ls: don't segfault on files in /proc with an old libselinux

* src/ls.c (gobble_file): Work around a bug in libselinux1-2.0.15
whereby getfilecon returns 0 yet sets the context to NULL.
Reported by Jan Moringen via Michael Stone in
http://bugs.debian.org/463043
* tests/ls/Makefile.am (TESTS): Add proc-selinux-segfault.
* tests/ls/proc-selinux-segfault: Test for the above fix.
* NEWS: Mention the fix.

diff --git a/ChangeLog b/ChangeLog
index f89f684..ff9070d 100644 (file)
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,14 @@
+2008-01-29  Jim Meyering  <meyering@redhat.com>
+
+       ls: don't segfault on files in /proc with an old libselinux
+       * src/ls.c (gobble_file): Work around a bug in libselinux1-2.0.15
+       whereby getfilecon returns 0 yet sets the context to NULL.
+       Reported by Jan Moringen via Michael Stone in
+       http://bugs.debian.org/463043
+       * tests/ls/Makefile.am (TESTS): Add proc-selinux-segfault.
+       * tests/ls/proc-selinux-segfault: Test for the above fix.
+       * NEWS: Mention the fix.
+
 2008-01-26  Jim Meyering  <meyering@redhat.com>
 
        Work around Darwin9's set-GID-like group ownership inheritance.

diff --git a/NEWS b/NEWS
index 4811296..f474141 100644 (file)
--- a/NEWS
+++ b/NEWS
@@ -4,6 +4,9 @@ GNU coreutils NEWS                                    -*- outline -*-
 
 ** Bug fixes
 
+  ls no longer segfaults on files in /proc when linked with an older version
+  of libselinux.  E.g., ls -l /proc/sys would dereference a NULL pointer.
+
   Fix a non-portable use of sed in configure.ac.
   [bug introduced in coreutils-6.9.92]
 

diff --git a/THANKS b/THANKS
index f9a4f62..1e04f9b 100644 (file)
--- a/THANKS
+++ b/THANKS
@@ -225,6 +225,7 @@ James Youngman                      james+usenet@free-lunch.demon.co.uk
 Jamie Lokier                        jamie@imbolc.ucc.ie
 Jamie McClelland                    jm@mayfirst.org
 Jan Fedak                           J.Fedak@sh.cvut.cz
+Jan Moringen                        jan.moringen@uni-bielefeld.de
 Jan Nieuwenhuizen                   janneke@gnu.org
 Janos Farkas                        chexum@shadow.banki.hu
 Jarkko Hietaniemi                   jhi@epsilon.hut.fi

diff --git a/src/ls.c b/src/ls.c
index 83fac90..46713f2 100644 (file)
--- a/src/ls.c
+++ b/src/ls.c
@@ -1,5 +1,5 @@
 /* `dir', `vdir' and `ls' directory listing programs for GNU.
-   Copyright (C) 85, 88, 90, 91, 1995-2007 Free Software Foundation, Inc.
+   Copyright (C) 85, 88, 90, 91, 1995-2008 Free Software Foundation, Inc.
 
    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -2667,6 +2667,17 @@ gobble_file (char const *name, enum filetype type, ino_t inode,
                          : lgetfilecon (absolute_name, &f->scontext));
          err = (attr_len < 0);
 
+         /* Contrary to its documented API, getfilecon may return 0,
+            yet set f->scontext to NULL (on at least Debian's libselinux1
+            2.0.15-2+b1), so work around that bug.
+            FIXME: remove this work-around in 2011, or whenever affected
+            versions of libselinux are long gone.  */
+         if (attr_len == 0)
+           {
+             err = 0;
+             f->scontext = xstrdup ("unlabeled");
+           }
+
          if (err == 0)
            have_acl = ! STREQ ("unlabeled", f->scontext);
          else

diff --git a/tests/ls/Makefile.am b/tests/ls/Makefile.am
index 2aea419..c9739c9 100644 (file)
--- a/tests/ls/Makefile.am
+++ b/tests/ls/Makefile.am
@@ -1,6 +1,6 @@
 # Make coreutils tests for "ls".               -*-Makefile-*-
 
-# Copyright (C) 1997-2003, 2006-2007 Free Software Foundation, Inc.
+# Copyright (C) 1997-2003, 2006-2008 Free Software Foundation, Inc.
 
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
@@ -16,6 +16,7 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 TESTS = \
+  proc-selinux-segfault \
   stat-free-symlinks \
   nameless-uid \
   color-dtype-dir \

diff --git a/tests/ls/proc-selinux-segfault b/tests/ls/proc-selinux-segfault
new file mode 100755 (executable)
index 0000000..320ba6f
--- /dev/null
+++ b/tests/ls/proc-selinux-segfault
@@ -0,0 +1,33 @@
+#!/bin/sh
+# ls -l /proc/sys would segfault when built against libselinux1 2.0.15-2+b1
+
+# Copyright (C) 2008 Free Software Foundation, Inc.
+
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+if test "$VERBOSE" = yes; then
+  set -x
+  ls --version
+fi
+
+. $srcdir/../envvar-check
+. $srcdir/../test-lib.sh
+
+f=/proc/sys
+test -r $f || f=.
+
+fail=0
+ls -l $f > out || fail=1
+
+(exit $fail); exit $fail