Fix #272: run c_obj_create under a lock.

See #272.

This commit adds a lock to run `c_obj_create` and `OBJ_create` thread-safely in
`OQS_PROVIDER_ENTRYPOINT_NAME`,

.circleci/config.yml

@@ -84,7 +84,7 @@ jobs:
           name: Run tests
           command: |
              if << parameters.OQS_PROVIDER_BUILD_STATIC >> ; then
-               ctest --test-dir _build/
+               ctest --output-on-failure --test-dir _build/
              else
                ./scripts/runtests.sh -V
              fi

oqsprov/oqsprov.c

@@ -13,6 +13,7 @@
 #include <openssl/core_names.h>
 #include <openssl/err.h>
 #include <openssl/objects.h>
+#include <openssl/objectserr.h>
 #include <openssl/params.h>
 #include <openssl/provider.h>
 #include <stdio.h>
@@ -917,6 +918,7 @@ int OQS_PROVIDER_ENTRYPOINT_NAME(const OSSL_CORE_HANDLE *handle,
     OSSL_PARAM version_request[] = {{"openssl-version", OSSL_PARAM_UTF8_PTR,
                                      &opensslv, sizeof(&opensslv), 0},
                                     {NULL, 0, NULL, 0, 0}};
+    unsigned long last_error = 0;
 
     OQS_init();
 
@@ -968,10 +970,13 @@ int OQS_PROVIDER_ENTRYPOINT_NAME(const OSSL_CORE_HANDLE *handle,
     for (i = 0; i < OQS_OID_CNT; i += 2) {
         if (!c_obj_create(handle, oqs_oid_alg_list[i], oqs_oid_alg_list[i + 1],
                           oqs_oid_alg_list[i + 1])) {
-            ERR_raise(ERR_LIB_USER, OQSPROV_R_OBJ_CREATE_ERR);
-            fprintf(stderr, "error registering NID for %s\n",
-                    oqs_oid_alg_list[i + 1]);
-            goto end_init;
+            last_error = ERR_peek_last_error();
+            if (last_error != ERR_PACK(ERR_LIB_OBJ, 0, OBJ_R_OID_EXISTS)) {
+                ERR_raise(ERR_LIB_USER, OQSPROV_R_OBJ_CREATE_ERR);
+                fprintf(stderr, "error registering NID for %s\n",
+                        oqs_oid_alg_list[i + 1]);
+                goto end_init;
+            }
         }
 
         /* create object (NID) again to avoid setup corner case problems
@@ -1016,9 +1021,12 @@ int OQS_PROVIDER_ENTRYPOINT_NAME(const OSSL_CORE_HANDLE *handle,
         || ((libctx = OSSL_LIB_CTX_new_child(handle, orig_in)) == NULL)
         || ((*provctx = oqsx_newprovctx(libctx, handle, corebiometh))
             == NULL)) {
-        OQS_PROV_PRINTF("OQS PROV: error creating new provider context\n");
-        ERR_raise(ERR_LIB_USER, OQSPROV_R_LIB_CREATE_ERR);
-        goto end_init;
+        last_error = ERR_peek_last_error();
+        if (last_error != ERR_PACK(ERR_LIB_OBJ, 0, OBJ_R_OID_EXISTS)) {
+            OQS_PROV_PRINTF("OQS PROV: error creating new provider context\n");
+            ERR_raise(ERR_LIB_USER, OQSPROV_R_LIB_CREATE_ERR);
+            goto end_init;
+        }
     }
 
     *out = oqsprovider_dispatch_table;

test/CMakeLists.txt

@@ -110,6 +110,18 @@ set_tests_properties(oqs_endecode
 )
 endif()
 
+add_executable(oqs_test_multi_thread oqs_test_multi_thread.c)
+target_link_libraries(oqs_test_multi_thread PRIVATE ${OPENSSL_CRYPTO_LIBRARY})
+add_test(
+  NAME oqs_multi_thread
+  COMMAND oqs_test_multi_thread
+          "oqsprovider"
+          "${CMAKE_CURRENT_SOURCE_DIR}/openssl-ca.cnf"
+)
+set_tests_properties(oqs_multi_thread
+    PROPERTIES ENVIRONMENT "OPENSSL_MODULES=${OQS_PROV_BINARY_DIR}"
+)
+
 if (OQS_PROVIDER_BUILD_STATIC)
   targets_set_static_provider(oqs_test_signatures
     oqs_test_kems

test/oqs_test_multi_thread.c

@@ -0,0 +1,99 @@
+// SPDX-License-Identifier: Apache-2.0 AND MIT
+
+#include <pthread.h>
+
+#include <openssl/crypto.h>
+#include <openssl/provider.h>
+
+#include "test_common.h"
+
+static const size_t N_THREADS = 32;
+
+static const char *kModuleName = NULL;
+static const char *kConfigFile = NULL;
+
+/** \brief Loads the oqs-provider in an `OSSL_LIB_CTX` object. */
+static int load_oqs_provider_thread(OSSL_LIB_CTX *lib_ctx)
+{
+    OSSL_PROVIDER *default_provider = NULL;
+    OSSL_PROVIDER *oqs_provider = NULL;
+    int ret = -1;
+
+#ifdef OQS_PROVIDER_STATIC
+
+    if ((default_provider = OSSL_PROVIDER_load(lib_ctx, "default")) == NULL) {
+        goto end;
+    }
+    if (OSSL_PROVIDER_add_builtin(lib_ctx, "oqsprovider",
+                                  OQS_PROVIDER_ENTRYPOINT_NAME)
+        != 1) {
+        putchar('-');
+        goto unload_default_provider;
+    }
+    if ((oqs_provider = OSSL_PROVIDER_load(lib_ctx, "oqsprovider")) == NULL) {
+        putchar('/');
+        goto unload_default_provider;
+    }
+    ret = 0;
+    OSS_PROVIDER_unload(oqs_provider);
+
+#else
+
+    if (OSSL_LIB_CTX_load_config(lib_ctx, kConfigFile) == 1
+        && OSSL_PROVIDER_available(lib_ctx, kModuleName)) {
+        putchar('>');
+        ret = 0;
+    }
+    goto end;
+
+#endif // ifdef OQS_PROVIDER_STATIC
+
+unload_default_provider:
+    OSSL_PROVIDER_unload(default_provider);
+
+end:
+    return ret;
+}
+
+/** \brief Creates an OSSL_LIB_CTX object and loads oqs-provider. */
+static void *thread_create_ossl_lib_ctx(void *arg)
+{
+    OSSL_LIB_CTX *lib_ctx = NULL;
+    int ret = -1;
+
+    (void)arg;
+
+    if ((lib_ctx = OSSL_LIB_CTX_new()) == NULL) {
+        goto end;
+    }
+    ret = load_oqs_provider_thread(lib_ctx);
+    OSSL_LIB_CTX_free(lib_ctx);
+
+end:
+    return (void *)(size_t)ret;
+}
+
+int main(int argc, char **argv)
+{
+    size_t i;
+    pthread_t threads[N_THREADS];
+    void *result;
+    int ret = 0;
+
+    T(argc == 3);
+
+    kModuleName = argv[1];
+    kConfigFile = argv[2];
+
+    for (i = 0; i < N_THREADS; ++i) {
+        pthread_create(threads + i, NULL, thread_create_ossl_lib_ctx, NULL);
+    }
+
+    for (i = 0; i < N_THREADS; ++i) {
+        result = NULL;
+        pthread_join(threads[i], &result);
+        ret |= (int)(size_t)result;
+    }
+
+    return ret;
+}