Bug #74777 for Params-Validate: compiling with -Werror=format-security fails

Wed Feb 08 06:29:41 2012 voegelas [...] cpan.org - Ticket created

Subject:

GCC complains about "croak(SvPV_nolen(buffer))" when compiling Params/Validate/XS.xs with -Werror=format-security

When Params::Validate's XS module is compiled with -Werror=format-security (as described in http://article.gmane.org/gmane.comp.lang.perl.perl5.porters/105559), the build fails with the following error message: lib/Params/Validate/XS.xs: In function 'validate_named_depends': lib/Params/Validate/XS.xs:1005:29: error: format not a string literal and no format arguments [-Werror=format-security] GCC complains about this function call: croak(SvPV_nolen(buffer)); I don't know if "buffer" could contain format specifiers but passing "%s" as the format string should be safer and makes GCC happy: croak("%s", SvPV_nolen(buffer));

Subject:

lib_Params_Validate_XS_xs.diff.txt

--- lib/Params/Validate/XS.xs 2012-02-08 10:08:42.000000000 +0100 +++ lib/Params/Validate/XS.xs.orig 2012-02-06 23:45:04.000000000 +0100 @@ -1002,7 +1002,7 @@ sv_catpv(buffer, "' does not exist in spec: "); sv_catsv(buffer, depend_name); - croak("%s", SvPV_nolen(buffer)); + croak(SvPV_nolen(buffer)); } /* if we got here, the spec was correct. we just * need to issue a regular validation failure

Wed Feb 08 13:02:19 2012 voegelas [...] cpan.org - Subject changed from 'GCC complains about "croak(SvPV_nolen(buffer))" when compiling Params/Validate/XS.xs with -Werror=format-security' to 'compiling with -Werror=format-security fails'

Wed Feb 08 15:12:15 2012 autarch [...] urth.org - Correspondence added

Subject:	Re: [rt.cpan.org #74777] GCC complains about "croak(SvPV_nolen(buffer))" when compiling Params/Validate/XS.xs with -Werror=format-security
Date:	Wed, 8 Feb 2012 14:12:06 -0600 (CST)
To:	Andreas Voegele via RT <bug-Params-Validate [...] rt.cpan.org>
From:	Dave Rolsky <autarch [...] urth.org>

On Wed, 8 Feb 2012, Andreas Voegele via RT wrote: Show quoted text

> When Params::Validate's XS module is compiled with > -Werror=format-security (as described in > http://article.gmane.org/gmane.comp.lang.perl.perl5.porters/105559), the > build fails with the following error message: > > lib/Params/Validate/XS.xs: In function 'validate_named_depends': > lib/Params/Validate/XS.xs:1005:29: error: format not a string literal > and no format arguments [-Werror=format-security]

I can't replicate this when passing the same flag to my gcc (4.5.2). Is this a new warning, or one that's been eliminated in my version of gcc? -dave /*============================================================ http://VegGuide.org http://blog.urth.org Your guide to all that's veg House Absolute(ly Pointless) ============================================================*/

Wed Feb 08 15:12:16 2012 The RT System itself - Status changed from 'new' to 'open'

Wed Feb 08 16:12:56 2012 voegelas [...] cpan.org - Correspondence added

Am Mi 08. Feb 2012, 15:12:15, autarch@urth.org schrieb: Show quoted text

> On Wed, 8 Feb 2012, Andreas Voegele via RT wrote: >

> > When Params::Validate's XS module is compiled with > > -Werror=format-security (as described in > > http://article.gmane.org/gmane.comp.lang.perl.perl5.porters/105559), the > > build fails with the following error message: > > > > lib/Params/Validate/XS.xs: In function 'validate_named_depends': > > lib/Params/Validate/XS.xs:1005:29: error: format not a string literal > > and no format arguments [-Werror=format-security]

> > I can't replicate this when passing the same flag to my gcc (4.5.2). Is > this a new warning, or one that's been eliminated in my version of gcc?

Hm, both gcc 4.6 on my Slackware Linux box as well as 4.2 under OpenBSD support "-Werror=format-security". But actually that compiler option is not that important. I've attached a program that demonstrates the problem. The program segfaults unless the patch that I sent earlier is applied. croak() must never be called with user-supplied data as a format string. See the CAVEATS section in L<http://www.openbsd.org/cgi-bin/man.cgi?query=printf#end> for an explanation. That comment also applies to Perl's croak() function.

Subject:

crash_params_validate.pl

use strict; use warnings; use Params::Validate qw(:all); sub foo { validate( @_, { a => { type => SCALAR, depends => [ '%s%s%s' ] }, } ); } foo({a => 1});

Wed Feb 08 22:52:24 2012 autarch [...] urth.org - Correspondence added

Subject:	Re: [rt.cpan.org #74777] compiling with -Werror=format-security fails
Date:	Wed, 8 Feb 2012 21:52:14 -0600 (CST)
To:	Andreas Voegele via RT <bug-Params-Validate [...] rt.cpan.org>
From:	Dave Rolsky <autarch [...] urth.org>

On Wed, 8 Feb 2012, Andreas Voegele via RT wrote: Show quoted text

> But actually that compiler option is not that important. I've attached a > program that demonstrates the problem. The program segfaults unless the > patch that I sent earlier is applied. croak() must never be called with > user-supplied data as a format string. See the CAVEATS section in > L<http://www.openbsd.org/cgi-bin/man.cgi?query=printf#end> for an > explanation. That comment also applies to Perl's croak() function.

This doesn't crash my system, but the fix certainly makes sense. -dave /*============================================================ http://VegGuide.org http://blog.urth.org Your guide to all that's veg House Absolute(ly Pointless) ============================================================*/

Fri Feb 10 12:43:26 2012 DROLSKY [...] cpan.org - Status changed from 'open' to 'resolved'

Fri Feb 10 12:43:27 2012 DROLSKY [...] cpan.org - Fixed in 1.05 added