Fix issue with codec initialization

Due to a change in SQLite's behaviour in version 3.48.0 it is no longer possible to locate the cipher configuration table via an SQL function. A named connection parameter is now used for this purpose.

Author: utelle

src/cipher_common.c

@@ -55,6 +55,7 @@ typedef struct _CipherName
   char m_name[CIPHER_NAME_MAXLEN];
 } CipherName;
 
+static char globalConfigTableName[CIPHER_NAME_MAXLEN] = "";
 static int globalCipherCount = 0;
 static char* globalSentinelName = "";
 static CipherName globalCipherNameTable[CODEC_COUNT_LIMIT + 2] = { 0 };

src/cipher_config.c

@@ -29,18 +29,7 @@ sqlite3mcConfigTable(sqlite3_context* context, int argc, sqlite3_value** argv)
 SQLITE_PRIVATE CodecParameter*
 sqlite3mcGetCodecParams(sqlite3* db)
 {
-  CodecParameter* codecParams = NULL;
-  sqlite3_stmt* pStmt = 0;
-  int rc = sqlite3_prepare_v2(db, "SELECT sqlite3mc_config_table();", -1, &pStmt, 0);
-  if (rc == SQLITE_OK)
-  {
-    if (SQLITE_ROW == sqlite3_step(pStmt))
-    {
-      sqlite3_value* ptrValue = sqlite3_column_value(pStmt, 0);
-      codecParams = (CodecParameter*) sqlite3_value_pointer(ptrValue, "sqlite3mc_codec_params");
-    }
-    sqlite3_finalize(pStmt);
-  }
+  CodecParameter* codecParams = (CodecParameter*) sqlite3_get_clientdata(db, globalConfigTableName);
   return codecParams;
 }
 
@@ -909,8 +898,16 @@ sqlite3mcFileControlPragma(sqlite3* db, const char* zDbName, int op, void* pArg)
         {
           value = sqlite3mc_config(db, "cipher", cipherId);
         }
-        rc = SQLITE_OK;
-        ((char**)pArg)[0] = sqlite3_mprintf("%s", globalCodecDescriptorTable[value - 1].m_name);
+        if (value > 0)
+        {
+          ((char**)pArg)[0] = sqlite3_mprintf("%s", globalCodecDescriptorTable[value - 1].m_name);
+          rc = SQLITE_OK;
+        }
+        else
+        {
+          ((char**)pArg)[0] = sqlite3_mprintf("Cipher '%s' could not be located.", pragmaValue);
+          rc = SQLITE_ERROR;
+        }
       }
       else
       {

src/codecext.c

@@ -360,7 +360,8 @@ sqlite3_key_v2(sqlite3* db, const char* zDbName, const void* zKey, int nKey)
       return rc;
     }
     /* Configure cipher from URI parameters if requested */
-    if (sqlite3FindFunction(db, "sqlite3mc_config_table", 0, SQLITE_UTF8, 0) == NULL)
+    void* codecParamTable = sqlite3_get_clientdata(db, globalConfigTableName);
+    if (codecParamTable == NULL)
     {
       /*
       ** Encryption extension of database connection not yet initialized;

src/sqlite3mc.c

@@ -381,7 +381,8 @@ mcRegisterCodecExtensions(sqlite3* db, char** pzErrMsg, const sqlite3_api_routin
   int rc = SQLITE_OK;
   CodecParameter* codecParameterTable = NULL;
 
-  if (sqlite3FindFunction(db, "sqlite3mc_config_table", 1, SQLITE_UTF8, 0) != NULL)
+  void* codecParamTable = sqlite3_get_clientdata(db, globalConfigTableName);
+  if (codecParamTable)
   {
     /* Return if codec extension functions are already defined */
     return rc;
@@ -392,8 +393,7 @@ mcRegisterCodecExtensions(sqlite3* db, char** pzErrMsg, const sqlite3_api_routin
   rc = (codecParameterTable != NULL) ? SQLITE_OK : SQLITE_NOMEM;
   if (rc == SQLITE_OK)
   {
-    rc = sqlite3_create_function_v2(db, "sqlite3mc_config_table", 0, SQLITE_UTF8 | SQLITE_DETERMINISTIC,
-                                    codecParameterTable, sqlite3mcConfigTable, 0, 0, sqlite3mcFreeCodecParameterTable);
+    sqlite3_set_clientdata(db, globalConfigTableName, codecParameterTable, sqlite3mcFreeCodecParameterTable);
   }
 
   rc = (codecParameterTable != NULL) ? SQLITE_OK : SQLITE_NOMEM;
@@ -610,6 +610,15 @@ sqlite3mcInitCipherTables()
 {
   size_t n;
 
+  /* Initialize global configuration table name */
+  sqlite3_randomness(CIPHER_NAME_MAXLEN, globalConfigTableName);
+  for (n = 0; n < CIPHER_NAME_MAXLEN-1; ++n)
+  {
+    if (globalConfigTableName[n] == 0)
+      globalConfigTableName[n] = '@';
+  }
+  globalConfigTableName[CIPHER_NAME_MAXLEN-1] = 0;
+
   /* Initialize cipher name table */
   strcpy(globalCipherNameTable[0].m_name, "global");
   for (n = 1; n < CODEC_COUNT_MAX + 2; ++n)