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Chet Ramey
53 lines
2.1 KiB
Plaintext
53 lines
2.1 KiB
Plaintext
From chet Mon Jul 27 14:54:45 1992
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Flags: 50
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Received: by odin.INS.CWRU.Edu (5.65b+ida+/CWRU-1.5-ins)
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id AA15494; Mon, 27 Jul 92 14:54:45 -0400 (from chet for /usr/homes/chet/bin/mailfilter.sh /usr/homes/chet/mbox)
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Date: Mon, 27 Jul 1992 14:29:55 -0400
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From: Chet Ramey <chet@odin.INS.CWRU.Edu>
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To: stud7b43@x400gate.bnr.ca
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Subject: Re: Bug in Bash 1.12.1
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Cc: bug-bash@ai.mit.edu, chet
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Reply-To: chet@po.CWRU.Edu
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In-Reply-To: Message from stud7b43@x400gate.bnr.ca of Mon, 27 Jul 1992 12:30:00 +0000
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Message-Id: <9207271829.AA14484.SM@odin.INS.CWRU.Edu>
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Read-Receipt-To: chet@po.CWRU.Edu
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> I seem to have found a bug in Bash.
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>
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> How to cause the bug to appear:
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> 1) Start a long username-completion, e.g.
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> cat ~user<TAB>
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> Let it run for a while (don't know exactly how long...)
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> Before it's finished, hit ^C (or whatever the break character
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> is set to)
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> 2) As the next command, run a filename completion with a username in it, eg.
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> cat ~username/.log<TAB>
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>
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> Error message: "free: Called with already freed block argument
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This is a bug in the Sun YP code that everyone seems to have picked up.
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Sun keeps static state in the YP library code -- a pointer into the
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data returned from the server. When YP initializes itself (setpwent),
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it looks at this pointer and calls free on it if it's non-null. So far,
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so good.
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If one of the YP functions is interrupted during getpwent (the exact function
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is interpretwithsave()), and returns NULL, the pointer is freed without being
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reset to NULL, and the function returns. The next time getpwent is called,
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it sees that this pointer is non-null, calls free, and the Gnu free()
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blows up because it's being asked to free freed memory.
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The traditional Unix mallocs allow memory to be freed multiple times; that's
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probably why this has never been fixed. You can probably stop it by adding
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an #undef USE_GNU_MALLOC to the appropriate machine description in machines.h.
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Chet
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--
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``The use of history as therapy means the corruption of history as history.''
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-- Arthur Schlesinger
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Chet Ramey, Case Western Reserve University Internet: chet@po.CWRU.Edu
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