1. 25 Jul, 2022 7 commits
  2. 24 Jul, 2022 2 commits
  3. 22 Jul, 2022 22 commits
  4. 21 Jul, 2022 7 commits
  5. 20 Jul, 2022 2 commits
    • Linus Torvalds's avatar
      watchqueue: make sure to serialize 'wqueue->defunct' properly · 353f7988
      Linus Torvalds authored
      When the pipe is closed, we mark the associated watchqueue defunct by
      calling watch_queue_clear().  However, while that is protected by the
      watchqueue lock, new watchqueue entries aren't actually added under that
      lock at all: they use the pipe->rd_wait.lock instead, and looking up
      that pipe happens without any locking.
      
      The watchqueue code uses the RCU read-side section to make sure that the
      wqueue entry itself hasn't disappeared, but that does not protect the
      pipe_info in any way.
      
      So make sure to actually hold the wqueue lock when posting watch events,
      properly serializing against the pipe being torn down.
      Reported-by: default avatarNoam Rathaus <noamr@ssd-disclosure.com>
      Cc: Greg KH <gregkh@linuxfoundation.org>
      Cc: David Howells <dhowells@redhat.com>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      353f7988
    • Eric Snowberg's avatar
      lockdown: Fix kexec lockdown bypass with ima policy · 543ce63b
      Eric Snowberg authored
      The lockdown LSM is primarily used in conjunction with UEFI Secure Boot.
      This LSM may also be used on machines without UEFI.  It can also be
      enabled when UEFI Secure Boot is disabled.  One of lockdown's features
      is to prevent kexec from loading untrusted kernels.  Lockdown can be
      enabled through a bootparam or after the kernel has booted through
      securityfs.
      
      If IMA appraisal is used with the "ima_appraise=log" boot param,
      lockdown can be defeated with kexec on any machine when Secure Boot is
      disabled or unavailable.  IMA prevents setting "ima_appraise=log" from
      the boot param when Secure Boot is enabled, but this does not cover
      cases where lockdown is used without Secure Boot.
      
      To defeat lockdown, boot without Secure Boot and add ima_appraise=log to
      the kernel command line; then:
      
        $ echo "integrity" > /sys/kernel/security/lockdown
        $ echo "appraise func=KEXEC_KERNEL_CHECK appraise_type=imasig" > \
          /sys/kernel/security/ima/policy
        $ kexec -ls unsigned-kernel
      
      Add a call to verify ima appraisal is set to "enforce" whenever lockdown
      is enabled.  This fixes CVE-2022-21505.
      
      Cc: stable@vger.kernel.org
      Fixes: 29d3c1c8 ("kexec: Allow kexec_file() with appropriate IMA policy when locked down")
      Signed-off-by: default avatarEric Snowberg <eric.snowberg@oracle.com>
      Acked-by: default avatarMimi Zohar <zohar@linux.ibm.com>
      Reviewed-by: default avatarJohn Haxby <john.haxby@oracle.com>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      543ce63b