Add an implementation of PBKDF2

diff --git a/ykpbkdf2.c b/ykpbkdf2.c
new file mode 100644 (file)
index 0000000..87a687b
--- /dev/null
+++ b/ykpbkdf2.c
@@ -0,0 +1,91 @@
+/* -*- mode:C; c-file-style: "bsd" -*- */
+/* Copyright (c) 2008, Yubico AB
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *
+ *     * Redistributions in binary form must reproduce the above
+ *       copyright notice, this list of conditions and the following
+ *       disclaimer in the documentation and/or other materials provided
+ *       with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <string.h>
+
+#include <ykpbkdf2.h>
+
+#include "rfc4634/sha.h"
+
+static int hmac_sha1(const char *key, size_t key_len,
+                    const char *text, size_t text_len,
+                    uint8_t *output, size_t output_size)
+{
+       if (output_size < SHA1HashSize)
+               return 0;
+
+       if (hmac(SHA1,
+                (unsigned char *)text, (int)text_len,
+                (unsigned char *)key, (int)key_len,
+                output))
+               return 0;
+       return 1;
+}
+YK_PRF_METHOD yk_hmac_sha1 = { SHA1HashSize, hmac_sha1 };
+
+int yk_pbkdf2(const char *passphrase,
+             const unsigned char *salt, size_t salt_len,
+             unsigned int iterations,
+             unsigned char *dk, size_t dklen,
+             YK_PRF_METHOD *prf_method)
+{
+       size_t l = ((dklen - 1 + prf_method->output_size)
+                   / prf_method->output_size);
+       size_t r = dklen - ((l - 1) * prf_method->output_size);
+
+       unsigned int block_count;
+
+       for (block_count = 1; block_count <= l; block_count++) {
+               unsigned char block[256]; /* A big chunk, that's 2048 bits */
+               size_t block_len;
+               unsigned int iteration;
+
+               memcpy(block, salt, salt_len);
+               block[salt_len + 0] = (block_count & 0xff000000) >> 24;
+               block[salt_len + 1] = (block_count & 0x00ff0000) >> 16;
+               block[salt_len + 2] = (block_count & 0x0000ff00) >>  8;
+               block[salt_len + 3] = (block_count & 0x000000ff) >>  0;
+               block_len = salt_len + 4;
+
+               for (iteration = 0; iteration < iterations; iteration++) {
+                       if (!prf_method->prf_fn(passphrase, strlen(passphrase),
+                                               block, block_len,
+                                               block, sizeof(block)))
+                               return 0;
+                       block_len = prf_method->output_size;
+               }
+
+               if (block_len > dklen)
+                       block_len = dklen; /* This happens in the last block */
+               memcpy(dk, block, block_len);
+               dk += block_len;
+               dklen -= block_len;
+       }
+       return 1;
+}

diff --git a/ykpbkdf2.h b/ykpbkdf2.h
new file mode 100644 (file)
index 0000000..836eb1b
--- /dev/null
+++ b/ykpbkdf2.h
@@ -0,0 +1,52 @@
+/* -*- mode:C; c-file-style: "bsd" -*- */
+/* Copyright (c) 2008, Yubico AB
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *
+ *     * Redistributions in binary form must reproduce the above
+ *       copyright notice, this list of conditions and the following
+ *       disclaimer in the documentation and/or other materials provided
+ *       with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef        __YKPBKDF2_H_INCLUDED__
+#define        __YKPBKDF2_H_INCLUDED__
+
+#include <stddef.h>
+#include <stdint.h>
+
+typedef struct yk_prf_context YK_PRF_CTX;
+typedef struct yk_prf_method YK_PRF_METHOD;
+struct yk_prf_method {
+       size_t output_size;
+       int (*prf_fn)(const char *key, size_t key_len,
+                     const char *text, size_t text_len,
+                     uint8_t *output, size_t output_size);
+};
+extern YK_PRF_METHOD yk_hmac_sha1;
+
+int yk_pbkdf2(const char *passphrase,
+             const unsigned char *salt, size_t salt_len,
+             unsigned int iterations,
+             unsigned char *dk, size_t dklen,
+             YK_PRF_METHOD *prf_method);
+
+#endif