[PATCH v7 08/14] ima: Introduce is_signed()

[Thiago Jung Bauermann]

With the introduction of another IMA signature type (modsig), some places
will need to check for both of them. It is cleaner to do that if there's a
helper function to tell whether an xattr_value represents an IMA
signature.

Suggested-by: Mimi Zohar <zo...@linux.vnet.ibm.com>
Signed-off-by: Thiago Jung Bauermann <bauer...@linux.ibm.com>
---
 security/integrity/ima/ima.h              | 5 +++++
 security/integrity/ima/ima_appraise.c     | 7 +++----
 security/integrity/ima/ima_template_lib.c | 2 +-
 3 files changed, 9 insertions(+), 5 deletions(-)

diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h
index 354bb5716ce3..43d4aaf31f7a 100644
--- a/security/integrity/ima/ima.h
+++ b/security/integrity/ima/ima.h
@@ -154,6 +154,11 @@ unsigned long ima_get_binary_runtime_size(void);
 int ima_init_template(void);
 void ima_init_template_list(void);
 
+static inline bool is_signed(const struct evm_ima_xattr_data *xattr_value)
+{
+       return xattr_value && xattr_value->type == EVM_IMA_XATTR_DIGSIG;
+}
+
 /*
  * used to protect h_table and sha_table
  */
diff --git a/security/integrity/ima/ima_appraise.c 
b/security/integrity/ima/ima_appraise.c
index a6b2995b7d0b..bcbbd8f86fe1 100644
--- a/security/integrity/ima/ima_appraise.c
+++ b/security/integrity/ima/ima_appraise.c
@@ -325,15 +325,14 @@ int ima_appraise_measurement(enum ima_hooks func,
        } else if (status != INTEGRITY_PASS) {
                /* Fix mode, but don't replace file signatures. */
                if ((ima_appraise & IMA_APPRAISE_FIX) &&
-                   (!xattr_value ||
-                    xattr_value->type != EVM_IMA_XATTR_DIGSIG)) {
+                   !is_signed(xattr_value)) {
                        if (!ima_fix_xattr(dentry, iint))
                                status = INTEGRITY_PASS;
                }
 
                /* Permit new files with file signatures, but without data. */
                if (inode->i_size == 0 && iint->flags & IMA_NEW_FILE &&
-                   xattr_value && xattr_value->type == EVM_IMA_XATTR_DIGSIG) {
+                   is_signed(xattr_value)) {
                        status = INTEGRITY_PASS;
                }
 
@@ -448,7 +447,7 @@ int ima_inode_setxattr(struct dentry *dentry, const char 
*xattr_name,
                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);
+                                        is_signed(xvalue));
                result = 0;
        }
        return result;
diff --git a/security/integrity/ima/ima_template_lib.c 
b/security/integrity/ima/ima_template_lib.c
index 43752002c222..300912914b17 100644
--- a/security/integrity/ima/ima_template_lib.c
+++ b/security/integrity/ima/ima_template_lib.c
@@ -382,7 +382,7 @@ int ima_eventsig_init(struct ima_event_data *event_data,
 {
        struct evm_ima_xattr_data *xattr_value = event_data->xattr_value;
 
-       if ((!xattr_value) || (xattr_value->type != EVM_IMA_XATTR_DIGSIG))
+       if (!is_signed(xattr_value))
                return 0;
 
        return ima_write_template_field_data(xattr_value, event_data->xattr_len,