[RFC][PATCH v2 10/12] diglim: Interfaces - digests_count

Roberto Sassu
2021-07-26T16:41:09Z

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

Reported-by: kernel test robot <lkp@intel.com> (frame size warning)
Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
---
security/integrity/diglim/fs.c | 48 ++++++++++++++++++++++++++++++++++
1 file changed, 48 insertions(+)

diff --git a/security/integrity/diglim/fs.c b/security/integrity/diglim/fs.c
index f1c1fc56448a..3b1d9616cb62 100644
--- a/security/integrity/diglim/fs.c
+++ b/security/integrity/diglim/fs.c
@@ -23,6 +23,7 @@
#include "diglim.h"

#define MAX_DIGEST_LIST_SIZE (64 * 1024 * 1024 - 1)
+#define TMPBUF_SIZE 512

static struct dentry *diglim_dir;
/**
@@ -36,6 +37,13 @@ static struct dentry *diglim_dir;
* removed.
*/
static struct dentry *digest_lists_loaded_dir;
+/**
+ * DOC: digests_count
+ *
+ * digests_count shows the current number of digests stored in the hash
+ * table by type.
+ */
+static struct dentry *digests_count;
/**
* DOC: digest_label
*
@@ -73,6 +81,39 @@ 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 diglim_show_htable_len(struct file *filp, char __user *buf,
+ size_t count, loff_t *ppos)
+{
+ char *tmpbuf;
+ ssize_t ret, len = 0;
+ int i;
+
+ tmpbuf = kmalloc(TMPBUF_SIZE, GFP_KERNEL);
+ if (!tmpbuf)
+ return -ENOMEM;
+
+ for (i = COMPACT_PARSER; i < COMPACT__LAST; i++)
+ len += scnprintf(tmpbuf + len, TMPBUF_SIZE - len,
+ "%s digests: %lu\n", types_str[i],
+ htable[i].len);
+
+ ret = simple_read_from_buffer(buf, count, ppos, tmpbuf, len);
+ kfree(tmpbuf);
+ return ret;
+}
+
+static const struct file_operations htable_len_ops = {
+ .read = diglim_show_htable_len,
+ .llseek = generic_file_llseek,
+};
+
static int parse_digest_list_filename(const char *digest_list_filename,
u8 *digest, enum hash_algo *algo)
{
@@ -696,6 +737,12 @@ static int __init diglim_fs_init(void)
if (IS_ERR(digest_lists_loaded_dir))
goto out;

+ digests_count = securityfs_create_file("digests_count", 0440,
+ diglim_dir, NULL,
+ &htable_len_ops);
+ if (IS_ERR(digests_count))
+ goto out;
+
digest_list_add_dentry = securityfs_create_file("digest_list_add", 0200,
diglim_dir, NULL,
&digest_list_upload_ops);
@@ -726,6 +773,7 @@ static int __init diglim_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(diglim_dir);
return -1;
--
2.25.1