From owner-freebsd-bugs  Mon Jan 15 18:20:23 2001
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Date: Mon, 15 Jan 2001 18:20:02 -0800 (PST)
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From: Tor.Egge@fast.no
Subject: Re: bin/15070: vfprintf/cvt/__dtoa race condition in threaded programs
Reply-To: Tor.Egge@fast.no
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The following reply was made to PR bin/15070; it has been noted by GNATS.

From: Tor.Egge@fast.no
To: wollman@khavrinen.lcs.mit.edu
Cc: freebsd-gnats-submit@FreeBSD.ORG
Subject: Re: bin/15070: vfprintf/cvt/__dtoa race condition in threaded programs
Date: Tue, 16 Jan 2001 03:11:04 +0100

 This uncovered another old __dtoa() bug.
 
 	*resultp = (char *) malloc(i);
 
 in the patch must be changed to
 
 	*resultp = (char *) malloc(i + 1);
 
 in order to avoid writing beyond the end of the allocated memory.
 Otherwise the sample program
 
 
 	#include <sys/types.h>
 	#include <stdio.h>
 	
 	
 	int
 	main(int argc,char **argv)
 	{
 	  (void) malloc(4);
 	  printf("%.23e\n", 2.4);
 	
 	  return 0;
 	}
 
 linked with Electric Fence crashes on the i386 platform.
 
 - Tor Egge
 


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