GNU bug report logs - #7992
cut segmentation fault with unbounded ranges

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From: help-debbugs <at> gnu.org (GNU bug Tracking System)
To: Jim Meyering <jim <at> meyering.net>
Cc: tracker <at> debbugs.gnu.org
Subject: bug#7992: closed (cut segmentation fault with unbounded ranges)
Date: Fri, 22 Jul 2011 21:55:02 +0000

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Your message dated Fri, 22 Jul 2011 23:54:45 +0200
with message-id <87ei1i6kwq.fsf <at> rho.meyering.net>
and subject line Re: bug#7992: cut segmentation fault with unbounded ranges
has caused the GNU bug report #7992,
regarding cut segmentation fault with unbounded ranges
to be marked as done.

(If you believe you have received this mail in error, please contact
help-debbugs <at> gnu.org.)


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7992: http://debbugs.gnu.org/cgi/bugreport.cgi?bug=7992
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From: Paul Marinescu <paul.marinescu <at> imperial.ac.uk>
To: bug-coreutils <at> gnu.org
Subject: cut segmentation fault with unbounded ranges
Date: Sun, 06 Feb 2011 16:15:30 +0000

In coreutils 8.9 (latest), the following commands trigger an invalid
memory access.

cut -c1234567890- --output-d=: foo
cut -f1234567890- --output-d=: foo
cut -b1234567890- --output-d=: foo

The number 1234567890 is just a random number 'big enough' to make the
invalid access generate a segmentation fault but the invalid access
happens for values as low as 8 (valgrind)

The problem is that ranges going to end of line (i.e., 'x-') are not
taken into account when calculating the size of the printable_field
vector, but their lower bound is used as an index on line 525:

  if (output_delimiter_specified
      && !complement
      && eol_range_start && !is_printable_field (eol_range_start))


Paul

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From: Jim Meyering <jim <at> meyering.net>
To: Paul Marinescu <paul.marinescu <at> imperial.ac.uk>
Cc: 7992-done <at> debbugs.gnu.org
Subject: Re: bug#7992: cut segmentation fault with unbounded ranges
Date: Fri, 22 Jul 2011 23:54:45 +0200

Jim Meyering wrote:
> Paul Marinescu wrote:
>> In coreutils 8.9 (latest), the following commands trigger an invalid
>> memory access.
>>
>> cut -c1234567890- --output-d=: foo
>> cut -f1234567890- --output-d=: foo
>> cut -b1234567890- --output-d=: foo
>>
>> The number 1234567890 is just a random number 'big enough' to make the
>> invalid access generate a segmentation fault but the invalid access
>> happens for values as low as 8 (valgrind)
>>
>> The problem is that ranges going to end of line (i.e., 'x-') are not
>> taken into account when calculating the size of the printable_field
>> vector, but their lower bound is used as an index on line 525:
>>
>>   if (output_delimiter_specified
>>       && !complement
>>       && eol_range_start && !is_printable_field (eol_range_start))
>
> Thanks a lot for the report.
> Here's a fix:
>
...
> Subject: [PATCH] cut: don't segfault for large unbounded range
>
> * src/cut.c (set_fields): When computing the maximum range endpoint,
> take into consideration the start of any unbounded range, like "999-".
> * NEWS (Bug fixes): Mention it.
> * tests/misc/cut (big-unbounded-b,c,f): Add tests.
> Reported by Paul Marinescu in http://debbugs.gnu.org/7993
> The bug was introduced on 2004-12-04 via commit 7380cf79.
...
>  * Noteworthy changes in release ?.? (????-??-??) [?]
>
> +** Bug fixes
> +
> +  cut could segfault when invoked with a user-specified output
> +  delimiter and an unbounded range like "-f1234567890-".
> +  [bug introduced in coreutils-5.3.0]
> +

Fixed, so closing.

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