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basic: remove khash helpers

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No longer used anywhere. So long, and thanks for all the hashes!
This commit is contained in:
Luca Boccassi 2021-10-07 21:49:19 +01:00
parent ec4afb4606
commit 1fc8d0c9dd
6 changed files with 0 additions and 440 deletions
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2
TODO
View File

@ -352,11 +352,9 @@ Features:
* unify on openssl (as soon as OpenSSL 3.0 is out, and the Debian license
confusion is gone)
- port sd_id128_get_machine_app_specific() over from khash
- port resolved over from libgcrypt (DNSSEC code)
- port journald + fsprg over from libgcrypt
- port importd over from libgcrypt
- when that's done: kill khash.c
- when that's done: kill gnutls support in resolved
* add growvol and makevol options for /etc/crypttab, similar to

321
src/basic/khash.c
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@ -1,321 +0,0 @@
/* SPDX-License-Identifier: LGPL-2.1-or-later */
#include <linux/if_alg.h>
#include <stdbool.h>
#include <sys/socket.h>
#include "alloc-util.h"
#include "fd-util.h"
#include "hexdecoct.h"
#include "khash.h"
#include "macro.h"
#include "missing_socket.h"
#include "string-util.h"
#include "util.h"
/* On current kernels the maximum digest (according to "grep digestsize /proc/crypto | sort -u") is actually 32, but
* let's add some extra room, the few wasted bytes don't really matter... */
#define LONGEST_DIGEST 128
struct khash {
int fd;
char *algorithm;
uint8_t digest[LONGEST_DIGEST+1];
size_t digest_size;
bool digest_valid;
};
int khash_supported(void) {
static const union {
struct sockaddr sa;
struct sockaddr_alg alg;
} sa = {
.alg.salg_family = AF_ALG,
.alg.salg_type = "hash",
.alg.salg_name = "sha256", /* a very common algorithm */
};
static int cached = -1;
if (cached < 0) {
_cleanup_close_ int fd1 = -1, fd2 = -1;
uint8_t buf[LONGEST_DIGEST+1];
fd1 = socket(AF_ALG, SOCK_SEQPACKET|SOCK_CLOEXEC, 0);
if (fd1 < 0) {
/* The kernel returns EAFNOSUPPORT if AF_ALG is not supported at all */
if (IN_SET(errno, EAFNOSUPPORT, EOPNOTSUPP))
return (cached = false);
return -errno;
}
if (bind(fd1, &sa.sa, sizeof(sa)) < 0) {
/* The kernel returns ENOENT if the selected algorithm is not supported at all. We use a check
* for SHA256 as a proxy for whether the whole API is supported at all. After all it's one of
* the most common hash functions, and if it isn't supported, that's ample indication that
* something is really off. */
if (IN_SET(errno, ENOENT, EOPNOTSUPP))
return (cached = false);
return -errno;
}
fd2 = accept4(fd1, NULL, 0, SOCK_CLOEXEC);
if (fd2 < 0) {
if (errno == EOPNOTSUPP)
return (cached = false);
return -errno;
}
if (recv(fd2, buf, sizeof(buf), 0) < 0) {
/* On some kernels we get ENOKEY for non-keyed hash functions (such as sha256), let's refuse
* using the API in those cases, since the kernel is
* broken. https://github.com/systemd/systemd/issues/8278 */
if (IN_SET(errno, ENOKEY, EOPNOTSUPP))
return (cached = false);
}
cached = true;
}
return cached;
}
int khash_new_with_key(khash **ret, const char *algorithm, const void *key, size_t key_size) {
union {
struct sockaddr sa;
struct sockaddr_alg alg;
} sa = {
.alg.salg_family = AF_ALG,
.alg.salg_type = "hash",
};
_cleanup_(khash_unrefp) khash *h = NULL;
_cleanup_close_ int fd = -1;
int supported;
ssize_t n;
assert(ret);
assert(key || key_size == 0);
/* Filter out an empty algorithm early, as we do not support an algorithm by that name. */
if (isempty(algorithm))
return -EINVAL;
/* Overly long hash algorithm names we definitely do not support */
if (strlen(algorithm) >= sizeof(sa.alg.salg_name))
return -EOPNOTSUPP;
supported = khash_supported();
if (supported < 0)
return supported;
if (supported == 0)
return -EOPNOTSUPP;
fd = socket(AF_ALG, SOCK_SEQPACKET|SOCK_CLOEXEC, 0);
if (fd < 0)
return -errno;
strcpy((char*) sa.alg.salg_name, algorithm);
if (bind(fd, &sa.sa, sizeof(sa)) < 0) {
if (errno == ENOENT)
return -EOPNOTSUPP;
return -errno;
}
if (key) {
if (setsockopt(fd, SOL_ALG, ALG_SET_KEY, key, key_size) < 0)
return -errno;
}
h = new0(khash, 1);
if (!h)
return -ENOMEM;
h->fd = accept4(fd, NULL, 0, SOCK_CLOEXEC);
if (h->fd < 0)
return -errno;
h->algorithm = strdup(algorithm);
if (!h->algorithm)
return -ENOMEM;
/* Temporary fix for rc kernel bug: https://bugzilla.redhat.com/show_bug.cgi?id=1395896 */
(void) send(h->fd, NULL, 0, 0);
/* Figure out the digest size */
n = recv(h->fd, h->digest, sizeof(h->digest), 0);
if (n < 0)
return -errno;
if (n >= LONGEST_DIGEST) /* longer than what we expected? If so, we don't support this */
return -EOPNOTSUPP;
h->digest_size = (size_t) n;
h->digest_valid = true;
/* Temporary fix for rc kernel bug: https://bugzilla.redhat.com/show_bug.cgi?id=1395896 */
(void) send(h->fd, NULL, 0, 0);
*ret = TAKE_PTR(h);
return 0;
}
int khash_new(khash **ret, const char *algorithm) {
return khash_new_with_key(ret, algorithm, NULL, 0);
}
khash* khash_unref(khash *h) {
if (!h)
return NULL;
safe_close(h->fd);
free(h->algorithm);
return mfree(h);
}
int khash_dup(khash *h, khash **ret) {
_cleanup_(khash_unrefp) khash *copy = NULL;
assert(h);
assert(ret);
copy = newdup(khash, h, 1);
if (!copy)
return -ENOMEM;
copy->fd = -1;
copy->algorithm = strdup(h->algorithm);
if (!copy->algorithm)
return -ENOMEM;
copy->fd = accept4(h->fd, NULL, 0, SOCK_CLOEXEC);
if (copy->fd < 0)
return -errno;
*ret = TAKE_PTR(copy);
return 0;
}
const char *khash_get_algorithm(khash *h) {
assert(h);
return h->algorithm;
}
size_t khash_get_size(khash *h) {
assert(h);
return h->digest_size;
}
int khash_reset(khash *h) {
ssize_t n;
assert(h);
n = send(h->fd, NULL, 0, 0);
if (n < 0)
return -errno;
h->digest_valid = false;
return 0;
}
int khash_put(khash *h, const void *buffer, size_t size) {
ssize_t n;
assert(h);
assert(buffer || size == 0);
if (size <= 0)
return 0;
n = send(h->fd, buffer, size, MSG_MORE);
if (n < 0)
return -errno;
h->digest_valid = false;
return 0;
}
int khash_put_iovec(khash *h, const struct iovec *iovec, size_t n) {
struct msghdr mh = {
.msg_iov = (struct iovec*) iovec,
.msg_iovlen = n,
};
ssize_t k;
assert(h);
assert(iovec || n == 0);
if (n <= 0)
return 0;
k = sendmsg(h->fd, &mh, MSG_MORE);
if (k < 0)
return -errno;
h->digest_valid = false;
return 0;
}
static int retrieve_digest(khash *h) {
ssize_t n;
assert(h);
if (h->digest_valid)
return 0;
n = recv(h->fd, h->digest, h->digest_size, 0);
if (n < 0)
return n;
if ((size_t) n != h->digest_size) /* digest size changed? */
return -EIO;
h->digest_valid = true;
return 0;
}
int khash_digest_data(khash *h, const void **ret) {
int r;
assert(h);
assert(ret);
r = retrieve_digest(h);
if (r < 0)
return r;
*ret = h->digest;
return 0;
}
int khash_digest_string(khash *h, char **ret) {
int r;
char *p;
assert(h);
assert(ret);
r = retrieve_digest(h);
if (r < 0)
return r;
p = hexmem(h->digest, h->digest_size);
if (!p)
return -ENOMEM;
*ret = p;
return 0;
}

37
src/basic/khash.h
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@ -1,37 +0,0 @@
/* SPDX-License-Identifier: LGPL-2.1-or-later */
#pragma once
#include <inttypes.h>
#include <sys/types.h>
#include <sys/uio.h>
#include "macro.h"
typedef struct khash khash;
int khash_supported(void);
/* For plain hash functions. Hash functions commonly supported on today's kernels are: crc32c, crct10dif, crc32,
* sha224, sha256, sha512, sha384, sha1, md5, md4, sha3-224, sha3-256, sha3-384, sha3-512, and more. */
int khash_new(khash **ret, const char *algorithm);
/* For keyed hash functions. Hash functions commonly supported on today's kernels are: hmac(sha256), cmac(aes),
* cmac(des3_ede), hmac(sha3-512), hmac(sha3-384), hmac(sha3-256), hmac(sha3-224), hmac(rmd160), hmac(rmd128),
* hmac(sha224), hmac(sha512), hmac(sha384), hmac(sha1), hmac(md5), and more. */
int khash_new_with_key(khash **ret, const char *algorithm, const void *key, size_t key_size);
int khash_dup(khash *h, khash **ret);
khash* khash_unref(khash *h);
const char *khash_get_algorithm(khash *h);
size_t khash_get_size(khash *h);
int khash_reset(khash *h);
int khash_put(khash *h, const void *buffer, size_t size);
int khash_put_iovec(khash *h, const struct iovec *iovec, size_t n);
int khash_digest_data(khash *h, const void **ret);
int khash_digest_string(khash *h, char **ret);
DEFINE_TRIVIAL_CLEANUP_FUNC(khash*, khash_unref);

2
src/basic/meson.build
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@ -82,8 +82,6 @@ basic_sources = files('''
inotify-util.h
io-util.c
io-util.h
khash.c
khash.h
limits-util.c
limits-util.h
linux/btrfs.h

2
src/test/meson.build
View File

@ -592,8 +592,6 @@ tests += [
[['src/test/test-id128.c']],
[['src/test/test-hash.c']],
[['src/test/test-gcrypt-util.c'],
[], [], [], 'HAVE_GCRYPT'],

76
src/test/test-hash.c
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@ -1,76 +0,0 @@
/* SPDX-License-Identifier: LGPL-2.1-or-later */
#include <errno.h>
#include <stdio.h>
#include "alloc-util.h"
#include "log.h"
#include "string-util.h"
#include "khash.h"
#include "tests.h"
int main(int argc, char *argv[]) {
_cleanup_(khash_unrefp) khash *h = NULL, *copy = NULL;
_cleanup_free_ char *s = NULL;
int r;
test_setup_logging(LOG_DEBUG);
assert_se(khash_new(&h, NULL) == -EINVAL);
assert_se(khash_new(&h, "") == -EINVAL);
r = khash_supported();
assert_se(r >= 0);
if (r == 0)
return log_tests_skipped("khash not supported on this kernel");
assert_se(khash_new(&h, "foobar") == -EOPNOTSUPP); /* undefined hash function */
assert_se(khash_new(&h, "sha256") >= 0);
assert_se(khash_get_size(h) == 32);
assert_se(streq(khash_get_algorithm(h), "sha256"));
assert_se(khash_digest_string(h, &s) >= 0);
assert_se(streq(s, "e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855"));
s = mfree(s);
assert_se(khash_put(h, "foobar", 6) >= 0);
assert_se(khash_digest_string(h, &s) >= 0);
assert_se(streq(s, "c3ab8ff13720e8ad9047dd39466b3c8974e592c2fa383d4a3960714caef0c4f2"));
s = mfree(s);
assert_se(khash_put(h, "piep", 4) >= 0);
assert_se(khash_digest_string(h, &s) >= 0);
assert_se(streq(s, "f114d872b5ea075d3be9040d0b7a429514b3f9324a8e8e3dc3fb24c34ee56bea"));
s = mfree(s);
assert_se(khash_put(h, "foo", 3) >= 0);
assert_se(khash_dup(h, &copy) >= 0);
assert_se(khash_put(h, "bar", 3) >= 0);
assert_se(khash_put(copy, "bar", 3) >= 0);
assert_se(khash_digest_string(h, &s) >= 0);
assert_se(streq(s, "c3ab8ff13720e8ad9047dd39466b3c8974e592c2fa383d4a3960714caef0c4f2"));
s = mfree(s);
assert_se(khash_digest_string(copy, &s) >= 0);
assert_se(streq(s, "c3ab8ff13720e8ad9047dd39466b3c8974e592c2fa383d4a3960714caef0c4f2"));
s = mfree(s);
h = khash_unref(h);
assert_se(khash_new_with_key(&h, "hmac(sha256)", "quux", 4) >= 0);
assert_se(khash_get_size(h) == 32);
assert_se(streq(khash_get_algorithm(h), "hmac(sha256)"));
assert_se(khash_digest_string(h, &s) >= 0);
assert_se(streq(s, "abed9f8218ab473f77218a6a7d39abf1d21fa46d0700c4898e330ba88309d5ae"));
s = mfree(s);
assert_se(khash_put(h, "foobar", 6) >= 0);
assert_se(khash_digest_string(h, &s) >= 0);
assert_se(streq(s, "33f6c70a60db66007d5325d5d1dea37c371354e5b83347a59ad339ce9f4ba3dc"));
return 0;
}