Merge tag 'selinux-pr-20210426' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux

Pull selinux updates from Paul Moore:

 - Add support for measuring the SELinux state and policy capabilities
   using IMA.

 - A handful of SELinux/NFS patches to compare the SELinux state of one
   mount with a set of mount options. Olga goes into more detail in the
   patch descriptions, but this is important as it allows more
   flexibility when using NFS and SELinux context mounts.

 - Properly differentiate between the subjective and objective LSM
   credentials; including support for the SELinux and Smack. My clumsy
   attempt at a proper fix for AppArmor didn't quite pass muster so John
   is working on a proper AppArmor patch, in the meantime this set of
   patches shouldn't change the behavior of AppArmor in any way. This
   change explains the bulk of the diffstat beyond security/.

 - Fix a problem where we were not properly terminating the permission
   list for two SELinux object classes.

* tag 'selinux-pr-20210426' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux:
  selinux: add proper NULL termination to the secclass_map permissions
  smack: differentiate between subjective and objective task credentials
  selinux: clarify task subjective and objective credentials
  lsm: separate security_task_getsecid() into subjective and objective variants
  nfs: account for selinux security context when deciding to share superblock
  nfs: remove unneeded null check in nfs_fill_super()
  lsm,selinux: add new hook to compare new mount to an existing mount
  selinux: fix misspellings using codespell tool
  selinux: fix misspellings using codespell tool
  selinux: measure state and policy capabilities
  selinux: Allow context mounts for unpriviliged overlayfs

1 files changed, 10 insertions, 1 deletions

diff --git a/drivers/android/binder.c b/drivers/android/binder.c
index 63d2c4339689..61d34e1dc59c 100644
--- a/drivers/android/binder.c
+++ b/drivers/android/binder.c
@@ -2713,7 +2713,16 @@ static void binder_transaction(struct binder_proc *proc,
 		u32 secid;
 		size_t added_size;
 
-		security_task_getsecid(proc->tsk, &secid);
+		/*
+		 * Arguably this should be the task's subjective LSM secid but
+		 * we can't reliably access the subjective creds of a task
+		 * other than our own so we must use the objective creds, which
+		 * are safe to access.  The downside is that if a task is
+		 * temporarily overriding it's creds it will not be reflected
+		 * here; however, it isn't clear that binder would handle that
+		 * case well anyway.
+		 */
+		security_task_getsecid_obj(proc->tsk, &secid);
 		ret = security_secid_to_secctx(secid, &secctx, &secctx_sz);
 		if (ret) {
 			return_error = BR_FAILED_REPLY;