ima: don't allocate a copy of template_fmt in template_desc_init_fields()

[firefly-linux-kernel-4.4.55.git] / security / integrity / ima / ima_template.c

diff --git a/security/integrity/ima/ima_template.c b/security/integrity/ima/ima_template.c
index b7b359ca39ee12017a0721f011558314c84c9153..d93a58e603df2c0acdc50cbdb30ae37f8088822e 100644 (file)
--- a/security/integrity/ima/ima_template.c
+++ b/security/integrity/ima/ima_template.c
@@ -116,9 +116,9 @@ static int template_desc_init_fields(const char *template_fmt,
                                     struct ima_template_field ***fields,
                                     int *num_fields)
 {
-       char *c, *template_fmt_copy, *template_fmt_ptr;
+       const char *template_fmt_ptr;
        int template_num_fields = template_fmt_size(template_fmt);
-       int i, result = 0;
+       int i, len, result = 0;
 
        if (template_num_fields > IMA_TEMPLATE_NUM_FIELDS_MAX) {
                pr_err("format string '%s' contains too many fields\n",
@@ -126,24 +126,29 @@ static int template_desc_init_fields(const char *template_fmt,
                return -EINVAL;
        }
 
-       /* copying is needed as strsep() modifies the original buffer */
-       template_fmt_copy = kstrdup(template_fmt, GFP_KERNEL);
-       if (template_fmt_copy == NULL)
-               return -ENOMEM;
-
        *fields = kzalloc(template_num_fields * sizeof(*fields), GFP_KERNEL);
        if (*fields == NULL) {
                result = -ENOMEM;
                goto out;
        }
 
-       template_fmt_ptr = template_fmt_copy;
-       for (i = 0; (c = strsep(&template_fmt_ptr, "|")) != NULL &&
-            i < template_num_fields; i++) {
-               struct ima_template_field *f = lookup_template_field(c);
+       for (i = 0, template_fmt_ptr = template_fmt; i < template_num_fields;
+            i++, template_fmt_ptr += len + 1) {
+               char tmp_field_id[IMA_TEMPLATE_FIELD_ID_MAX_LEN + 1];
+               struct ima_template_field *f;
+
+               len = strchrnul(template_fmt_ptr, '|') - template_fmt_ptr;
+               if (len == 0 || len > IMA_TEMPLATE_FIELD_ID_MAX_LEN) {
+                       pr_err("Invalid field with length %d\n", len);
+                       result = -EINVAL;
+                       goto out;
+               }
 
+               memcpy(tmp_field_id, template_fmt_ptr, len);
+               tmp_field_id[len] = '\0';
+               f = lookup_template_field(tmp_field_id);
                if (!f) {
-                       pr_err("field '%s' not found\n", c);
+                       pr_err("field '%s' not found\n", tmp_field_id);
                        result = -ENOENT;
                        goto out;
                }
@@ -155,7 +160,6 @@ out:
                kfree(*fields);
                *fields = NULL;
        }
-       kfree(template_fmt_copy);
        return result;
 }