Paulo Alcantara 73948ab9f2 cifs: fix potential use-after-free in cifs_echo_request()
commit 212253367dc7b49ed3fc194ce71b0992eacaecf2 upstream.

This patch fixes a potential use-after-free bug in
cifs_echo_request().

For instance,

  thread 1
  --------
  cifs_demultiplex_thread()
    clean_demultiplex_info()
      kfree(server)

  thread 2 (workqueue)
  --------
  apic_timer_interrupt()
    smp_apic_timer_interrupt()
      irq_exit()
        __do_softirq()
          run_timer_softirq()
            call_timer_fn()
	      cifs_echo_request() <- use-after-free in server ptr

Signed-off-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
CC: Stable <stable@vger.kernel.org>
Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-12-11 13:23:29 +01:00
..
2020-10-29 09:57:28 +01:00
2020-12-02 08:49:45 +01:00
2019-09-26 16:37:43 -05:00
2020-11-05 11:43:21 +01:00
2019-09-24 23:31:32 -05:00
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2019-09-23 23:28:59 -05:00