1 files changed, 82 insertions, 0 deletions
diff --git a/src/auth/password-scheme-pbkdf2.c b/src/auth/password-scheme-pbkdf2.c
new file mode 100644
index 0000000..1e8eb3b
--- /dev/null
+++ b/src/auth/password-scheme-pbkdf2.c
@@ -0,0 +1,82 @@
+/* Copyright (c) 2015-2018 Dovecot authors, see the included COPYING file */
+
+#include "lib.h"
+#include "buffer.h"
+#include "str.h"
+#include "password-scheme.h"
+#include "hex-binary.h"
+#include "hash-method.h"
+#include "pkcs5.h"
+
+#define PBKDF2_KEY_SIZE_SHA1 20
+
+#define PBKDF2_GENERATE_SALT_LEN      16
+#define PBKDF2_ROUNDS_DEFAULT          5000
+
+static void
+pbkdf_run(const char *plaintext, const char *salt,
+	  unsigned int rounds, unsigned char key_r[PBKDF2_KEY_SIZE_SHA1])
+{
+	memset(key_r, 0, PBKDF2_KEY_SIZE_SHA1);
+	buffer_t buf;
+	buffer_create_from_data(&buf, key_r, PBKDF2_KEY_SIZE_SHA1);
+
+	pkcs5_pbkdf(PKCS5_PBKDF2, hash_method_lookup("sha1"),
+		(const unsigned char *)plaintext, strlen(plaintext),
+		(const unsigned char *)salt, strlen(salt),
+		rounds, PBKDF2_KEY_SIZE_SHA1, &buf);
+}
+
+void pbkdf2_generate(const char *plaintext, const struct password_generate_params *params ATTR_UNUSED,
+		const unsigned char **raw_password_r, size_t *size_r)
+{
+	unsigned char key[PBKDF2_KEY_SIZE_SHA1];
+	const char *salt;
+	string_t *str = t_str_new(64);
+	unsigned int rounds = params->rounds;
+
+	if (rounds == 0)
+		rounds = PBKDF2_ROUNDS_DEFAULT;
+	salt = password_generate_salt(PBKDF2_GENERATE_SALT_LEN);
+	pbkdf_run(plaintext, salt, rounds, key);
+
+	str_printfa(str, "$1$%s$%u$", salt, rounds);
+	binary_to_hex_append(str, key, sizeof(key));
+
+	*raw_password_r = str_data(str);
+	*size_r = str_len(str);
+}
+
+int pbkdf2_verify(const char *plaintext, const struct password_generate_params *params ATTR_UNUSED,
+	      const unsigned char *raw_password, size_t size,
+	      const char **error_r)
+{
+	const char *const *fields;
+	const char *salt;
+	unsigned int rounds;
+	unsigned char key1[PBKDF2_KEY_SIZE_SHA1], key2[PBKDF2_KEY_SIZE_SHA1];
+	buffer_t buf;
+
+	/* $1$salt$rounds$hash */
+	if (size < 3 || memcmp(raw_password, "$1$", 3) != 0) {
+		*error_r = "Invalid PBKDF2 passdb entry prefix";
+		return -1;
+	}
+
+	fields = t_strsplit(t_strndup(raw_password + 3, size - 3), "$");
+	salt = fields[0];
+	if (str_array_length(fields) != 3 ||
+	    str_to_uint(fields[1], &rounds) < 0) {
+		*error_r = "Invalid PBKDF2 passdb entry format";
+		return -1;
+	}
+	buffer_create_from_data(&buf, key1, sizeof(key1));
+	if (strlen(fields[2]) != sizeof(key1)*2 ||
+	    hex_to_binary(fields[2], &buf) < 0) {
+		*error_r = "PBKDF2 hash not 160bit hex-encoded";
+		return -1;
+	}
+
+	pbkdf_run(plaintext, salt, rounds, key2);
+	return mem_equals_timing_safe(key1, key2, sizeof(key1)) ? 1 : 0;
+}