[yocto] [prelink-cross][PATCH] rtld: get machine from undef_map for protected symbols

Kyle Russell bkylerussell at gmail.com
Fri Sep 28 08:38:05 PDT 2018 

No objections, please go ahead.  Sorry I forgot!  I realize I didn't do
that on the other patch I just sent either.

On Fri, Sep 28, 2018 at 11:19 AM Mark Hatle <mark.hatle at windriver.com>
wrote:

> On 9/28/18 9:55 AM, Kyle Russell wrote:
> > Avoids rtld segfault when _dl_lookup_symbol_x is called with NULL
> > for skip_map on a protected symbol relocation.
> >
> > Global protected symbols may not actually require a copy relocaton,
> > in which case skip_map is undefined, so use the undef_map to determine
> > the symbol arch.
>
> Thank you.  Any objections with me adding a 'Signed-off-by: ' line with
> your name?
>
> I'm going to start enforcing submissions need a signed-off-by line per the
> terms
> of the "Developer's Certificate of Origin",
>
>
> https://www.kernel.org/doc/html/latest/process/submitting-patches.html#sign-your-work-the-developer-s-certificate-of-origin
>
> (While it is not yet a requirement, I'd like to start doing it now.)
>
> Thanks!
> --Mark
>
> > ---
> >  src/rtld/dl-lookupX.h   |  6 +++---
> >  testsuite/Makefile.am   |  2 +-
> >  testsuite/reloc12.c     | 19 +++++++++++++++++++
> >  testsuite/reloc12.h     | 11 +++++++++++
> >  testsuite/reloc12.sh    | 20 ++++++++++++++++++++
> >  testsuite/reloc12lib1.c | 11 +++++++++++
> >  testsuite/reloc12lib2.c | 16 ++++++++++++++++
> >  7 files changed, 81 insertions(+), 4 deletions(-)
> >  create mode 100644 testsuite/reloc12.c
> >  create mode 100644 testsuite/reloc12.h
> >  create mode 100755 testsuite/reloc12.sh
> >  create mode 100644 testsuite/reloc12lib1.c
> >  create mode 100644 testsuite/reloc12lib2.c
> >
> > diff --git a/src/rtld/dl-lookupX.h b/src/rtld/dl-lookupX.h
> > index 425bb4b..250c509 100644
> > --- a/src/rtld/dl-lookupX.h
> > +++ b/src/rtld/dl-lookupX.h
> > @@ -679,10 +679,10 @@ _dl_lookup_symbol_x (const char *undef_name,
> struct link_map *undef_map,
> >           if (do_lookup_x (undef_name, new_hash, &old_hash, *ref,
> >                            &protected_value, *scope, i, version, flags,
> >                            skip_map,
> > -
> (ELF_RTYPE_CLASS_EXTERN_PROTECTED_DATA(skip_map->machine)
> > +
> (ELF_RTYPE_CLASS_EXTERN_PROTECTED_DATA(undef_map->machine)
> >                             && ELFW(ST_TYPE) ((*ref)->st_info) ==
> STT_OBJECT
> > -                           && type_class ==
> ELF_RTYPE_CLASS_EXTERN_PROTECTED_DATA(skip_map->machine))
> > -                          ?
> ELF_RTYPE_CLASS_EXTERN_PROTECTED_DATA(skip_map->machine)
> > +                           && type_class ==
> ELF_RTYPE_CLASS_EXTERN_PROTECTED_DATA(undef_map->machine))
> > +                          ?
> ELF_RTYPE_CLASS_EXTERN_PROTECTED_DATA(undef_map->machine)
> >                            : ELF_RTYPE_CLASS_PLT, NULL) != 0)
> >             break;
> >
> > diff --git a/testsuite/Makefile.am b/testsuite/Makefile.am
> > index 030f65b..21de6a9 100644
> > --- a/testsuite/Makefile.am
> > +++ b/testsuite/Makefile.am
> > @@ -5,7 +5,7 @@ AM_CFLAGS = -Wall
> >
> >  TESTS = movelibs.sh \
> >       reloc1.sh reloc2.sh reloc3.sh reloc4.sh reloc5.sh reloc6.sh \
> > -     reloc7.sh reloc8.sh reloc9.sh reloc10.sh reloc11.sh \
> > +     reloc7.sh reloc8.sh reloc9.sh reloc10.sh reloc11.sh reloc12.sh \
> >       shuffle1.sh shuffle2.sh shuffle3.sh shuffle4.sh shuffle5.sh \
> >       shuffle6.sh shuffle7.sh shuffle8.sh shuffle9.sh undo1.sh \
> >       layout1.sh layout2.sh unprel1.sh \
> > diff --git a/testsuite/reloc12.c b/testsuite/reloc12.c
> > new file mode 100644
> > index 0000000..cfa8888
> > --- /dev/null
> > +++ b/testsuite/reloc12.c
> > @@ -0,0 +1,19 @@
> > +#include "reloc12.h"
> > +#include <stdlib.h>
> > +
> > +int main()
> > +{
> > +  A* ptr = find('b');
> > +  if(b(ptr) != 0)
> > +    abort();
> > +
> > +  ptr = find('a');
> > +  if(b(ptr) != 1)
> > +    abort();
> > +
> > +  ptr = find('r');
> > +  if(b(ptr) != 2)
> > +    abort();
> > +
> > +  exit(0);
> > +}
> > diff --git a/testsuite/reloc12.h b/testsuite/reloc12.h
> > new file mode 100644
> > index 0000000..8e09405
> > --- /dev/null
> > +++ b/testsuite/reloc12.h
> > @@ -0,0 +1,11 @@
> > +typedef struct
> > +  {
> > +    char a;
> > +    int b;
> > +  } A;
> > +
> > +extern A foo[] __attribute ((visibility ("protected")));
> > +
> > +A* find(char a);
> > +char a(const A*);
> > +int b(const A*);
> > diff --git a/testsuite/reloc12.sh b/testsuite/reloc12.sh
> > new file mode 100755
> > index 0000000..a8a43c7
> > --- /dev/null
> > +++ b/testsuite/reloc12.sh
> > @@ -0,0 +1,20 @@
> > +#!/bin/bash
> > +. `dirname $0`/functions.sh
> > +rm -f reloc12 reloc12lib*.so reloc12.log
> > +rm -f prelink.cache
> > +$RUN_HOST $CC -shared -O2 -fpic -o reloc12lib1.so $srcdir/reloc12lib1.c
> > +$RUN_HOST $CC -shared -O2 -fpic -o reloc12lib2.so $srcdir/reloc12lib2.c
> > +BINS="reloc12"
> > +LIBS="reloc12lib1.so reloc12lib2.so"
> > +$RUN_HOST $CCLINK -o reloc12 $srcdir/reloc12.c -Wl,--rpath-link,.
> ${LIBS}
> > +savelibs
> > +echo $PRELINK ${PRELINK_OPTS--vm} ./reloc12 > reloc12.log
> > +$RUN_HOST $PRELINK ${PRELINK_OPTS--vm} ./reloc12 >> reloc12.log 2>&1 ||
> exit 1
> > +grep -q ^`echo $PRELINK | sed 's/ .*$/: /'` reloc12.log && exit 2
> > +if [ "x$CROSS" = "x" ]; then
> > + $RUN LD_LIBRARY_PATH=. ./reloc12 || exit 3
> > +fi
> > +$RUN_HOST $READELF -a ./reloc12 >> reloc12.log 2>&1 || exit 4
> > +# So that it is not prelinked again
> > +chmod -x ./reloc12
> > +comparelibs >> reloc12.log 2>&1 || exit 5
> > diff --git a/testsuite/reloc12lib1.c b/testsuite/reloc12lib1.c
> > new file mode 100644
> > index 0000000..db7e64f
> > --- /dev/null
> > +++ b/testsuite/reloc12lib1.c
> > @@ -0,0 +1,11 @@
> > +#include "reloc12.h"
> > +
> > +char a(const A *d)
> > +{
> > +  return d ? d->a : 0;
> > +}
> > +
> > +int b(const A *d)
> > +{
> > +  return d ? d->b : -1;
> > +}
> > diff --git a/testsuite/reloc12lib2.c b/testsuite/reloc12lib2.c
> > new file mode 100644
> > index 0000000..ffa60a0
> > --- /dev/null
> > +++ b/testsuite/reloc12lib2.c
> > @@ -0,0 +1,16 @@
> > +#include "reloc12.h"
> > +
> > +A foo[] = {
> > +  { 'b', 0 },
> > +  { 'a', 1 },
> > +  { 'r', 2 }
> > +};
> > +
> > +A* find(char a)
> > +{
> > +  for(A* ptr = foo; ptr < foo + sizeof(foo)/sizeof(foo[0]); ptr++)
> > +    if(ptr->a == a)
> > +      return ptr;
> > +
> > +  return 0;
> > +}
> >
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.yoctoproject.org/pipermail/yocto/attachments/20180928/901ebbff/attachment.html>

More information about the yocto mailing list