Merge branch 'next-integrity' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security

Pull security subsystem integrity updates from James Morris:
 "There is a mixture of bug fixes, code cleanup, preparatory code for
  new functionality and new functionality.

  Commit 26ddabfe96bb ("evm: enable EVM when X509 certificate is
  loaded") enabled EVM without loading a symmetric key, but was limited
  to defining the x509 certificate pathname at build. Included in this
  set of patches is the ability of enabling EVM, without loading the EVM
  symmetric key, from userspace. New is the ability to prevent the
  loading of an EVM symmetric key."

* 'next-integrity' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security:
  ima: Remove redundant conditional operator
  ima: Fix bool initialization/comparison
  ima: check signature enforcement against cmdline param instead of CONFIG
  module: export module signature enforcement status
  ima: fix hash algorithm initialization
  EVM: Only complain about a missing HMAC key once
  EVM: Allow userspace to signal an RSA key has been loaded
  EVM: Include security.apparmor in EVM measurements
  ima: call ima_file_free() prior to calling fasync
  integrity: use kernel_read_file_from_path() to read x509 certs
  ima: always measure and audit files in policy
  ima: don't remove the securityfs policy file
  vfs: fix mounting a filesystem with i_version

1 files changed, 34 insertions, 14 deletions

diff --git a/Documentation/ABI/testing/evm b/Documentation/ABI/testing/evm
index ca622c9aa24c..9578247e1792 100644
--- a/Documentation/ABI/testing/evm
+++ b/Documentation/ABI/testing/evm
@@ -7,17 +7,37 @@ Description:
 		HMAC-sha1 value across the extended attributes, storing the
 		value as the extended attribute 'security.evm'.
 
-		EVM depends on the Kernel Key Retention System to provide it
-		with a trusted/encrypted key for the HMAC-sha1 operation.
-		The key is loaded onto the root's keyring using keyctl.  Until
-		EVM receives notification that the key has been successfully
-		loaded onto the keyring (echo 1 > <securityfs>/evm), EVM
-		can not create or validate the 'security.evm' xattr, but
-		returns INTEGRITY_UNKNOWN.  Loading the key and signaling EVM
-		should be done as early as possible.  Normally this is done
-		in the initramfs, which has already been measured as part
-		of the trusted boot.  For more information on creating and
-		loading existing trusted/encrypted keys, refer to:
-		Documentation/security/keys/trusted-encrypted.rst.  (A sample
-		dracut patch, which loads the trusted/encrypted key and enables
-		EVM, is available from http://linux-ima.sourceforge.net/#EVM.)
+		EVM supports two classes of security.evm. The first is
+		an HMAC-sha1 generated locally with a
+		trusted/encrypted key stored in the Kernel Key
+		Retention System. The second is a digital signature
+		generated either locally or remotely using an
+		asymmetric key. These keys are loaded onto root's
+		keyring using keyctl, and EVM is then enabled by
+		echoing a value to <securityfs>/evm:
+
+		1: enable HMAC validation and creation
+		2: enable digital signature validation
+		3: enable HMAC and digital signature validation and HMAC
+		   creation
+
+		Further writes will be blocked if HMAC support is enabled or
+		if bit 32 is set:
+
+		echo 0x80000002 ><securityfs>/evm
+
+		will enable digital signature validation and block
+		further writes to <securityfs>/evm.
+
+		Until this is done, EVM can not create or validate the
+		'security.evm' xattr, but returns INTEGRITY_UNKNOWN.
+		Loading keys and signaling EVM should be done as early
+		as possible.  Normally this is done in the initramfs,
+		which has already been measured as part of the trusted
+		boot.  For more information on creating and loading
+		existing trusted/encrypted keys, refer to:
+
+		Documentation/security/keys/trusted-encrypted.rst. Both dracut
+		(via 97masterkey and 98integrity) and systemd (via
+		core/ima-setup) have support for loading keys at boot
+		time.