diff options
Diffstat (limited to 'src/basic/khash.c')
| -rw-r--r-- | src/basic/khash.c | 275 |
1 files changed, 275 insertions, 0 deletions
diff --git a/src/basic/khash.c b/src/basic/khash.c new file mode 100644 index 0000000000..9a2a3edb75 --- /dev/null +++ b/src/basic/khash.c @@ -0,0 +1,275 @@ +/*** + This file is part of systemd. + + Copyright 2016 Lennart Poettering + + systemd is free software; you can redistribute it and/or modify it + under the terms of the GNU Lesser General Public License as published by + the Free Software Foundation; either version 2.1 of the License, or + (at your option) any later version. + + systemd is distributed in the hope that it will be useful, but + WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public License + along with systemd; If not, see <http://www.gnu.org/licenses/>. +***/ + +#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.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_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; + 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; + + 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 = h; + h = NULL; + + 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); + free(h); + + return NULL; +} + +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) + return -ENOMEM; + + copy->fd = accept4(h->fd, NULL, 0, SOCK_CLOEXEC); + if (copy->fd < 0) + return -errno; + + *ret = copy; + copy = NULL; + + 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 = { + mh.msg_iov = (struct iovec*) iovec, + mh.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; +} |