GNU bug report logs - #25684
25.1; (downcase -1) segfaults Emacs on GNU/Linux

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Package: emacs;

Reported by: Wilfred Hughes <me <at> wilfred.me.uk>

Date: Sat, 11 Feb 2017 00:03:02 UTC

Severity: normal

Found in version 25.1

Fixed in version 26.1

Done: Glenn Morris <rgm <at> gnu.org>

Bug is archived. No further changes may be made.

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From: Andreas Schwab <schwab <at> linux-m68k.org>
To: Glenn Morris <rgm <at> gnu.org>
Cc: Wilfred Hughes <me <at> wilfred.me.uk>, 25684 <at> debbugs.gnu.org
Subject: bug#25684: 25.1; (downcase -1) segfaults Emacs on GNU/Linux
Date: Tue, 14 Feb 2017 16:04:24 +0100

On Feb 13 2017, Glenn Morris <rgm <at> gnu.org> wrote:

> Wilfred Hughes wrote:
>
>> The elisp primitives downcase and upcase cause Emacs to segfault when
>> given a negative argument. For example, (downcase -1).
>>
>> I can reproduce this on Emacs 25.1 as well as on master. It occurs on
>> GNU/Linux but not on OS X.
>
> I can't reproduce this, but it seems to me that (downcase -1) should
> signal a wrong-type-argument error, since negative numbers are not characters.
> But I think there are probably subtleties here that I don't get.

The function uses XFASTINT, which only works for non-negative numbers.
This is checked when runtime checking is enabled.

Andreas.

-- 
Andreas Schwab, schwab <at> linux-m68k.org
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This bug report was last modified 8 years and 97 days ago.

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