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Filename Latest commit message Latest commit date
Lin Ma ef5f7bfa19 hamradio: defer ax25 kfree after unregister_netdev
commit 3e0588c291d6ce225f2b891753ca41d45ba42469 upstream.

There is a possible race condition (use-after-free) like below

 (USE)                       |  (FREE)
ax25_sendmsg                 |
 ax25_queue_xmit             |
  dev_queue_xmit             |
   __dev_queue_xmit          |
    __dev_xmit_skb           |
     sch_direct_xmit         | ...
      xmit_one               |
       netdev_start_xmit     | tty_ldisc_kill
        __netdev_start_xmit  |  mkiss_close
         ax_xmit             |   kfree
          ax_encaps          |
                             |

Even though there are two synchronization primitives before the kfree:
1. wait_for_completion(&ax->dead). This can prevent the race with
routines from mkiss_ioctl. However, it cannot stop the routine coming
from upper layer, i.e., the ax25_sendmsg.

2. netif_stop_queue(ax->dev). It seems that this line of code aims to
halt the transmit queue but it fails to stop the routine that already
being xmit.

This patch reorder the kfree after the unregister_netdev to avoid the
possible UAF as the unregister_netdev() is well synchronized and won't
return if there is a running routine.

Signed-off-by: Lin Ma <linma@zju.edu.cn>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-12-29 12:23:38 +01:00
arch ARM: 9169/1: entry: fix Thumb2 bug in iWMMXt exception handling 2021-12-29 12:23:37 +01:00
block block: fix ioprio_get(IOPRIO_WHO_PGRP) vs setuid(2) 2021-12-14 14:49:02 +01:00
certs certs: Trigger creation of RSA module signing key if it's not an RSA key 2021-09-15 09:47:29 +02:00
crypto crypto: pcrypt - Delay write to padata->info 2021-11-17 09:48:40 +01:00
Documentation KVM: VMX: Fix stale docs for kvm-intel.emulate_invalid_guest_state 2021-12-29 12:23:37 +01:00
drivers hamradio: defer ax25 kfree after unregister_netdev 2021-12-29 12:23:38 +01:00
fs f2fs: fix to do sanity check on last xattr entry in __f2fs_setxattr() 2021-12-29 12:23:37 +01:00
include net: skip virtio_net_hdr_set_proto if protocol already set 2021-12-29 12:23:34 +01:00
init kbuild: add CONFIG_LD_IS_LLD 2021-06-30 08:47:44 -04:00
ipc shm: extend forced shm destroy to support objects from several IPC nses 2021-12-01 09:23:35 +01:00
kernel rcu: Mark accesses to rcu_state.n_force_qs 2021-12-22 09:29:40 +01:00
lib siphash: use _unaligned version by default 2021-12-08 09:01:12 +01:00
LICENSES
mm mm: mempolicy: fix THP allocations escaping mempolicy restrictions 2021-12-29 12:23:37 +01:00
net ax25: NPD bug when detaching AX25 device 2021-12-29 12:23:38 +01:00
samples samples/kretprobes: Fix return value if register_kretprobe() failed 2021-11-17 09:48:39 +01:00
scripts recordmcount.pl: look for jgnop instruction as well as bcrl on s390 2021-12-22 09:29:35 +01:00
security selinux: fix race condition when computing ocontext SIDs 2021-12-17 10:12:24 +01:00
sound ALSA: hda/realtek: Amp init fixup for HP ZBook 15 G6 2021-12-29 12:23:36 +01:00
tools selftest/net/forwarding: declare NETIFS p9 p10 2021-12-22 09:29:36 +01:00
usr
virt KVM: do not shrink halt_poll_ns below grow_start 2021-10-09 14:39:50 +02:00
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap
COPYING
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Kbuild
Kconfig
MAINTAINERS
Makefile Linux 5.4.168 2021-12-22 09:29:41 +01:00
README

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.