--- a/src/lib-dcrypt/dcrypt.c	Thu Nov 24 19:53:17 2016 +0200
+++ b/src/lib-dcrypt/dcrypt.c	Fri Nov 25 10:22:18 2016 +0200
@@ -58,144 +58,175 @@
 
 bool dcrypt_ctx_sym_create(const char *algorithm, enum dcrypt_sym_mode mode, struct dcrypt_context_symmetric **ctx_r, const char **error_r)
 {
+	i_assert(dcrypt_vfs != NULL);
 	return dcrypt_vfs->ctx_sym_create(algorithm, mode, ctx_r, error_r);
 }
 void dcrypt_ctx_sym_destroy(struct dcrypt_context_symmetric **ctx)
 {
+	i_assert(dcrypt_vfs != NULL);
 	dcrypt_vfs->ctx_sym_destroy(ctx);
 }
 
 void dcrypt_ctx_sym_set_key(struct dcrypt_context_symmetric *ctx, const unsigned char *key, size_t key_len)
 {
+	i_assert(dcrypt_vfs != NULL);
 	dcrypt_vfs->ctx_sym_set_key(ctx, key, key_len);
 }
 void dcrypt_ctx_sym_set_iv(struct dcrypt_context_symmetric *ctx, const unsigned char *iv, size_t iv_len)
 {
+	i_assert(dcrypt_vfs != NULL);
 	dcrypt_vfs->ctx_sym_set_iv(ctx, iv, iv_len);
 }
 void dcrypt_ctx_sym_set_key_iv_random(struct dcrypt_context_symmetric *ctx)
 {
+	i_assert(dcrypt_vfs != NULL);
 	dcrypt_vfs->ctx_sym_set_key_iv_random(ctx);
 }
 
 bool dcrypt_ctx_sym_get_key(struct dcrypt_context_symmetric *ctx, buffer_t *key)
 {
+	i_assert(dcrypt_vfs != NULL);
 	return dcrypt_vfs->ctx_sym_get_key(ctx, key);
 }
 bool dcrypt_ctx_sym_get_iv(struct dcrypt_context_symmetric *ctx, buffer_t *iv)
 {
+	i_assert(dcrypt_vfs != NULL);
 	return dcrypt_vfs->ctx_sym_get_iv(ctx, iv);
 }
 
 unsigned int dcrypt_ctx_sym_get_key_length(struct dcrypt_context_symmetric *ctx)
 {
+	i_assert(dcrypt_vfs != NULL);
 	return dcrypt_vfs->ctx_sym_get_key_length(ctx);
 }
 
 unsigned int dcrypt_ctx_sym_get_iv_length(struct dcrypt_context_symmetric *ctx)
 {
+	i_assert(dcrypt_vfs != NULL);
 	return dcrypt_vfs->ctx_sym_get_iv_length(ctx);
 }
 
 void dcrypt_ctx_sym_set_aad(struct dcrypt_context_symmetric *ctx, const unsigned char *aad, size_t aad_len)
 {
+	i_assert(dcrypt_vfs != NULL);
 	dcrypt_vfs->ctx_sym_set_aad(ctx, aad, aad_len);
 }
 
 bool dcrypt_ctx_sym_get_aad(struct dcrypt_context_symmetric *ctx, buffer_t *aad)
 {
+	i_assert(dcrypt_vfs != NULL);
 	return dcrypt_vfs->ctx_sym_get_aad(ctx, aad);
 }
 
 void dcrypt_ctx_sym_set_tag(struct dcrypt_context_symmetric *ctx, const unsigned char *tag, size_t tag_len)
 {
+	i_assert(dcrypt_vfs != NULL);
 	dcrypt_vfs->ctx_sym_set_tag(ctx, tag, tag_len);
 }
 
 bool dcrypt_ctx_sym_get_tag(struct dcrypt_context_symmetric *ctx, buffer_t *tag)
 {
+	i_assert(dcrypt_vfs != NULL);
 	return dcrypt_vfs->ctx_sym_get_tag(ctx, tag);
 }
 
 unsigned int dcrypt_ctx_sym_get_block_size(struct dcrypt_context_symmetric *ctx) {
+	i_assert(dcrypt_vfs != NULL);
 	return dcrypt_vfs->ctx_sym_get_block_size(ctx);
 }
 
 bool dcrypt_ctx_sym_init(struct dcrypt_context_symmetric *ctx, const char **error_r)
 {
+	i_assert(dcrypt_vfs != NULL);
 	return dcrypt_vfs->ctx_sym_init(ctx, error_r);
 }
 bool dcrypt_ctx_sym_update(struct dcrypt_context_symmetric *ctx, const unsigned char *data, size_t data_len, buffer_t *result, const char **error_r)
 {
+	i_assert(dcrypt_vfs != NULL);
 	return dcrypt_vfs->ctx_sym_update(ctx, data, data_len, result, error_r);
 }
 bool dcrypt_ctx_sym_final(struct dcrypt_context_symmetric *ctx, buffer_t *result, const char **error_r)
 {
+	i_assert(dcrypt_vfs != NULL);
 	return dcrypt_vfs->ctx_sym_final(ctx, result, error_r);
 }
 
 void dcrypt_ctx_sym_set_padding(struct dcrypt_context_symmetric *ctx, bool padding)
 {
+	i_assert(dcrypt_vfs != NULL);
 	dcrypt_vfs->ctx_sym_set_padding(ctx, padding);
 }
 
 bool dcrypt_ctx_hmac_create(const char *algorithm, struct dcrypt_context_hmac **ctx_r, const char **error_r)
 {
+	i_assert(dcrypt_vfs != NULL);
 	return dcrypt_vfs->ctx_hmac_create(algorithm, ctx_r, error_r);
 }
 void dcrypt_ctx_hmac_destroy(struct dcrypt_context_hmac **ctx)
 {
+	i_assert(dcrypt_vfs != NULL);
 	dcrypt_vfs->ctx_hmac_destroy(ctx);
 }
 
 void dcrypt_ctx_hmac_set_key(struct dcrypt_context_hmac *ctx, const unsigned char *key, size_t key_len)
 {
+	i_assert(dcrypt_vfs != NULL);
 	dcrypt_vfs->ctx_hmac_set_key(ctx, key, key_len);
 }
 bool dcrypt_ctx_hmac_get_key(struct dcrypt_context_hmac *ctx, buffer_t *key)
 {
+	i_assert(dcrypt_vfs != NULL);
 	return dcrypt_vfs->ctx_hmac_get_key(ctx, key);
 }
 void dcrypt_ctx_hmac_set_key_random(struct dcrypt_context_hmac *ctx)
 {
+	i_assert(dcrypt_vfs != NULL);
 	dcrypt_vfs->ctx_hmac_set_key_random(ctx);
 }
 
 unsigned int dcrypt_ctx_hmac_get_digest_length(struct dcrypt_context_hmac *ctx)
 {
+	i_assert(dcrypt_vfs != NULL);
 	return dcrypt_vfs->ctx_hmac_get_digest_length(ctx);
 }
 
 bool dcrypt_ctx_hmac_init(struct dcrypt_context_hmac *ctx, const char **error_r)
 {
+	i_assert(dcrypt_vfs != NULL);
 	return dcrypt_vfs->ctx_hmac_init(ctx, error_r);
 }
 bool dcrypt_ctx_hmac_update(struct dcrypt_context_hmac *ctx, const unsigned char *data, size_t data_len, const char **error_r)
 {
+	i_assert(dcrypt_vfs != NULL);
 	return dcrypt_vfs->ctx_hmac_update(ctx, data, data_len, error_r);
 }
 bool dcrypt_ctx_hmac_final(struct dcrypt_context_hmac *ctx, buffer_t *result, const char **error_r)
 {
+	i_assert(dcrypt_vfs != NULL);
 	return dcrypt_vfs->ctx_hmac_final(ctx, result, error_r);
 }
 
 bool dcrypt_ecdh_derive_secret_local(struct dcrypt_private_key *local_key, buffer_t *R, buffer_t *S, const char **error_r)
 {
+	i_assert(dcrypt_vfs != NULL);
 	return dcrypt_vfs->ecdh_derive_secret_local(local_key, R, S, error_r);
 }
 bool dcrypt_ecdh_derive_secret_peer(struct dcrypt_public_key *peer_key, buffer_t *R, buffer_t *S, const char **error_r)
 {
+	i_assert(dcrypt_vfs != NULL);
 	return dcrypt_vfs->ecdh_derive_secret_peer(peer_key, R, S, error_r);
 }
 
 bool dcrypt_pbkdf2(const unsigned char *password, size_t password_len, const unsigned char *salt, size_t salt_len,
 	const char *hash, unsigned int rounds, buffer_t *result, unsigned int result_len, const char **error_r)
 {
+	i_assert(dcrypt_vfs != NULL);
 	return dcrypt_vfs->pbkdf2(password, password_len, salt, salt_len, hash, rounds, result, result_len, error_r);
 }
 
 bool dcrypt_keypair_generate(struct dcrypt_keypair *pair_r, enum dcrypt_key_type kind, unsigned int bits, const char *curve, const char **error_r)
 {
+	i_assert(dcrypt_vfs != NULL);
 	memset(pair_r, 0, sizeof(*pair_r));
 	return dcrypt_vfs->generate_keypair(pair_r, kind, bits, curve, error_r);
 }
@@ -203,94 +234,115 @@
 bool dcrypt_key_load_private(struct dcrypt_private_key **key_r, const char *data,
 	const char *password, struct dcrypt_private_key *dec_key, const char **error_r)
 {
+	i_assert(dcrypt_vfs != NULL);
 	return dcrypt_vfs->load_private_key(key_r, data, password, dec_key, error_r);
 }
 bool dcrypt_key_load_public(struct dcrypt_public_key **key_r, const char *data, const char **error_r)
 {
+	i_assert(dcrypt_vfs != NULL);
 	return dcrypt_vfs->load_public_key(key_r, data, error_r);
 }
 bool dcrypt_key_store_private(struct dcrypt_private_key *key, enum dcrypt_key_format format, const char *cipher, buffer_t *destination,
 	const char *password, struct dcrypt_public_key *enc_key, const char **error_r)
 {
+	i_assert(dcrypt_vfs != NULL);
 	return dcrypt_vfs->store_private_key(key, format, cipher, destination, password, enc_key, error_r);
 }
 bool dcrypt_key_store_public(struct dcrypt_public_key *key, enum dcrypt_key_format format, buffer_t *destination, const char **error_r)
 {
+	i_assert(dcrypt_vfs != NULL);
 	return dcrypt_vfs->store_public_key(key, format, destination, error_r);
 }
 
 void dcrypt_key_convert_private_to_public(struct dcrypt_private_key *priv_key, struct dcrypt_public_key **pub_key_r)
 {
+	i_assert(dcrypt_vfs != NULL);
 	dcrypt_vfs->private_to_public_key(priv_key, pub_key_r);
 }
 bool dcrypt_key_string_get_info(const char *key_data, enum dcrypt_key_format *format_r, enum dcrypt_key_version *version_r,
 	enum dcrypt_key_kind *kind_r, enum dcrypt_key_encryption_type *encryption_type_r, const char **encryption_key_hash_r,
 	const char **key_hash_r, const char **error_r)
 {
+	i_assert(dcrypt_vfs != NULL);
 	return dcrypt_vfs->key_string_get_info(key_data, format_r, version_r, kind_r, encryption_type_r,
 		encryption_key_hash_r, key_hash_r, error_r);
 }
 
 enum dcrypt_key_type dcrypt_key_type_private(struct dcrypt_private_key *key)
 {
+	i_assert(dcrypt_vfs != NULL);
 	return dcrypt_vfs->private_key_type(key);
 }
 enum dcrypt_key_type dcrypt_key_type_public(struct dcrypt_public_key *key)
 {
+	i_assert(dcrypt_vfs != NULL);
 	return dcrypt_vfs->public_key_type(key);
 }
 bool dcrypt_key_id_public(struct dcrypt_public_key *key, const char *algorithm, buffer_t *result, const char **error_r)
 {
+	i_assert(dcrypt_vfs != NULL);
 	return dcrypt_vfs->public_key_id(key, algorithm, result, error_r);
 }
 bool dcrypt_key_id_public_old(struct dcrypt_public_key *key, buffer_t *result, const char **error_r)
 {
+	i_assert(dcrypt_vfs != NULL);
 	return dcrypt_vfs->public_key_id_old(key, result, error_r);
 }
 bool dcrypt_key_id_private(struct dcrypt_private_key *key, const char *algorithm, buffer_t *result, const char **error_r)
 {
+	i_assert(dcrypt_vfs != NULL);
 	return dcrypt_vfs->private_key_id(key, algorithm, result, error_r);
 }
 bool dcrypt_key_id_private_old(struct dcrypt_private_key *key, buffer_t *result, const char **error_r)
 {
+	i_assert(dcrypt_vfs != NULL);
 	return dcrypt_vfs->private_key_id_old(key, result, error_r);
 }
 void dcrypt_keypair_unref(struct dcrypt_keypair *keypair)
 {
+	i_assert(dcrypt_vfs != NULL);
 	dcrypt_vfs->unref_keypair(keypair);
 }
 void dcrypt_key_ref_public(struct dcrypt_public_key *key)
 {
+	i_assert(dcrypt_vfs != NULL);
 	dcrypt_vfs->ref_public_key(key);
 }
 void dcrypt_key_ref_private(struct dcrypt_private_key *key)
 {
+	i_assert(dcrypt_vfs != NULL);
 	dcrypt_vfs->ref_private_key(key);
 }
 void dcrypt_key_unref_public(struct dcrypt_public_key **key)
 {
+	i_assert(dcrypt_vfs != NULL);
 	dcrypt_vfs->unref_public_key(key);
 }
 void dcrypt_key_unref_private(struct dcrypt_private_key **key)
 {
+	i_assert(dcrypt_vfs != NULL);
 	dcrypt_vfs->unref_private_key(key);
 }
 
 bool dcrypt_rsa_encrypt(struct dcrypt_public_key *key, const unsigned char *data, size_t data_len, buffer_t *result, const char **error_r)
 {
+	i_assert(dcrypt_vfs != NULL);
 	return dcrypt_vfs->rsa_encrypt(key, data, data_len, result, error_r);
 }
 bool dcrypt_rsa_decrypt(struct dcrypt_private_key *key, const unsigned char *data, size_t data_len, buffer_t *result, const char **error_r)
 {
+	i_assert(dcrypt_vfs != NULL);
 	return dcrypt_vfs->rsa_decrypt(key, data, data_len, result, error_r);
 }
 
 const char *dcrypt_oid2name(const unsigned char *oid, size_t oid_len, const char **error_r)
 {
+	i_assert(dcrypt_vfs != NULL);
 	return dcrypt_vfs->oid2name(oid, oid_len, error_r);
 }
 bool dcrypt_name2oid(const char *name, buffer_t *oid, const char **error_r)
 {
+	i_assert(dcrypt_vfs != NULL);
 	return dcrypt_vfs->name2oid(name, oid, error_r);
 }