1 files changed, 167 insertions, 1 deletions

diff --git a/host/lib/cbfstool.c b/host/lib/cbfstool.c
index 4bbed028..0f6ed16f 100644
--- a/host/lib/cbfstool.c
+++ b/host/lib/cbfstool.c
@@ -4,9 +4,12 @@
  */
 
 #include "2common.h"
+#include "2crypto.h"
 #include "2return_codes.h"
-#include "subprocess.h"
 #include "cbfstool.h"
+#include "host_misc.h"
+#include "subprocess.h"
+#include "vboot_host.h"
 
 static const char *get_cbfstool_path(void)
 {
@@ -68,3 +71,166 @@ vb2_error_t cbfstool_truncate(const char *file, const char *region,
 
 	return VB2_SUCCESS;
 }
+
+/* Requires null-terminated buffer */
+static vb2_error_t extract_metadata_hash(const char *buf, struct vb2_hash *hash)
+{
+	enum vb2_hash_algorithm algo;
+	const char *to_find = "\n[METADATA HASH]";
+	char *algo_str = NULL;
+	char *hash_str = NULL;
+	vb2_error_t rv = VB2_ERROR_CBFSTOOL;
+
+	const char *start = strstr(buf, to_find);
+	if (start)
+		start += strlen(to_find);
+
+	if (start) {
+		const int matches = sscanf(start, " %m[^:\n\t ]:%m[^:\n\t ]",
+					   &algo_str, &hash_str);
+
+		if (matches < 2)
+			goto done;
+
+		if (!algo_str || !vb2_lookup_hash_alg(algo_str, &algo) ||
+		    algo == VB2_HASH_INVALID)
+			goto done;
+		hash->algo = algo;
+
+		if (!hash_str ||
+		    strlen(hash_str) != (vb2_digest_size(algo) * 2) ||
+		    !parse_hash(&hash->raw[0], vb2_digest_size(algo), hash_str))
+			goto done;
+
+		if (!strstr(buf, "] fully valid"))
+			goto done;
+
+		rv = VB2_SUCCESS;
+	}
+
+done:
+	if (rv != VB2_SUCCESS)
+		hash->algo = VB2_HASH_INVALID;
+
+	free(algo_str);
+	free(hash_str);
+
+	return rv;
+}
+
+vb2_error_t cbfstool_get_metadata_hash(const char *file, const char *region,
+				       struct vb2_hash *hash)
+{
+	int status;
+	const char *cbfstool = get_cbfstool_path();
+	const size_t data_buffer_sz = 1024 * 1024;
+	char *data_buffer = malloc(data_buffer_sz);
+	vb2_error_t rv = VB2_ERROR_CBFSTOOL;
+
+	if (!data_buffer)
+		goto done;
+
+	memset(hash, 0, sizeof(*hash));
+	hash->algo = VB2_HASH_INVALID;
+
+	struct subprocess_target output = {
+		.type = TARGET_BUFFER_NULL_TERMINATED,
+		.buffer = {
+			.buf = data_buffer,
+			.size = data_buffer_sz,
+		},
+	};
+	const char *argv[] = {
+		cbfstool, file, "print", "-kv",
+		region ? "-r" : NULL, region, NULL
+	};
+
+	status = subprocess_run(argv, &subprocess_null, &output,
+				&subprocess_null);
+
+	if (status < 0) {
+		fprintf(stderr, "%s(): cbfstool invocation failed: %m\n",
+			__func__);
+		exit(1);
+	}
+
+	if (status > 0)
+		goto done;
+
+	rv = extract_metadata_hash(data_buffer, hash);
+
+done:
+	free(data_buffer);
+	return rv;
+}
+
+/* Requires null-terminated buffer */
+static char *extract_config_value(const char *buf, const char *config_field)
+{
+	char *to_find = NULL;
+
+	if (asprintf(&to_find, "\n%s=", config_field) == -1) {
+		fprintf(stderr, "Out of Memory\n");
+		VB2_DIE("Out of memory\n");
+	}
+
+	const char *start = strstr(buf, to_find);
+	if (start)
+		start += strlen(to_find);
+
+	free(to_find);
+
+	if (start) {
+		char *end = strchr(start, '\n');
+		if (end)
+			return strndup(start, end - start);
+	}
+
+	return NULL;
+}
+
+vb2_error_t cbfstool_get_config_value(const char *file, const char *region,
+				      const char *config_field, char **value)
+{
+	int status;
+	const char *cbfstool = get_cbfstool_path();
+	const size_t data_buffer_sz = 1024 * 1024;
+	char *data_buffer = malloc(data_buffer_sz);
+	vb2_error_t rv = VB2_ERROR_CBFSTOOL;
+
+	*value = NULL;
+
+	if (!data_buffer)
+		goto done;
+
+	struct subprocess_target output = {
+		.type = TARGET_BUFFER_NULL_TERMINATED,
+		.buffer = {
+			.buf = data_buffer,
+			.size = data_buffer_sz,
+		},
+	};
+	const char *argv[] = {
+		cbfstool, file, "extract", "-n", "config", "-f", "/dev/stdout",
+		region ? "-r" : NULL, region, NULL
+	};
+
+	status = subprocess_run(argv, &subprocess_null, &output,
+				&subprocess_null);
+
+	if (status < 0) {
+		fprintf(stderr, "%s(): cbfstool invocation failed: %m\n",
+			__func__);
+		exit(1);
+	}
+
+	if (status > 0)
+		goto done;
+
+	*value = extract_config_value(data_buffer, config_field);
+
+	rv = VB2_SUCCESS;
+done:
+	free(data_buffer);
+	return rv;
+}