ima: properly free ima_template_entry structures

The new templates management mechanism records information associated
to an event into an array of 'ima_field_data' structures and makes it
available through the 'template_data' field of the 'ima_template_entry'
structure (the element of the measurements list created by IMA).

Since 'ima_field_data' contains dynamically allocated data (which length
varies depending on the data associated to a selected template field),
it is not enough to just free the memory reserved for a
'ima_template_entry' structure if something goes wrong.

This patch creates the new function ima_free_template_entry() which
walks the array of 'ima_field_data' structures, frees the memory
referenced by the 'data' pointer and finally the space reserved for
the 'ima_template_entry' structure. Further, it replaces existing kfree()
that have a pointer to an 'ima_template_entry' structure as argument
with calls to the new function.

Fixes: a71dc65: ima: switch to new template management mechanism
Signed-off-by: Roberto Sassu <roberto.sassu@polito.it>
Signed-off-by: Mimi Zohar <zohar@us.ibm.com>

diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h
index 9636e17c9f5d709ae735d60bccddd3d2bc481470..0356e1d437ca31cde30910567128168dbfd0a5ca 100644 (file)
--- a/security/integrity/ima/ima.h
+++ b/security/integrity/ima/ima.h
@@ -148,6 +148,7 @@ int ima_alloc_init_template(struct integrity_iint_cache *iint,
                            int xattr_len, struct ima_template_entry **entry);
 int ima_store_template(struct ima_template_entry *entry, int violation,
                       struct inode *inode, const unsigned char *filename);
+void ima_free_template_entry(struct ima_template_entry *entry);
 const char *ima_d_path(struct path *path, char **pathbuf);
 
 /* rbtree tree calls to lookup, insert, delete

diff --git a/security/integrity/ima/ima_api.c b/security/integrity/ima/ima_api.c
index 80374842fe0bb4cfef8a7dec8144eeff5278d408..c38bbce8c6a629e246d8f6bef7557e224707d88b 100644 (file)
--- a/security/integrity/ima/ima_api.c
+++ b/security/integrity/ima/ima_api.c
@@ -21,6 +21,19 @@
 #include <crypto/hash_info.h>
 #include "ima.h"
 
+/*
+ * ima_free_template_entry - free an existing template entry
+ */
+void ima_free_template_entry(struct ima_template_entry *entry)
+{
+       int i;
+
+       for (i = 0; i < entry->template_desc->num_fields; i++)
+               kfree(entry->template_data[i].data);
+
+       kfree(entry);
+}
+
 /*
  * ima_alloc_init_template - create and initialize a new template entry
  */
@@ -37,6 +50,7 @@ int ima_alloc_init_template(struct integrity_iint_cache *iint,
        if (!*entry)
                return -ENOMEM;
 
+       (*entry)->template_desc = template_desc;
        for (i = 0; i < template_desc->num_fields; i++) {
                struct ima_template_field *field = template_desc->fields[i];
                u32 len;
@@ -51,10 +65,9 @@ int ima_alloc_init_template(struct integrity_iint_cache *iint,
                (*entry)->template_data_len += sizeof(len);
                (*entry)->template_data_len += len;
        }
-       (*entry)->template_desc = template_desc;
        return 0;
 out:
-       kfree(*entry);
+       ima_free_template_entry(*entry);
        *entry = NULL;
        return result;
 }
@@ -134,7 +147,7 @@ void ima_add_violation(struct file *file, const unsigned char *filename,
        }
        result = ima_store_template(entry, violation, inode, filename);
        if (result < 0)
-               kfree(entry);
+               ima_free_template_entry(entry);
 err_out:
        integrity_audit_msg(AUDIT_INTEGRITY_PCR, inode, filename,
                            op, cause, result, 0);
@@ -269,7 +282,7 @@ void ima_store_measurement(struct integrity_iint_cache *iint,
        if (!result || result == -EEXIST)
                iint->flags |= IMA_MEASURED;
        if (result < 0)
-               kfree(entry);
+               ima_free_template_entry(entry);
 }
 
 void ima_audit_measurement(struct integrity_iint_cache *iint,

diff --git a/security/integrity/ima/ima_init.c b/security/integrity/ima/ima_init.c
index 76b8e2c4fd38f641de017bd45dcacf225b1b21dc..37122768554a9e69d4866f9c9a72864f157afef3 100644 (file)
--- a/security/integrity/ima/ima_init.c
+++ b/security/integrity/ima/ima_init.c
@@ -75,7 +75,7 @@ static void __init ima_add_boot_aggregate(void)
        result = ima_store_template(entry, violation, NULL,
                                    boot_aggregate_name);
        if (result < 0)
-               kfree(entry);
+               ima_free_template_entry(entry);
        return;
 err_out:
        integrity_audit_msg(AUDIT_INTEGRITY_PCR, NULL, boot_aggregate_name, op,