core: add "khash" API to src/basic/ (as wrapper around kernel AF_ALG)

Let's take inspiration from bluez's ELL library, and let's move our
cryptographic primitives away from libgcrypt and towards the kernel's AF_ALG
cryptographic userspace API.

In the long run we should try to remove the dependency on libgcrypt, in favour
of using only the kernel's own primitives, however this is unlikely to happen
anytime soon, as the kernel does not provide Elliptic Curve APIs to userspace
at this time, and we need them for the DNSSEC cryptographic.

This commit only covers hashing for now, symmetric encryption/decryption or
even asymetric encryption/decryption is not available for now.

"khash" is little more than a lightweight wrapper around the kernel's AF_ALG
socket API.

1 files changed, 82 insertions, 0 deletions

diff --git a/src/test/test-hash.c b/src/test/test-hash.c
new file mode 100644
index 000000000..74bd33c0d
--- /dev/null
+++ b/src/test/test-hash.c
@@ -0,0 +1,82 @@
+/***
+  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 "alloc-util.h"
+#include "log.h"
+#include "string-util.h"
+#include "khash.h"
+
+int main(int argc, char *argv[]) {
+        _cleanup_(khash_unrefp) khash *h = NULL, *copy = NULL;
+        _cleanup_free_ char *s = NULL;
+
+        log_set_max_level(LOG_DEBUG);
+
+        assert_se(khash_new(&h, NULL) == -EINVAL);
+        assert_se(khash_new(&h, "") == -EINVAL);
+        assert_se(khash_new(&h, "foobar") == -EOPNOTSUPP);
+
+        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;
+}