Port Bug Report: Backend crashes when comparisons are made to NULL values with certain types

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POSTGRESQL BUG REPORT TEMPLATE
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Your name : Mark Volpe
Your email address : mvolpe(at)eos(dot)ncsu(dot)edu

Category : runtime: back-end
Severity : serious

Summary: Backend crashes when comparisons are made to NULL values with certain types

System Configuration
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Operating System : Digital Unix version 4.0

PostgreSQL version : 6.2

Compiler used : gcc 2.7.2

Hardware:
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Digital alphaserver 128MB
> uname -a
OSF1 nts1.rtp.epa.gov V4.0 564 alpha

Versions of other tools:
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Problem Description:
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Some data types, most notably inet, cidr, and macaddr, are
missing null pointer checks in their comparison functions.
If I try to compare NULL values it crashes the backend.
See the example below.

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Test Case:
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CREATE TABLE test ( ip inet );
INSERT INTO test VALUES ( NULL );
SELECT * FROM test WHERE ( ip = '10.20.30.40' );
-- Backend crashes with memory fault

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Solution:
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Add the null pointer check at the beginning of any function
related to the datatype. Most of the other datatypes
user something like this:

if (arg1==NULL || arg2==NULL) return FALSE;

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