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// SPDX-License-Identifier: MIT
/*
* The 'fsverity sign' command
*
* Copyright 2018 Google LLC
*
* Use of this source code is governed by an MIT-style
* license that can be found in the LICENSE file or at
* https://opensource.org/licenses/MIT.
*/
#include "fsverity.h"
#include <fcntl.h>
#include <getopt.h>
static bool write_signature(const char *filename, const u8 *sig, u32 sig_size)
{
struct filedes file;
bool ok;
if (!open_file(&file, filename, O_WRONLY|O_CREAT|O_TRUNC, 0644))
return false;
ok = full_write(&file, sig, sig_size);
ok &= filedes_close(&file);
return ok;
}
static const struct option longopts[] = {
{"hash-alg", required_argument, NULL, OPT_HASH_ALG},
{"block-size", required_argument, NULL, OPT_BLOCK_SIZE},
{"salt", required_argument, NULL, OPT_SALT},
{"key", required_argument, NULL, OPT_KEY},
{"cert", required_argument, NULL, OPT_CERT},
{NULL, 0, NULL, 0}
};
/* Sign a file for fs-verity by computing its digest, then signing it. */
int fsverity_cmd_sign(const struct fsverity_command *cmd,
int argc, char *argv[])
{
struct filedes file = { .fd = -1 };
struct libfsverity_merkle_tree_params tree_params = { .version = 1 };
struct libfsverity_signature_params sig_params = {};
struct libfsverity_digest *digest = NULL;
char digest_hex[FS_VERITY_MAX_DIGEST_SIZE * 2 + 1];
u8 *sig = NULL;
size_t sig_size;
int status;
int c;
while ((c = getopt_long(argc, argv, "", longopts, NULL)) != -1) {
switch (c) {
case OPT_HASH_ALG:
case OPT_BLOCK_SIZE:
case OPT_SALT:
if (!parse_tree_param(c, optarg, &tree_params))
goto out_usage;
break;
case OPT_KEY:
if (sig_params.keyfile != NULL) {
error_msg("--key can only be specified once");
goto out_usage;
}
sig_params.keyfile = optarg;
break;
case OPT_CERT:
if (sig_params.certfile != NULL) {
error_msg("--cert can only be specified once");
goto out_usage;
}
sig_params.certfile = optarg;
break;
default:
goto out_usage;
}
}
argv += optind;
argc -= optind;
if (argc != 2)
goto out_usage;
if (sig_params.keyfile == NULL) {
error_msg("Missing --key argument");
goto out_usage;
}
if (sig_params.certfile == NULL)
sig_params.certfile = sig_params.keyfile;
if (!open_file(&file, argv[0], O_RDONLY, 0))
goto out_err;
if (!get_file_size(&file, &tree_params.file_size))
goto out_err;
if (libfsverity_compute_digest(&file, read_callback,
&tree_params, &digest) != 0) {
error_msg("failed to compute digest");
goto out_err;
}
if (libfsverity_sign_digest(digest, &sig_params,
&sig, &sig_size) != 0) {
error_msg("failed to sign digest");
goto out_err;
}
if (!write_signature(argv[1], sig, sig_size))
goto out_err;
ASSERT(digest->digest_size <= FS_VERITY_MAX_DIGEST_SIZE);
bin2hex(digest->digest, digest->digest_size, digest_hex);
printf("Signed file '%s' (%s:%s)\n", argv[0],
libfsverity_get_hash_name(digest->digest_algorithm), digest_hex);
status = 0;
out:
filedes_close(&file);
destroy_tree_params(&tree_params);
free(digest);
free(sig);
return status;
out_err:
status = 1;
goto out;
out_usage:
usage(cmd, stderr);
status = 2;
goto out;
}