Hi Rafael, I agree the signal code in Safe should stay ... however, on both 5.18.0 (Linux) and 5.10.1 (Solaris SPARC) I have found that the "local %SIG;" code snippet obviously leads to non-execution of the registered signal subroutines, and instead to Perl bailing out. For which Perl versions do you think stashing %SIG away should work?
Without understanding the details, I can just guess that the CHILD signal hits the process while just performing a Safe::reval ... Best regards, Markus -----Original Message----- From: rgarciasua...@gmail.com [mailto:rgarciasua...@gmail.com] On Behalf Of Rafael Garcia-Suarez Sent: Wednesday, July 17, 2013 9:31 AM To: Markus Jansen; perl5-port...@perl.org Cc: poe@perl.org Subject: Re: FW: Localizing %SIG in Safe.pm 2.{35,36,37} crashes POE::Wheel::Run ... Hi all Breaking out a Safe compartment is all about compiling code that will be executed later. It happens that there are working exploits that use a combination of %SIG and eval inside the safe-evaled block to execute such compilations; then arbitrary commands can be run on any signal received by the process that compiled the safe compartment. (I repeat it again -- without this fix it's possible to make perl execute `rm -fr /` through code passed to Safe. So the fix stays.) The fix I put in Safe was to simply wipe out %SIG in the Safe compartment. In theory that should not have been necessary, since %SIG is not shared between %main:: and the Safe root stash, but that's apparently not how the perl internals work; so, to have a fix back-portable to older perls, I did not found any other way. If someone wants to investigate, I'll be happy to provide details... Also I'd like to understand why you need to set signal handlers in a Safe compartment. As far as I can tell this has only ever worked by accident. On 16 July 2013 18:00, Markus Jansen <markus.jan...@ericsson.com> wrote: > Hi, > > FYI ... hope none of you wastes time with this really nasty trap ... > > Best regards, > Markus > > -----Original Message----- > From: Markus Jansen > Sent: Tuesday, July 16, 2013 5:57 PM > To: perl...@perl.org > Cc: Markus Jansen > Subject: Localizing %SIG in Safe.pm 2.{35,36,37} crashes POE::Wheel::Run ... > > > This is a bug report for perl from markus.jan...@ericsson.com, generated with > the help of perlbug 1.39 running under perl 5.18.0. > > > ----------------------------------------------------------------- > [Please describe your issue here] > > Dear Perl5 Porters, > > localizing %SIG in Safe.pm 2.35 (on CPAN, 2.{35,36,37} in Perl core) may be a > great step for security, but it unfortunatately spoils POE::Wheel::Run > (basically POE and all other asynchronous frameworks dealing with external > processes). > > The symptom experienced is that your application might sooner or later crash > (reliably when using POE::Component::Resolver upon exiting a Sidecar > subprocess) with the following famous last words: > > Signal SIGCHLD received, but no signal handler set. > > Please consider a version (also on CPAN) of Safe.pm which has e.g. the > localization of %SIG as a switchable feature. > > Best regards, > Markus > > > > [Please do not change anything below this line] > ----------------------------------------------------------------- > --- > Flags: > category=library > severity=critical > module=Safe > --- > Site configuration information for perl 5.18.0: > > Configured by ericsson at Fri Jul 12 19:17:48 CEST 2013. > > Summary of my perl5 (revision 5 version 18 subversion 0) configuration: > > Platform: > osname=linux, osvers=2.6.16.60-0.42.10-smp, > archname=x86_64-linux-thread-multi > uname='linux sekix562 2.6.16.60-0.42.10-smp #1 smp tue apr 27 05:11:27 > utc 2010 x86_64 x86_64 x86_64 gnulinux ' > config_args='-d -e -O -D cc=gcc -D > prefix=/vobs/cc/CCA-perl01/perl5_Linux_x64__________sixtyfive_char_pat > h/prod -D usemultiplicity -U use5005threads -D usedl -D useshrplib -D > libperl=libcmacperl.so -U usemymalloc -D cf_by=ericsson -D > cf_email=scm...@clearcase.ericsson.se -D > perladmin=scm...@clearcase.ericsson.se -D uselargefiles -D usethreads > -D useithreads -D use64bitall -D ldcc=CC -D optimize=-O3 -D > locincpth=/vobs/cc/CCA-perl01/perl5_Linux_x64__________sixtyfive_char_ > path/plib/include > /vobs/cc/CCA-perl01/perl5_Linux_x64__________sixtyfive_char_path/plib/ > apache/include -D > loclibpth=/vobs/cc/CCA-perl01/perl5_Linux_x64__________sixtyfive_char_ > path/plib/lib > /vobs/cc/CCA-perl01/perl5_Linux_x64__________sixtyfive_char_path/plib/ > apache/lib -D lddlflags=-shared -lpthread > -Wl,-L/vobs/cc/CCA-perl01/perl5_Linux_x64__________sixtyfive_char_path > /prod/lib/5.18.0/x86_64-linux-thread-multi/CORE > -Wl,-rpath,/vobs/cc/CCA-perl01/perl5_Linux_x64__________sixtyfive_char > _path/prod/lib/5.18.0 /x86_64-linux-thread-multi/CORE > -Wl,-L/vobs/cc/CCA-perl01/perl5_Linux_x64__________sixtyfive_char_path > /plib/lib > -Wl,-rpath,/vobs/cc/CCA-perl01/perl5_Linux_x64__________sixtyfive_char > _path/plib/lib > -Wl,-L/vobs/cc/CCA-perl01/perl5_Linux_x64__________sixtyfive_char_path > /plib/apache/lib > -Wl,-rpath,/vobs/cc/CCA-perl01/perl5_Linux_x64__________sixtyfive_char > _path/plib/apache/lib -Wl,--enable-new-dtags -D ldflags=-lpthread > -Wl,-L/vobs/cc/CCA-perl01/perl5_Linux_x64__________sixtyfive_char_path > /prod/lib/5.18.0/x86_64-linux-thread-multi/CORE > -Wl,-rpath,/vobs/cc/CCA-perl01/perl5_Linux_x64__________sixtyfive_char > _path/prod/lib/5.18.0/x86_64-linux-thread-multi/CORE > -Wl,-L/vobs/cc/CCA-perl01/perl5_Linux_x64__________sixtyfive_char_path > /plib/lib > -Wl,-rpath,/vobs/cc/CCA-perl01/perl5_Linux_x64__________sixtyfive_char > _path/plib/lib > -Wl,-L/vobs/cc/CCA-perl01/perl5_Linux_x64__________sixtyfive_char_path > /plib/apache/lib > -Wl,-rpath,/vobs/cc/CCA-perl01/perl5_Linux_x64__________sixtyfive_char > _path/ plib/apache/lib -Wl,--enable-new-dtags -D ccdlflags=-Bdynamic > -Wl,-L/vobs/cc/CCA-perl01/perl5_Linux_x64__________sixtyfive_char_path/prod/lib/5.18.0/x86_64-linux-thread-multi/CORE > > -Wl,-rpath,/vobs/cc/CCA-perl01/perl5_Linux_x64__________sixtyfive_char_path/prod/lib/5.18.0/x86_64-linux-thread-multi/CORE > > -Wl,-L/vobs/cc/CCA-perl01/perl5_Linux_x64__________sixtyfive_char_path/plib/lib > > -Wl,-rpath,/vobs/cc/CCA-perl01/perl5_Linux_x64__________sixtyfive_char_path/plib/lib > > -Wl,-L/vobs/cc/CCA-perl01/perl5_Linux_x64__________sixtyfive_char_path/plib/apache/lib > > -Wl,-rpath,/vobs/cc/CCA-perl01/perl5_Linux_x64__________sixtyfive_char_path/plib/apache/lib > -D ldlibpthname=LD_LIBRARY_PATH -D cccdlflags=-fPIC -D dlsrc=dl_dlopen.xs -D > ccflags=-O2 -D_REENTRANT -D_GNU_SOURCE -DTHREADS_HAVE_PIDS -pthread > -DPERL_IMPLICIT_CONTEXT -DPERL_USE_SAFE_PUTENV -m64 -pipe -D_LARGEFILE_SOURCE > -D_FILE_OFFSET_BITS=64 -fPIC -D so=so -D libswanted=nsl dl m crypt pthread c' > hint=recommended, useposix=true, d_sigaction=define > useithreads=define, usemultiplicity=define > useperlio=define, d_sfio=undef, uselargefiles=define, usesocks=undef > use64bitint=define, use64bitall=define, uselongdouble=undef > usemymalloc=n, bincompat5005=undef > Compiler: > cc='gcc', ccflags ='-D_REENTRANT -D_GNU_SOURCE -O2 -D_REENTRANT > -D_GNU_SOURCE -DTHREADS_HAVE_PIDS -pthread -DPERL_IMPLICIT_CONTEXT > -DPERL_USE_SAFE_PUTENV -m64 -pipe -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64 > -fPIC -fno-strict-aliasing -fstack-protector > -I/vobs/cc/CCA-perl01/perl5_Linux_x64__________sixtyfive_char_path/plib/include > > -I/vobs/cc/CCA-perl01/perl5_Linux_x64__________sixtyfive_char_path/plib/apache/include > -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64', > optimize='-O3', > cppflags='-D_REENTRANT -D_GNU_SOURCE -O2 -D_REENTRANT -D_GNU_SOURCE > -DTHREADS_HAVE_PIDS -pthread -DPERL_IMPLICIT_CONTEXT -DPERL_USE_SAFE_PUTENV > -m64 -pipe -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64 -fPIC > -fno-strict-aliasing -fstack-protector > -I/vobs/cc/CCA-perl01/perl5_Linux_x64__________sixtyfive_char_path/plib/include > > -I/vobs/cc/CCA-perl01/perl5_Linux_x64__________sixtyfive_char_path/plib/apache/include' > ccversion='', gccversion='4.1.2 20070115 (SUSE Linux)', gccosandvers='' > intsize=4, longsize=8, ptrsize=8, doublesize=8, byteorder=12345678 > d_longlong=define, longlongsize=8, d_longdbl=define, longdblsize=16 > ivtype='long', ivsize=8, nvtype='double', nvsize=8, Off_t='off_t', > lseeksize=8 > alignbytes=8, prototype=define > Linker and Libraries: > ld='gcc', ldflags ='-lpthread > -Wl,-L/vobs/cc/CCA-perl01/perl5_Linux_x64__________sixtyfive_char_path/prod/lib/5.18.0/x86_64-linux-thread-multi/CORE > > -Wl,-rpath,/vobs/cc/CCA-perl01/perl5_Linux_x64__________sixtyfive_char_path/prod/lib/5.18.0/x86_64-linux-thread-multi/CORE > > -Wl,-L/vobs/cc/CCA-perl01/perl5_Linux_x64__________sixtyfive_char_path/plib/lib > > -Wl,-rpath,/vobs/cc/CCA-perl01/perl5_Linux_x64__________sixtyfive_char_path/plib/lib > > -Wl,-L/vobs/cc/CCA-perl01/perl5_Linux_x64__________sixtyfive_char_path/plib/apache/lib > > -Wl,-rpath,/vobs/cc/CCA-perl01/perl5_Linux_x64__________sixtyfive_char_path/plib/apache/lib > -Wl,--enable-new-dtags -fstack-protector' > > libpth=/vobs/cc/CCA-perl01/perl5_Linux_x64__________sixtyfive_char_path/plib/lib > > /vobs/cc/CCA-perl01/perl5_Linux_x64__________sixtyfive_char_path/plib/apache/lib > /lib/../lib64 /usr/lib/../lib64 /lib /usr/lib /usr/local/lib /lib64 > /usr/lib64 /usr/local/lib64 > libs=-lnsl -ldl -lm -lcrypt -lpthread -lc > perllibs=-lnsl -ldl -lm -lcrypt -lpthread -lc > libc=/lib/libc-2.4.so, so=so, useshrplib=true, libperl=libcmacperl.so > gnulibc_version='2.4' > Dynamic Linking: > dlsrc=dl_dlopen.xs, dlext=so, d_dlsymun=undef, ccdlflags='-Bdynamic > -Wl,-L/vobs/cc/CCA-perl01/perl5_Linux_x64__________sixtyfive_char_path/prod/lib/5.18.0/x86_64-linux-thread-multi/CORE > > -Wl,-rpath,/vobs/cc/CCA-perl01/perl5_Linux_x64__________sixtyfive_char_path/prod/lib/5.18.0/x86_64-linux-thread-multi/CORE > > -Wl,-L/vobs/cc/CCA-perl01/perl5_Linux_x64__________sixtyfive_char_path/plib/lib > > -Wl,-rpath,/vobs/cc/CCA-perl01/perl5_Linux_x64__________sixtyfive_char_path/plib/lib > > -Wl,-L/vobs/cc/CCA-perl01/perl5_Linux_x64__________sixtyfive_char_path/plib/apache/lib > > -Wl,-rpath,/vobs/cc/CCA-perl01/perl5_Linux_x64__________sixtyfive_char_path/plib/apache/lib' > cccdlflags='-fPIC', lddlflags='-shared -lpthread > -Wl,-L/vobs/cc/CCA-perl01/perl5_Linux_x64__________sixtyfive_char_path/prod/lib/5.18.0/x86_64-linux-thread-multi/CORE > > -Wl,-rpath,/vobs/cc/CCA-perl01/perl5_Linux_x64__________sixtyfive_char_path/prod/lib/5.18.0/x86_64-linux-thread-multi/CORE > > -Wl,-L/vobs/cc/CCA-perl01/perl5_Linux_x64__________sixtyfive_char_path/plib/lib > > -Wl,-rpath,/vobs/cc/CCA-perl01/perl5_Linux_x64__________sixtyfive_char_path/plib/lib > > -Wl,-L/vobs/cc/CCA-perl01/perl5_Linux_x64__________sixtyfive_char_path/plib/apache/lib > > -Wl,-rpath,/vobs/cc/CCA-perl01/perl5_Linux_x64__________sixtyfive_char_path/plib/apache/lib > -Wl,--enable-new-dtags -fstack-protector' > > Locally applied patches: > > > --- > @INC for perl 5.18.0: > > /vobs/cc/CCA-perl01/perl5_Linux_x64__________sixtyfive_char_path/prod/lib/site_perl/5.18.0/x86_64-linux-thread-multi > > /vobs/cc/CCA-perl01/perl5_Linux_x64__________sixtyfive_char_path/prod/lib/site_perl/5.18.0 > > /vobs/cc/CCA-perl01/perl5_Linux_x64__________sixtyfive_char_path/prod/lib/5.18.0/x86_64-linux-thread-multi > > /vobs/cc/CCA-perl01/perl5_Linux_x64__________sixtyfive_char_path/prod/lib/5.18.0 > . > > --- > Environment for perl 5.18.0: > HOME=/home/eedmja > LANG=en_US.UTF-8 > LANGUAGE (unset) > LD_LIBRARY_PATH (unset) > LOGDIR (unset) > > PATH=/tmp/_cc_CCA-perl01/perl5_Linux_x64__________sixtyfive_char_path/prod/bin:/tmp/_cc_CCA-perl01/perl5_Linux_x64__________sixtyfive_char_path/plib/bin:/bin:/usr/bin:/sbin:/usr/sbin:/opt/gnome/bin:/opt/kde3/bin:/usr/bin/X11:/home/eedmja/bin:/opt/rational/clearcase/bin > PERL_BADLANG (unset) > SHELL=/bin/tcsh