[fdo-trac] #564: SHP provider crashed when reallocing memory in ReadRawDataBlock.

[FDO]

#564: SHP provider crashed when reallocing memory in ReadRawDataBlock.
----------------------+-----------------------------------------------------
 Reporter:  StevenXu  |         Owner:  StevenXu
     Type:  defect    |        Status:  assigned
 Priority:  major     |     Milestone:  3.5.0   
Component:  FDO API   |       Version:  3.4.0   
 Severity:  2         |    Resolution:          
 Keywords:            |   External_id:  1242062 
----------------------+-----------------------------------------------------
Comment (by StevenXu):

 It is obviously that SHP provider got the wrong size of memory in runtime.

 Why it would happen?

 In some cases, the user's SHP files violated the SHP file specification so
 that
 our SHP provider can't understand them and read an incredible size of the
 data
 block from them.

 Another possible reason, there is a defect in the function
 {{{
 ShpFileSet::MakeSpace
 }}}
 which could corrupt SHP file in some extreme cases. As a result, this
 corrupted SHP file leads to this crash.

 The attachment "Ticket_564.patch" is the fix against:
 http://svn.osgeo.org/fdo/trunk/Providers/SHP/Src/Provider/ShpFileSet.cpp

 It includes two fixes.

 1. While reading the shape from the file, if SHP provider run into some
 unknown
 exceptions, eat these exceptions and return a Null Shape.

 2. Correct the problem in function
 {{{
 ShpFileSet::MakeSpace
 }}}
  which would miss the last chunk in some extreme cases.

 {{{
 \Providers\SHP\Src\Provider\ShpFileSet.cpp
 }}}

 {{{
 ShpFileSet::MakeSpace
 {
 ......
 Line 655: while (shp->ReadFile (buffer + plus, size, &read) && (size ==
 read))
 Line 665: if (0 != read)
 ......
 }
 }}}

 The if statement isn't right and which would result in the last "excess"
 bytes
 of the file were missing , when the "while" statement success in reading
 the all
 bytes of the file once.

-- 
Ticket URL: <http://trac.osgeo.org/fdo/ticket/564#comment:2>
FDO <http://fdo.osgeo.org/>
Feature Data Objects