[PATCH 09/12] ima: introduce securityfs interfaces for digest lists

[Roberto Sassu]

This patch introduces the file 'digest_lists' in the securityfs
filesystem, to load digest lists metadata. IMA will parse the metadata
and loads the digest lists from the path provided.

It also introduces 'digests_count', to show the number of digests
stored in the digest hash table.

Signed-off-by: Roberto Sassu <roberto.sa...@huawei.com>
---
 security/integrity/ima/ima_fs.c | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)

diff --git a/security/integrity/ima/ima_fs.c b/security/integrity/ima/ima_fs.c
index ad3d674..08174c1 100644
--- a/security/integrity/ima/ima_fs.c
+++ b/security/integrity/ima/ima_fs.c
@@ -34,11 +34,15 @@ static struct dentry *ascii_runtime_measurements;
 static struct dentry *runtime_measurements_count;
 static struct dentry *violations;
 static struct dentry *ima_policy;
+static struct dentry *digest_lists;
+static struct dentry *digests_count;
 
 static enum kernel_read_file_id ima_get_file_id(struct dentry *dentry)
 {
        if (dentry == ima_policy)
                return READING_POLICY;
+       else if (dentry == digest_lists)
+               return READING_DIGEST_LIST;
 
        return READING_UNKNOWN;
 }
@@ -66,6 +70,8 @@ static ssize_t ima_show_htable_value(struct file *filp, char 
__user *buf,
                val = &ima_htable.violations;
        else if (filp->f_path.dentry == runtime_measurements_count)
                val = &ima_htable.len;
+       else if (filp->f_path.dentry == digests_count)
+               val = &ima_digests_htable.len;
 
        len = scnprintf(tmpbuf, TMPBUFLEN, "%li\n", atomic_long_read(val));
        return simple_read_from_buffer(buf, count, ppos, tmpbuf, len);
@@ -301,6 +307,9 @@ static ssize_t ima_read_file(char *path, enum 
kernel_read_file_id file_id)
 
                        pr_debug("rule: %s\n", p);
                        rc = ima_parse_add_rule(p);
+               } else if (file_id == READING_DIGEST_LIST) {
+                       rc = ima_parse_digest_list_metadata(size, datap);
+                       datap += rc;
                }
                if (rc < 0)
                        break;
@@ -510,8 +519,22 @@ int __init ima_fs_init(void)
        if (IS_ERR(ima_policy))
                goto out;
 
+#ifdef CONFIG_IMA_DIGEST_LIST
+       digest_lists = securityfs_create_file("digest_lists", S_IWUSR, ima_dir,
+                                             NULL, &ima_data_upload_ops);
+       if (IS_ERR(digest_lists))
+               goto out;
+
+       digests_count = securityfs_create_file("digests_count",
+                                              S_IRUSR | S_IRGRP, ima_dir,
+                                              NULL, &ima_htable_value_ops);
+       if (IS_ERR(digests_count))
+               goto out;
+#endif
        return 0;
 out:
+       securityfs_remove(digests_count);
+       securityfs_remove(digest_lists);
        securityfs_remove(violations);
        securityfs_remove(runtime_measurements_count);
        securityfs_remove(ascii_runtime_measurements);
-- 
2.9.3