1 files changed, 97 insertions, 0 deletions
diff --git a/src/lib/pkcs5.c b/src/lib/pkcs5.c
new file mode 100644
index 0000000..e035d47
--- /dev/null
+++ b/src/lib/pkcs5.c
@@ -0,0 +1,97 @@
+/* Copyright (c) 2016-2018 Dovecot authors, see the included COPYING file */
+
+#include "lib.h"
+#include "buffer.h"
+#include "hash-method.h"
+#include "hmac.h"
+#include "pkcs5.h"
+
+#include <stdint.h>
+#include <arpa/inet.h>
+
+static
+int pkcs5_pbkdf1(const struct hash_method *hash,
+	const unsigned char *password, size_t password_len,
+	const unsigned char *salt, size_t salt_len,
+	unsigned int iter, uint32_t length,
+	buffer_t *result)
+{
+	if (length < 1 ||
+		length > hash->digest_size) return -1;
+	if (iter < 1) return -1;
+
+	unsigned char dk[hash->digest_size];
+	unsigned char ctx[hash->context_size];
+
+	hash->init(ctx);
+	hash->loop(ctx, password, password_len);
+	hash->loop(ctx, salt, salt_len);
+	hash->result(ctx, dk);
+	length--;
+
+	for(;length>0;length--) {
+		hash->init(ctx);
+		hash->loop(ctx, dk, hash->digest_size);
+		hash->result(ctx, dk);
+	}
+
+	buffer_append(result, dk, hash->digest_size);
+
+	return 0;
+}
+
+static
+int pkcs5_pbkdf2(const struct hash_method *hash,
+	const unsigned char *password, size_t password_len,
+	const unsigned char *salt, size_t salt_len,
+	unsigned int iter, uint32_t length,
+	buffer_t *result)
+{
+	if (length < 1 || iter < 1) return -1;
+
+	size_t l = (length + hash->digest_size - 1)/hash->digest_size; /* same as ceil(length/hash->digest_size) */
+	unsigned char dk[l * hash->digest_size];
+	unsigned char *block;
+	struct hmac_context hctx;
+	unsigned int c,i,t;
+	unsigned char U_c[hash->digest_size];
+
+	for(t = 0; t < l; t++) {
+		block = &(dk[t*hash->digest_size]);
+		/* U_1 = PRF(Password, Salt|| INT_BE32(Block_Number)) */
+		c = htonl(t+1);
+		hmac_init(&hctx, password, password_len, hash);
+		hmac_update(&hctx, salt, salt_len);
+		hmac_update(&hctx, &c, sizeof(c));
+		hmac_final(&hctx, U_c);
+		/* block = U_1 ^ .. ^ U_iter */
+		memcpy(block, U_c, hash->digest_size);
+		/* U_c = PRF(Password, U_c-1) */
+		for(c = 1; c < iter; c++) {
+			hmac_init(&hctx, password, password_len, hash);
+			hmac_update(&hctx, U_c, hash->digest_size);
+			hmac_final(&hctx, U_c);
+			for(i = 0; i < hash->digest_size; i++)
+				block[i] ^= U_c[i];
+		}
+	}
+
+	buffer_append(result, dk, length);
+
+	return 0;
+}
+
+int pkcs5_pbkdf(enum pkcs5_pbkdf_mode mode, const struct hash_method *hash,
+	const unsigned char *password, size_t password_len,
+	const unsigned char *salt, size_t salt_len,
+	unsigned int iterations, uint32_t dk_len,
+	buffer_t *result)
+{
+	if (mode == PKCS5_PBKDF1)
+		return pkcs5_pbkdf1(hash,password,password_len,
+			salt,salt_len,iterations,dk_len,result);
+	else if (mode == PKCS5_PBKDF2)
+		return pkcs5_pbkdf2(hash,password,password_len,
+			salt,salt_len,iterations,dk_len,result);
+	i_unreached();
+}