Assert that a property definition cache entry is the first

[openssl.git] / crypto / property / defn_cache.c

diff --git a/crypto/property/defn_cache.c b/crypto/property/defn_cache.c
index b3aefe8f8eb3c9f871cb1edddf8dce7042f72ce4..c697e6f474f7f12b46bdaa226aee8c44a864ac6e 100644 (file)
--- a/crypto/property/defn_cache.c
+++ b/crypto/property/defn_cache.c
@@ -1,5 +1,5 @@
 /*
- * Copyright 2019-2020 The OpenSSL Project Authors. All Rights Reserved.
+ * Copyright 2019-2022 The OpenSSL Project Authors. All Rights Reserved.
  * Copyright (c) 2019, Oracle and/or its affiliates.  All rights reserved.
  *
  * Licensed under the Apache License 2.0 (the "License").  You may not use
@@ -13,7 +13,9 @@
 #include <openssl/lhash.h>
 #include "internal/propertyerr.h"
 #include "internal/property.h"
+#include "internal/core.h"
 #include "property_local.h"
+#include "crypto/context.h"
 
 /*
  * Implement a property definition cache.
@@ -46,7 +48,7 @@ static void property_defn_free(PROPERTY_DEFN_ELEM *elem)
     OPENSSL_free(elem);
 }
 
-static void property_defns_free(void *vproperty_defns)
+void ossl_property_defns_free(void *vproperty_defns)
 {
     LHASH_OF(PROPERTY_DEFN_ELEM) *property_defns = vproperty_defns;
 
@@ -57,51 +59,53 @@ static void property_defns_free(void *vproperty_defns)
     }
 }
 
-static void *property_defns_new(OSSL_LIB_CTX *ctx) {
+void *ossl_property_defns_new(OSSL_LIB_CTX *ctx) {
     return lh_PROPERTY_DEFN_ELEM_new(&property_defn_hash, &property_defn_cmp);
 }
 
-static const OSSL_LIB_CTX_METHOD property_defns_method = {
-    property_defns_new,
-    property_defns_free,
-};
-
 OSSL_PROPERTY_LIST *ossl_prop_defn_get(OSSL_LIB_CTX *ctx, const char *prop)
 {
     PROPERTY_DEFN_ELEM elem, *r;
     LHASH_OF(PROPERTY_DEFN_ELEM) *property_defns;
 
     property_defns = ossl_lib_ctx_get_data(ctx,
-                                           OSSL_LIB_CTX_PROPERTY_DEFN_INDEX,
-                                           &property_defns_method);
-    if (property_defns == NULL)
+                                           OSSL_LIB_CTX_PROPERTY_DEFN_INDEX);
+    if (property_defns == NULL || !ossl_lib_ctx_read_lock(ctx))
         return NULL;
 
     elem.prop = prop;
     r = lh_PROPERTY_DEFN_ELEM_retrieve(property_defns, &elem);
+    ossl_lib_ctx_unlock(ctx);
     return r != NULL ? r->defn : NULL;
 }
 
+/*
+ * Cache the property list for a given property string. Callers of this function
+ * should call ossl_prop_defn_get first to ensure that there is no existing
+ * cache entry for this property string.
+ */
 int ossl_prop_defn_set(OSSL_LIB_CTX *ctx, const char *prop,
                        OSSL_PROPERTY_LIST *pl)
 {
     PROPERTY_DEFN_ELEM elem, *old, *p = NULL;
     size_t len;
     LHASH_OF(PROPERTY_DEFN_ELEM) *property_defns;
+    int res = 1;
 
     property_defns = ossl_lib_ctx_get_data(ctx,
-                                           OSSL_LIB_CTX_PROPERTY_DEFN_INDEX,
-                                           &property_defns_method);
+                                           OSSL_LIB_CTX_PROPERTY_DEFN_INDEX);
     if (property_defns == NULL)
         return 0;
 
     if (prop == NULL)
         return 1;
 
+    if (!ossl_lib_ctx_write_lock(ctx))
+        return 0;
     if (pl == NULL) {
         elem.prop = prop;
         lh_PROPERTY_DEFN_ELEM_delete(property_defns, &elem);
-        return 1;
+        goto end;
     }
     len = strlen(prop);
     p = OPENSSL_malloc(sizeof(*p) + len);
@@ -110,13 +114,22 @@ int ossl_prop_defn_set(OSSL_LIB_CTX *ctx, const char *prop,
         p->defn = pl;
         memcpy(p->body, prop, len + 1);
         old = lh_PROPERTY_DEFN_ELEM_insert(property_defns, p);
-        if (old != NULL) {
-            property_defn_free(old);
-            return 1;
+        if (!ossl_assert(old == NULL)) {
+            /*
+             * This should not happen. Any caller of ossl_prop_defn_set should
+             * have called ossl_prop_defn_get first - so we should know that
+             * there is no existing entry. If we get here we have a bug. We
+             * deliberately leak the |old| reference in order to avoid a crash
+             * if there are any existing users of it.
+             */
+            goto end;
         }
         if (!lh_PROPERTY_DEFN_ELEM_error(property_defns))
-            return 1;
+            goto end;
     }
     OPENSSL_free(p);
-    return 0;
+    res = 0;
+ end:
+    ossl_lib_ctx_unlock(ctx);
+    return res;
 }