Bug 88052 - register_printf_function() forgets to clear table
register_printf_function() forgets to clear table
Product: Red Hat Linux
Classification: Retired
Component: glibc (Show other bugs)
i686 Linux
medium Severity medium
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Assigned To: Jakub Jelinek
Brian Brock
Depends On:
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Reported: 2003-04-04 17:01 EST by John Reiser
Modified: 2007-04-18 12:52 EDT (History)
0 users

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Fixed In Version:
Doc Type: Bug Fix
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Last Closed: 2003-04-09 15:21:37 EDT
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Description John Reiser 2003-04-04 17:01:43 EST
From Bugzilla Helper:
User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.0.0) Gecko/20020529

Description of problem:
Routine register_printf_function() in stdio-common/reg-printf.c forgets to clear
the table when allocating it, before inserting the first translation function. 
The table is consulted for all format characters, not just those that use the
registered arginfo or functions.  So if malloc() happens to return a block that
was used before, then parse_one_spec() will go wrong if the consulted slot has
non-zero garbage.

Version-Release number of selected component (if applicable):

How reproducible:

Steps to Reproduce:
1. Run testcase stdio-common/tst-printfsz.
2. Watch as parse_one_spec() examines the entry for 'g' which has not been

Actual Results:  __printf_arginfo_table['g'] and __printf_function_table['g']
are used even though they have not been initialized.  In the usual case,
malloc() without any preceding free() happens to return zeroed memory [as if

Expected Results:  _printf_arginfo_table and __printf_function_table should be
initialized before use.

Additional info:

Fix: s/malloc/calloc/ in stdio-common/reg-printf.c line 49.

This could have been detected by running valgrind (or any other uninit memory
detector) when running the glibc testcases.
Comment 1 Jakub Jelinek 2003-04-09 15:21:37 EDT
An errata has been issued which should help the problem described in this bug report. 
This report is therefore being closed with a resolution of ERRATA. For more information
on the solution and/or where to find the updated files, please follow the link below. You may reopen 
this bug report if the solution does not work for you.


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