postgres

Commit Graph

Author	SHA1	Message	Date
Tom Lane	ac7e13d6fc	Prevent access to external files/URLs via contrib/xml2's xslt_process(). libxslt offers the ability to read and write both files and URLs through stylesheet commands, thus allowing unprivileged database users to both read and write data with the privileges of the database server. Disable that through proper use of libxslt's security options. Also, remove xslt_process()'s ability to fetch documents and stylesheets from external files/URLs. While this was a documented "feature", it was long regarded as a terrible idea. The fix for CVE-2012-3489 broke that capability, and rather than expend effort on trying to fix it, we're just going to summarily remove it. While the ability to write as well as read makes this security hole considerably worse than CVE-2012-3489, the problem is mitigated by the fact that xslt_process() is not available unless contrib/xml2 is installed, and the longstanding warnings about security risks from that should have discouraged prudent DBAs from installing it in security-exposed databases. Reported and fixed by Peter Eisentraut. Security: CVE-2012-3488	14 years ago
Tom Lane	d6a6f8c6be	Fix contrib/xml2 so regression test still works when it's built without libxslt. This involves modifying the module to have a stable ABI, that is, the xslt_process() function still exists even without libxslt. It throws a runtime error if called, but doesn't prevent executing the CREATE FUNCTION call. This is a good thing anyway to simplify cross-version upgrades.	16 years ago
Tom Lane	936c4af1c6	Fix up memory management problems in contrib/xml2. Get rid of the code that attempted to funnel libxml2's memory allocations into palloc. We already knew from experience with the core xml datatype that trying to do this is simply not reliable. Unlike the core code, I did not bother adding a lot of PG_TRY/PG_CATCH logic to try to ensure that everything is cleaned up on error exit. Hence, we might leak some memory if one of these functions fails partway through. Given the deprecated status of this contrib module and the fact that errors partway through the functions shouldn't be too common, it doesn't seem worth worrying about. Also fix a separate bug in xpath_table, that it did the wrong things if given a result tuple descriptor with less than 2 columns. While such a case isn't very useful in practice, we shouldn't fail or stomp memory when it occurs. Add some simple regression tests based on all the reported crash cases that I have on hand. This should be back-patched, but let's see if the buildfarm likes it first.	16 years ago

Author

SHA1

Message

Date

Tom Lane

ac7e13d6fc

Prevent access to external files/URLs via contrib/xml2's xslt_process().

libxslt offers the ability to read and write both files and URLs through
stylesheet commands, thus allowing unprivileged database users to both read
and write data with the privileges of the database server.  Disable that
through proper use of libxslt's security options.

Also, remove xslt_process()'s ability to fetch documents and stylesheets
from external files/URLs.  While this was a documented "feature", it was
long regarded as a terrible idea.  The fix for CVE-2012-3489 broke that
capability, and rather than expend effort on trying to fix it, we're just
going to summarily remove it.

While the ability to write as well as read makes this security hole
considerably worse than CVE-2012-3489, the problem is mitigated by the fact
that xslt_process() is not available unless contrib/xml2 is installed,
and the longstanding warnings about security risks from that should have
discouraged prudent DBAs from installing it in security-exposed databases.

Reported and fixed by Peter Eisentraut.

Security: CVE-2012-3488

14 years ago

Tom Lane

d6a6f8c6be

Fix contrib/xml2 so regression test still works when it's built without libxslt.

This involves modifying the module to have a stable ABI, that is, the
xslt_process() function still exists even without libxslt.  It throws a
runtime error if called, but doesn't prevent executing the CREATE FUNCTION
call.  This is a good thing anyway to simplify cross-version upgrades.

16 years ago

Tom Lane

936c4af1c6

Fix up memory management problems in contrib/xml2.

Get rid of the code that attempted to funnel libxml2's memory allocations
into palloc.   We already knew from experience with the core xml datatype
that trying to do this is simply not reliable.  Unlike the core code, I
did not bother adding a lot of PG_TRY/PG_CATCH logic to try to ensure that
everything is cleaned up on error exit.  Hence, we might leak some memory
if one of these functions fails partway through.  Given the deprecated
status of this contrib module and the fact that errors partway through
the functions shouldn't be too common, it doesn't seem worth worrying about.

Also fix a separate bug in xpath_table, that it did the wrong things
if given a result tuple descriptor with less than 2 columns.  While
such a case isn't very useful in practice, we shouldn't fail or stomp
memory when it occurs.

Add some simple regression tests based on all the reported crash cases
that I have on hand.

This should be back-patched, but let's see if the buildfarm likes it first.

16 years ago

3 Commits (af4a9c19c23acddeb139bbedafeb90d987fb91bf)