This patch introduces the parser for the compact digest list.
Its format is:
entry_id[2] count[4] data_len[4]
data[data_len]
entry_id[2] count[4] data_len[4]
data[data_len]
...
entry_id, count and data_len are in little endian.
This format is suitable to store a large number of digests, as there is no
metadata provided for each. Digests (which have all the same size) are
concatenated together and placed after the header.
COMPACT_DIGEST (0) and COMPACT_DIGEST_MUTABLE (1) entry IDs are supported.
If the entry ID is COMPACT_DIGEST and appraisal is in enforcing mode, file
updates are denied. If the entry ID is COMPACT_DIGEST_MUTABLE, file updates
are permitted.
Changelog
v1:
- Renamed COMPACT_LIST_ID_DIGEST to COMPACT_DIGEST
- Added support for immutable/mutable files
Signed-off-by: Roberto Sassu <roberto.sassu@xxxxxxxxxx>
---
security/integrity/ima/ima_digest_list.c | 66 ++++++++++++++++++++++++++++++++
1 file changed, 66 insertions(+)
diff --git a/security/integrity/ima/ima_digest_list.c b/security/integrity/ima/ima_digest_list.c
index 28172424e5a2..6ad00ba32c94 100644
--- a/security/integrity/ima/ima_digest_list.c
+++ b/security/integrity/ima/ima_digest_list.c
@@ -23,6 +23,69 @@ enum digest_metadata_fields {DATA_ALGO, DATA_DIGEST, DATA_SIGNATURE,
DATA_FILE_PATH, DATA_REF_ID, DATA_TYPE,
DATA__LAST};
+enum digest_data_types {DATA_TYPE_COMPACT_LIST};
+
+enum compact_list_entry_ids {COMPACT_DIGEST, COMPACT_DIGEST_MUTABLE};
+
+struct compact_list_hdr {
+ u16 entry_id;
+ u32 count;
+ u32 datalen;
+} __packed;
+
+static int ima_parse_compact_list(loff_t size, void *buf)
+{
+ void *bufp = buf, *bufendp = buf + size;
+ int digest_len = hash_digest_size[ima_hash_algo];
+ struct compact_list_hdr *hdr;
+ u8 is_mutable = 0;
+ int ret, i;
+
+ while (bufp < bufendp) {
+ if (bufp + sizeof(*hdr) > bufendp) {
+ pr_err("compact list, missing header\n");
+ return -EINVAL;
+ }
+
+ hdr = bufp;
+
+ if (ima_canonical_fmt) {
+ hdr->entry_id = le16_to_cpu(hdr->entry_id);
+ hdr->count = le32_to_cpu(hdr->count);
+ hdr->datalen = le32_to_cpu(hdr->datalen);
+ }
+
+ switch (hdr->entry_id) {
+ case COMPACT_DIGEST_MUTABLE:
+ is_mutable = 1;
+ case COMPACT_DIGEST:
+ break;
+ default:
+ pr_err("compact list, invalid data type\n");
+ return -EINVAL;
+ }
+
+ bufp += sizeof(*hdr);
+
+ for (i = 0; i < hdr->count &&
+ bufp + digest_len <= bufendp; i++) {
+ ret = ima_add_digest_data_entry(bufp, is_mutable);
+ if (ret < 0 && ret != -EEXIST)
+ return ret;
+
+ bufp += digest_len;
+ }
+
+ if (i != hdr->count ||
+ bufp != (void *)hdr + sizeof(*hdr) + hdr->datalen) {
+ pr_err("compact list, invalid data\n");
+ return -EINVAL;
+ }
+ }
+
+ return 0;
+}
+
static int ima_parse_digest_list_data(struct ima_field_data *data)
{
void *digest_list;
@@ -47,6 +110,9 @@ static int ima_parse_digest_list_data(struct ima_field_data *data)
}
switch (data_type) {
+ case DATA_TYPE_COMPACT_LIST:
+ ret = ima_parse_compact_list(digest_list_size, digest_list);
+ break;
default:
pr_err("Parser for data type %d not implemented\n", data_type);
ret = -EINVAL;
--
2.11.0
