Merge tag 'selinux-pr-20240105' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux

Pull selinux updates from Paul Moore:

 - Add a new SELinux initial SID, SECINITSID_INIT, to represent
   userspace processes started before the SELinux policy is loaded in
   early boot.

   Prior to this patch all processes were marked as SECINITSID_KERNEL
   before the SELinux policy was loaded, making it difficult to
   distinquish early boot userspace processes from the kernel in the
   SELinux policy.

   For most users this will be a non-issue as the policy is loaded early
   enough during boot, but for users who load their SELinux policy
   relatively late, this should make it easier to construct meaningful
   security policies.

 - Cleanups to the selinuxfs code by Al, mostly on VFS related issues
   during a policy reload.

   The commit description has more detail, but the quick summary is that
   we are replacing a disconnected directory approach with a temporary
   directory that we swapover at the end of the reload.

 - Fix an issue where the input sanity checking on socket bind()
   operations was slightly different depending on the presence of
   SELinux.

   This is caused by the placement of the LSM hooks in the generic
   socket layer as opposed to the protocol specific bind() handler where
   the protocol specific sanity checks are performed. Mickaël has
   mentioned that he is working to fix this, but in the meantime we just
   ensure that we are replicating the checks properly.

   We need to balance the placement of the LSM hooks with the number of
   LSM hooks; pushing the hooks down into the protocol layers is likely
   not the right answer.

 - Update the avc_has_perm_noaudit() prototype to better match the
   function definition.

 - Migrate from using partial_name_hash() to full_name_hash() the
   filename transition hash table.

   This improves the quality of the code and has the potential for a
   minor performance bump.

 - Consolidate some open coded SELinux access vector comparisions into a
   single new function, avtab_node_cmp(), and use that instead.

   A small, but nice win for code quality and maintainability.

 - Updated the SELinux MAINTAINERS entry with additional information
   around process, bug reporting, etc.

   We're also updating some of our "official" roles: dropping Eric Paris
   and adding Ondrej as a reviewer.

 - Cleanup the coding style crimes in security/selinux/include.

   While I'm not a fan of code churn, I am pushing for more automated
   code checks that can be done at the developer level and one of the
   obvious things to check for is coding style.

   In an effort to start from a "good" base I'm slowly working through
   our source files cleaning them up with the help of clang-format and
   good ol' fashioned human eyeballs; this has the first batch of these
   changes.

   I've been splitting the changes up per-file to help reduce the impact
   if backports are required (either for LTS or distro kernels), and I
   expect the some of the larger files, e.g. hooks.c and ss/services.c,
   will likely need to be split even further.

 - Cleanup old, outdated comments.

* tag 'selinux-pr-20240105' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux: (24 commits)
  selinux: Fix error priority for bind with AF_UNSPEC on PF_INET6 socket
  selinux: fix style issues in security/selinux/include/initial_sid_to_string.h
  selinux: fix style issues in security/selinux/include/xfrm.h
  selinux: fix style issues in security/selinux/include/security.h
  selinux: fix style issues with security/selinux/include/policycap_names.h
  selinux: fix style issues in security/selinux/include/policycap.h
  selinux: fix style issues in security/selinux/include/objsec.h
  selinux: fix style issues with security/selinux/include/netlabel.h
  selinux: fix style issues in security/selinux/include/netif.h
  selinux: fix style issues in security/selinux/include/ima.h
  selinux: fix style issues in security/selinux/include/conditional.h
  selinux: fix style issues in security/selinux/include/classmap.h
  selinux: fix style issues in security/selinux/include/avc_ss.h
  selinux: align avc_has_perm_noaudit() prototype with definition
  selinux: fix style issues in security/selinux/include/avc.h
  selinux: fix style issues in security/selinux/include/audit.h
  MAINTAINERS: drop Eric Paris from his SELinux role
  MAINTAINERS: add Ondrej Mosnacek as a SELinux reviewer
  selinux: remove the wrong comment about multithreaded process handling
  selinux: introduce an initial SID for early boot processes
  ...

1 files changed, 35 insertions, 1 deletions

diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 340b2bbbb2dd..c96836da3802 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -2313,6 +2313,19 @@ static int selinux_bprm_creds_for_exec(struct linux_binprm *bprm)
 	new_tsec->keycreate_sid = 0;
 	new_tsec->sockcreate_sid = 0;
 
+	/*
+	 * Before policy is loaded, label any task outside kernel space
+	 * as SECINITSID_INIT, so that any userspace tasks surviving from
+	 * early boot end up with a label different from SECINITSID_KERNEL
+	 * (if the policy chooses to set SECINITSID_INIT != SECINITSID_KERNEL).
+	 */
+	if (!selinux_initialized()) {
+		new_tsec->sid = SECINITSID_INIT;
+		/* also clear the exec_sid just in case */
+		new_tsec->exec_sid = 0;
+		return 0;
+	}
+
 	if (old_tsec->exec_sid) {
 		new_tsec->sid = old_tsec->exec_sid;
 		/* Reset exec SID on execve. */
@@ -4547,6 +4560,21 @@ static int sock_has_perm(struct sock *sk, u32 perms)
 	if (sksec->sid == SECINITSID_KERNEL)
 		return 0;
 
+	/*
+	 * Before POLICYDB_CAP_USERSPACE_INITIAL_CONTEXT, sockets that
+	 * inherited the kernel context from early boot used to be skipped
+	 * here, so preserve that behavior unless the capability is set.
+	 *
+	 * By setting the capability the policy signals that it is ready
+	 * for this quirk to be fixed. Note that sockets created by a kernel
+	 * thread or a usermode helper executed without a transition will
+	 * still be skipped in this check regardless of the policycap
+	 * setting.
+	 */
+	if (!selinux_policycap_userspace_initial_context() &&
+	    sksec->sid == SECINITSID_INIT)
+		return 0;
+
 	ad_net_init_from_sk(&ad, &net, sk);
 
 	return avc_has_perm(current_sid(), sksec->sid, sksec->sclass, perms,
@@ -4661,6 +4689,13 @@ static int selinux_socket_bind(struct socket *sock, struct sockaddr *address, in
 				return -EINVAL;
 			addr4 = (struct sockaddr_in *)address;
 			if (family_sa == AF_UNSPEC) {
+				if (family == PF_INET6) {
+					/* Length check from inet6_bind_sk() */
+					if (addrlen < SIN6_LEN_RFC2133)
+						return -EINVAL;
+					/* Family check from __inet6_bind() */
+					goto err_af;
+				}
 				/* see __inet_bind(), we only want to allow
 				 * AF_UNSPEC if the address is INADDR_ANY
 				 */
@@ -6425,7 +6460,6 @@ static int selinux_setprocattr(const char *name, void *value, size_t size)
 		if (sid == 0)
 			goto abort_change;
 
-		/* Only allow single threaded processes to change context */
 		if (!current_is_single_threaded()) {
 			error = security_bounded_transition(tsec->sid, sid);
 			if (error)