GNU bug report logs - #15472
segmentation fault if input line is too long

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Message #5 received at submit <at> debbugs.gnu.org (full text, mbox):

From: Holger Then <Holger.Then <at> bristol.ac.uk>
To: bug-grep <at> gnu.org
Subject: segmentation fault if input line is too long
Date: Thu, 26 Sep 2013 14:21:54 +0200 (CEST)

If grep searches through a line that is longer than
INT_MAX (= 2147483647) characters, then grep causes
a segmentation fault.

Interestingly this bug does not occur with fgrep or
with grep -F

Kind regards,
Holger


$ wc grep_bug.txt
         1   12200610 3281667946 grep_bug.txt
$ fgrep -e 1 grep_bug.txt | wc
      1 12200610 3281667946
$ grep -Fe 1 grep_bug.txt | wc
      1 12200610 3281667946
$ grep -e 1 grep_bug.txt | wc
      0       0       0
$ grep -e 1 grep_bug.txt
Segmentation fault

$ tail -c 2147483647 grep_bug.txt | grep -e 1 | wc
      1 8385663 2147483647
$ tail -c 2147483648 grep_bug.txt | grep -e 1 | wc
      0       0       0
$ tail -c 2147483648 grep_bug.txt | grep -e 1
Segmentation fault

$ uname 
-a
Linux c-0-0.local 2.6.32-358.11.1.el6.x86_64 #1 SMP Wed Jun 12 03:34:52 
UTC 2013 x86_64 x86_64 x86_64 GNU/Linux
$ grep --version
GNU grep 2.6.3

Copyright (C) 2009 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later 
<http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.

Message #8 received at 15472 <at> debbugs.gnu.org (full text, mbox):

From: Jim Meyering <jim <at> meyering.net>
To: Holger Then <Holger.Then <at> bristol.ac.uk>
Cc: 15472 <at> debbugs.gnu.org
Subject: Re: bug#15472: segmentation fault if input line is too long
Date: Sat, 28 Sep 2013 21:14:10 -0700

On Thu, Sep 26, 2013 at 5:21 AM, Holger Then <Holger.Then <at> bristol.ac.uk> wrote:
> If grep searches through a line that is longer than
> INT_MAX (= 2147483647) characters, then grep causes
...
> $ tail -c 2147483647 grep_bug.txt | grep -e 1 | wc
>       1 8385663 2147483647
> $ tail -c 2147483648 grep_bug.txt | grep -e 1 | wc
>       0       0       0
> $ tail -c 2147483648 grep_bug.txt | grep -e 1
> Segmentation fault
>
> $ uname -a
> Linux c-0-0.local 2.6.32-358.11.1.el6.x86_64 #1 SMP Wed Jun 12 03:34:52 UTC
> 2013 x86_64 x86_64 x86_64 GNU/Linux
> $ grep --version
> GNU grep 2.6.3

tags 15472 notabug
close 15472
thanks

Thank you for the report.
Your version of grep is rather old.  The latest is grep-2.14,
and that particular bug was fixed in 2.11 a year and a half ago.
Here is the relevant NEWS entry:

* Noteworthy changes in release 2.11 (2012-03-02) [stable]

** Bug fixes

  grep no longer dumps core on lines whose lengths do not fit in 'int'.
  (e.g., lines longer than 2 GiB on a typical 64-bit host).
  Instead, grep either works as expected, or reports an error.
  An error can occur if not enough main memory is available, or if the
  GNU C library's regular expression functions cannot handle such long lines.
  [bug present since "the beginning"]

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