Merge tag 'integrity-v5.14' of git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity

Pull integrity subsystem updates from Mimi Zohar:
 "The large majority of the changes are EVM portable & immutable
  signature related: removing a dependency on loading an HMAC key,
  safely allowing file metadata included in the EVM portable & immutable
  signatures to be modified, allowing EVM signatures to fulfill IMA file
  signature policy requirements, including the EVM file metadata
  signature in lieu of an IMA file data signature in the measurement
  list, and adding dynamic debugging of EVM file metadata.

  In addition, in order to detect critical data or file change
  reversions, duplicate measurement records are permitted in the IMA
  measurement list.

  The remaining patches address compiler, sparse, and doc warnings"

* tag 'integrity-v5.14' of git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity: (31 commits)
  evm: Check xattr size discrepancy between kernel and user
  evm: output EVM digest calculation info
  IMA: support for duplicate measurement records
  ima: Fix warning: no previous prototype for function 'ima_add_kexec_buffer'
  ima: differentiate between EVM failures in the audit log
  ima: Fix fall-through warning for Clang
  ima: Pass NULL instead of 0 to ima_get_action() in ima_file_mprotect()
  ima: Include header defining ima_post_key_create_or_update()
  ima/evm: Fix type mismatch
  ima: Set correct casting types
  doc: Fix warning in Documentation/security/IMA-templates.rst
  evm: Don't return an error in evm_write_xattrs() if audit is not enabled
  ima: Define new template evm-sig
  ima: Define new template fields xattrnames, xattrlengths and xattrvalues
  evm: Verify portable signatures against all protected xattrs
  ima: Define new template field imode
  ima: Define new template fields iuid and igid
  ima: Add ima_show_template_uint() template library function
  ima: Don't remove security.ima if file must not be appraised
  ima: Introduce template field evmsig and write to field sig as fallback
  ...

1 files changed, 30 insertions, 14 deletions

diff --git a/security/integrity/ima/ima_appraise.c b/security/integrity/ima/ima_appraise.c
index 4e5eb0236278..ef9dcfce45d4 100644
--- a/security/integrity/ima/ima_appraise.c
+++ b/security/integrity/ima/ima_appraise.c
@@ -242,12 +242,16 @@ static int xattr_verify(enum ima_hooks func, struct integrity_iint_cache *iint,
 		hash_start = 1;
 		fallthrough;
 	case IMA_XATTR_DIGEST:
-		if (iint->flags & IMA_DIGSIG_REQUIRED) {
-			*cause = "IMA-signature-required";
-			*status = INTEGRITY_FAIL;
-			break;
+		if (*status != INTEGRITY_PASS_IMMUTABLE) {
+			if (iint->flags & IMA_DIGSIG_REQUIRED) {
+				*cause = "IMA-signature-required";
+				*status = INTEGRITY_FAIL;
+				break;
+			}
+			clear_bit(IMA_DIGSIG, &iint->atomic_flags);
+		} else {
+			set_bit(IMA_DIGSIG, &iint->atomic_flags);
 		}
-		clear_bit(IMA_DIGSIG, &iint->atomic_flags);
 		if (xattr_len - sizeof(xattr_value->type) - hash_start >=
 				iint->ima_hash->length)
 			/*
@@ -416,6 +420,10 @@ int ima_appraise_measurement(enum ima_hooks func,
 	case INTEGRITY_NOLABEL:		/* No security.evm xattr. */
 		cause = "missing-HMAC";
 		goto out;
+	case INTEGRITY_FAIL_IMMUTABLE:
+		set_bit(IMA_DIGSIG, &iint->atomic_flags);
+		cause = "invalid-fail-immutable";
+		goto out;
 	case INTEGRITY_FAIL:		/* Invalid HMAC/signature. */
 		cause = "invalid-HMAC";
 		goto out;
@@ -459,9 +467,12 @@ out:
 				status = INTEGRITY_PASS;
 		}
 
-		/* Permit new files with file signatures, but without data. */
+		/*
+		 * Permit new files with file/EVM portable signatures, but
+		 * without data.
+		 */
 		if (inode->i_size == 0 && iint->flags & IMA_NEW_FILE &&
-		    xattr_value && xattr_value->type == EVM_IMA_XATTR_DIGSIG) {
+		    test_bit(IMA_DIGSIG, &iint->atomic_flags)) {
 			status = INTEGRITY_PASS;
 		}
 
@@ -522,8 +533,6 @@ void ima_inode_post_setattr(struct user_namespace *mnt_userns,
 		return;
 
 	action = ima_must_appraise(mnt_userns, inode, MAY_ACCESS, POST_SETATTR);
-	if (!action)
-		__vfs_removexattr(&init_user_ns, dentry, XATTR_NAME_IMA);
 	iint = integrity_iint_find(inode);
 	if (iint) {
 		set_bit(IMA_CHANGE_ATTR, &iint->atomic_flags);
@@ -570,6 +579,7 @@ int ima_inode_setxattr(struct dentry *dentry, const char *xattr_name,
 		       const void *xattr_value, size_t xattr_value_len)
 {
 	const struct evm_ima_xattr_data *xvalue = xattr_value;
+	int digsig = 0;
 	int result;
 
 	result = ima_protect_xattr(dentry, xattr_name, xattr_value,
@@ -577,9 +587,14 @@ int ima_inode_setxattr(struct dentry *dentry, const char *xattr_name,
 	if (result == 1) {
 		if (!xattr_value_len || (xvalue->type >= IMA_XATTR_LAST))
 			return -EINVAL;
-		ima_reset_appraise_flags(d_backing_inode(dentry),
-			xvalue->type == EVM_IMA_XATTR_DIGSIG);
-		result = 0;
+		digsig = (xvalue->type == EVM_IMA_XATTR_DIGSIG);
+	} else if (!strcmp(xattr_name, XATTR_NAME_EVM) && xattr_value_len > 0) {
+		digsig = (xvalue->type == EVM_XATTR_PORTABLE_DIGSIG);
+	}
+	if (result == 1 || evm_revalidate_status(xattr_name)) {
+		ima_reset_appraise_flags(d_backing_inode(dentry), digsig);
+		if (result == 1)
+			result = 0;
 	}
 	return result;
 }
@@ -589,9 +604,10 @@ int ima_inode_removexattr(struct dentry *dentry, const char *xattr_name)
 	int result;
 
 	result = ima_protect_xattr(dentry, xattr_name, NULL, 0);
-	if (result == 1) {
+	if (result == 1 || evm_revalidate_status(xattr_name)) {
 		ima_reset_appraise_flags(d_backing_inode(dentry), 0);
-		result = 0;
+		if (result == 1)
+			result = 0;
 	}
 	return result;
 }