diff options
author | Eric Biggers <ebiggers@google.com> | 2020-11-16 12:56:27 -0800 |
---|---|---|
committer | Eric Biggers <ebiggers@google.com> | 2020-11-17 08:42:39 -0800 |
commit | f76d01b8ce8ce13538bac89afa8acfea9e2bdd57 (patch) | |
tree | a68791d62ae6777186f1d14b28a22362a4ebc090 | |
parent | ecac40ae0f9a6eb9a36704befbfa53f2b83cda4b (diff) | |
download | fsverity-utils-f76d01b8ce8ce13538bac89afa8acfea9e2bdd57.tar.gz |
lib: add libfsverity_enable() and libfsverity_enable_with_sig()
Add convenience functions that wrap FS_IOC_ENABLE_VERITY but take a
'struct libfsverity_merkle_tree_params' instead of
'struct fsverity_enable_arg'. This is useful because it allows
libfsverity users to deal with one common struct, and also get the
default parameter handling that libfsverity_compute_digest() does.
Acked-by: Luca Boccassi <luca.boccassi@microsoft.com>
Link: https://lore.kernel.org/r/20201116205628.262173-4-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@google.com>
-rw-r--r-- | include/libfsverity.h | 36 | ||||
-rw-r--r-- | lib/enable.c | 47 | ||||
-rw-r--r-- | programs/cmd_enable.c | 26 | ||||
-rw-r--r-- | programs/fsverity.h | 3 |
4 files changed, 95 insertions, 17 deletions
diff --git a/include/libfsverity.h b/include/libfsverity.h index 985b364..369e1cf 100644 --- a/include/libfsverity.h +++ b/include/libfsverity.h @@ -138,6 +138,42 @@ libfsverity_sign_digest(const struct libfsverity_digest *digest, uint8_t **sig_ret, size_t *sig_size_ret); /** + * libfsverity_enable() - Enable fs-verity on a file + * @fd: read-only file descriptor to the file + * @params: pointer to the Merkle tree parameters + * + * This is a simple wrapper around the FS_IOC_ENABLE_VERITY ioctl. + * + * Return: 0 on success, -EINVAL for invalid arguments, or a negative errno + * value from the FS_IOC_ENABLE_VERITY ioctl. See + * Documentation/filesystems/fsverity.rst in the kernel source tree for + * the possible error codes from FS_IOC_ENABLE_VERITY. + */ +int +libfsverity_enable(int fd, const struct libfsverity_merkle_tree_params *params); + +/** + * libfsverity_enable_with_sig() - Enable fs-verity on a file, with a signature + * @fd: read-only file descriptor to the file + * @params: pointer to the Merkle tree parameters + * @sig: pointer to the file's signature + * @sig_size: size of the file's signature in bytes + * + * Like libfsverity_enable(), but allows specifying a built-in signature (i.e. a + * singature created with libfsverity_sign_digest()) to associate with the file. + * This is only needed if the in-kernel signature verification support is being + * used; it is not needed if signatures are being verified in userspace. + * + * If @sig is NULL and @sig_size is 0, this is the same as libfsverity_enable(). + * + * Return: See libfsverity_enable(). + */ +int +libfsverity_enable_with_sig(int fd, + const struct libfsverity_merkle_tree_params *params, + const uint8_t *sig, size_t sig_size); + +/** * libfsverity_find_hash_alg_by_name() - Find hash algorithm by name * @name: Pointer to name of hash algorithm * diff --git a/lib/enable.c b/lib/enable.c new file mode 100644 index 0000000..c27ec89 --- /dev/null +++ b/lib/enable.c @@ -0,0 +1,47 @@ +// SPDX-License-Identifier: MIT +/* + * Implementation of libfsverity_enable() and libfsverity_enable_with_sig(). + * + * Copyright 2020 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 "lib_private.h" + +#include <sys/ioctl.h> + +LIBEXPORT int +libfsverity_enable(int fd, const struct libfsverity_merkle_tree_params *params) +{ + return libfsverity_enable_with_sig(fd, params, NULL, 0); +} + +LIBEXPORT int +libfsverity_enable_with_sig(int fd, + const struct libfsverity_merkle_tree_params *params, + const uint8_t *sig, size_t sig_size) +{ + struct fsverity_enable_arg arg = {}; + + if (!params) { + libfsverity_error_msg("missing required parameters for enable"); + return -EINVAL; + } + + arg.version = 1; + arg.hash_algorithm = + params->hash_algorithm ?: FS_VERITY_HASH_ALG_DEFAULT; + arg.block_size = + params->block_size ?: FS_VERITY_BLOCK_SIZE_DEFAULT; + arg.salt_size = params->salt_size; + arg.salt_ptr = (uintptr_t)params->salt; + arg.sig_size = sig_size; + arg.sig_ptr = (uintptr_t)sig; + + if (ioctl(fd, FS_IOC_ENABLE_VERITY, &arg) != 0) + return -errno; + return 0; +} diff --git a/programs/cmd_enable.c b/programs/cmd_enable.c index ba5b088..b0e0c98 100644 --- a/programs/cmd_enable.c +++ b/programs/cmd_enable.c @@ -68,9 +68,10 @@ static const struct option longopts[] = { int fsverity_cmd_enable(const struct fsverity_command *cmd, int argc, char *argv[]) { - struct fsverity_enable_arg arg = { .version = 1 }; + struct libfsverity_merkle_tree_params tree_params = { .version = 1 }; u8 *salt = NULL; u8 *sig = NULL; + u32 sig_size = 0; struct filedes file; int status; int c; @@ -78,26 +79,28 @@ int fsverity_cmd_enable(const struct fsverity_command *cmd, while ((c = getopt_long(argc, argv, "", longopts, NULL)) != -1) { switch (c) { case OPT_HASH_ALG: - if (!parse_hash_alg_option(optarg, &arg.hash_algorithm)) + if (!parse_hash_alg_option(optarg, + &tree_params.hash_algorithm)) goto out_usage; break; case OPT_BLOCK_SIZE: - if (!parse_block_size_option(optarg, &arg.block_size)) + if (!parse_block_size_option(optarg, + &tree_params.block_size)) goto out_usage; break; case OPT_SALT: - if (!parse_salt_option(optarg, &salt, &arg.salt_size)) + if (!parse_salt_option(optarg, &salt, + &tree_params.salt_size)) goto out_usage; - arg.salt_ptr = (uintptr_t)salt; + tree_params.salt = 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)) + if (!read_signature(optarg, &sig, &sig_size)) goto out_err; - arg.sig_ptr = (uintptr_t)sig; break; default: goto out_usage; @@ -110,15 +113,10 @@ int fsverity_cmd_enable(const struct fsverity_command *cmd, 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 = 4096; - if (!open_file(&file, argv[0], O_RDONLY, 0)) goto out_err; - if (ioctl(file.fd, FS_IOC_ENABLE_VERITY, &arg) != 0) { + + if (libfsverity_enable_with_sig(file.fd, &tree_params, sig, sig_size)) { error_msg_errno("FS_IOC_ENABLE_VERITY failed on '%s'", file.name); filedes_close(&file); diff --git a/programs/fsverity.h b/programs/fsverity.h index 2af5527..37a6294 100644 --- a/programs/fsverity.h +++ b/programs/fsverity.h @@ -14,9 +14,6 @@ #include "utils.h" #include "../common/fsverity_uapi.h" -/* The hash algorithm that 'fsverity' assumes when none is specified */ -#define FS_VERITY_HASH_ALG_DEFAULT FS_VERITY_HASH_ALG_SHA256 - /* * Largest digest size among all hash algorithms supported by fs-verity. * This can be increased if needed. |