisoned struct pages
    - PCI / ACPI / PM: Resume bridges w/o drivers on suspend-to-RAM
    - ACPICA: Drop leading newlines from error messages
    - ACPI / battery: Safe unregistering of hooks
    - drm/amdgpu: Make struct amdgpu_atif private to amdgpu_acpi.c
    - tracing: Avoid string overflow
    - tracing: Fix missing return symbol in function_graph output
    - scsi: sg: mitigate read/write abuse
    - scsi: aacraid: Fix PD performance regression over incorrect qd being set
    - scsi: target: Fix truncated PR-in ReadKeys response
    - s390: Correct register corruption in critical section cleanup
    - drbd: fix access after free
    - vfio: Use get_user_pages_longterm correctly
    - ARM: dts: imx51-zii-rdu1: fix touchscreen pinctrl
    - ARM: dts: omap3: Fix am3517 mdio and emac clock references
    - ARM: dts: dra7: Disable metastability workaround for USB2
    - cifs: Fix use after free of a mid_q_entry
    - cifs: Fix memory leak in smb2_set_ea()
    - cifs: Fix slab-out-of-bounds in send_set_info() on SMB2 ACE setting
    - cifs: Fix infinite loop when using hard mount option
    - drm: Use kvzalloc for allocating blob property memory
    - drm/udl: fix display corruption of the last line
    - drm/amdgpu: Add amdgpu_atpx_get_dhandle()
    - drm/amdgpu: Dynamically probe for ATIF handle (v2)
    - jbd2: don't mark block as modified if the handle is out of credits
    - ext4: add corruption check in ext4_xattr_set_entry()
    - ext4: always verify the magic number in xattr blocks
    - ext4: make sure bitmaps and the inode table don't overlap with bg
      descriptors
    - ext4: always check block group bounds in ext4_init_block_bitmap()
    - ext4: only look at the bg_flags field if it is valid
    - ext4: verify the depth of extent tree in ext4_find_extent()
    - ext4: include the illegal physical block in the bad map ext4_error msg
    - ext4: clear i_data in ext4_inode_info when removing inline data
    - ext4: never move the system.data xattr out of the inode body
    - ext4: avoid running out of journal credits when appending to an inline file
    - ext4: add more inode number paranoia checks
    - ext4: add more mount time checks of the superblock
    - ext4: check superblock mapped prior to committing
    - HID: i2c-hid: Fix "incomplete report" noise
    - HID: hiddev: fix potential Spectre v1
    - HID: debug: check length before copy_to_user()
    - HID: core: allow concurrent registr...

[Brad Figg (brad-figg)]

This bug is awaiting verification that the kernel in -proposed solves the problem. Please test the kernel and update this bug with the results. If the problem is solved, change the tag 'verification-needed-bionic' to 'verification-done-bionic'. If the problem still exists, change the tag 'verification-needed-bionic' to 'verification-failed-bionic'.

If verification is not done by 5 working days from today, this fix will be dropped from the source code, and this bug will be closed.

See https://wiki.ubuntu.com/Testing/EnableProposed for documentation how to enable and use -proposed. Thank you!

[Kleber Sacilotto de Souza (kleber-souza)]

Verified by Paolo.

$ uname -a
<ppisati> Linux dragon410c 4.15.0-33-snapdragon #36-Ubuntu SMP Wed Aug 15 15:57:54 UTC 2018 aarch64 aarch64 aarch64 GNU/Linux

[Launchpad Janitor (janitor)]

This bug was fixed in the package linux - 4.15.0-33.36

---------------
linux (4.15.0-33.36) bionic; urgency=medium

  * linux: 4.15.0-33.36 -proposed tracker (LP: #1787149)

  * RTNL assertion failure on ipvlan (LP: #1776927)
    - ipvlan: drop ipv6 dependency
    - ipvlan: use per device spinlock to protect addrs list updates
    - SAUCE: fix warning from "ipvlan: drop ipv6 dependency"

  * ubuntu_bpf_jit test failed on Bionic s390x systems (LP: #1753941)
    - test_bpf: flag tests that cannot be jited on s390

  * HDMI/DP audio can't work on the laptop of Dell Latitude 5495 (LP: #1782689)
    - drm/nouveau: fix nouveau_dsm_get_client_id()'s return type
    - drm/radeon: fix radeon_atpx_get_client_id()'s return type
    - drm/amdgpu: fix amdgpu_atpx_get_client_id()'s return type
    - platform/x86: apple-gmux: fix gmux_get_client_id()'s return type
    - ALSA: hda: use PCI_BASE_CLASS_DISPLAY to replace PCI_CLASS_DISPLAY_VGA
    - vga_switcheroo: set audio client id according to bound GPU id

  * locking sockets broken due to missing AppArmor socket mediation patches
    (LP: #1780227)
    - UBUNTU SAUCE: apparmor: fix apparmor mediating locking non-fs, unix sockets

  * Update2 for ocxl driver (LP: #1781436)
    - ocxl: Fix page fault handler in case of fault on dying process

  * netns: unable to follow an interface that moves to another netns
    (LP: #1774225)
    - net: core: Expose number of link up/down transitions
    - dev: always advertise the new nsid when the netns iface changes
    - dev: advertise the new ifindex when the netns iface changes

  * [Bionic] Disk IO hangs when using BFQ as io scheduler (LP: #1780066)
    - block, bfq: fix occurrences of request finish method's old name
    - block, bfq: remove batches of confusing ifdefs
    - block, bfq: add requeue-request hook

  * HP ProBook 455 G5 needs mute-led-gpio fixup (LP: #1781763)
    - ALSA: hda: add mute led support for HP ProBook 455 G5

  * [Bionic] bug fixes to improve stability of the ThunderX2 i2c driver
    (LP: #1781476)
    - i2c: xlp9xx: Fix issue seen when updating receive length
    - i2c: xlp9xx: Make sure the transfer size is not more than
      I2C_SMBUS_BLOCK_SIZE

  * x86/kvm: fix LAPIC timer drift when guest uses periodic mode (LP: #1778486)
    - x86/kvm: fix LAPIC timer drift when guest uses periodic mode

  * Please include ax88179_178a and r8152 modules in d-i udeb (LP: #1771823)
    - [Config:] d-i: Add ax88179_178a and r8152 to nic-modules

  * Nvidia fails after switching its mode (LP: #1778658)
    - PCI: Restore config space on runtime resume despite being unbound

  * Kernel error "task zfs:pid blocked for more than 120 seconds" (LP: #1781364)
    - SAUCE: (noup) zfs to 0.7.5-1ubuntu16.3

  * CVE-2018-12232
    - PATCH 1/1] socket: close race condition between sock_close() and
      sockfs_setattr()

  * CVE-2018-10323
    - xfs: set format back to extents if xfs_bmap_extents_to_btree

  * change front mic location for more lenovo m7/8/9xx machines (LP: #1781316)
    - ALSA: hda/realtek - Fix the problem of two front mics on more machines
    - ALSA: hda/realtek - two more lenovo models need fixup of MIC_LOCATION

  * Cephfs + fscache: unab...