1. 07 Oct, 2009 1 commit
    • Stephen Smalley's avatar
      selinux: dynamic class/perm discovery · c6d3aaa4
      Stephen Smalley authored
      Modify SELinux to dynamically discover class and permission values
      upon policy load, based on the dynamic object class/perm discovery
      logic from libselinux.  A mapping is created between kernel-private
      class and permission indices used outside the security server and the
      policy values used within the security server.
      
      The mappings are only applied upon kernel-internal computations;
      similar mappings for the private indices of userspace object managers
      is handled on a per-object manager basis by the userspace AVC.  The
      interfaces for compute_av and transition_sid are split for kernel
      vs. userspace; the userspace functions are distinguished by a _user
      suffix.
      
      The kernel-private class indices are no longer tied to the policy
      values and thus do not need to skip indices for userspace classes;
      thus the kernel class index values are compressed.  The flask.h
      definitions were regenerated by deleting the userspace classes from
      refpolicy's definitions and then regenerating the headers.  Going
      forward, we can just maintain the flask.h, av_permissions.h, and
      classmap.h definitions separately from policy as they are no longer
      tied to the policy values.  The next patch introduces a utility to
      automate generation of flask.h and av_permissions.h from the
      classmap.h definitions.
      
      The older kernel class and permission string tables are removed and
      replaced by a single security class mapping table that is walked at
      policy load to generate the mapping.  The old kernel class validation
      logic is completely replaced by the mapping logic.
      
      The handle unknown logic is reworked.  reject_unknown=1 is handled
      when the mappings are computed at policy load time, similar to the old
      handling by the class validation logic.  allow_unknown=1 is handled
      when computing and mapping decisions - if the permission was not able
      to be mapped (i.e. undefined, mapped to zero), then it is
      automatically added to the allowed vector.  If the class was not able
      to be mapped (i.e. undefined, mapped to zero), then all permissions
      are allowed for it if allow_unknown=1.
      
      avc_audit leverages the new security class mapping table to lookup the
      class and permission names from the kernel-private indices.
      
      The mdp program is updated to use the new table when generating the
      class definitions and allow rules for a minimal boot policy for the
      kernel.  It should be noted that this policy will not include any
      userspace classes, nor will its policy index values for the kernel
      classes correspond with the ones in refpolicy (they will instead match
      the kernel-private indices).
      Signed-off-by: default avatarStephen Smalley <sds@tycho.nsa.gov>
      Signed-off-by: default avatarJames Morris <jmorris@namei.org>
      c6d3aaa4
  2. 23 Sep, 2009 1 commit
  3. 05 Sep, 2008 1 commit
  4. 26 Aug, 2008 1 commit
    • Serge E. Hallyn's avatar
      selinux: add support for installing a dummy policy (v2) · 93c06cbb
      Serge E. Hallyn authored
      In August 2006 I posted a patch generating a minimal SELinux policy.  This
      week, David P. Quigley posted an updated version of that as a patch against
      the kernel.  It also had nice logic for auto-installing the policy.
      
      Following is David's original patch intro (preserved especially
      bc it has stats on the generated policies):
      
      se interested in the changes there were only two significant
      changes. The first is that the iteration through the list of classes
      used NULL as a sentinel value. The problem with this is that the
      class_to_string array actually has NULL entries in its table as place
      holders for the user space object classes.
      
      The second change was that it would seem at some point the initial sids
      table was NULL terminated. This is no longer the case so that iteration
      has to be done on array length instead of looking for NULL.
      
      Some statistics on the policy that it generates:
      
      The policy consists of 523 lines which contain no blank lines. Of those
      523 lines 453 of them are class, permission, and initial sid
      definitions. These lines are usually little to no concern to the policy
      developer since they will not be adding object classes or permissions.
      Of the remaining 70 lines there is one type, one role, and one user
      statement. The remaining lines are broken into three portions. The first
      group are TE allow rules which make up 29 of the remaining lines, the
      second is assignment of labels to the initial sids which consist of 27
      lines, and file system labeling statements which are the remaining 11.
      
      In addition to the policy.conf generated there is a single file_contexts
      file containing two lines which labels the entire system with base_t.
      
      This policy generates a policy.23 binary that is 7920 bytes.
      
      (then a few versions later...):
      
      The new policy is 587 lines (stripped of blank lines) with 476 of those
      lines being the boilerplate that I mentioned last time. The remaining
      111 lines have the 3 lines for type, user, and role, 70 lines for the
      allow rules (one for each object class including user space object
      classes), 27 lines to assign types to the initial sids, and 11 lines for
      file system labeling. The policy binary is 9194 bytes.
      
      Changelog:
      
      	Aug 26: Added Documentation/SELinux.txt
      	Aug 26: Incorporated a set of comments by Stephen Smalley:
      		1. auto-setup SELINUXTYPE=dummy
      		2. don't auto-install if selinux is enabled with
      			non-dummy policy
      		3. don't re-compute policy version
      		4. /sbin/setfiles not /usr/sbin/setfiles
      	Aug 22: As per JMorris comments, made sure make distclean
      		cleans up the mdp directory.
      		Removed a check for file_contexts which is now
      		created in the same file as the check, making it
      		superfluous.
      Signed-off-by: default avatarSerge Hallyn <serue@us.ibm.com>
      Signed-off-by: default avatarDavid Quigley <dpquigl@tycho.nsa.gov>
      Signed-off-by: default avatarJames Morris <jmorris@namei.org>
      93c06cbb