From: Tom Lane <tgl@sss.pgh.pa.us>
To: pgsql-committers@lists.postgresql.org
Subject: pgsql: Fix issue with reading zero bytes in Gzip_read.
Date: Mon, 13 Oct 2025 16:44:30 +0000
Message-ID: <E1v8Lew-001W7q-34@gemulon.postgresql.org> (raw)
Fix issue with reading zero bytes in Gzip_read.
pg_dump expects a read request of zero bytes to be a no-op; see for
example ReadStr(). Gzip_read got this wrong and falsely supposed
that the resulting gzret == 0 indicated an error. We could complicate
that error-checking logic some more, but it seems best to just fall
out immediately when passed size == 0.
This bug breaks the nominally-supported case of manually gzip'ing
the toc.dat file within a directory-style dump, so back-patch to v16
where this code came in. (Prior branches already have a short-circuit
for size == 0 before their only gzread call.)
Author: Tom Lane <tgl@sss.pgh.pa.us>
Reviewed-by: Chao Li <li.evan.chao@gmail.com>
Discussion: https://postgr.es/m/3515357.1760128017@sss.pgh.pa.us
Backpatch-through: 16
Branch
------
REL_16_STABLE
Details
-------
https://git.postgresql.org/pg/commitdiff/1518b7d76aadcbdffa6214555b82b995e7404b38
Modified Files
--------------
src/bin/pg_dump/compress_gzip.c | 4 ++++
1 file changed, 4 insertions(+)
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To: pgsql-committers@postgresql.org
Cc: tgl@sss.pgh.pa.us, pgsql-committers@lists.postgresql.org
Subject: Re: pgsql: Fix issue with reading zero bytes in Gzip_read.
In-Reply-To: <E1v8Lew-001W7q-34@gemulon.postgresql.org>
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