From 863f7cebd79e76f90bd8f1e3e0c1a1de5fe77d07 Mon Sep 17 00:00:00 2001 From: Sreeharsha Ramanavarapu Date: Fri, 8 Jan 2016 06:46:59 +0530 Subject: Bug #22232332: SAVING TEXT FIELD TO TEXT VARIABLE IN A PROCEDURE RESULTS IN GARBAGE BYTES Issue: ----- This problem occurs under the following conditions: a) Stored procedure has a variable is declared as TEXT/BLOB. b) Data is copied into the the variable using the SELECT...INTO syntax from a TEXT/BLOB column. Data corruption can occur in such cases. SOLUTION: --------- The blob type does not allocate space for the string to be stored. Instead it contains a pointer to the source string. Since the source is deallocated immediately after the select statement, this can cause data corruption. As part of the fix for Bug #21143080, when the source was part of the table's write-set, blob would allocate the neccessary space. But this fix missed the possibility that, as in the above case, the target might be a variable. The fix will add the copy_blobs check that was removed by the earlier fix. --- sql/field_conv.cc | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) (limited to 'sql/field_conv.cc') diff --git a/sql/field_conv.cc b/sql/field_conv.cc index 7eb49b9dd92..d98f19c3e01 100644 --- a/sql/field_conv.cc +++ b/sql/field_conv.cc @@ -1,4 +1,4 @@ -/* Copyright (c) 2000, 2015, Oracle and/or its affiliates. All rights reserved. +/* Copyright (c) 2000, 2016, Oracle and/or its affiliates. All rights reserved. This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by @@ -826,7 +826,12 @@ int field_conv(Field *to,Field *from) Field_blob *blob=(Field_blob*) to; from->val_str(&blob->value); - if (!blob->value.is_alloced() && from->is_updatable()) + /* + Copy value if copy_blobs is set, or source is part of the table's + writeset. + */ + if (to->table->copy_blobs || + (!blob->value.is_alloced() && from->is_updatable())) blob->value.copy(); return blob->store(blob->value.ptr(),blob->value.length(),from->charset()); -- cgit v1.2.1