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-rw-r--r--src/lib/pkcs5.c97
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();
+}