[Bug nscd/12125] New: Problems linking nscd under certain gcc conditions

[Bug nscd/12125] New: Problems linking nscd under certain gcc conditions

[viriketo at gmail dot com]

http://sourceware.org/bugzilla/show_bug.cgi?id=12125

           Summary: Problems linking nscd under certain gcc conditions
           Product: glibc
           Version: 2.12
            Status: NEW
          Severity: normal
          Priority: P2
         Component: nscd
        AssignedTo: drepper.fsp@gmail.com
        ReportedBy: viriketo@gmail.com


The 'nscd' makefile reads:
ifeq (yes,$(have-ssp))
nscd-cflags += -fstack-protector
endif
...
ifeq (yesyes,$(have-fpie)$(build-shared))
relro-LDFLAGS += -Wl,-z,now

$(objpfx)nscd: $(addprefix $(objpfx),$(nscd-modules:=.o))
    $(+link-pie)
endif



And the link-pie defined in 'Makeconfig' says to use "-nostdlib" in the gcc
linking call.

The check for the stack protector does not use "-nostdlib", so a simple
"-fstack-protector" succeeds. Here is the gcc spec part:
*link_ssp:
%{fstack-protector|fstack-protector-all:-lssp_nonshared -lssp}

*link_command:
... %{!nostdlib:%{!nodefaultlibs:%(link_ssp) %(link_gcc_c_sequence)} ...

So, the trouble appears when glibc is:
- build as shared
- -fpie found
- -fstack-protector found

Because it tries to link nscd with -nostdlib but without supplying
-lssp_noshared -lssp

This problem happens in glibc 2.12.1 and glibc 2.11 at least.

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[Bug nscd/12125] Problems linking nscd under certain gcc conditions

[viriketo at gmail dot com]

http://sourceware.org/bugzilla/show_bug.cgi?id=12125

--- Comment #1 from Lluís <viriketo at gmail dot com> 2010-10-15 21:27:28 UTC ---
Created attachment 5064
  --> http://sourceware.org/bugzilla/attachment.cgi?id=5064
Proposal for the fix

Here is a patch over glibc 2.12.1, of what I came up with to overcome the stack
protector libraries linking problem.
The best would be to look at the gcc specs to get what libraries the stack
protector will enable, through some configure settings, I imagine. But by now
this fits my situation.

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[Bug nscd/12125] Problems linking nscd under certain gcc conditions

[viriketo at gmail dot com]

http://sourceware.org/bugzilla/show_bug.cgi?id=12125

--- Comment #2 from Lluís <viriketo at gmail dot com> 2010-10-15 23:18:13 UTC ---
Created attachment 5065
  --> http://sourceware.org/bugzilla/attachment.cgi?id=5065
For static linking with libssp

Due to the usua gcc/glibc/gcc bootstrap procedure, it may be of interest of the
user to link to libssp statically. Then, the patch can go like this.

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[Bug nscd/12125] Problems linking nscd under certain gcc conditions

[drepper.fsp at gmail dot com]

http://sourceware.org/bugzilla/show_bug.cgi?id=12125

--- Comment #3 from Ulrich Drepper <drepper.fsp at gmail dot com> 2010-10-26 03:11:44 UTC ---
What are you talking about?  Linux platforms shouldn't (mustn't?) need libssp.

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[Bug nscd/12125] Problems linking nscd under certain gcc conditions

[viriketo at gmail dot com]

http://sourceware.org/bugzilla/show_bug.cgi?id=12125

--- Comment #4 from Lluís <viriketo at gmail dot com> 2010-10-26 07:18:11 UTC ---
Sorry, I am not aware of what should have libssp and what not.

Do you mean that Linux systems should not have libssp installed, from gcc?
Should we install gcc with "--disable-libssp"? Otherwise it gets installed.

I understand that the 'glibc' configure system tries "-fstack-protector", and
if it is available, it builds nscd with it. This is how it behaves here, and
this is what I understand from the Makefiles.

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[Bug nscd/12125] Problems linking nscd under certain gcc conditions

[viriketo at gmail dot com]

http://sourceware.org/bugzilla/show_bug.cgi?id=12125

--- Comment #5 from Lluís Batlle <viriketo at gmail dot com> 2010-10-26 18:54:52 UTC ---
I investigated a bit, and I understood why my gcc built libssp. It did not find
the glibc headers, as I don't have it in the place it looked for them:
/usr/include.

I adapted my gcc 'configure' script, and then this problem disappears.

As for me, you can close the report if you want.

Thank you.

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[Bug nscd/12125] Problems linking nscd under certain gcc conditions

[pasky at suse dot cz]

http://sourceware.org/bugzilla/show_bug.cgi?id=12125

Petr Baudis <pasky at suse dot cz> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
                 CC|                            |pasky at suse dot cz
         Resolution|                            |INVALID

--- Comment #6 from Petr Baudis <pasky at suse dot cz> 2010-10-27 02:38:14 UTC ---
I'm closing it then. :)

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[Bug nscd/12125] Problems linking nscd under certain gcc conditions

[fweimer at redhat dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=12125

Florian Weimer <fweimer at redhat dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
              Flags|                            |security-

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