]> git.baikalelectronics.ru Git - kernel.git/commit
ima: fix add LSM rule bug
authorMimi Zohar <zohar@linux.vnet.ibm.com>
Mon, 3 Jan 2011 22:59:10 +0000 (14:59 -0800)
committerLinus Torvalds <torvalds@linux-foundation.org>
Tue, 4 Jan 2011 00:36:33 +0000 (16:36 -0800)
commitb7b9f375a2fed06bdc6bea24be3a95e8cb1cf7f8
tree7873555d6a0e100fb1faa90da6e6366a430c3403
parentf6f098c963795c81444b6d5ef5bc9663cfac14b2
ima: fix add LSM rule bug

If security_filter_rule_init() doesn't return a rule, then not everything
is as fine as the return code implies.

This bug only occurs when the LSM (eg. SELinux) is disabled at runtime.

Adding an empty LSM rule causes ima_match_rules() to always succeed,
ignoring any remaining rules.

 default IMA TCB policy:
  # PROC_SUPER_MAGIC
  dont_measure fsmagic=0x9fa0
  # SYSFS_MAGIC
  dont_measure fsmagic=0x62656572
  # DEBUGFS_MAGIC
  dont_measure fsmagic=0x64626720
  # TMPFS_MAGIC
  dont_measure fsmagic=0x01021994
  # SECURITYFS_MAGIC
  dont_measure fsmagic=0x73636673

  < LSM specific rule >
  dont_measure obj_type=var_log_t

  measure func=BPRM_CHECK
  measure func=FILE_MMAP mask=MAY_EXEC
  measure func=FILE_CHECK mask=MAY_READ uid=0

Thus without the patch, with the boot parameters 'tcb selinux=0', adding
the above 'dont_measure obj_type=var_log_t' rule to the default IMA TCB
measurement policy, would result in nothing being measured.  The patch
prevents the default TCB policy from being replaced.

Signed-off-by: Mimi Zohar <zohar@us.ibm.com>
Cc: James Morris <jmorris@namei.org>
Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
Cc: David Safford <safford@watson.ibm.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
security/integrity/ima/ima_policy.c