ima: define a new template field named 'd-ngv2' and templates

In preparation to differentiate between unsigned regular IMA file
hashes and fs-verity's file digests in the IMA measurement list,
define a new template field named 'd-ngv2'.

Also define two new templates named 'ima-ngv2' and 'ima-sigv2', which
include the new 'd-ngv2' field.

Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>

1 files changed, 65 insertions, 11 deletions

diff --git a/security/integrity/ima/ima_template_lib.c b/security/integrity/ima/ima_template_lib.c
index 4b6706f864d4..409023e620d6 100644
--- a/security/integrity/ima/ima_template_lib.c
+++ b/security/integrity/ima/ima_template_lib.c
@@ -24,11 +24,22 @@ static bool ima_template_hash_algo_allowed(u8 algo)
 enum data_formats {
 	DATA_FMT_DIGEST = 0,
 	DATA_FMT_DIGEST_WITH_ALGO,
+	DATA_FMT_DIGEST_WITH_TYPE_AND_ALGO,
 	DATA_FMT_STRING,
 	DATA_FMT_HEX,
 	DATA_FMT_UINT
 };
 
+enum digest_type {
+	DIGEST_TYPE_IMA,
+	DIGEST_TYPE__LAST
+};
+
+#define DIGEST_TYPE_NAME_LEN_MAX 4	/* including NUL */
+static const char * const digest_type_name[DIGEST_TYPE__LAST] = {
+	[DIGEST_TYPE_IMA] = "ima"
+};
+
 static int ima_write_template_field_data(const void *data, const u32 datalen,
 					 enum data_formats datafmt,
 					 struct ima_field_data *field_data)
@@ -72,8 +83,9 @@ static void ima_show_template_data_ascii(struct seq_file *m,
 	u32 buflen = field_data->len;
 
 	switch (datafmt) {
+	case DATA_FMT_DIGEST_WITH_TYPE_AND_ALGO:
 	case DATA_FMT_DIGEST_WITH_ALGO:
-		buf_ptr = strnchr(field_data->data, buflen, ':');
+		buf_ptr = strrchr(field_data->data, ':');
 		if (buf_ptr != field_data->data)
 			seq_printf(m, "%s", field_data->data);
 
@@ -178,6 +190,14 @@ void ima_show_template_digest_ng(struct seq_file *m, enum ima_show_type show,
 				     field_data);
 }
 
+void ima_show_template_digest_ngv2(struct seq_file *m, enum ima_show_type show,
+				   struct ima_field_data *field_data)
+{
+	ima_show_template_field_data(m, show,
+				     DATA_FMT_DIGEST_WITH_TYPE_AND_ALGO,
+				     field_data);
+}
+
 void ima_show_template_string(struct seq_file *m, enum ima_show_type show,
 			      struct ima_field_data *field_data)
 {
@@ -265,28 +285,35 @@ int ima_parse_buf(void *bufstartp, void *bufendp, void **bufcurp,
 }
 
 static int ima_eventdigest_init_common(const u8 *digest, u32 digestsize,
-				       u8 hash_algo,
+				       u8 digest_type, u8 hash_algo,
 				       struct ima_field_data *field_data)
 {
 	/*
 	 * digest formats:
 	 *  - DATA_FMT_DIGEST: digest
 	 *  - DATA_FMT_DIGEST_WITH_ALGO: <hash algo> + ':' + '\0' + digest,
+	 *  - DATA_FMT_DIGEST_WITH_TYPE_AND_ALGO:
+	 *	<digest type> + ':' + <hash algo> + ':' + '\0' + digest,
 	 *
 	 *    where 'DATA_FMT_DIGEST' is the original digest format ('d')
 	 *      with a hash size limitation of 20 bytes,
+	 *    where <digest type> is "ima",
 	 *    where <hash algo> is the hash_algo_name[] string.
 	 */
-	u8 buffer[CRYPTO_MAX_ALG_NAME + 2 + IMA_MAX_DIGEST_SIZE] = { 0 };
+	u8 buffer[DIGEST_TYPE_NAME_LEN_MAX + CRYPTO_MAX_ALG_NAME + 2 +
+		IMA_MAX_DIGEST_SIZE] = { 0 };
 	enum data_formats fmt = DATA_FMT_DIGEST;
 	u32 offset = 0;
 
-	if (hash_algo < HASH_ALGO__LAST) {
+	if (digest_type < DIGEST_TYPE__LAST && hash_algo < HASH_ALGO__LAST) {
+		fmt = DATA_FMT_DIGEST_WITH_TYPE_AND_ALGO;
+		offset += 1 + sprintf(buffer, "%s:%s:",
+				      digest_type_name[digest_type],
+				      hash_algo_name[hash_algo]);
+	} else if (hash_algo < HASH_ALGO__LAST) {
 		fmt = DATA_FMT_DIGEST_WITH_ALGO;
-		offset += snprintf(buffer, CRYPTO_MAX_ALG_NAME + 1, "%s",
-				   hash_algo_name[hash_algo]);
-		buffer[offset] = ':';
-		offset += 2;
+		offset += 1 + sprintf(buffer, "%s:",
+				      hash_algo_name[hash_algo]);
 	}
 
 	if (digest)
@@ -361,7 +388,8 @@ int ima_eventdigest_init(struct ima_event_data *event_data,
 	cur_digestsize = hash.hdr.length;
 out:
 	return ima_eventdigest_init_common(cur_digest, cur_digestsize,
-					   HASH_ALGO__LAST, field_data);
+					   DIGEST_TYPE__LAST, HASH_ALGO__LAST,
+					   field_data);
 }
 
 /*
@@ -382,7 +410,32 @@ int ima_eventdigest_ng_init(struct ima_event_data *event_data,
 	hash_algo = event_data->iint->ima_hash->algo;
 out:
 	return ima_eventdigest_init_common(cur_digest, cur_digestsize,
-					   hash_algo, field_data);
+					   DIGEST_TYPE__LAST, hash_algo,
+					   field_data);
+}
+
+/*
+ * This function writes the digest of an event (without size limit),
+ * prefixed with both the digest type and hash algorithm.
+ */
+int ima_eventdigest_ngv2_init(struct ima_event_data *event_data,
+			      struct ima_field_data *field_data)
+{
+	u8 *cur_digest = NULL, hash_algo = ima_hash_algo;
+	u32 cur_digestsize = 0;
+	u8 digest_type = DIGEST_TYPE_IMA;
+
+	if (event_data->violation)	/* recording a violation. */
+		goto out;
+
+	cur_digest = event_data->iint->ima_hash->digest;
+	cur_digestsize = event_data->iint->ima_hash->length;
+
+	hash_algo = event_data->iint->ima_hash->algo;
+out:
+	return ima_eventdigest_init_common(cur_digest, cur_digestsize,
+					   digest_type, hash_algo,
+					   field_data);
 }
 
 /*
@@ -417,7 +470,8 @@ int ima_eventdigest_modsig_init(struct ima_event_data *event_data,
 	}
 
 	return ima_eventdigest_init_common(cur_digest, cur_digestsize,
-					   hash_algo, field_data);
+					   DIGEST_TYPE__LAST, hash_algo,
+					   field_data);
 }
 
 static int ima_eventname_init_common(struct ima_event_data *event_data,