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Tom Lane bc30c704ad Harden astreamer tar parsing logic against archives it can't handle.
Previously, there was essentially no verification in this code that
the input is a tar file at all, let alone that it fits into the
subset of valid tar files that we can handle.  This was exposed by
the discovery that we couldn't handle files that FreeBSD's tar
makes, because it's fairly aggressive about converting sparse WAL
files into sparse tar entries.  To fix:

* Bail out if we find a pax extension header.  This covers the
sparse-file case, and also protects us against scenarios where
the pax header changes other file properties that we care about.
(Eventually we may extend the logic to actually handle such
headers, but that won't happen in time for v19.)

* Be more wary about tar file type codes in general: do not assume
that anything that's neither a directory nor a symlink must be a
regular file.  Instead, we just ignore entries that are none of the
three supported types.

* Apply pg_dump's isValidTarHeader to verify that a purported
header block is actually in tar format.  To make this possible,
move isValidTarHeader into src/port/tar.c, which is probably where
it should have been since that file was created.

I also took the opportunity to const-ify the arguments of
isValidTarHeader and tarChecksum, and to use symbols not hard-wired
constants inside tarChecksum.

Back-patch to v18 but not further.  Although this code exists inside
pg_basebackup in older branches, it's not really exposed in that
usage to tar files that weren't generated by our own code, so it
doesn't seem worth back-porting these changes across 3c9056981
and f80b09bac.  I did choose to include a back-patch of 5868372bb
into v18 though, to minimize cosmetic differences between these
two branches.

Author: Tom Lane <tgl@sss.pgh.pa.us>
Reviewed-by: Thomas Munro <thomas.munro@gmail.com>
Discussion: https://postgr.es/m/3049460.1775067940@sss.pgh.pa.us>
Backpatch-through: 18
2026-04-02 12:20:36 -04:00
.github Add CODE_OF_CONDUCT.md, CONTRIBUTING.md, and SECURITY.md. 2024-07-02 13:03:58 -05:00
config Hardcode override of typeof_unqual for clang-for-bitcode 2026-03-16 19:24:49 +01:00
contrib Add UPDATE/DELETE FOR PORTION OF 2026-04-01 19:06:03 +02:00
doc jit: Change the default to off. 2026-04-02 13:40:29 +02:00
src Harden astreamer tar parsing logic against archives it can't handle. 2026-04-02 12:20:36 -04:00
.cirrus.star ci: Simplify ci-os-only handling 2025-08-14 12:09:34 -04:00
.cirrus.tasks.yml Enable test_cplusplusext with MSVC 2026-04-01 07:48:47 +02:00
.cirrus.yml ci: Per-repo configuration for manually trigger tasks 2025-08-14 11:54:03 -04:00
.dir-locals.el Make Emacs perl-mode indent more like perltidy. 2019-01-13 11:32:31 -08:00
.editorconfig Update .editorconfig and .gitattributes for postgresql.conf.sample. 2025-11-18 10:28:36 -06:00
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.gitignore Update top-level .gitignore. 2022-12-04 15:23:00 -05:00
.mailmap Add a Git .mailmap file 2024-11-05 13:56:02 +01:00
aclocal.m4 autoconf: Move export_dynamic determination to configure 2022-12-06 18:55:28 -08:00
configure Check for __cpuidex and __get_cpuid_count separately 2026-04-02 19:39:57 +07:00
configure.ac Check for __cpuidex and __get_cpuid_count separately 2026-04-02 19:39:57 +07:00
COPYRIGHT Update copyright for 2026 2026-01-01 13:24:10 -05:00
GNUmakefile.in Allow selecting the git revision to be packaged by "make dist". 2024-05-03 11:08:50 -04:00
HISTORY Canonicalize some URLs 2020-02-10 20:47:50 +01:00
Makefile Restore AIX support. 2026-02-23 13:34:22 -05:00
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README.md Revise the style of a paragraph in README.md. 2024-03-21 10:16:41 -05:00

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.

Copyright and license information can be found in the file COPYRIGHT.

General documentation about this version of PostgreSQL can be found at https://www.postgresql.org/docs/devel/. In particular, information about building PostgreSQL from the source code can be found at https://www.postgresql.org/docs/devel/installation.html.

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