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  1. 04 Aug, 2023 3 commits
    • Linus Torvalds's avatar
      Merge tag 'drm-fixes-2023-08-04' of git://anongit.freedesktop.org/drm/drm · 4142fc67
      Linus Torvalds authored 
      Pull drm fixes from Dave Airlie:
 "Small set of fixes this week, i915 and a few misc ones. I didn't see
  an amd pull so maybe next week it'll have a few more on that driver.

  ttm:
   - NULL ptr deref fix

  panel:
   - add missing MODULE_DEVICE_TABLE

  imx/ipuv3:
   - timing fix

  i915:
   - Fix bug in getting msg length in AUX CH registers handler
   - Gen12 AUX invalidation fixes
   - Fix premature release of request's reusable memory"

* tag 'drm-fixes-2023-08-04' of git://anongit.freedesktop.org/drm/drm:
  drm/panel: samsung-s6d7aa0: Add MODULE_DEVICE_TABLE
  drm/i915: Fix premature release of request's reusable memory
  drm/i915/gt: Support aux invalidation on all engines
  drm/i915/gt: Poll aux invalidation register bit on invalidation
  drm/i915/gt: Enable the CCS_FLUSH bit in the pipe control and in the CS
  drm/i915/gt: Rename flags with bit_group_X according to the datasheet
  drm/i915/gt: Ensure memory quiesced before invalidation
  drm/i915: Add the gen12_needs_ccs_aux_inv helper
  drm/i915/gt: Cleanup aux invalidation registers
  drm/i915/gvt: Fix bug in getting msg length in AUX CH registers handler
  drm/imx/ipuv3: Fix front porch adjustment upon hactive aligning
  drm/ttm: check null pointer before accessing when swapping
      4142fc67
    • Linus Torvalds's avatar
      Merge tag 'ceph-for-6.5-rc5' of https://github.com/ceph/ceph-client · 4593f3c2
      Linus Torvalds authored 
      Pull ceph fixes from Ilya Dryomov:
 "Two patches to improve RBD exclusive lock interaction with
  osd_request_timeout option and another fix to reduce the potential for
  erroneous blocklisting -- this time in CephFS. All going to stable"

* tag 'ceph-for-6.5-rc5' of https://github.com/ceph/ceph-client:
  libceph: fix potential hang in ceph_osdc_notify()
  rbd: prevent busy loop when requesting exclusive lock
  ceph: defer stopping mdsc delayed_work
      4593f3c2
    • Linus Torvalds's avatar
      file: reinstate f_pos locking optimization for regular files · 79796425
      Linus Torvalds authored 
      In commit 20ea1e7d ("file: always lock position for
FMODE_ATOMIC_POS") we ended up always taking the file pos lock, because
pidfd_getfd() could get a reference to the file even when it didn't have
an elevated file count due to threading of other sharing cases.

But Mateusz Guzik reports that the extra locking is actually measurable,
so let's re-introduce the optimization, and only force the locking for
directory traversal.

Directories need the lock for correctness reasons, while regular files
only need it for "POSIX semantics".  Since pidfd_getfd() is about
debuggers etc special things that are _way_ outside of POSIX, we can
relax the rules for that case.
Reported-by: default avatarMateusz Guzik <mjguzik@gmail.com>
Cc: Christian Brauner <brauner@kernel.org>
Link: https://lore.kernel.org/linux-fsdevel/20230803095311.ijpvhx3fyrbkasul@f/Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      79796425
  3. 03 Aug, 2023 27 commits
  5. 02 Aug, 2023 10 commits
    • Linus Torvalds's avatar
      Merge tag 'exfat-for-6.5-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/linkinjeon/exfat · 4b954598
      Linus Torvalds authored 
      Pull exfat fixes from Namjae Jeon:

 - Fix page allocation failure from allocation bitmap by using
   kvmalloc_array/kvfree

 - Add the check to validate if filename entries exceeds max filename
   length

 - Fix potential deadlock condition from dir_emit*()

* tag 'exfat-for-6.5-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/linkinjeon/exfat:
  exfat: release s_lock before calling dir_emit()
  exfat: check if filename entries exceeds max filename length
  exfat: use kvmalloc_array/kvfree instead of kmalloc_array/kfree
      4b954598
    • Linus Torvalds's avatar
      Merge tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi · 79d65ee5
      Linus Torvalds authored 
      Pull SCSI fixes from James Bottomley:
 "Three small fixes, all in drivers"

* tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi:
  scsi: pm80xx: Fix error return code in pm8001_pci_probe()
  scsi: zfcp: Defer fc_rport blocking until after ADISC response
  scsi: storvsc: Limit max_sectors for virtual Fibre Channel devices
      79d65ee5
    • ndesaulniers@google.com's avatar
      word-at-a-time: use the same return type for has_zero regardless of endianness · 79e8328e
      ndesaulniers@google.com authored 
      Compiling big-endian targets with Clang produces the diagnostic:

  fs/namei.c:2173:13: warning: use of bitwise '|' with boolean operands [-Wbitwise-instead-of-logical]
	} while (!(has_zero(a, &adata, &constants) | has_zero(b, &bdata, &constants)));
	          ~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
                                               ||
  fs/namei.c:2173:13: note: cast one or both operands to int to silence this warning

It appears that when has_zero was introduced, two definitions were
produced with different signatures (in particular different return
types).

Looking at the usage in hash_name() in fs/namei.c, I suspect that
has_zero() is meant to be invoked twice per while loop iteration; using
logical-or would not update `bdata` when `a` did not have zeros.  So I
think it's preferred to always return an unsigned long rather than a
bool than update the while loop in hash_name() to use a logical-or
rather than bitwise-or.

[ Also changed powerpc version to do the same  - Linus ]

Link: https://github.com/ClangBuiltLinux/linux/issues/1832
Link: https://lore.kernel.org/lkml/20230801-bitwise-v1-1-799bec468dc4@google.com/
Fixes: 36126f8f ("word-at-a-time: make the interfaces truly generic")
Debugged-by: default avatarNathan Chancellor <nathan@kernel.org>
Signed-off-by: default avatarNick Desaulniers <ndesaulniers@google.com>
Acked-by: default avatarHeiko Carstens <hca@linux.ibm.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      79e8328e
    • Hans de Goede's avatar
      wifi: brcmfmac: Fix field-spanning write in brcmf_scan_params_v2_to_v1() · 16e455a4
      Hans de Goede authored 
      Using brcmfmac with 6.5-rc3 on a brcmfmac43241b4-sdio triggers
a backtrace caused by the following field-spanning warning:

memcpy: detected field-spanning write (size 120) of single field
  "&params_le->channel_list[0]" at
  drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c:1072 (size 2)

The driver still works after this warning. The warning was introduced by the
new field-spanning write checks which were enabled recently.

Fix this by replacing the channel_list[1] declaration at the end of
the struct with a flexible array declaration.

Most users of struct brcmf_scan_params_le calculate the size to alloc
using the size of the non flex-array part of the struct + needed extra
space, so they do not care about sizeof(struct brcmf_scan_params_le).

brcmf_notify_escan_complete() however uses the struct on the stack,
expecting there to be room for at least 1 entry in the channel-list
to store the special -1 abort channel-id.

To make this work use an anonymous union with a padding member
added + the actual channel_list flexible array.

Cc: Kees Cook <keescook@chromium.org>
Signed-off-by: default avatarHans de Goede <hdegoede@redhat.com>
Reviewed-by: default avatarKees Cook <keescook@chromium.org>
Reviewed-by: default avatarFranky Lin <franky.lin@broadcom.com>
Signed-off-by: default avatarKalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/20230729140500.27892-1-hdegoede@redhat.com
      16e455a4
    • Benjamin Poirier's avatar
      vxlan: Fix nexthop hash size · 0756384f
      Benjamin Poirier authored 
      The nexthop code expects a 31 bit hash, such as what is returned by
fib_multipath_hash() and rt6_multipath_hash(). Passing the 32 bit hash
returned by skb_get_hash() can lead to problems related to the fact that
'int hash' is a negative number when the MSB is set.

In the case of hash threshold nexthop groups, nexthop_select_path_hthr()
will disproportionately select the first nexthop group entry. In the case
of resilient nexthop groups, nexthop_select_path_res() may do an out of
bounds access in nh_buckets[], for example:
    hash = -912054133
    num_nh_buckets = 2
    bucket_index = 65535

which leads to the following panic:

BUG: unable to handle page fault for address: ffffc900025910c8
PGD 100000067 P4D 100000067 PUD 10026b067 PMD 0
Oops: 0002 [#1] PREEMPT SMP KASAN NOPTI
CPU: 4 PID: 856 Comm: kworker/4:3 Not tainted 6.5.0-rc2+ #34
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
Workqueue: ipv6_addrconf addrconf_dad_work
RIP: 0010:nexthop_select_path+0x197/0xbf0
Code: c1 e4 05 be 08 00 00 00 4c 8b 35 a4 14 7e 01 4e 8d 6c 25 00 4a 8d 7c 25 08 48 01 dd e8 c2 25 15 ff 49 8d 7d 08 e8 39 13 15 ff <4d> 89 75 08 48 89 ef e8 7d 12 15 ff 48 8b 5d 00 e8 14 55 2f 00 85
RSP: 0018:ffff88810c36f260 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 00000000002000c0 RCX: ffffffffaf02dd77
RDX: dffffc0000000000 RSI: 0000000000000008 RDI: ffffc900025910c8
RBP: ffffc900025910c0 R08: 0000000000000001 R09: fffff520004b2219
R10: ffffc900025910cf R11: 31392d2068736168 R12: 00000000002000c0
R13: ffffc900025910c0 R14: 00000000fffef608 R15: ffff88811840e900
FS:  0000000000000000(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffc900025910c8 CR3: 0000000129d00000 CR4: 0000000000750ee0
PKRU: 55555554
Call Trace:
 <TASK>
 ? __die+0x23/0x70
 ? page_fault_oops+0x1ee/0x5c0
 ? __pfx_is_prefetch.constprop.0+0x10/0x10
 ? __pfx_page_fault_oops+0x10/0x10
 ? search_bpf_extables+0xfe/0x1c0
 ? fixup_exception+0x3b/0x470
 ? exc_page_fault+0xf6/0x110
 ? asm_exc_page_fault+0x26/0x30
 ? nexthop_select_path+0x197/0xbf0
 ? nexthop_select_path+0x197/0xbf0
 ? lock_is_held_type+0xe7/0x140
 vxlan_xmit+0x5b2/0x2340
 ? __lock_acquire+0x92b/0x3370
 ? __pfx_vxlan_xmit+0x10/0x10
 ? __pfx___lock_acquire+0x10/0x10
 ? __pfx_register_lock_class+0x10/0x10
 ? skb_network_protocol+0xce/0x2d0
 ? dev_hard_start_xmit+0xca/0x350
 ? __pfx_vxlan_xmit+0x10/0x10
 dev_hard_start_xmit+0xca/0x350
 __dev_queue_xmit+0x513/0x1e20
 ? __pfx___dev_queue_xmit+0x10/0x10
 ? __pfx_lock_release+0x10/0x10
 ? mark_held_locks+0x44/0x90
 ? skb_push+0x4c/0x80
 ? eth_header+0x81/0xe0
 ? __pfx_eth_header+0x10/0x10
 ? neigh_resolve_output+0x215/0x310
 ? ip6_finish_output2+0x2ba/0xc90
 ip6_finish_output2+0x2ba/0xc90
 ? lock_release+0x236/0x3e0
 ? ip6_mtu+0xbb/0x240
 ? __pfx_ip6_finish_output2+0x10/0x10
 ? find_held_lock+0x83/0xa0
 ? lock_is_held_type+0xe7/0x140
 ip6_finish_output+0x1ee/0x780
 ip6_output+0x138/0x460
 ? __pfx_ip6_output+0x10/0x10
 ? __pfx___lock_acquire+0x10/0x10
 ? __pfx_ip6_finish_output+0x10/0x10
 NF_HOOK.constprop.0+0xc0/0x420
 ? __pfx_NF_HOOK.constprop.0+0x10/0x10
 ? ndisc_send_skb+0x2c0/0x960
 ? __pfx_lock_release+0x10/0x10
 ? __local_bh_enable_ip+0x93/0x110
 ? lock_is_held_type+0xe7/0x140
 ndisc_send_skb+0x4be/0x960
 ? __pfx_ndisc_send_skb+0x10/0x10
 ? mark_held_locks+0x65/0x90
 ? find_held_lock+0x83/0xa0
 ndisc_send_ns+0xb0/0x110
 ? __pfx_ndisc_send_ns+0x10/0x10
 addrconf_dad_work+0x631/0x8e0
 ? lock_acquire+0x180/0x3f0
 ? __pfx_addrconf_dad_work+0x10/0x10
 ? mark_held_locks+0x24/0x90
 process_one_work+0x582/0x9c0
 ? __pfx_process_one_work+0x10/0x10
 ? __pfx_do_raw_spin_lock+0x10/0x10
 ? mark_held_locks+0x24/0x90
 worker_thread+0x93/0x630
 ? __kthread_parkme+0xdc/0x100
 ? __pfx_worker_thread+0x10/0x10
 kthread+0x1a5/0x1e0
 ? __pfx_kthread+0x10/0x10
 ret_from_fork+0x34/0x60
 ? __pfx_kthread+0x10/0x10
 ret_from_fork_asm+0x1b/0x30
RIP: 0000:0x0
Code: Unable to access opcode bytes at 0xffffffffffffffd6.
RSP: 0000:0000000000000000 EFLAGS: 00000000 ORIG_RAX: 0000000000000000
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
 </TASK>
Modules linked in:
CR2: ffffc900025910c8
---[ end trace 0000000000000000 ]---
RIP: 0010:nexthop_select_path+0x197/0xbf0
Code: c1 e4 05 be 08 00 00 00 4c 8b 35 a4 14 7e 01 4e 8d 6c 25 00 4a 8d 7c 25 08 48 01 dd e8 c2 25 15 ff 49 8d 7d 08 e8 39 13 15 ff <4d> 89 75 08 48 89 ef e8 7d 12 15 ff 48 8b 5d 00 e8 14 55 2f 00 85
RSP: 0018:ffff88810c36f260 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 00000000002000c0 RCX: ffffffffaf02dd77
RDX: dffffc0000000000 RSI: 0000000000000008 RDI: ffffc900025910c8
RBP: ffffc900025910c0 R08: 0000000000000001 R09: fffff520004b2219
R10: ffffc900025910cf R11: 31392d2068736168 R12: 00000000002000c0
R13: ffffc900025910c0 R14: 00000000fffef608 R15: ffff88811840e900
FS:  0000000000000000(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffffffffd6 CR3: 0000000129d00000 CR4: 0000000000750ee0
PKRU: 55555554
Kernel panic - not syncing: Fatal exception in interrupt
Kernel Offset: 0x2ca00000 from 0xffffffff81000000 (relocation range: 0xffffffff80000000-0xffffffffbfffffff)
---[ end Kernel panic - not syncing: Fatal exception in interrupt ]---

Fix this problem by ensuring the MSB of hash is 0 using a right shift - the
same approach used in fib_multipath_hash() and rt6_multipath_hash().

Fixes: 1274e1cc ("vxlan: ecmp support for mac fdb entries")
Signed-off-by: default avatarBenjamin Poirier <bpoirier@nvidia.com>
Reviewed-by: default avatarIdo Schimmel <idosch@nvidia.com>
Reviewed-by: default avatarSimon Horman <horms@kernel.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      0756384f
    • Yue Haibing's avatar
      ip6mr: Fix skb_under_panic in ip6mr_cache_report() · 30e0191b
      Yue Haibing authored 
      skbuff: skb_under_panic: text:ffffffff88771f69 len:56 put:-4
 head:ffff88805f86a800 data:ffff887f5f86a850 tail:0x88 end:0x2c0 dev:pim6reg
 ------------[ cut here ]------------
 kernel BUG at net/core/skbuff.c:192!
 invalid opcode: 0000 [#1] PREEMPT SMP KASAN
 CPU: 2 PID: 22968 Comm: kworker/2:11 Not tainted 6.5.0-rc3-00044-g0a8db05b #236
 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014
 Workqueue: ipv6_addrconf addrconf_dad_work
 RIP: 0010:skb_panic+0x152/0x1d0
 Call Trace:
  <TASK>
  skb_push+0xc4/0xe0
  ip6mr_cache_report+0xd69/0x19b0
  reg_vif_xmit+0x406/0x690
  dev_hard_start_xmit+0x17e/0x6e0
  __dev_queue_xmit+0x2d6a/0x3d20
  vlan_dev_hard_start_xmit+0x3ab/0x5c0
  dev_hard_start_xmit+0x17e/0x6e0
  __dev_queue_xmit+0x2d6a/0x3d20
  neigh_connected_output+0x3ed/0x570
  ip6_finish_output2+0x5b5/0x1950
  ip6_finish_output+0x693/0x11c0
  ip6_output+0x24b/0x880
  NF_HOOK.constprop.0+0xfd/0x530
  ndisc_send_skb+0x9db/0x1400
  ndisc_send_rs+0x12a/0x6c0
  addrconf_dad_completed+0x3c9/0xea0
  addrconf_dad_work+0x849/0x1420
  process_one_work+0xa22/0x16e0
  worker_thread+0x679/0x10c0
  ret_from_fork+0x28/0x60
  ret_from_fork_asm+0x11/0x20

When setup a vlan device on dev pim6reg, DAD ns packet may sent on reg_vif_xmit().
reg_vif_xmit()
    ip6mr_cache_report()
        skb_push(skb, -skb_network_offset(pkt));//skb_network_offset(pkt) is 4
And skb_push declared as:
	void *skb_push(struct sk_buff *skb, unsigned int len);
		skb->data -= len;
		//0xffff88805f86a84c - 0xfffffffc = 0xffff887f5f86a850
skb->data is set to 0xffff887f5f86a850, which is invalid mem addr, lead to skb_push() fails.

Fixes: 14fb64e1 ("[IPV6] MROUTE: Support PIM-SM (SSM).")
Signed-off-by: default avatarYue Haibing <yuehaibing@huawei.com>
Reviewed-by: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      30e0191b
    • Alexandra Winter's avatar
      s390/qeth: Don't call dev_close/dev_open (DOWN/UP) · 1cfef80d
      Alexandra Winter authored 
      dev_close() and dev_open() are issued to change the interface state to DOWN
or UP (dev->flags IFF_UP). When the netdev is set DOWN it loses e.g its
Ipv6 addresses and routes. We don't want this in cases of device recovery
(triggered by hardware or software) or when the qeth device is set
offline.

Setting a qeth device offline or online and device recovery actions call
netif_device_detach() and/or netif_device_attach(). That will reset or
set the LOWER_UP indication i.e. change the dev->state Bit
__LINK_STATE_PRESENT. That is enough to e.g. cause bond failovers, and
still preserves the interface settings that are handled by the network
stack.

Don't call dev_open() nor dev_close() from the qeth device driver. Let the
network stack handle this.

Fixes: d4560150 ("s390/qeth: call dev_close() during recovery")
Signed-off-by: default avatarAlexandra Winter <wintera@linux.ibm.com>
Reviewed-by: default avatarWenjia Zhang <wenjia@linux.ibm.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      1cfef80d
    • David S. Miller's avatar
      Merge branch 'tun-tap-uid' · 666c135b
      David S. Miller authored 
      Laszlo Ersek says:

====================
tun/tap: set sk_uid from current_fsuid()

The original patches fixing CVE-2023-1076 are incorrect in my opinion.
This small series fixes them up; see the individual commit messages for
explanation.

I have a very elaborate test procedure demonstrating the problem for
both tun and tap; it involves libvirt, qemu, and "crash". I can share
that procedure if necessary, but it's indeed quite long (I wrote it
originally for our QE team).

The patches in this series are supposed to "re-fix" CVE-2023-1076; given
that said CVE is classified as Low Impact (CVSSv3=5.5), I'm posting this
publicly, and not suggesting any embargo. Red Hat Product Security may
assign a new CVE number later.

I've tested the patches on top of v6.5-rc4, with "crash" built at commit
c74f375e0ef7.

Cc: Eric Dumazet <edumazet@google.com>
Cc: Lorenzo Colitti <lorenzo@google.com>
Cc: Paolo Abeni <pabeni@redhat.com>
Cc: Pietro Borrello <borrello@diag.uniroma1.it>
Cc: netdev@vger.kernel.org
Cc: stable@vger.kernel.org
====================
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      666c135b
    • Laszlo Ersek's avatar
      net: tap_open(): set sk_uid from current_fsuid() · 5c9241f3
      Laszlo Ersek authored 
      Commit 66b2c338 initializes the "sk_uid" field in the protocol socket
(struct sock) from the "/dev/tapX" device node's owner UID. Per original
commit 86741ec2 ("net: core: Add a UID field to struct sock.",
2016-11-04), that's wrong: the idea is to cache the UID of the userspace
process that creates the socket. Commit 86741ec2 mentions socket() and
accept(); with "tap", the action that creates the socket is
open("/dev/tapX").

Therefore the device node's owner UID is irrelevant. In most cases,
"/dev/tapX" will be owned by root, so in practice, commit 66b2c338 has
no observable effect:

- before, "sk_uid" would be zero, due to undefined behavior
  (CVE-2023-1076),

- after, "sk_uid" would be zero, due to "/dev/tapX" being owned by root.

What matters is the (fs)UID of the process performing the open(), so cache
that in "sk_uid".

Cc: Eric Dumazet <edumazet@google.com>
Cc: Lorenzo Colitti <lorenzo@google.com>
Cc: Paolo Abeni <pabeni@redhat.com>
Cc: Pietro Borrello <borrello@diag.uniroma1.it>
Cc: netdev@vger.kernel.org
Cc: stable@vger.kernel.org
Fixes: 66b2c338 ("tap: tap_open(): correctly initialize socket uid")
Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=2173435Signed-off-by: default avatarLaszlo Ersek <lersek@redhat.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      5c9241f3
    • Laszlo Ersek's avatar
      net: tun_chr_open(): set sk_uid from current_fsuid() · 9bc30473
      Laszlo Ersek authored 
      Commit a096ccca initializes the "sk_uid" field in the protocol socket
(struct sock) from the "/dev/net/tun" device node's owner UID. Per
original commit 86741ec2 ("net: core: Add a UID field to struct
sock.", 2016-11-04), that's wrong: the idea is to cache the UID of the
userspace process that creates the socket. Commit 86741ec2 mentions
socket() and accept(); with "tun", the action that creates the socket is
open("/dev/net/tun").

Therefore the device node's owner UID is irrelevant. In most cases,
"/dev/net/tun" will be owned by root, so in practice, commit a096ccca
has no observable effect:

- before, "sk_uid" would be zero, due to undefined behavior
  (CVE-2023-1076),

- after, "sk_uid" would be zero, due to "/dev/net/tun" being owned by root.

What matters is the (fs)UID of the process performing the open(), so cache
that in "sk_uid".

Cc: Eric Dumazet <edumazet@google.com>
Cc: Lorenzo Colitti <lorenzo@google.com>
Cc: Paolo Abeni <pabeni@redhat.com>
Cc: Pietro Borrello <borrello@diag.uniroma1.it>
Cc: netdev@vger.kernel.org
Cc: stable@vger.kernel.org
Fixes: a096ccca ("tun: tun_chr_open(): correctly initialize socket uid")
Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=2173435Signed-off-by: default avatarLaszlo Ersek <lersek@redhat.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      9bc30473
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