- 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@

1 files changed, 148 insertions, 0 deletions

diff --git a/digest.c b/digest.c
new file mode 100644
index 000000000..59a8ffe0d
--- /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);
+}