Bug 391899 – sys-devel/binutils-2.22: static bins segfault after __libc_csu_init on hardened

• Status: RESOLVED FIXED
• Product: Gentoo Linux

[Description Bertrand Jacquin 2011-11-25 20:49:11 UTC]

If I try to compile that small program staticaly :

$ cat conftest.c 
int
main ()
{

  ;
  return 0;
}

$ x86_64-pc-linux-gnu-gcc -march=core2 -O2 -pipe -fomit-frame-pointer -mtune=core2  -D_GNU_SOURCE -g -ggdb -static  conftest.c

It segfault :

$ ./a.out 
Segmentation fault

A backtrace :

$ gdb ./a.out 
...
(gdb) r
Starting program: /var/tmp/a.out 

Program received signal SIGSEGV, Segmentation fault.
0xffffffffffffffff in ?? ()
(gdb) bt
#0  0xffffffffffffffff in ?? ()
#1  0x0000000000400c8c in __libc_csu_init ()
#2  0x0000000000400699 in __libc_start_main ()
#3  0x0000000000400409 in _start ()

If I compile it as shared, all is fine :


$ x86_64-pc-linux-gnu-gcc -march=core2 -O2 -pipe -fomit-frame-pointer -mtune=core2  -D_GNU_SOURCE -g -ggdb conftest.c
$ ./a.out 

Attached a emerge --info

Is a objdump -d necessary ?

Reproducible: Always

[Comment 1 Bertrand Jacquin 2011-11-25 20:50:14 UTC]

Created attachment 293761 [details]
emerge --info

[Comment 2 iGentoo 2011-11-26 08:36:54 UTC]

*** Bug 391939 has been marked as a duplicate of this bug. ***

[Comment 3 Magnus Granberg 2011-11-27 13:10:45 UTC]

Looks like binutils-2.22 make the linking fail some way so the static bin don't work.

[Comment 4 Magnus Granberg 2011-12-01 20:11:14 UTC]

Looks like binutils 2.22 don't like the pie/static hybrid crtbeginTS.o
Something get wrong. On older binutils it was working fine.
Mike do you have any hint where to look in the binutils code for it?

[Comment 5 iGentoo 2011-12-02 14:28:16 UTC]

Created attachment 294519 [details, diff]
binutils-2.22-initfini-pie.patch

[Comment 6 Magnus Granberg 2011-12-02 16:08:20 UTC]

(In reply to comment #5)
> Created attachment 294519 [details, diff] [details, diff]
> binutils-2.22-initfini-pie.patch

Tested and it works, thank you
Mike can we include it in next patch bump?

[Comment 7 SpanKY 2011-12-02 20:10:22 UTC]

if we look at ld/scripttempl/elf.sc, i'm a bit uneasy by our crt handling.  aren't we already missing handling later on in the file ?

...
CTOR=".ctors        ${CONSTRUCTING-0} :
...
    KEEP (*crtbegin.o(.ctors))
    KEEP (*crtbegin?.o(.ctors))
...
    KEEP (*(EXCLUDE_FILE (*crtend.o *crtend?.o $OTHER_EXCLUDE_FILES) .ctors))
    KEEP (*(SORT(.ctors.*)))
    KEEP (*(.ctors))
...
DTOR=".dtors        ${CONSTRUCTING-0} :
...
    KEEP (*crtbegin.o(.dtors))
    KEEP (*crtbegin?.o(.dtors))
    KEEP (*(EXCLUDE_FILE (*crtend.o *crtend?.o $OTHER_EXCLUDE_FILES) .dtors))
    KEEP (*(SORT(.dtors.*)))
...

[Comment 8 SpanKY 2011-12-02 20:15:38 UTC]

more related URLs:
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46770
http://sourceware.org/ml/binutils/2010-12/msg00439.html

[Comment 9 iGentoo 2011-12-02 22:28:56 UTC]

Like this...?

@@ -264,6 +264,7 @@ CTOR=".ctors        ${CONSTRUCTING-0} :
 
     KEEP (*crtbegin.o(.ctors))
     KEEP (*crtbegin?.o(.ctors))
+    KEEP (*crtbeginTS.o(.ctors))
 
     /* We don't want to include the .ctor section from
        the crtend.o file until after the sorted ctors.
@@ -280,6 +281,7 @@ DTOR=".dtors        ${CONSTRUCTING-0} :
     ${CONSTRUCTING+${DTOR_START}}
     KEEP (*crtbegin.o(.dtors))
     KEEP (*crtbegin?.o(.dtors))
+    KEEP (*crtbeginTS.o(.dtors))
     KEEP (*(EXCLUDE_FILE (*crtend.o *crtend?.o $OTHER_EXCLUDE_FILES) .dtors))
     KEEP (*(SORT(.dtors.*)))
     KEEP (*(.dtors))

[Comment 10 SpanKY 2011-12-02 22:50:30 UTC]

that would be my guess ... but i'd like it if some hardened peeps did some testing before we commit that :)

[Comment 11 Anthony Basile 2011-12-03 13:51:52 UTC]

(In reply to comment #10)
> that would be my guess ... but i'd like it if some hardened peeps did some
> testing before we commit that :)

I tested applying the patch in comments 5 and 9 and it resolves the issue.

[Comment 12 Magnus Granberg 2011-12-03 13:53:11 UTC]

Works fine here to.

[Comment 13 SpanKY 2011-12-03 16:59:14 UTC]

someone should post a patch i can actually d/l and apply ;)

[Comment 14 Magnus Granberg 2011-12-05 21:23:09 UTC]

Created attachment 294895 [details, diff]
Add support for crtbeginTS.o

Add support for the crtbeginTS.o from hardened gcc.

[Comment 15 SpanKY 2011-12-05 21:33:57 UTC]

Comment on attachment 294895 [details, diff]
Add support for crtbeginTS.o

i think you've got a copy & paste typo here; i'll fix it up when i commit:
     KEEP (*crtbegin?.o(.dtors))
+    KEEP (*crtbeginTS.o(.ctors))

pretty sure that should be .dtors

[Comment 16 SpanKY 2011-12-05 21:41:41 UTC]

queued in the 2.22 patchset.  i'll bump once i go through open bugs to make sure there are no other pending things to include.

[Comment 17 Magnus Granberg 2011-12-11 21:59:16 UTC]

*** Bug 393327 has been marked as a duplicate of this bug. ***

[Comment 18 SpanKY 2016-07-04 03:21:07 UTC]

FYI i'm dropping this patch starting with 2.26.1 since it's been in gcc long enough.  i'll prob drop it from older binutils too, just not do an explicit patchset push for it.