Bug 30216

Summary:	make PIE optional and/or make the check more thorough
Product:	dbus	Reporter:	Ivan Krasilnikov <infnty>
Component:	core	Assignee:	Simon McVittie <smcv>
Status:	RESOLVED DUPLICATE	QA Contact:	John (J5) Palmieri <johnp>
Severity:	normal
Priority:	medium	CC:	hp
Version:	unspecified
Hardware:	All
OS:	All
Whiteboard:
i915 platform:		i915 features:

Description Ivan Krasilnikov 2010-09-15 14:37:14 UTC

I've tried to compile dbus 1.4.0 and 1.3.1 from source tarball (with expat-2.0.1 library also compiled from sources, if that matters) on a freshly-installed 64-bit FreeBSD 7.2 machine.

Output from gcc --version and uname -a:
gcc (GCC) 4.2.1 20070719  [FreeBSD]
FreeBSD  7.2-RELEASE FreeBSD 7.2-RELEASE #0: Fri May  1 07:18:07 UTC 2009     root@driscoll.cse.buffalo.edu:/usr/obj/usr/src/sys/GENERIC  amd64


./configure && make V=1 fails, printing these messages:

/bin/sh ../libtool  --tag=CC    --mode=link gcc  -ffunction-sections -fdata-sect
ions -g -O2 -Wall -Wchar-subscripts -Wmissing-declarations -Wmissing-prototypes 
-Wnested-externs -Wpointer-arith -Wcast-align -Wdeclaration-after-statement -fno
-common -Wno-unused -Wno-sign-compare -Wno-pointer-sign -fno-strict-aliasing  -W
l,--gc-sections  -pie -Wl,-z,relro  -o dbus-daemon dbus_daemon-activation.o  dbu
s_daemon-bus.o dbus_daemon-config-parser.o  dbus_daemon-config-parser-common.o  
dbus_daemon-connection.o  dbus_daemon-desktop-file.o dbus_daemon-dir-watch-kqueu
e.o  dbus_daemon-dispatch.o dbus_daemon-driver.o  dbus_daemon-expirelist.o dbus_
daemon-policy.o  dbus_daemon-selinux.o dbus_daemon-services.o  dbus_daemon-signa
ls.o dbus_daemon-test.o  dbus_daemon-utils.o dbus_daemon-config-loader-expat.o d
bus_daemon-main.o ../dbus/libdbus-internal.la                                   
         -lexpat   -lpthread -lrt                                               
libtool: link: gcc -ffunction-sections -fdata-sections -g -O2 -Wall -Wchar-subsc
ripts -Wmissing-declarations -Wmissing-prototypes -Wnested-externs -Wpointer-ari
th -Wcast-align -Wdeclaration-after-statement -fno-common -Wno-unused -Wno-sign-
compare -Wno-pointer-sign -fno-strict-aliasing -Wl,--gc-sections -pie -Wl,-z -Wl
,relro -o dbus-daemon dbus_daemon-activation.o dbus_daemon-bus.o dbus_daemon-con
fig-parser.o dbus_daemon-config-parser-common.o dbus_daemon-connection.o dbus_da
emon-desktop-file.o dbus_daemon-dir-watch-kqueue.o dbus_daemon-dispatch.o dbus_d
aemon-driver.o dbus_daemon-expirelist.o dbus_daemon-policy.o dbus_daemon-selinux
.o dbus_daemon-services.o dbus_daemon-signals.o dbus_daemon-test.o dbus_daemon-u
tils.o dbus_daemon-config-loader-expat.o dbus_daemon-main.o  ../dbus/.libs/libdb
us-internal.a /usr/local/lib/libexpat.so -lpthread -lrt -Wl,-rpath -Wl,/usr/loca
l/lib -Wl,-rpath -Wl,/usr/local/lib                                             
/usr/bin/ld: /usr/lib/crt1.o: relocation R_X86_64_32 can not be used when making
 a shared object; recompile with -fPIC                                          
/usr/lib/crt1.o: could not read symbols: Bad value                              

The problem is with -pie flag. Even though gcc accepts it, it's not really supported in my build environment:

$ echo 'int main() { return 0; }' >foo.c; gcc -fPIC -pie -o foo foo.c
/usr/bin/ld: /usr/lib/crt1.o: relocation R_X86_64_32 can not be used when making
 a shared object; recompile with -fPIC                                          
/usr/lib/crt1.o: could not read symbols: Bad value

Comment 1 Thiago Macieira 2010-09-15 15:40:43 UTC

That means you should fix your toolchain instead.

GCC shouldn't accept options that don't work. Either the option should work, or it should be removed/disabled.

Comment 2 Ivan Krasilnikov 2010-09-15 16:04:09 UTC

Yes, I agree, but that's the toolchain that shipped with this FreeBSD release. (And I suspect the situation is the same on FreeBSD 6.x-7.1). I can't easily fix it.

It should be easy to add to Configure.in a check that verifies that gcc is capable of build executables with -pie option. Why don't you want to add it?

Comment 3 Ivan Krasilnikov 2010-09-16 03:09:06 UTC

dbus' configure.in doesn't properly check that -pie is supported (it only checks for -fPIE flag), so I have to disagree with your assessment that it's "NOT-OUR-BUG", and reopen it.

Look how another respectable open-source project checks for -pie: http://svn.apache.org/viewvc/httpd/httpd/trunk/configure.in?view=markup (search for "ap_cv_cc_pie").

Please, integrate that check in your configure.in.

Comment 4 Thiago Macieira 2010-09-16 14:45:26 UTC

Patches are accepted.

Comment 5 Simon McVittie 2011-01-07 08:30:42 UTC

It would also be good to make PIE optional. In Maemo it's patched out of configure.in altogether[1], because on (some version of?) their ARM toolchain, it produces/produced executables that usually work, but not reliably (which we can't really check in configure).

Debian has also had problems with PIE on various less mainstream architectures at various times (at least mips[2], hppa/m68k[3], avr32[4]). Debian's dbus is currently compiled with PIE on those architectures, though.

If we add a --disable-pie option, distros with known-unreliable PIE support in (some of) their toolchains can at least use it as a workaround (for particular architectures or globally) without having to patch configure.

[1] http://maemo.gitorious.org/maemo-gnome-essentials/dbus/blobs/maemo/debian/patches/80-remove-fpie-pie.patch which fixes NB#171940, according to debian/changelog
[2] http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=526961
[3] http://wiki.debian.org/Hardening#DEBBUILDHARDENINGPIE.28gcc.2BAC8-g.2B-.2B--fPIE-pie.29
[5] http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=574716

Comment 6 Simon McVittie 2011-01-17 10:54:50 UTC


*** This bug has been marked as a duplicate of bug 16621 ***

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