Ensure that the database encoding cannot be changed while there are statements running. And that the connection is left in a valid state after an obscure OOM within sqlite3_deserialize().

FossilOrigin-Name: a02da71f3a80dd8e817e89cdaa775c95e38c90d2471f8fec516bed086539e2c0

2 files changed, 26 insertions, 6 deletions

diff --git a/src/attach.c b/src/attach.c
index 1732be27b..917fcad67 100644
--- a/src/attach.c
+++ b/src/attach.c
@@ -105,13 +105,26 @@ static void attachFunc(
     /* This is not a real ATTACH.  Instead, this routine is being called
     ** from sqlite3_deserialize() to close database db->init.iDb and
     ** reopen it as a MemDB */
+    Btree *pNewBt = 0;
     pVfs = sqlite3_vfs_find("memdb");
     if( pVfs==0 ) return;
-    pNew = &db->aDb[db->init.iDb];
-    if( pNew->pBt ) sqlite3BtreeClose(pNew->pBt);
-    pNew->pBt = 0;
-    pNew->pSchema = 0;
-    rc = sqlite3BtreeOpen(pVfs, "x\0", db, &pNew->pBt, 0, SQLITE_OPEN_MAIN_DB);
+    rc = sqlite3BtreeOpen(pVfs, "x\0", db, &pNewBt, 0, SQLITE_OPEN_MAIN_DB);
+    if( rc==SQLITE_OK ){
+      Schema *pNewSchema = sqlite3SchemaGet(db, pNewBt);
+      if( pNewSchema ){
+        /* Both the Btree and the new Schema were allocated successfully.
+        ** Close the old db and update the aDb[] slot with the new memdb
+        ** values.  */
+        pNew = &db->aDb[db->init.iDb];
+        if( pNew->pBt ) sqlite3BtreeClose(pNew->pBt);
+        pNew->pBt = pNewBt;
+        pNew->pSchema = pNewSchema;
+      }else{
+        sqlite3BtreeClose(pNewBt);
+        rc = SQLITE_NOMEM;
+      }
+    }
+    if( rc ) goto attach_error;
   }else{
     /* This is a real ATTACH
     **
@@ -341,6 +354,8 @@ static void codeAttach(
   sqlite3* db = pParse->db;
   int regArgs;
 
+  if( SQLITE_OK!=sqlite3ReadSchema(pParse) ) goto attach_end;
+
   if( pParse->nErr ) goto attach_end;
   memset(&sName, 0, sizeof(NameContext));
   sName.pParse = pParse;
diff --git a/src/prepare.c b/src/prepare.c
index 760738740..b2613e2c1 100644
--- a/src/prepare.c
+++ b/src/prepare.c
@@ -306,7 +306,12 @@ int sqlite3InitOne(sqlite3 *db, int iDb, char **pzErrMsg, u32 mFlags){
 #else
       encoding = SQLITE_UTF8;
 #endif
-      sqlite3SetTextEncoding(db, encoding);
+      if( db->nVdbeActive>0 && encoding!=ENC(db) ){
+        rc = SQLITE_LOCKED;
+        goto initone_error_out;
+      }else{
+        sqlite3SetTextEncoding(db, encoding);
+      }
     }else{
       /* If opening an attached database, the encoding much match ENC(db) */
       if( (meta[BTREE_TEXT_ENCODING-1] & 3)!=ENC(db) ){