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Subject[PATCH 07/12] ima: added parser for compact digest list
Date
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]
...

The parser supports the COMPACT_LIST_ID_DIGEST entry ID.

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.

Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
---
security/integrity/ima/ima_digest_list.c | 60 ++++++++++++++++++++++++++++++++
1 file changed, 60 insertions(+)

diff --git a/security/integrity/ima/ima_digest_list.c b/security/integrity/ima/ima_digest_list.c
index 3e1ff69b..c1ef79a 100644
--- a/security/integrity/ima/ima_digest_list.c
+++ b/security/integrity/ima/ima_digest_list.c
@@ -23,6 +23,63 @@ 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_LIST_ID_DIGEST};
+
+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;
+ 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);
+ }
+
+ if (hdr->entry_id != COMPACT_LIST_ID_DIGEST) {
+ 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);
+ 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 +104,9 @@ 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;
--
2.9.3
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