--- /dev/null
+/***
+ This file is part of elogind.
+
+ Copyright 2016 Lennart Poettering
+
+ elogind 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.
+
+ elogind 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 elogind; 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;
+}
~ianmdlvl / elogind.git / blobdiff