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, 22 insertions, 9 deletions

diff --git a/security/integrity/evm/evm_secfs.c b/security/integrity/evm/evm_secfs.c
index bbc85637e18b..8a9db7dfca7e 100644
--- a/security/integrity/evm/evm_secfs.c
+++ b/security/integrity/evm/evm_secfs.c
@@ -66,12 +66,13 @@ static ssize_t evm_read_key(struct file *filp, char __user *buf,
 static ssize_t evm_write_key(struct file *file, const char __user *buf,
 			     size_t count, loff_t *ppos)
 {
-	int i, ret;
+	unsigned int i;
+	int ret;
 
 	if (!capable(CAP_SYS_ADMIN) || (evm_initialized & EVM_SETUP_COMPLETE))
 		return -EPERM;
 
-	ret = kstrtoint_from_user(buf, count, 0, &i);
+	ret = kstrtouint_from_user(buf, count, 0, &i);
 
 	if (ret)
 		return ret;
@@ -80,12 +81,12 @@ static ssize_t evm_write_key(struct file *file, const char __user *buf,
 	if (!i || (i & ~EVM_INIT_MASK) != 0)
 		return -EINVAL;
 
-	/* Don't allow a request to freshly enable metadata writes if
-	 * keys are loaded.
+	/*
+	 * Don't allow a request to enable metadata writes if
+	 * an HMAC key is loaded.
 	 */
 	if ((i & EVM_ALLOW_METADATA_WRITES) &&
-	    ((evm_initialized & EVM_KEY_MASK) != 0) &&
-	    !(evm_initialized & EVM_ALLOW_METADATA_WRITES))
+	    (evm_initialized & EVM_INIT_HMAC) != 0)
 		return -EPERM;
 
 	if (i & EVM_INIT_HMAC) {
@@ -138,8 +139,12 @@ static ssize_t evm_read_xattrs(struct file *filp, char __user *buf,
 	if (rc)
 		return -ERESTARTSYS;
 
-	list_for_each_entry(xattr, &evm_config_xattrnames, list)
+	list_for_each_entry(xattr, &evm_config_xattrnames, list) {
+		if (!xattr->enabled)
+			continue;
+
 		size += strlen(xattr->name) + 1;
+	}
 
 	temp = kmalloc(size + 1, GFP_KERNEL);
 	if (!temp) {
@@ -148,6 +153,9 @@ static ssize_t evm_read_xattrs(struct file *filp, char __user *buf,
 	}
 
 	list_for_each_entry(xattr, &evm_config_xattrnames, list) {
+		if (!xattr->enabled)
+			continue;
+
 		sprintf(temp + offset, "%s\n", xattr->name);
 		offset += strlen(xattr->name) + 1;
 	}
@@ -189,7 +197,7 @@ static ssize_t evm_write_xattrs(struct file *file, const char __user *buf,
 
 	ab = audit_log_start(audit_context(), GFP_KERNEL,
 			     AUDIT_INTEGRITY_EVM_XATTR);
-	if (!ab)
+	if (!ab && IS_ENABLED(CONFIG_AUDIT))
 		return -ENOMEM;
 
 	xattr = kmalloc(sizeof(struct xattr_list), GFP_KERNEL);
@@ -198,6 +206,7 @@ static ssize_t evm_write_xattrs(struct file *file, const char __user *buf,
 		goto out;
 	}
 
+	xattr->enabled = true;
 	xattr->name = memdup_user_nul(buf, count);
 	if (IS_ERR(xattr->name)) {
 		err = PTR_ERR(xattr->name);
@@ -244,6 +253,10 @@ static ssize_t evm_write_xattrs(struct file *file, const char __user *buf,
 	list_for_each_entry(tmp, &evm_config_xattrnames, list) {
 		if (strcmp(xattr->name, tmp->name) == 0) {
 			err = -EEXIST;
+			if (!tmp->enabled) {
+				tmp->enabled = true;
+				err = count;
+			}
 			mutex_unlock(&xattr_list_mutex);
 			goto out;
 		}
@@ -255,7 +268,7 @@ static ssize_t evm_write_xattrs(struct file *file, const char __user *buf,
 	audit_log_end(ab);
 	return count;
 out:
-	audit_log_format(ab, " res=%d", err);
+	audit_log_format(ab, " res=%d", (err < 0) ? err : 0);
 	audit_log_end(ab);
 	if (xattr) {
 		kfree(xattr->name);