Date: 6 Jan 1997 15:45:33 -0800 From: jdp@polstra.com (John Polstra) To: freebsd-hackers@freebsd.org Subject: Re: ld with -R weirdness Message-ID: <5as2qt$add@austin.polstra.com> References: <Mutt.19970105234525.roberto@keltia.freenix.fr>
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In article <Mutt.19970105234525.roberto@keltia.freenix.fr>,
Ollivier Robert <roberto@keltia.freenix.fr> wrote:
> In suidperl case, the command line given to gcc (then ld) is the following:
>
> cc -L/usr/local/lib -Wl,-R,/usr/local/lib/perl5/i386-freebsd/5.00319/CORE
> -o suidperl perlmain.o sperl.o lib/auto/DynaLoader/DynaLoader.a
> libperl.so.3.19 `cat ext.libs` -lm -lc -lcrypt
>
> The problem is that afterward, ld.so is NOT able to find libperl.so.3.19...
>
> 608 [23:40] roberto@keltia:/build/perl5.003_10> ( cd lib ; ldd ../suidperl)
> ../suidperl:
> libperl.so.3.19 (0x0)
> -lm.2 => /usr/lib/libm.so.2.0 (0x8025000)
> -lc.3 => /usr/lib/libc.so.3.0 (0x803c000)
> -lcrypt.2 => /usr/lib/libcrypt.so.2.0 (0x80ad000)
>
> Even WITH LD_LIBRARY_PATH defined...
For security reasons, LD_LIBRARY_PATH is ignored for setuid and setgid
programs.
> When I patch the Makefile to have
>
> cc -L/usr/local/lib -Wl,-R,/usr/local/lib/perl5/i386-freebsd/5.00319/CORE
> -o suidperl perlmain.o sperl.o lib/auto/DynaLoader/DynaLoader.a
> -lperl `cat ext.libs` -lm -lc -lcrypt
>
> It works !
If you specify the library name explicitly ("libperl.so.3.19"), it is
recorded as a direct reference to that particular file, and no searching
is done. Directories are searched only if you specify the library
generically ("-lperl").
> Looking inside the suidperl executable, I find the following weird strings:
>
> o/usr/local/lib/perl5/i386-freebsd/5.00319/CORE
> libperl.so.3.19
> crypt
>
> Where does the 'o' before the path come from ?
This is not anything to worry about. The string begins with the "/"
character. The byte before the string happens to contain a value which
is the same as the ASCII for "o". Every byte contains _some_ value, and
there is a reasonably high probability that any given byte will contain
the ASCII code for a printable character.
I should mention one other thing. If LD(1) is to be believed, there
should be no space between ld's "-R" option and the
"record-library-search-path" that follows it. (Just like the "-L"
option.) You probably should remove the "," after "-Wl,-R".
John
--
John Polstra jdp@polstra.com
John D. Polstra & Co., Inc. Seattle, Washington USA
"Self-knowledge is always bad news." -- John Barth
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