ima: allocate field pointers array on demand in template_desc_init_fields()
The allocation of a field pointers array is moved at the end of
template_desc_init_fields() and done only if the value of the 'fields'
and 'num_fields' parameters is not NULL. For just validating a template
format string, retrieved template field pointers are placed in a temporary
array.
Changelog:
- v3:
- do not check in this patch if 'fields' and 'num_fields' are NULL
(suggested by Mimi Zohar)
Signed-off-by: Roberto Sassu <roberto.sassu@polito.it>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
diff --git a/security/integrity/ima/ima_template.c b/security/integrity/ima/ima_template.c
index d93a58e..65117ba 100644
--- a/security/integrity/ima/ima_template.c
+++ b/security/integrity/ima/ima_template.c
@@ -117,8 +117,9 @@
int *num_fields)
{
const char *template_fmt_ptr;
+ struct ima_template_field *found_fields[IMA_TEMPLATE_NUM_FIELDS_MAX];
int template_num_fields = template_fmt_size(template_fmt);
- int i, len, result = 0;
+ int i, len;
if (template_num_fields > IMA_TEMPLATE_NUM_FIELDS_MAX) {
pr_err("format string '%s' contains too many fields\n",
@@ -126,41 +127,32 @@
return -EINVAL;
}
- *fields = kzalloc(template_num_fields * sizeof(*fields), GFP_KERNEL);
- if (*fields == NULL) {
- result = -ENOMEM;
- goto out;
- }
-
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;
+ return -EINVAL;
}
memcpy(tmp_field_id, template_fmt_ptr, len);
tmp_field_id[len] = '\0';
- f = lookup_template_field(tmp_field_id);
- if (!f) {
+ found_fields[i] = lookup_template_field(tmp_field_id);
+ if (!found_fields[i]) {
pr_err("field '%s' not found\n", tmp_field_id);
- result = -ENOENT;
- goto out;
+ return -ENOENT;
}
- (*fields)[i] = f;
}
+
+ *fields = kmalloc_array(i, sizeof(*fields), GFP_KERNEL);
+ if (*fields == NULL)
+ return -ENOMEM;
+
+ memcpy(*fields, found_fields, i * sizeof(*fields));
*num_fields = i;
-out:
- if (result < 0) {
- kfree(*fields);
- *fields = NULL;
- }
- return result;
+ return 0;
}
struct ima_template_desc *ima_template_desc_current(void)
