Linux 6.18 Merge Window

Linux v6.17 was released on Sunday,
September 29th, with the Linux v6.18 merge window opening immediately afterwards.
Below are the highlights of the
LSM,
SELinux, and
audit
pull requests which have been merged into Linus’ tree.

LSM

• 
  

  Management of the BPF LSM security blobs was moved into the LSM framework.
  Previously the LSM security blobs were managed by SELinux as it was the only
  LSM with BPF access controls. Moving the blob lifecycle managment to the LSM
  framework enables other LSMs to implement their own BPF access controls or
  observation implementations.

  
  


• 
  

  Convert the LSM block device security blob allocator to use the existing
  allocator helper function. This should have no effect on users, but helps
  reduce code duplication and ease maintenance of the code moving forward.

  
  


• 
  

  Update the Rust credentials code to use sync::aref. This is part of a
  larger effort to move the Rust kernel code over the sync module.

  
  

SELinux

• 
  

  Support per-file labeling on
  functionfs,
  a pseudo-filesystem that can be used to implement USB gadget drivers.

  
  


• 
  

  Convert sel_read_bool() to use a small stack buffer instead of a memory
  page allocated via get_zeroed_page(). There are a limited number of pages
  available via get_zeroed_page(), migrating SELinux away from these pages
  helps ensure that system does not exhaust this limited resource.

  
  


• 
  

  Make better use of the network helper functions to retrieve the sock
  associated with a network packet. While this has no real effect on the code,
  it does make it cleaner and easier to maintain.

  
  


• 
  

  Remove some unused and redundant code.

  
  

Audit

• Create a new AUDIT_MAC_TASK_CONTEXTS audit record to log all of the LSM
  labels associated with a task on a system with multiple LSMs enabled. Casey
  Schaufler, the patch’s author, provides an example and an explanation of when
  the record may be generated in the patch’s description:
  

  
  

  Create a new audit record AUDIT_MAC_TASK_CONTEXTS. An example of the
  MAC_TASK_CONTEXTS record is:

  
  
  

   type=MAC_TASK_CONTEXTS
  
     msg=audit(1600880931.832:113)
  
     subj_apparmor=unconfined
  
     subj_smack=_
  
  

  
  
  

  When an audit event includes a AUDIT_MAC_TASK_CONTEXTS record the “subj=”
  field in other records in the event will be “subj=?”. An
  AUDIT_MAC_TASK_CONTEXTS record is supplied when the system has multiple
  security modules that may make access decisions based on a subject security
  context.

  
  

  
  


• Similar to the new AUDIT_MAC_TASK_CONTEXTS record, create a new
  AUDIT_MAC_OBJ_CONTEXTS audit record to log all of the LSM labels associated
  with an object on a system with multiple LSMs enabled. Casey Schaufler, the
  patch’s author, describes the work in the patch description:
  

  
  

  Create a new audit record AUDIT_MAC_OBJ_CONTEXTS. An example of the
  MAC_OBJ_CONTEXTS record is:

  
  
  

  type=MAC_OBJ_CONTEXTS
  
    msg=audit(1601152467.009:1050):
  
    obj_selinux=unconfined_u:object_r:user_home_t:s0
  
  

  
  
  

  When an audit event includes a AUDIT_MAC_OBJ_CONTEXTS record the “obj=” field
  in other records in the event will be “obj=?”. An AUDIT_MAC_OBJ_CONTEXTS
  record is supplied when the system has multiple security modules that may
  make access decisions based on an object security context.

  
  

  
  


• 
  

  Ensure that
  fanotify events
  are always generated. Previously fanotify events were only logged when audit
  was explicitly configured, in contrast to the Linux audit convention where
  security relevant events are always logged.

  
  


• Minor comment and coding style fixes.