Merge tag 'selinux-pr-20211101' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux

Pull selinux updates from Paul Moore:

 - Add LSM/SELinux/Smack controls and auditing for io-uring.

   As usual, the individual commit descriptions have more detail, but we
   were basically missing two things which we're adding here:

      + establishment of a proper audit context so that auditing of
        io-uring ops works similarly to how it does for syscalls (with
        some io-uring additions because io-uring ops are *not* syscalls)

      + additional LSM hooks to enable access control points for some of
        the more unusual io-uring features, e.g. credential overrides.

   The additional audit callouts and LSM hooks were done in conjunction
   with the io-uring folks, based on conversations and RFC patches
   earlier in the year.

 - Fixup the binder credential handling so that the proper credentials
   are used in the LSM hooks; the commit description and the code
   comment which is removed in these patches are helpful to understand
   the background and why this is the proper fix.

 - Enable SELinux genfscon policy support for securityfs, allowing
   improved SELinux filesystem labeling for other subsystems which make
   use of securityfs, e.g. IMA.

* tag 'selinux-pr-20211101' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux:
  security: Return xattr name from security_dentry_init_security()
  selinux: fix a sock regression in selinux_ip_postroute_compat()
  binder: use cred instead of task for getsecid
  binder: use cred instead of task for selinux checks
  binder: use euid from cred instead of using task
  LSM: Avoid warnings about potentially unused hook variables
  selinux: fix all of the W=1 build warnings
  selinux: make better use of the nf_hook_state passed to the NF hooks
  selinux: fix race condition when computing ocontext SIDs
  selinux: remove unneeded ipv6 hook wrappers
  selinux: remove the SELinux lockdown implementation
  selinux: enable genfscon labeling for securityfs
  Smack: Brutalist io_uring support
  selinux: add support for the io_uring access controls
  lsm,io_uring: add LSM hooks to io_uring
  io_uring: convert io_uring to the secure anon inode interface
  fs: add anon_inode_getfile_secure() similar to anon_inode_getfd_secure()
  audit: add filtering for io_uring records
  audit,io_uring,io-wq: add some basic audit support to io_uring
  audit: prepare audit_context for use in calling contexts beyond syscalls

1 files changed, 46 insertions, 0 deletions

diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index 0622e67c73e9..efd35b07c7f8 100644
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -4700,6 +4700,48 @@ static int smack_dentry_create_files_as(struct dentry *dentry, int mode,
 	return 0;
 }
 
+#ifdef CONFIG_IO_URING
+/**
+ * smack_uring_override_creds - Is io_uring cred override allowed?
+ * @new: the target creds
+ *
+ * Check to see if the current task is allowed to override it's credentials
+ * to service an io_uring operation.
+ */
+static int smack_uring_override_creds(const struct cred *new)
+{
+	struct task_smack *tsp = smack_cred(current_cred());
+	struct task_smack *nsp = smack_cred(new);
+
+	/*
+	 * Allow the degenerate case where the new Smack value is
+	 * the same as the current Smack value.
+	 */
+	if (tsp->smk_task == nsp->smk_task)
+		return 0;
+
+	if (smack_privileged_cred(CAP_MAC_OVERRIDE, current_cred()))
+		return 0;
+
+	return -EPERM;
+}
+
+/**
+ * smack_uring_sqpoll - check if a io_uring polling thread can be created
+ *
+ * Check to see if the current task is allowed to create a new io_uring
+ * kernel polling thread.
+ */
+static int smack_uring_sqpoll(void)
+{
+	if (smack_privileged_cred(CAP_MAC_ADMIN, current_cred()))
+		return 0;
+
+	return -EPERM;
+}
+
+#endif /* CONFIG_IO_URING */
+
 struct lsm_blob_sizes smack_blob_sizes __lsm_ro_after_init = {
 	.lbs_cred = sizeof(struct task_smack),
 	.lbs_file = sizeof(struct smack_known *),
@@ -4852,6 +4894,10 @@ static struct security_hook_list smack_hooks[] __lsm_ro_after_init = {
 	LSM_HOOK_INIT(inode_copy_up, smack_inode_copy_up),
 	LSM_HOOK_INIT(inode_copy_up_xattr, smack_inode_copy_up_xattr),
 	LSM_HOOK_INIT(dentry_create_files_as, smack_dentry_create_files_as),
+#ifdef CONFIG_IO_URING
+	LSM_HOOK_INIT(uring_override_creds, smack_uring_override_creds),
+	LSM_HOOK_INIT(uring_sqpoll, smack_uring_sqpoll),
+#endif
 };