tree c5379a8c9e4c4f72ad0f9ea8ba3067fed25fb1a3
parent 6a2e352de7720906fbd34413970dba8b9913325d
author Nick Kralevich <nnk@google.com> 1484334959 -0800
committer Stephen Smalley <sds@tycho.nsa.gov> 1484336618 -0500

policy_define.c: don't free memory returned from queue_head()

Unlike queue_remove(), queue_head() does not modify the queue, but
rather, returns a pointer to an element within the queue. Freeing the
memory associated with a value returned from that function corrupts
subsequent users of the queue, who may try to reference this
now-deallocated memory.

This causes the following policy generation errors on Android:

  FAILED:
  out/target/product/bullhead/obj/ETC/plat_sepolicy.cil_intermediates/plat_policy_nvr.cil
  /bin/bash -c "out/host/linux-x86/bin/checkpolicy -M -C -c 30 -o
  out/target/product/bullhead/obj/ETC/plat_sepolicy.cil_intermediates/plat_policy_nvr.cil
  out/target/product/bullhead/obj/ETC/plat_sepolicy.cil_intermediates/plat_policy.conf"
  system/sepolicy/public/app.te:241:ERROR 'only ioctl extended permissions
  are supported' at token ';' on line 6784:
  #line 241
  } };
  checkpolicy:  error(s) encountered while parsing configuration

because the value of "id" in:

  id = queue_remove(id_queue);
  if (strcmp(id,"ioctl") == 0) {
    ...
  } else {
    yyerror("only ioctl extended permissions are supported");
    ...
  }

is now garbage.

This is a partial revert of the following commit:

  c1ba8311 checkpolicy: free id where it was leaked

Signed-off-by: Nick Kralevich <nnk@google.com>