Date: Mon, 15 Feb 2010 16:57:00 -0800 From: Garrett Cooper <yanefbsd@gmail.com> To: FreeBSD-Hackers <freebsd-hackers@freebsd.org> Subject: Re: read(1) garbage when input redirected from make incorrectly Message-ID: <7d6fde3d1002151657q560b701bre44419d56e61f7ac@mail.gmail.com> In-Reply-To: <7d6fde3d1002151655q184c8a21k8a0c6c07b9b0ae79@mail.gmail.com> References: <364299f41002151649y2e4d4120p918759afb1fd8f6c@mail.gmail.com> <7d6fde3d1002151655q184c8a21k8a0c6c07b9b0ae79@mail.gmail.com>
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On Mon, Feb 15, 2010 at 4:55 PM, Garrett Cooper <yanefbsd@gmail.com> wrote: > Hi Hackers, > =A0 =A0I accidentally reproduced the following after executing read > properly in a pipeline with make: s/properly/improperly/ > [garrcoop@garrcoop-fbsd /usr/home/garrcoop]$ read DESTDIR SRCCONF < > /usr/bin/make -V DESTDIR -V SRCCONF > bash: read: `-V': not a valid identifier > [garrcoop@garrcoop-fbsd /usr/home/garrcoop]$ echo $DESTDIR > =A0ELF > [garrcoop@garrcoop-fbsd /usr/home/garrcoop]$ hexdump -C foo > 00000000 =A07f 45 4c 46 01 01 01 0a =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 = =A0 =A0 =A0 =A0 |.ELF....| > 00000008 > [garrcoop@garrcoop-fbsd /usr/home/garrcoop]$ And just for completeness because I executed the above directly in bash... [root@garrcoop-fbsd /usr/home/garrcoop]# sh -c 'read DESTDIR SRCCONF < /usr/bin/make -V DESTDIR -V SRCCONF; echo $DESTDIR > foo; hexdump -C foo' read: -V: bad variable name 00000000 7f 45 4c 46 01 01 01 0a |.ELF....| 00000008 > =A0 =A0Is this an issue to be concerned about apart from cosmetic noise, > i.e. potential buffer access problem? I see the same garbage from > bash/coreutils on RHEL 4.6 as well as read(1) and /bin/sh on FreeBSD > with RELENG_8, so the issue appears to be consistent on multiple > OSes... Thanks, -Garrett
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