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// SPDX-License-Identifier: GPL-2.0+
/*
* The 'fsverity enable' command
*
* Copyright (C) 2018 Google LLC
*
* Written by Eric Biggers.
*/
#include "commands.h"
#include "fsverity_uapi.h"
#include "hash_algs.h"
#include <fcntl.h>
#include <getopt.h>
#include <limits.h>
#include <stdlib.h>
#include <string.h>
#include <sys/ioctl.h>
static bool parse_hash_alg_option(const char *arg, u32 *alg_ptr)
{
char *end;
unsigned long n = strtoul(arg, &end, 10);
const struct fsverity_hash_alg *alg;
if (*alg_ptr != 0) {
error_msg("--hash-alg can only be specified once");
return false;
}
/* Specified by number? */
if (n > 0 && n < INT32_MAX && *end == '\0') {
*alg_ptr = n;
return true;
}
/* Specified by name? */
alg = find_hash_alg_by_name(arg);
if (alg != NULL) {
*alg_ptr = alg - fsverity_hash_algs;
return true;
}
return false;
}
static bool read_signature(const char *filename, u8 **sig_ret,
u32 *sig_size_ret)
{
struct filedes file = { .fd = -1 };
u64 file_size;
u8 *sig = NULL;
bool ok = false;
if (!open_file(&file, filename, O_RDONLY, 0))
goto out;
if (!get_file_size(&file, &file_size))
goto out;
if (file_size <= 0) {
error_msg("signature file '%s' is empty", filename);
goto out;
}
if (file_size > 1000000) {
error_msg("signature file '%s' is too large", filename);
goto out;
}
sig = xmalloc(file_size);
if (!full_read(&file, sig, file_size))
goto out;
*sig_ret = sig;
*sig_size_ret = file_size;
sig = NULL;
ok = true;
out:
filedes_close(&file);
free(sig);
return ok;
}
enum {
OPT_HASH_ALG,
OPT_BLOCK_SIZE,
OPT_SALT,
OPT_SIGNATURE,
};
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},
{"signature", required_argument, NULL, OPT_SIGNATURE},
{NULL, 0, NULL, 0}
};
/* Enable fs-verity on a file. */
int fsverity_cmd_enable(const struct fsverity_command *cmd,
int argc, char *argv[])
{
struct fsverity_enable_arg arg = { .version = 1 };
u8 *salt = NULL;
u8 *sig = NULL;
struct filedes file;
int status;
int c;
while ((c = getopt_long(argc, argv, "", longopts, NULL)) != -1) {
switch (c) {
case OPT_HASH_ALG:
if (!parse_hash_alg_option(optarg, &arg.hash_algorithm))
goto out_usage;
break;
case OPT_BLOCK_SIZE:
if (!parse_block_size_option(optarg, &arg.block_size))
goto out_usage;
break;
case OPT_SALT:
if (!parse_salt_option(optarg, &salt, &arg.salt_size))
goto out_usage;
arg.salt_ptr = (uintptr_t)salt;
break;
case OPT_SIGNATURE:
if (sig != NULL) {
error_msg("--signature can only be specified once");
goto out_usage;
}
if (!read_signature(optarg, &sig, &arg.sig_size))
goto out_err;
arg.sig_ptr = (uintptr_t)sig;
break;
default:
goto out_usage;
}
}
argv += optind;
argc -= optind;
if (argc != 1)
goto out_usage;
if (arg.hash_algorithm == 0)
arg.hash_algorithm = FS_VERITY_HASH_ALG_DEFAULT;
if (arg.block_size == 0)
arg.block_size = get_default_block_size();
if (!open_file(&file, argv[0], O_RDONLY, 0))
goto out_err;
if (ioctl(file.fd, FS_IOC_ENABLE_VERITY, &arg) != 0) {
error_msg_errno("FS_IOC_ENABLE_VERITY failed on '%s'",
file.name);
filedes_close(&file);
goto out_err;
}
if (!filedes_close(&file))
goto out_err;
status = 0;
out:
free(salt);
free(sig);
return status;
out_err:
status = 1;
goto out;
out_usage:
usage(cmd, stderr);
status = 2;
goto out;
}
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