Bug#661540: libapache2-mod-perl2: FTBFS with hardening flags enabled: -Werror=format-security

On Mon, Feb 27, 2012 at 09:39:53PM +0000, Dominic Hargreaves wrote:

Source: libapache2-mod-perl2
Severity: normal
Version: 2.0.5-5
User:
Usertags: hardening-format-security hardening

With hardening flags enabled, this package FTBFS:

In file included from Pool.xs:26:0:
/build/dom-libapache2-mod-perl2_2.0.5-5-i386-x1v_OO/libapache2-mod-perl2-2.0.5/xs/APR/Pool/APR__Pool.h: In function 'mpxs_cleanup_run':
/build/dom-libapache2-mod-perl2_2.0.5-5-i386-x1v_OO/libapache2-mod-perl2-2.0.5/xs/APR/Pool/APR__Pool.h:315:9: error: format not a string literal and no format arguments [-Werror=format-security]
cc1: some warnings being treated as errors

There are three other places where a variable is used as a format
string to Perl_croak(). I'm attaching a trivial patch that fixes those.
This makes the build with -Werror=format-security succeed.

If the variable can be externally controlled by untrusted input, this
is a security problem. The two usage warnings use constant strings so
they seem safe, but I'm afraid I can't tell whether this is the case
for ERRSV in the mpxs_cleanup_run() phase.

I'm cc'ing the modperl development list. Could somebody please look
into this? Also cc'ing the Debian security team as a heads up.

In any case, please consider the patch for 2.0.6.

Thanks for your work on mod_perl,
Niko Tyni


From 94bdae4a6c6e480e9b287813be2fd1eb01fd7bd3 Mon Sep 17 00:00:00 2001
From: Niko Tyni
Date: Fri, 9 Mar 2012 22:26:37 +0200
Subject: [PATCH] Use controlled format strings for Perl_croak()

This fixed builds with gcc -Werror=format-security.

xs/APR/Pool/APR__Pool.h | 2 +-
xs/Apache2/ServerUtil/Apache2__ServerUtil.h | 2 +-
xs/Apache2/SubProcess/Apache2__SubProcess.h | 4 ++--
3 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/xs/APR/Pool/APR__Pool.h b/xs/APR/Pool/APR__Pool.h
index 4ea8da3..058864f 100644
a/xs/APR/Pool/APR__Pool.h
+++ b/xs/APR/Pool/APR__Pool.h
@@ -312,7 +312,7 @@ static apr_status_t mpxs_cleanup_run(void *data)
#endif

if (SvTRUE(ERRSV)) {
- Perl_croak(aTHX_ SvPV_nolen(ERRSV));
+ Perl_croak(aTHX_ "%s", SvPV_nolen(ERRSV));
}

/* the return value is ignored by apr_pool_destroy anyway */
diff --git a/xs/Apache2/ServerUtil/Apache2__ServerUtil.h b/xs/Apache2/ServerUtil/Apache2__ServerUtil.h
index ced1c38..c64a140 100644
a/xs/Apache2/ServerUtil/Apache2__ServerUtil.h
+++ b/xs/Apache2/ServerUtil/Apache2__ServerUtil.h
@@ -80,7 +80,7 @@ static apr_status_t mpxs_cleanup_run(void *data)
}

if (SvTRUE(ERRSV)) {
- Perl_croak(aTHX_ SvPV_nolen(ERRSV));
+ Perl_croak(aTHX_ "%s", SvPV_nolen(ERRSV));
}

/* the return value is ignored by apr_pool_destroy anyway */
diff --git a/xs/Apache2/SubProcess/Apache2__SubProcess.h b/xs/Apache2/SubProcess/Apache2__SubProcess.h
index aca73a3..ae9807f 100644
a/xs/Apache2/SubProcess/Apache2__SubProcess.h
+++ b/xs/Apache2/SubProcess/Apache2__SubProcess.h
@@ -135,7 +135,7 @@ MP_STATIC XS(MPXS_modperl_spawn_proc_prog)
const char *usage = "Usage: spawn_proc_prog($r, $command, [\\@argv])";

if (items < 2) {
- Perl_croak(aTHX_ usage);
+ Perl_croak(aTHX_ "%s", usage);
}

SP -= items;
@@ -156,7 +156,7 @@ MP_STATIC XS(MPXS_modperl_spawn_proc_prog)
av_items = len+1;
}
else {
- Perl_croak(aTHX_ usage);
+ Perl_croak(aTHX_ "%s", usage);
}
}

1.7.9.1





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