1 files changed, 69 insertions, 0 deletions
diff --git a/src/librepgp/stream-ctx.cpp b/src/librepgp/stream-ctx.cpp
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+++ b/src/librepgp/stream-ctx.cpp
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+/*
+ * Copyright (c) 2019-2020, [Ribose Inc](https://www.ribose.com).
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modification,
+ * are permitted provided that the following conditions are met:
+ *
+ * 1.  Redistributions of source code must retain the above copyright notice,
+ *     this list of conditions and the following disclaimer.
+ *
+ * 2.  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 <assert.h>
+#include "defaults.h"
+#include "utils.h"
+#include "stream-ctx.h"
+
+rnp_result_t
+rnp_ctx_t::add_encryption_password(const std::string &password,
+                                   pgp_hash_alg_t     halg,
+                                   pgp_symm_alg_t     ealg,
+                                   size_t             iterations)
+{
+    rnp_symmetric_pass_info_t info = {};
+
+    info.s2k.usage = PGP_S2KU_ENCRYPTED_AND_HASHED;
+    info.s2k.specifier = PGP_S2KS_ITERATED_AND_SALTED;
+    info.s2k.hash_alg = halg;
+    ctx->rng.get(info.s2k.salt, sizeof(info.s2k.salt));
+    if (!iterations) {
+        iterations = ctx->s2k_iterations(halg);
+    }
+    if (!iterations) {
+        return RNP_ERROR_BAD_PARAMETERS;
+    }
+    info.s2k.iterations = pgp_s2k_encode_iterations(iterations);
+    info.s2k_cipher = ealg;
+    /* Note: we're relying on the fact that a longer-than-needed key length
+     * here does not change the entire derived key (it just generates unused
+     * extra bytes at the end). We derive a key of our maximum supported length,
+     * which is a bit wasteful.
+     *
+     * This is done because we do not yet know what cipher this key will actually
+     * end up being used with until later.
+     *
+     * An alternative would be to keep a list of actual passwords and s2k params,
+     * and save the key derivation for later.
+     */
+    if (!pgp_s2k_derive_key(&info.s2k, password.c_str(), info.key.data(), info.key.size())) {
+        return RNP_ERROR_GENERIC;
+    }
+    passwords.push_back(info);
+    return RNP_SUCCESS;
+}