- djm@cvs.openbsd.org 2014/01/09 23:20:00
[digest.c digest.h hostfile.c kex.c kex.h kexc25519.c kexc25519c.c]
[kexc25519s.c kexdh.c kexecdh.c kexecdhc.c kexecdhs.c kexgex.c kexgexc.c]
[kexgexs.c key.c key.h roaming_client.c roaming_common.c schnorr.c]
[schnorr.h ssh-dss.c ssh-ecdsa.c ssh-rsa.c sshconnect2.c]
Introduce digest API and use it to perform all hashing operations
rather than calling OpenSSL EVP_Digest* directly. Will make it easier
to build a reduced-feature OpenSSH without OpenSSL in future;
feedback, ok markus@
diff --git a/digest.c b/digest.c
new file mode 100644
index 0000000..59a8ffe
--- /dev/null
+++ b/digest.c
@@ -0,0 +1,148 @@
+/* $OpenBSD: digest.c,v 1.1 2014/01/09 23:20:00 djm Exp $ */
+/*
+ * Copyright (c) 2013 Damien Miller <djm@mindrot.org>
+ *
+ * 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 <limits.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <openssl/bn.h> /* for buffer.h */
+#include <openssl/ec.h> /* for buffer.h */
+#include <openssl/evp.h>
+
+#include "buffer.h"
+#include "digest.h"
+
+struct ssh_digest_ctx {
+ int alg;
+ EVP_MD_CTX mdctx;
+};
+
+struct ssh_digest {
+ int id;
+ const char *name;
+ size_t digest_len;
+ const EVP_MD *(*mdfunc)(void);
+};
+
+/* NB. Indexed directly by algorithm number */
+const struct ssh_digest digests[] = {
+ { SSH_DIGEST_MD5, "MD5", 16, EVP_md5 },
+ { SSH_DIGEST_RIPEMD160, "RIPEMD160", 20, EVP_ripemd160 },
+ { SSH_DIGEST_SHA1, "SHA1", 20, EVP_sha1 },
+#ifdef HAVE_EVP_SHA256 /* XXX replace with local if missing */
+ { SSH_DIGEST_SHA256, "SHA256", 32, EVP_sha256 },
+ { SSH_DIGEST_SHA384, "SHA384", 48, EVP_sha384 },
+ { SSH_DIGEST_SHA512, "SHA512", 64, EVP_sha512 },
+#endif
+ { -1, NULL, 0, NULL },
+};
+
+static const struct ssh_digest *
+ssh_digest_by_alg(int alg)
+{
+ if (alg < 0 || alg >= SSH_DIGEST_MAX)
+ return NULL;
+ if (digests[alg].id != alg) /* sanity */
+ return NULL;
+ return &(digests[alg]);
+}
+
+size_t
+ssh_digest_bytes(int alg)
+{
+ const struct ssh_digest *digest = ssh_digest_by_alg(alg);
+
+ return digest == NULL ? 0 : digest->digest_len;
+}
+
+struct ssh_digest_ctx *
+ssh_digest_start(int alg)
+{
+ const struct ssh_digest *digest = ssh_digest_by_alg(alg);
+ struct ssh_digest_ctx *ret;
+
+ if (digest == NULL || ((ret = calloc(1, sizeof(*ret))) == NULL))
+ return NULL;
+ ret->alg = alg;
+ EVP_MD_CTX_init(&ret->mdctx);
+ if (EVP_DigestInit_ex(&ret->mdctx, digest->mdfunc(), NULL) != 1) {
+ free(ret);
+ return NULL;
+ }
+ return ret;
+}
+
+int
+ssh_digest_update(struct ssh_digest_ctx *ctx, const void *m, size_t mlen)
+{
+ if (EVP_DigestUpdate(&ctx->mdctx, m, mlen) != 1)
+ return -1;
+ return 0;
+}
+
+int
+ssh_digest_update_buffer(struct ssh_digest_ctx *ctx, const Buffer *b)
+{
+ return ssh_digest_update(ctx, buffer_ptr(b), buffer_len(b));
+}
+
+int
+ssh_digest_final(struct ssh_digest_ctx *ctx, u_char *d, size_t dlen)
+{
+ const struct ssh_digest *digest = ssh_digest_by_alg(ctx->alg);
+ u_int l = dlen;
+
+ if (dlen > UINT_MAX)
+ return -1;
+ if (dlen < digest->digest_len) /* No truncation allowed */
+ return -1;
+ if (EVP_DigestFinal_ex(&ctx->mdctx, d, &l) != 1)
+ return -1;
+ if (l != digest->digest_len) /* sanity */
+ return -1;
+ return 0;
+}
+
+void
+ssh_digest_free(struct ssh_digest_ctx *ctx)
+{
+ EVP_MD_CTX_cleanup(&ctx->mdctx);
+ memset(ctx, 0, sizeof(*ctx));
+}
+
+int
+ssh_digest_memory(int alg, const void *m, size_t mlen, u_char *d, size_t dlen)
+{
+ struct ssh_digest_ctx *ctx = ssh_digest_start(alg);
+
+ if (ctx == NULL)
+ return -1;
+ if (ssh_digest_update(ctx, m, mlen) != 0 ||
+ ssh_digest_final(ctx, d, dlen) != 0)
+ return -1;
+ ssh_digest_free(ctx);
+ return 0;
+}
+
+int
+ssh_digest_buffer(int alg, const Buffer *b, u_char *d, size_t dlen)
+{
+ return ssh_digest_memory(alg, buffer_ptr(b), buffer_len(b), d, dlen);
+}