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-rw-r--r--hmac.c197
1 files changed, 197 insertions, 0 deletions
diff --git a/hmac.c b/hmac.c
new file mode 100644
index 0000000..1c87964
--- /dev/null
+++ b/hmac.c
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+/* $OpenBSD: hmac.c,v 1.12 2015/03/24 20:03:44 markus Exp $ */
+/*
+ * Copyright (c) 2014 Markus Friedl. All rights reserved.
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include "includes.h"
+
+#include <sys/types.h>
+#include <string.h>
+
+#include "sshbuf.h"
+#include "digest.h"
+#include "hmac.h"
+
+struct ssh_hmac_ctx {
+ int alg;
+ struct ssh_digest_ctx *ictx;
+ struct ssh_digest_ctx *octx;
+ struct ssh_digest_ctx *digest;
+ u_char *buf;
+ size_t buf_len;
+};
+
+size_t
+ssh_hmac_bytes(int alg)
+{
+ return ssh_digest_bytes(alg);
+}
+
+struct ssh_hmac_ctx *
+ssh_hmac_start(int alg)
+{
+ struct ssh_hmac_ctx *ret;
+
+ if ((ret = calloc(1, sizeof(*ret))) == NULL)
+ return NULL;
+ ret->alg = alg;
+ if ((ret->ictx = ssh_digest_start(alg)) == NULL ||
+ (ret->octx = ssh_digest_start(alg)) == NULL ||
+ (ret->digest = ssh_digest_start(alg)) == NULL)
+ goto fail;
+ ret->buf_len = ssh_digest_blocksize(ret->ictx);
+ if ((ret->buf = calloc(1, ret->buf_len)) == NULL)
+ goto fail;
+ return ret;
+fail:
+ ssh_hmac_free(ret);
+ return NULL;
+}
+
+int
+ssh_hmac_init(struct ssh_hmac_ctx *ctx, const void *key, size_t klen)
+{
+ size_t i;
+
+ /* reset ictx and octx if no is key given */
+ if (key != NULL) {
+ /* truncate long keys */
+ if (klen <= ctx->buf_len)
+ memcpy(ctx->buf, key, klen);
+ else if (ssh_digest_memory(ctx->alg, key, klen, ctx->buf,
+ ctx->buf_len) < 0)
+ return -1;
+ for (i = 0; i < ctx->buf_len; i++)
+ ctx->buf[i] ^= 0x36;
+ if (ssh_digest_update(ctx->ictx, ctx->buf, ctx->buf_len) < 0)
+ return -1;
+ for (i = 0; i < ctx->buf_len; i++)
+ ctx->buf[i] ^= 0x36 ^ 0x5c;
+ if (ssh_digest_update(ctx->octx, ctx->buf, ctx->buf_len) < 0)
+ return -1;
+ explicit_bzero(ctx->buf, ctx->buf_len);
+ }
+ /* start with ictx */
+ if (ssh_digest_copy_state(ctx->ictx, ctx->digest) < 0)
+ return -1;
+ return 0;
+}
+
+int
+ssh_hmac_update(struct ssh_hmac_ctx *ctx, const void *m, size_t mlen)
+{
+ return ssh_digest_update(ctx->digest, m, mlen);
+}
+
+int
+ssh_hmac_update_buffer(struct ssh_hmac_ctx *ctx, const struct sshbuf *b)
+{
+ return ssh_digest_update_buffer(ctx->digest, b);
+}
+
+int
+ssh_hmac_final(struct ssh_hmac_ctx *ctx, u_char *d, size_t dlen)
+{
+ size_t len;
+
+ len = ssh_digest_bytes(ctx->alg);
+ if (dlen < len ||
+ ssh_digest_final(ctx->digest, ctx->buf, len))
+ return -1;
+ /* switch to octx */
+ if (ssh_digest_copy_state(ctx->octx, ctx->digest) < 0 ||
+ ssh_digest_update(ctx->digest, ctx->buf, len) < 0 ||
+ ssh_digest_final(ctx->digest, d, dlen) < 0)
+ return -1;
+ return 0;
+}
+
+void
+ssh_hmac_free(struct ssh_hmac_ctx *ctx)
+{
+ if (ctx != NULL) {
+ ssh_digest_free(ctx->ictx);
+ ssh_digest_free(ctx->octx);
+ ssh_digest_free(ctx->digest);
+ if (ctx->buf) {
+ explicit_bzero(ctx->buf, ctx->buf_len);
+ free(ctx->buf);
+ }
+ explicit_bzero(ctx, sizeof(*ctx));
+ free(ctx);
+ }
+}
+
+#ifdef TEST
+
+/* cc -DTEST hmac.c digest.c buffer.c cleanup.c fatal.c log.c xmalloc.c -lcrypto */
+static void
+hmac_test(void *key, size_t klen, void *m, size_t mlen, u_char *e, size_t elen)
+{
+ struct ssh_hmac_ctx *ctx;
+ size_t i;
+ u_char digest[16];
+
+ if ((ctx = ssh_hmac_start(SSH_DIGEST_MD5)) == NULL)
+ printf("ssh_hmac_start failed");
+ if (ssh_hmac_init(ctx, key, klen) < 0 ||
+ ssh_hmac_update(ctx, m, mlen) < 0 ||
+ ssh_hmac_final(ctx, digest, sizeof(digest)) < 0)
+ printf("ssh_hmac_xxx failed");
+ ssh_hmac_free(ctx);
+
+ if (memcmp(e, digest, elen)) {
+ for (i = 0; i < elen; i++)
+ printf("[%zu] %2.2x %2.2x\n", i, e[i], digest[i]);
+ printf("mismatch\n");
+ } else
+ printf("ok\n");
+}
+
+int
+main(int argc, char **argv)
+{
+ /* try test vectors from RFC 2104 */
+
+ u_char key1[16] = {
+ 0xb, 0xb, 0xb, 0xb, 0xb, 0xb, 0xb, 0xb,
+ 0xb, 0xb, 0xb, 0xb, 0xb, 0xb, 0xb, 0xb };
+ u_char *data1 = "Hi There";
+ u_char dig1[16] = {
+ 0x92, 0x94, 0x72, 0x7a, 0x36, 0x38, 0xbb, 0x1c,
+ 0x13, 0xf4, 0x8e, 0xf8, 0x15, 0x8b, 0xfc, 0x9d };
+
+ u_char *key2 = "Jefe";
+ u_char *data2 = "what do ya want for nothing?";
+ u_char dig2[16] = {
+ 0x75, 0x0c, 0x78, 0x3e, 0x6a, 0xb0, 0xb5, 0x03,
+ 0xea, 0xa8, 0x6e, 0x31, 0x0a, 0x5d, 0xb7, 0x38 };
+
+ u_char key3[16];
+ u_char data3[50];
+ u_char dig3[16] = {
+ 0x56, 0xbe, 0x34, 0x52, 0x1d, 0x14, 0x4c, 0x88,
+ 0xdb, 0xb8, 0xc7, 0x33, 0xf0, 0xe8, 0xb3, 0xf6 };
+ memset(key3, 0xaa, sizeof(key3));
+ memset(data3, 0xdd, sizeof(data3));
+
+ hmac_test(key1, sizeof(key1), data1, strlen(data1), dig1, sizeof(dig1));
+ hmac_test(key2, strlen(key2), data2, strlen(data2), dig2, sizeof(dig2));
+ hmac_test(key3, sizeof(key3), data3, sizeof(data3), dig3, sizeof(dig3));
+
+ return 0;
+}
+
+#endif