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Michael Paquier 4be308edee intarray: Prevent out-of-bound memory reads with gist__int_ops 
As gist__int_ops stands in intarray, it is possible to store GiST
entries for leaf pages that can cause corruptions when decompressed.
Leaf nodes are stored as decompressed all the time by the compression
method, and the decompression method should map with that, retrieving
the contents of the page without doing any decompression.  However, the
code authorized the insertion of leaf page data with a higher number of
array items than what can be supported, generating a NOTICE message to
inform about this matter (199 for a 8k page, for reference).  When
calling the decompression method, a decompression would be attempted on
this leaf node item but the contents should be retrieved as they are.

The NOTICE message generated when dealing with the compression of a leaf
page and too many elements in the input array for gist__int_ops has been
introduced by 08ee64e, removing the marker stored in the array to track
if this is actually a leaf node.  However, it also missed the fact that
the decompression path should do nothing for a leaf page.  Hence, as the
code stand, a too-large array would be stored as uncompressed but the
decompression path would attempt a decompression rather that retrieving
the contents as they are.

This leads to various problems.  First, even if 08ee64e tried to address
that, it is possible to do out-of-bound chunk writes with a large input
array, with the backend informing about that with WARNINGs.  On
decompression, retrieving the stored leaf data would lead to incorrect
memory reads, leading to crashes or even worse.

Perhaps somebody would be interested in expanding the number of array
items that can be handled in a leaf page for this operator in the
future, which would require revisiting the choice done in 08ee64e, but
based on the lack of reports about this problem since 2005 it does not
look so.  For now, this commit prevents the insertion of data for leaf
pages when using more array items that the code can handle on
decompression, switching the NOTICE message to an ERROR.  If one wishes
to use more array items, gist__intbig_ops is an optional choice.

While on it, use ERRCODE_PROGRAM_LIMIT_EXCEEDED as error code when a
limit is reached, because that's what the module is facing in such
cases.

Author: Ankit Kumar Pandey, Alexander Lakhin
Reviewed-by: Richard Guo, Michael Paquier
Discussion: https://postgr.es/m/796b65c3-57b7-bddf-b0d5-a8afafb8b627@gmail.com
Discussion: https://postgr.es/m/17888-f72930e6b5ce8c14@postgresql.org
Backpatch-through: 11
 		2023-06-15 13:45:38 +09:00
config Use --strip-unneeded when stripping static libraries with GNU strip. 2023-04-20 18:12:48 -04:00
contrib intarray: Prevent out-of-bound memory reads with gist__int_ops 2023-06-15 13:45:38 +09:00
doc doc: Fix example command for ALTER FOREIGN TABLE ... OPTIONS. 2023-06-08 20:14:04 +09:00
src Fix make_etags breakage on certain platforms. 2023-06-14 11:11:18 +09:00
.cirrus.yml ci: Use windows VMs instead of windows containers 2023-02-02 21:31:48 -08:00
.dir-locals.el Make Emacs perl-mode indent more like perltidy. 2019-01-13 11:32:31 -08:00
.editorconfig Add .editorconfig 2019-12-18 09:13:13 +01:00
.git-blame-ignore-revs Backpatch addition of .git-blame-ignore-revs 2022-08-05 19:36:24 +02:00
.gitattributes Remove trailing whitespace from *.sgml files. 2022-04-20 11:04:49 -04:00
.gitignore Add portlock directory to .gitignore 2022-11-26 07:47:01 -05:00
COPYRIGHT Update copyright for 2023 2023-01-02 15:00:37 -05:00
GNUmakefile.in Remove temporary portlock directory during make [dist]clean. 2022-11-26 10:30:46 -05:00
HISTORY Canonicalize some URLs 2020-02-10 20:47:50 +01:00
Makefile Dynamically find correct installation docs in Makefile. 2022-01-19 14:48:25 +01:00
README Canonicalize some URLs 2020-02-10 20:47:50 +01:00
README.git Canonicalize some URLs 2020-02-10 20:47:50 +01:00
aclocal.m4 Probe $PROVE not $PERL while checking for modules needed by TAP tests. 2021-11-22 12:54:52 -05:00
configure Stamp 15.3. 2023-05-08 17:13:20 -04:00
configure.ac Stamp 15.3. 2023-05-08 17:13:20 -04:00

README 

PostgreSQL Database Management System
=====================================

This directory contains the source code distribution of the PostgreSQL
database management system.

PostgreSQL is an advanced object-relational database management system
that supports an extended subset of the SQL standard, including
transactions, foreign keys, subqueries, triggers, user-defined types
and functions.  This distribution also contains C language bindings.

PostgreSQL has many language interfaces, many of which are listed here:

	https://www.postgresql.org/download/

See the file INSTALL for instructions on how to build and install
PostgreSQL.  That file also lists supported operating systems and
hardware platforms and contains information regarding any other
software packages that are required to build or run the PostgreSQL
system.  Copyright and license information can be found in the
file COPYRIGHT.  A comprehensive documentation set is included in this
distribution; it can be read as described in the installation
instructions.

The latest version of this software may be obtained at
https://www.postgresql.org/download/.  For more information look at our
web site located at https://www.postgresql.org/.