Bug 1399580 (CVE-2016-1251)

Summary:	CVE-2016-1251 perl-DBD-MySQL: Use after free when using prepared statements
Product:	[Other] Security Response	Reporter:	Adam Mariš <amaris>
Component:	vulnerability	Assignee:	Red Hat Product Security <security-response-team>
Status:	CLOSED WONTFIX	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	CC:	hhorak, jorton, jplesnik, perl-devel, perl-maint-list, ppisar, psabata, sardella, yozone
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:	perl-DBD-MySQL 4.041	Doc Type:	If docs needed, set a value
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2019-06-08 03:02:45 UTC	Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Bug Depends On:	1399581, 1405899
Bug Blocks:	1399583

Description Adam Mariš 2016-11-29 10:41:15 UTC

A use after free vulnerability when using prepared statements was found in DBD::mysql. Function dbd_st_fetch() via Renew() can reallocate output buffer for mysql_stmt_fetch() call, but it does not update pointer to that buffer in imp_sth->stmt structure initialized by mysql_stmt_bind_result() function, which leads to use after free in any mysql function which access imp_sth->stmt structure.

This vulnerability is present in all releases at least back to versions 3.0 of the driver, which were released in 2005.

Upstream patch:

https://github.com/perl5-dbi/DBD-mysql/commit/3619c170461a3107a258d1fd2d00ed4832adb1b1

References:

http://seclists.org/oss-sec/2016/q4/536

Comment 1 Adam Mariš 2016-11-29 10:41:44 UTC

Created perl-DBD-MySQL tracking bugs for this issue:

Affects: fedora-all [bug 1399581]

Comment 7 Dhiru Kholia 2017-01-04 05:04:33 UTC

Mitigation:

This problem is only exposed when the user uses server-side prepared statement support (mysql_server_prepare=1), which is NOT default behavior and was turned off back for all drivers per MySQL AB decision in 2006 due to issues with server-side prepared statements in the server.

Use the default driver setting which uses emulated prepared statements.