Edit report at https://bugs.php.net/bug.php?id=69975&edit=1
ID: 69975
Updated by: cmb@php.net
Reported by: jgeert1 at its dot jnj dot com
Summary: PHP segfaults when accessing nvarchar(max) defined
columns
Status: Closed
Type: Bug
Package: ODBC related
Operating System: Windows Server 2012R2
PHP Version: 5.5.26
Assigned To: cmb
Block user comment: N
Private report: N
New Comment:
The fix for this bug has been committed for PHP 5.6 and master.
You can download the latest Windows snapshot from
<http://windows.php.net/snapshots/>. Note that
it might take some
time for the next snapshot to be built.
Thank you for the report, and for helping us make PHP better.
I have not been able to reproduce #67437, and therefore didn't
cater to it; see also the commit message.
Previous Comments:
------------------------------------------------------------------------
[2015-07-02 22:30:03] cmb@php.net
Automatic comment on behalf of cmb
Revision: http://git.php.net/?p=php-src.git;a=commit;h=16db4d1462bf3eacb93c0cd940f799160a284b24
Log: Fix #69975: PHP segfaults when accessing nvarchar(max) defined columns
------------------------------------------------------------------------
[2015-07-02 21:04:28] cmb@php.net
I've tested with odbcver=0x0350 and 0x0351 and got segfaults, too.
Actually the problem is rather clear in the meantime. According to
MSDN[1] nvarchar(max) has a maximum size of 2GB. Even if the
driver would report this as displaylength, so much memory could
usually not be allocated. Apparently, nvarchar(max) has to be
treated the same as SQL_WLONGVARCHAR. The SQL Server driver does
this, but not the SQL Server Native Client 11.0 driver
(2011.110.3000.0). The fix appears to be a no-brainer (similar to
the attached draft patch, but additionally setting .coltype to
SQL_WLONGVARCHAR, and of course fixing the assignment in the if
condition).
I can confirm that #68964 is already fixed. An ntext column is
reported as SQL_WLONGVARCHAR by both drivers (ODBCVER 03x00 as
well as 0x351).
Interestingly, bug #67437 suggests that some drivers report a size
of ~ 2GB for nvarchar(max). I'll have a closer look on that.
[1] <https://msdn.microsoft.com/en-us/library/ms186939(v=sql.120).aspx>
------------------------------------------------------------------------
[2015-07-02 20:04:44] ab@php.net
@jgeert1, ahh, you're right. Still, it could be a driver mess.
@cmb, have you tried to raise the ODBCVER? See ext/odbc/config.w32, IMHO 3.5 could be done for
master, if there's no other solution. Still many issues with 3.0 and older. But on the other
hand, if you can fix it with 3.0, so be.
Thanks.
------------------------------------------------------------------------
[2015-07-02 16:59:23] cmb@php.net
I have now set up a testing environment with SQL Server 2014 and
can reproduce the issue. My patch was way too short-sighted (it
prevents the segfault, but does return empty strings). I'll have
to investigate further.
------------------------------------------------------------------------
[2015-07-02 14:24:05] jgeert1 at its dot jnj dot com
Wow that was fast :-)
What do I need to do to get a compiled version for Windows 64-bit?
Thanks.
------------------------------------------------------------------------
The remainder of the comments for this report are too long. To view
the rest of the comments, please view the bug report online at
https://bugs.php.net/bug.php?id=69975
--
Edit this bug report at https://bugs.php.net/bug.php?id=69975&edit=1