Add the STORE module

This STORE module adds the following functionality:

- A function OSSL_STORE_open(), OSSL_STORE_load() and OSSL_STORE_close()
  that accesses a URI and helps loading the supported objects (PKEYs,
  CERTs and CRLs for the moment) from it.
- An opaque type OSSL_STORE_INFO that holds information on each loaded
  object.
- A few functions to retrieve desired data from a OSSL_STORE_INFO
  reference.
- Functions to register and unregister loaders for different URI
  schemes.  This enables dynamic addition of loaders from applications
  or from engines.

Reviewed-by: Matt Caswell <matt@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/3542)

1 files changed, 259 insertions, 0 deletions

diff --git a/crypto/store/store_register.c b/crypto/store/store_register.c
new file mode 100644
index 0000000000..a138edc636
--- /dev/null
+++ b/crypto/store/store_register.c
@@ -0,0 +1,259 @@
+/*
+ * Copyright 2016-2017 The OpenSSL Project Authors. All Rights Reserved.
+ *
+ * Licensed under the OpenSSL license (the "License").  You may not use
+ * this file except in compliance with the License.  You can obtain a copy
+ * in the file LICENSE in the source distribution or at
+ * https://www.openssl.org/source/license.html
+ */
+
+#include <string.h>
+#include <ctype.h>
+#include <assert.h>
+
+#include <openssl/err.h>
+#include <openssl/lhash.h>
+#include "store_locl.h"
+
+static CRYPTO_RWLOCK *registry_lock;
+static CRYPTO_ONCE registry_init = CRYPTO_ONCE_STATIC_INIT;
+
+DEFINE_RUN_ONCE_STATIC(do_registry_init)
+{
+    registry_lock = CRYPTO_THREAD_lock_new();
+    return registry_lock != NULL;
+}
+
+/*
+ *  Functions for manipulating OSSL_STORE_LOADERs
+ */
+
+OSSL_STORE_LOADER *OSSL_STORE_LOADER_new(const char *scheme)
+{
+    OSSL_STORE_LOADER *res = OPENSSL_zalloc(sizeof(*res));
+
+    if (res == NULL) {
+        OSSL_STOREerr(OSSL_STORE_F_OSSL_STORE_LOADER_NEW, ERR_R_MALLOC_FAILURE);
+        return NULL;
+    }
+
+    /*
+     * We usually don't check NULL arguments.  For loaders, though, the
+     * scheme is crucial and must never be NULL, or the user will get
+     * mysterious errors when trying to register the created loader
+     * later on.
+     */
+    if (scheme == NULL) {
+        OSSL_STOREerr(OSSL_STORE_F_OSSL_STORE_LOADER_NEW,
+                      OSSL_STORE_R_INVALID_SCHEME);
+        return NULL;
+    }
+
+    res->scheme = scheme;
+    return res;
+}
+
+const char *OSSL_STORE_LOADER_get0_scheme(const OSSL_STORE_LOADER *loader)
+{
+    return loader->scheme;
+}
+
+int OSSL_STORE_LOADER_set_open(OSSL_STORE_LOADER *loader,
+                               OSSL_STORE_open_fn open_function)
+{
+    loader->open = open_function;
+    return 1;
+}
+
+int OSSL_STORE_LOADER_set_ctrl(OSSL_STORE_LOADER *loader,
+                               OSSL_STORE_ctrl_fn ctrl_function)
+{
+    loader->ctrl = ctrl_function;
+    return 1;
+}
+
+int OSSL_STORE_LOADER_set_load(OSSL_STORE_LOADER *loader,
+                               OSSL_STORE_load_fn load_function)
+{
+    loader->load = load_function;
+    return 1;
+}
+
+int OSSL_STORE_LOADER_set_eof(OSSL_STORE_LOADER *loader,
+                              OSSL_STORE_eof_fn eof_function)
+{
+    loader->eof = eof_function;
+    return 1;
+}
+
+int OSSL_STORE_LOADER_set_error(OSSL_STORE_LOADER *loader,
+                                OSSL_STORE_error_fn error_function)
+{
+    loader->error = error_function;
+    return 1;
+}
+
+int OSSL_STORE_LOADER_set_close(OSSL_STORE_LOADER *loader,
+                                OSSL_STORE_close_fn close_function)
+{
+    loader->close = close_function;
+    return 1;
+}
+
+void OSSL_STORE_LOADER_free(OSSL_STORE_LOADER *loader)
+{
+    OPENSSL_free(loader);
+}
+
+/*
+ *  Functions for registering OSSL_STORE_LOADERs
+ */
+
+static unsigned long store_loader_hash(const OSSL_STORE_LOADER *v)
+{
+    return OPENSSL_LH_strhash(v->scheme);
+}
+
+static int store_loader_cmp(const OSSL_STORE_LOADER *a,
+                            const OSSL_STORE_LOADER *b)
+{
+    if (a->scheme != NULL && b->scheme != NULL)
+        return strcmp(a->scheme, b->scheme);
+    else if (a->scheme == b->scheme)
+        return 0;
+    return a->scheme == NULL ? -1 : 1;
+}
+
+static LHASH_OF(OSSL_STORE_LOADER) *loader_register = NULL;
+
+int ossl_store_register_loader_int(OSSL_STORE_LOADER *loader)
+{
+    const char *scheme = loader->scheme;
+    int ok = 0;
+
+    /*
+     * Check that the given scheme conforms to correct scheme syntax as per
+     * RFC 3986:
+     *
+     * scheme        = ALPHA *( ALPHA / DIGIT / "+" / "-" / "." )
+     */
+    if (isalpha(*scheme))
+        while (*scheme != '\0'
+               && (isalpha(*scheme)
+                   || isdigit(*scheme)
+                   || strchr("+-.", *scheme) != NULL))
+            scheme++;
+    if (*scheme != '\0') {
+        OSSL_STOREerr(OSSL_STORE_F_OSSL_STORE_REGISTER_LOADER_INT,
+                      OSSL_STORE_R_INVALID_SCHEME);
+        ERR_add_error_data(4, "scheme=", loader->scheme);
+        return 0;
+    }
+
+    if (!RUN_ONCE(&registry_init, do_registry_init)) {
+        OSSL_STOREerr(OSSL_STORE_F_OSSL_STORE_REGISTER_LOADER_INT,
+                      ERR_R_MALLOC_FAILURE);
+        return 0;
+    }
+    CRYPTO_THREAD_write_lock(registry_lock);
+
+    if (loader_register == NULL) {
+        loader_register = lh_OSSL_STORE_LOADER_new(store_loader_hash,
+                                                   store_loader_cmp);
+    }
+
+    if (loader_register != NULL
+        && (lh_OSSL_STORE_LOADER_insert(loader_register, loader) != NULL
+            || lh_OSSL_STORE_LOADER_error(loader_register) == 0))
+        ok = 1;
+
+    CRYPTO_THREAD_unlock(registry_lock);
+
+    return ok;
+}
+int OSSL_STORE_register_loader(OSSL_STORE_LOADER *loader)
+{
+    if (!ossl_store_init_once())
+        return 0;
+    return ossl_store_register_loader_int(loader);
+}
+
+const OSSL_STORE_LOADER *ossl_store_get0_loader_int(const char *scheme)
+{
+    OSSL_STORE_LOADER template;
+    OSSL_STORE_LOADER *loader = NULL;
+
+    template.scheme = scheme;
+    template.open = NULL;
+    template.load = NULL;
+    template.eof = NULL;
+    template.close = NULL;
+
+    if (!ossl_store_init_once())
+        return NULL;
+
+    if (!RUN_ONCE(&registry_init, do_registry_init)) {
+        OSSL_STOREerr(OSSL_STORE_F_OSSL_STORE_GET0_LOADER_INT,
+                      ERR_R_MALLOC_FAILURE);
+        return NULL;
+    }
+    CRYPTO_THREAD_write_lock(registry_lock);
+
+    loader = lh_OSSL_STORE_LOADER_retrieve(loader_register, &template);
+
+    if (loader == NULL) {
+        OSSL_STOREerr(OSSL_STORE_F_OSSL_STORE_GET0_LOADER_INT,
+                      OSSL_STORE_R_UNREGISTERED_SCHEME);
+        ERR_add_error_data(2, "scheme=", scheme);
+    }
+
+    CRYPTO_THREAD_unlock(registry_lock);
+
+    return loader;
+}
+
+OSSL_STORE_LOADER *ossl_store_unregister_loader_int(const char *scheme)
+{
+    OSSL_STORE_LOADER template;
+    OSSL_STORE_LOADER *loader = NULL;
+
+    template.scheme = scheme;
+    template.open = NULL;
+    template.load = NULL;
+    template.eof = NULL;
+    template.close = NULL;
+
+    if (!RUN_ONCE(&registry_init, do_registry_init)) {
+        OSSL_STOREerr(OSSL_STORE_F_OSSL_STORE_UNREGISTER_LOADER_INT,
+                      ERR_R_MALLOC_FAILURE);
+        return NULL;
+    }
+    CRYPTO_THREAD_write_lock(registry_lock);
+
+    loader = lh_OSSL_STORE_LOADER_delete(loader_register, &template);
+
+    if (loader == NULL) {
+        OSSL_STOREerr(OSSL_STORE_F_OSSL_STORE_UNREGISTER_LOADER_INT,
+                      OSSL_STORE_R_UNREGISTERED_SCHEME);
+        ERR_add_error_data(2, "scheme=", scheme);
+    }
+
+    CRYPTO_THREAD_unlock(registry_lock);
+
+    return loader;
+}
+OSSL_STORE_LOADER *OSSL_STORE_unregister_loader(const char *scheme)
+{
+    if (!ossl_store_init_once())
+        return 0;
+    return ossl_store_unregister_loader_int(scheme);
+}
+
+void ossl_store_destroy_loaders_int(void)
+{
+    assert(lh_OSSL_STORE_LOADER_num_items(loader_register) == 0);
+    lh_OSSL_STORE_LOADER_free(loader_register);
+    loader_register = NULL;
+    CRYPTO_THREAD_lock_free(registry_lock);
+    registry_lock = NULL;
+}