From: PG Bug reporting form <noreply@postgresql.org>
To: pgsql-bugs@lists.postgresql.org
Cc: exclusion@gmail.com
Subject: BUG #17935: Incorrect memory access in fuzzystrmatch/difference()
Date: Tue, 16 May 2023 13:00:00 +0000
Message-ID: <17935-b99316aa79c18513@postgresql.org> (raw)
The following bug has been logged on the website:
Bug reference: 17935
Logged by: Alexander Lakhin
Email address: exclusion@gmail.com
PostgreSQL version: 15.3
Operating system: Ubuntu 22.04
Description:
When the following query executed:
CREATE EXTENSION fuzzystrmatch;
SELECT difference('', '');
Valgrind detects the following issue:
==00:00:00:04.351 1561837== Conditional jump or move depends on
uninitialised value(s)
==00:00:00:04.351 1561837== at 0x4867265: difference
(fuzzystrmatch.c:787)
==00:00:00:04.351 1561837== by 0x3FFC24: ExecInterpExpr
(execExprInterp.c:751)
==00:00:00:04.351 1561837== by 0x3FC3D8: ExecInterpExprStillValid
(execExprInterp.c:1826)
==00:00:00:04.351 1561837== by 0x4EDE9C: ExecEvalExprSwitchContext
(executor.h:341)
==00:00:00:04.351 1561837== by 0x4EDE9C: evaluate_expr (clauses.c:4823)
==00:00:00:04.351 1561837== by 0x4EE078: evaluate_function
(clauses.c:4325)
==00:00:00:04.351 1561837== by 0x4F0530: simplify_function
(clauses.c:3908)
==00:00:00:04.351 1561837== by 0x4EE33C: eval_const_expressions_mutator
(clauses.c:2427)
==00:00:00:04.351 1561837== by 0x47F0B5: expression_tree_mutator
(nodeFuncs.c:3080)
==00:00:00:04.351 1561837== by 0x4EF776: eval_const_expressions_mutator
(clauses.c:3527)
==00:00:00:04.351 1561837== by 0x47F2FF: expression_tree_mutator
(nodeFuncs.c:3166)
==00:00:00:04.351 1561837== by 0x4EF776: eval_const_expressions_mutator
(clauses.c:3527)
==00:00:00:04.351 1561837== by 0x4EF8F1: eval_const_expressions
(clauses.c:2107)
==00:00:00:04.351 1561837==
In this case, _soundex() exits prematurely and sets only first and last
char
of it's parameter outstr, but difference() loops through SOUNDEX_LEN
chars,
and thus uses initialized data.
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To: pgsql-bugs@postgresql.org
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Subject: Re: BUG #17935: Incorrect memory access in fuzzystrmatch/difference()
In-Reply-To: <17935-b99316aa79c18513@postgresql.org>
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