[RFC][PATCH 11/12] digest_lists: Interfaces - digests_count

Roberto Sassu
2021-06-25T16:59:22Z

This patch introduces the digests_count interface, which shows the current
number of digests stored in the hash table by type.

Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
---
Documentation/security/digest_lists.rst | 7 +++++
security/integrity/digest_lists/fs.c | 35 +++++++++++++++++++++++++
2 files changed, 42 insertions(+)

diff --git a/Documentation/security/digest_lists.rst b/Documentation/security/digest_lists.rst
index f3900a6e92f6..25b5665bbeaa 100644
--- a/Documentation/security/digest_lists.rst
+++ b/Documentation/security/digest_lists.rst
@@ -697,3 +697,10 @@ digest list (buffer) loaded ``through digest_list_add``.

``digest_query``: allows to write a query in the format ``<algo>-<digest>``
and to obtain all digest lists that include that digest.
+
+
+``digests_count``
+~~~~~~~~~~~~~~~~~
+
+``digests_count`` shows the current number of digests stored in the hash
+table by type.
diff --git a/security/integrity/digest_lists/fs.c b/security/integrity/digest_lists/fs.c
index bdfeb8797760..37091db50df5 100644
--- a/security/integrity/digest_lists/fs.c
+++ b/security/integrity/digest_lists/fs.c
@@ -37,6 +37,7 @@

static struct dentry *digest_lists_dir;
static struct dentry *digest_lists_loaded_dir;
+static struct dentry *digests_count;
static struct dentry *digest_label_dentry;
static struct dentry *digest_query_dentry;
static struct dentry *digest_list_add_dentry;
@@ -44,6 +45,33 @@ static struct dentry *digest_list_del_dentry;
char digest_query[CRYPTO_MAX_ALG_NAME + 1 + IMA_MAX_DIGEST_SIZE * 2 + 1];
char digest_label[NAME_MAX + 1];

+static char *types_str[COMPACT__LAST] = {
+ [COMPACT_PARSER] = "Parser",
+ [COMPACT_FILE] = "File",
+ [COMPACT_METADATA] = "Metadata",
+ [COMPACT_DIGEST_LIST] = "Digest list",
+};
+
+static ssize_t digest_lists_show_htable_len(struct file *filp, char __user *buf,
+ size_t count, loff_t *ppos)
+{
+ char tmpbuf[1024];
+ ssize_t len = 0;
+ int i;
+
+ for (i = COMPACT_PARSER; i < COMPACT__LAST; i++)
+ len += scnprintf(tmpbuf + len, sizeof(tmpbuf) - len,
+ "%s digests: %li\n", types_str[i],
+ atomic_long_read(&htable[i].len));
+
+ return simple_read_from_buffer(buf, count, ppos, tmpbuf, len);
+}
+
+static const struct file_operations htable_len_ops = {
+ .read = digest_lists_show_htable_len,
+ .llseek = generic_file_llseek,
+};
+
static int parse_digest_list_filename(const char *digest_list_filename,
u8 *digest, enum hash_algo *algo)
{
@@ -646,6 +674,12 @@ static int __init digest_lists_fs_init(void)
if (IS_ERR(digest_lists_loaded_dir))
goto out;

+ digests_count = securityfs_create_file("digests_count", 0440,
+ digest_lists_dir, NULL,
+ &htable_len_ops);
+ if (IS_ERR(digests_count))
+ goto out;
+
digest_list_add_dentry = securityfs_create_file("digest_list_add", 0200,
digest_lists_dir, NULL,
&digest_list_upload_ops);
@@ -676,6 +710,7 @@ static int __init digest_lists_fs_init(void)
securityfs_remove(digest_label_dentry);
securityfs_remove(digest_list_del_dentry);
securityfs_remove(digest_list_add_dentry);
+ securityfs_remove(digests_count);
securityfs_remove(digest_lists_loaded_dir);
securityfs_remove(digest_lists_dir);
return -1;
--
2.25.1