Add SELinux context store/restore/list support.

* gnulib.modules: Add selinux-at.
* src/Makefile.am (tar_LDADD): Add LIB_SELINUX.

* src/create.c (start_header, dump_file0): Handle selinux contexts.
* src/extract.c (delayed_set_stat) <cntx_name>: New member.
(delayed_link) <cntx_name>: New member.
(set_stat, delay_set_stat)
(apply_nonancestor_delayed_set_stat): Handle selinux contexts.
* src/tar.c: New options: "--selinux", "--no-selinux".
(tar_stat_destroy): Free cntx_name.
* src/tar.h (tar_stat_info) <cntx_name>: New member.
* src/xattrs.c (xattrs_selinux_get)
(xattrs_selinux_set): New functions.
(xattrs_print_char): Honor selinux_context_option.
(xattrs_print): Print selinux context.
* src/xheader.c: Handle new keyword "RHT.security.selinux".
* tests/Makefile.am: Add new tests.
* tests/testsuite.at: Likewise.
* tests/selacl01.at: New test.
* tests/selnx01.at: New test.

gnulib.modules

@@ -50,6 +50,7 @@ root-uid
 rpmatch
 safe-read
 savedir
+selinux-at
 setenv
 snprintf
 stat-time

src/Makefile.am

@@ -49,4 +49,4 @@ INCLUDES = -I$(top_srcdir)/gnu -I../ -I../gnu -I$(top_srcdir)/lib -I../lib
 
 LDADD = ../lib/libtar.a ../gnu/libgnu.a $(LIBINTL) $(LIBICONV)
 
-tar_LDADD = $(LIBS) $(LDADD) $(LIB_CLOCK_GETTIME) $(LIB_EACCESS)
+tar_LDADD = $(LIBS) $(LDADD) $(LIB_CLOCK_GETTIME) $(LIB_EACCESS) $(LIB_SELINUX)

src/create.c

@@ -953,6 +953,8 @@ start_header (struct tar_stat_info *st)
           if (st->acls_d_ptr)
             xheader_store ("SCHILY.acl.default", st, NULL);
         }
+      if ((selinux_context_option > 0) && st->cntx_name)
+        xheader_store ("RHT.security.selinux", st, NULL);
       if (xattrs_option > 0)
         {
           size_t scan_xattr = 0;
@@ -1742,6 +1744,7 @@ dump_file0 (struct tar_stat_info *st, char const *name, char const *p)
       struct stat final_stat;
 
       xattrs_acls_get (parentfd, name, st, 0, !is_dir);
+      xattrs_selinux_get (parentfd, name, st, fd);
       xattrs_xattrs_get (parentfd, name, st, fd);
 
       if (is_dir)
@@ -1862,6 +1865,7 @@ dump_file0 (struct tar_stat_info *st, char const *name, char const *p)
       if (NAME_FIELD_SIZE - (archive_format == OLDGNU_FORMAT) < size)
 	write_long_link (st);
 
+      xattrs_selinux_get (parentfd, name, st, 0);
       xattrs_xattrs_get (parentfd, name, st, 0);
 
       block_ordinal = current_block_ordinal ();
@@ -1885,18 +1889,21 @@ dump_file0 (struct tar_stat_info *st, char const *name, char const *p)
     {
       type = CHRTYPE;
       xattrs_acls_get (parentfd, name, st, 0, true);
+      xattrs_selinux_get (parentfd, name, st, 0);
       xattrs_xattrs_get (parentfd, name, st, 0);
     }
   else if (S_ISBLK (st->stat.st_mode))
     {
       type = BLKTYPE;
       xattrs_acls_get (parentfd, name, st, 0, true);
+      xattrs_selinux_get (parentfd, name, st, 0);
       xattrs_xattrs_get (parentfd, name, st, 0);
     }
   else if (S_ISFIFO (st->stat.st_mode))
     {
       type = FIFOTYPE;
       xattrs_acls_get (parentfd, name, st, 0, true);
+      xattrs_selinux_get (parentfd, name, st, 0);
       xattrs_xattrs_get (parentfd, name, st, 0);
     }
   else if (S_ISSOCK (st->stat.st_mode))

src/extract.c

@@ -100,6 +100,7 @@ struct delayed_set_stat
     int change_dir;
 
     /* extended attributes*/
+    char *cntx_name;
     char *acls_a_ptr;
     size_t acls_a_len;
     char *acls_d_ptr;
@@ -146,6 +147,9 @@ struct delayed_link
        hard-linked together.  */
     struct string_list *sources;
 
+    /* SELinux context */
+    char *cntx_name;
+
     /* ACLs */
     char *acls_a_ptr;
     size_t acls_a_len;
@@ -386,6 +390,7 @@ set_stat (char const *file_name,
      causes that linux capabilities becomes cleared. */
   xattrs_xattrs_set (st, file_name, typeflag, 1);
   xattrs_acls_set (st, file_name, typeflag);
+  xattrs_selinux_set (st, file_name, typeflag);
 }
 
 /* For each entry H in the leading prefix of entries in HEAD that do
@@ -457,6 +462,9 @@ delay_set_stat (char const *file_name, struct tar_stat_info const *st,
   data->atflag = atflag;
   data->after_links = 0;
   data->change_dir = chdir_current;
+  data->cntx_name = NULL;
+  if (st)
+    assign_string (&data->cntx_name, st->cntx_name);
   if (st && st->acls_a_ptr)
     {
       data->acls_a_ptr = xmemdup (st->acls_a_ptr, st->acls_a_len + 1);
@@ -825,6 +833,7 @@ apply_nonancestor_delayed_set_stat (char const *file_name, bool after_links)
 	  sb.stat.st_gid = data->gid;
 	  sb.atime = data->atime;
 	  sb.mtime = data->mtime;
+	  sb.cntx_name = data->cntx_name;
 	  sb.acls_a_ptr = data->acls_a_ptr;
 	  sb.acls_a_len = data->acls_a_len;
 	  sb.acls_d_ptr = data->acls_d_ptr;
@@ -838,6 +847,7 @@ apply_nonancestor_delayed_set_stat (char const *file_name, bool after_links)
 
       delayed_set_stat_head = data->next;
       xheader_xattr_free (data->xattr_map, data->xattr_map_size);
+      free (data->cntx_name);
       free (data->acls_a_ptr);
       free (data->acls_d_ptr);
       free (data);
@@ -1210,6 +1220,8 @@ create_placeholder_file (char *file_name, bool is_symlink, bool *interdir_made)
 			    + strlen (file_name) + 1);
       p->sources->next = 0;
       strcpy (p->sources->string, file_name);
+      p->cntx_name = NULL;
+      assign_string (&p->cntx_name, current_stat_info.cntx_name);
       p->acls_a_ptr = NULL;
       p->acls_a_len = 0;
       p->acls_d_ptr = NULL;
@@ -1650,6 +1662,7 @@ apply_delayed_links (void)
 		  st1.stat.st_gid = ds->gid;
 		  st1.atime = ds->atime;
 		  st1.mtime = ds->mtime;
+                  st1.cntx_name = ds->cntx_name;
                   st1.acls_a_ptr = ds->acls_a_ptr;
                   st1.acls_a_len = ds->acls_a_len;
                   st1.acls_d_ptr = ds->acls_d_ptr;
@@ -1671,6 +1684,7 @@ apply_delayed_links (void)
 	}
 
    xheader_xattr_free (ds->xattr_map, ds->xattr_map_size);
+   free (ds->cntx_name);
 
       {
 	struct delayed_link *next = ds->next;

src/tar.c

@@ -304,6 +304,7 @@ enum
   NO_SAME_OWNER_OPTION,
   NO_SAME_PERMISSIONS_OPTION,
   NO_SEEK_OPTION,
+  NO_SELINUX_CONTEXT_OPTION,
   NO_UNQUOTE_OPTION,
   NO_WILDCARDS_MATCH_SLASH_OPTION,
   NO_WILDCARDS_OPTION,
@@ -329,6 +330,7 @@ enum
   RMT_COMMAND_OPTION,
   RSH_COMMAND_OPTION,
   SAME_OWNER_OPTION,
+  SELINUX_CONTEXT_OPTION,
   SHOW_DEFAULTS_OPTION,
   SHOW_OMITTED_DIRS_OPTION,
   SHOW_TRANSFORMED_NAMES_OPTION,
@@ -549,6 +551,10 @@ static struct argp_option options[] = {
    N_("specify the include pattern for xattr keys"), GRID+1 },
   {"xattrs-exclude", XATTR_EXCLUDE, N_("MASK"), 0,
    N_("specify the exclude pattern for xattr keys"), GRID+1 },
+  {"selinux", SELINUX_CONTEXT_OPTION, 0, 0,
+   N_("Enable the SELinux context support"), GRID+1 },
+  {"no-selinux", NO_SELINUX_CONTEXT_OPTION, 0, 0,
+   N_("Disable the SELinux context support"), GRID+1 },
   {"acls", ACLS_OPTION, 0, 0,
    N_("Enable the POSIX ACLs support"), GRID+1 },
   {"no-acls", NO_ACLS_OPTION, 0, 0,
@@ -2184,6 +2190,15 @@ parse_opt (int key, char *arg, struct argp_state *state)
       acls_option = -1;
       break;
 
+    case SELINUX_CONTEXT_OPTION:
+      set_archive_format ("posix");
+      selinux_context_option = 1;
+      break;
+
+    case NO_SELINUX_CONTEXT_OPTION:
+      selinux_context_option = -1;
+      break;
+
     case XATTR_OPTION:
       set_archive_format ("posix");
       xattrs_option = 1;
@@ -2585,6 +2600,11 @@ decode_options (int argc, char **argv)
       && !READ_LIKE_SUBCOMMAND)
     USAGE_ERROR ((0, 0, _("--acls can be used only on POSIX archives")));
 
+  if ((selinux_context_option > 0)
+      && archive_format != POSIX_FORMAT
+      && !READ_LIKE_SUBCOMMAND)
+    USAGE_ERROR ((0, 0, _("--selinux can be used only on POSIX archives")));
+
   if ((xattrs_option > 0)
       && archive_format != POSIX_FORMAT
       && !READ_LIKE_SUBCOMMAND)
@@ -2849,6 +2869,7 @@ tar_stat_destroy (struct tar_stat_info *st)
   free (st->link_name);
   free (st->uname);
   free (st->gname);
+  free (st->cntx_name);
   free (st->acls_a_ptr);
   free (st->acls_d_ptr);
   free (st->sparse_map);

src/tar.h

@@ -297,6 +297,8 @@ struct tar_stat_info
   char          *uname;     /* user name of owner */
   char          *gname;     /* group name of owner */
 
+  char *cntx_name;          /* SELinux context for the current archive entry. */
+
   char *acls_a_ptr;         /* Access ACLs for the current archive entry. */
   size_t acls_a_len;        /* Access ACLs for the current archive entry. */
 

src/xattrs.c

@@ -28,6 +28,7 @@
 #include "common.h"
 
 #include "xattr-at.h"
+#include "selinux-at.h"
 
 struct xattrs_mask_map
 {
@@ -490,6 +491,64 @@ static void xattrs__fd_set (struct tar_stat_info const *st,
     }
 }
 
+/* lgetfileconat is called against FILE_NAME iff the FD parameter is set to
+   zero, otherwise the fgetfileconat is used against correct file descriptor */
+void xattrs_selinux_get (int parentfd, char const *file_name,
+                         struct tar_stat_info *st,  int fd)
+{
+  if (selinux_context_option > 0)
+    {
+#if HAVE_SELINUX_SELINUX_H != 1
+      static int done = 0;
+      if (!done)
+        WARN ((0, 0, _("SELinux support is not available")));
+      done = 1;
+#else
+      int result = (fd ? fgetfilecon (fd, &st->cntx_name)
+                       : lgetfileconat (parentfd, file_name, &st->cntx_name));
+
+      if (result == -1 && errno != ENODATA && errno != ENOTSUP)
+        call_arg_warn (fd ? "fgetfilecon" : "lgetfileconat", file_name);
+#endif
+    }
+}
+
+void xattrs_selinux_set (struct tar_stat_info const *st,
+                         char const *file_name, char typeflag)
+{
+  if (selinux_context_option > 0)
+    {
+#if HAVE_SELINUX_SELINUX_H != 1
+      static int done = 0;
+      if (!done)
+        WARN ((0, 0, _("SELinux support is not available")));
+      done = 1;
+#else
+      const char *sysname = "setfilecon";
+      int ret;
+
+      if (!st->cntx_name)
+        return;
+
+      if (typeflag != SYMTYPE)
+        {
+          ret = setfileconat (chdir_fd, file_name, st->cntx_name);
+          sysname = "setfileconat";
+        }
+      else
+        {
+          ret = lsetfileconat (chdir_fd, file_name, st->cntx_name);
+          sysname = "lsetfileconat";
+        }
+
+      if (ret == -1)
+        WARNOPT (WARN_XATTR_WRITE, (0, errno,
+            _("%s: Cannot set SELinux context for file '%s'"), sysname,
+            file_name));
+#endif
+    }
+}
+
 static bool xattrs_matches_mask (const char *kw, struct xattrs_mask_map *mm)
 {
   int i;
@@ -589,7 +648,7 @@ void xattrs_print_char (struct tar_stat_info const *st, char *output)
       return;
     }
 
-  if (xattrs_option > 0 || acls_option > 0)
+  if (xattrs_option > 0 ||  selinux_context_option > 0 || acls_option > 0)
     {
       /* placeholders */
       *output = ' ';
@@ -606,6 +665,9 @@ void xattrs_print_char (struct tar_stat_info const *st, char *output)
         break;
       }
 
+  if (selinux_context_option > 0 && st->cntx_name)
+    *output = '.';
+
   if (acls_option && (st->acls_a_len || st->acls_d_len))
     *output = '+';
 }
@@ -615,6 +677,10 @@ void xattrs_print (struct tar_stat_info const *st)
   if (verbose_option < 3)
     return;
 
+  /* selinux */
+  if (selinux_context_option && st->cntx_name)
+    fprintf (stdlis, "  s: %s\n", st->cntx_name);
+
   /* acls */
   if (acls_option && (st->acls_a_len || st->acls_d_len))
     {

src/xheader.c

@@ -469,6 +469,7 @@ void xheader_xattr_init (struct tar_stat_info *st)
   st->acls_a_len = 0;
   st->acls_d_ptr = NULL;
   st->acls_d_len = 0;
+  st->cntx_name = NULL;
 }
 
 void xheader_xattr_free (struct xattr_array *xattr_map, size_t xattr_map_size)
@@ -1554,6 +1555,20 @@ volume_filename_decoder (struct tar_stat_info *st,
   decode_string (&continued_file_name, arg);
 }
 
+static void
+xattr_selinux_coder (struct tar_stat_info const *st, char const *keyword,
+                     struct xheader *xhdr, void const *data)
+{
+  code_string (st->cntx_name, keyword, xhdr);
+}
+
+static void
+xattr_selinux_decoder (struct tar_stat_info *st,
+                       char const *keyword, char const *arg, size_t size)
+{
+  decode_string (&st->cntx_name, arg);
+}
+
 static void
 xattr_acls_a_coder (struct tar_stat_info const *st , char const *keyword,
                     struct xheader *xhdr, void const *data)
@@ -1703,6 +1718,11 @@ struct xhdr_tab const xhdr_tab[] = {
   { "GNU.volume.offset", volume_offset_coder, volume_offset_decoder,
     XHDR_PROTECTED | XHDR_GLOBAL, false },
 
+  /* We get the SELinux value from filecon, so add a namespace for SELinux
+     instead of storing it in SCHILY.xattr.* (which would be RAW). */
+  { "RHT.security.selinux",
+    xattr_selinux_coder, xattr_selinux_decoder, 0, false },
+
   /* ACLs, use the star format... */
   { "SCHILY.acl.access",
     xattr_acls_a_coder, xattr_acls_a_decoder, 0, false },

tests/Makefile.am

@@ -180,6 +180,8 @@ TESTSUITE_AT = \
  xattr04.at\
  acls01.at\
  acls02.at\
+ selnx01.at\
+ selacl01.at\
  capabs_raw01.at
 
 TESTSUITE = $(srcdir)/testsuite

tests/selacl01.at

@@ -0,0 +1,63 @@
+# Process this file with autom4te to create testsuite. -*- Autotest -*-
+#
+# Test suite for GNU tar.
+# Copyright (C) 2011 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, 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/>.
+#
+# Test description:
+#
+# This is basic test for support of extended attributes.
+
+AT_SETUP([acls/selinux: special files & fifos])
+AT_KEYWORDS([xattrs selinux acls selacls01])
+
+AT_TAR_CHECK([
+AT_PRIVILEGED_PREREQ
+AT_XATTRS_UTILS_PREREQ
+AT_SELINUX_PREREQ
+AT_ACLS_PREREQ
+
+mkdir dir
+mkfifo dir/fifo
+MAJOR=$( stat /dev/urandom --printf="%t" )
+MINOR=$( stat /dev/urandom --printf="%T" )
+mknod dir/chartype c $MAJOR $MINOR
+
+# setup attributes
+chcon -h --user=system_u dir/fifo
+chcon -h --user=system_u dir/chartype
+setfacl -m u:$UID:--- dir/fifo
+setfacl -m u:$UID:rwx dir/chartype
+
+getfacl dir/fifo >> before
+getfattr -msecurity.selinux dir/chartype >> before
+
+tar --xattrs --selinux --acls -cf archive.tar dir
+
+mv dir olddir
+
+tar --xattrs --selinux --acls -xf archive.tar
+
+getfacl dir/fifo >> after
+getfattr -msecurity.selinux dir/chartype >> after
+
+diff before after
+echo separator
+],
+[0],
+[separator
+])
+
+AT_CLEANUP

tests/selnx01.at

@@ -0,0 +1,95 @@
+# Process this file with autom4te to create testsuite. -*- Autotest -*-
+#
+# Test suite for GNU tar.
+# Copyright (C) 2012 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, 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/>.
+#
+# Test description:
+#
+# This is basic test for selinux support (store & restore).
+
+AT_SETUP([selinux: basic store/restore])
+AT_KEYWORDS([xattrs selinux selnx01])
+
+AT_TAR_CHECK([
+AT_XATTRS_UTILS_PREREQ
+AT_SELINUX_PREREQ
+
+mkdir dir
+genfile --file dir/file
+ln -s file dir/link
+
+getfattr -h -d -msecurity.selinux dir dir/file dir/link > start
+
+chcon -h --user=system_u     dir
+chcon -h --user=unconfined_u dir/file
+chcon -h --user=system_u     dir/link
+
+# archive whole directory including selinux contexts
+tar --selinux -cf archive.tar dir
+
+# clear the directory
+rm -rf dir
+
+# ================================================
+# check if selinux contexts are correctly restored
+
+tar --selinux -xf archive.tar
+
+# archive for later debugging
+cp archive.tar archive_origin.tar
+
+# check if selinux contexts were restored
+getfattr -h -d dir dir/file dir/link -msecurity.selinux | \
+    grep -v -e '^#' -e ^$ | cut -d: -f1
+
+# ===========================================================================
+# check if selinux contexts are not restored when --selinux option is missing
+
+getfattr -h -d -msecurity.selinux dir dir/file dir/link > with_selinux
+rm -rf dir
+tar -xf archive.tar
+getfattr -h -d -msecurity.selinux dir dir/file dir/link > without_selinux
+
+diff with_selinux without_selinux > diff_with_without
+if test "$?" -eq "0"; then
+    echo "selinux contexts probably restored while --selinux is off"
+fi
+
+# =================================================================
+# check if selinux is not archived when --selinux option is missing
+
+tar -cf archive.tar dir
+
+# clear the directory
+rm -rf dir
+
+# restore (with --selinux)
+tar --selinux -xf archive.tar dir
+
+getfattr -h -d -msecurity.selinux dir dir/file dir/link > final
+diff start final > final_diff
+if test "$?" -ne "0"; then
+    echo "bad result"
+fi
+
+],
+[0],
+[security.selinux="system_u
+security.selinux="unconfined_u
+security.selinux="system_u
+])
+
+AT_CLEANUP

tests/testsuite.at

@@ -130,6 +130,11 @@ m4_define([AT_XATTRS_UTILS_PREREQ],[
   AT_CHECK_UTIL(setfattr -n user.test -v test $file,0)
   AT_CHECK_UTIL(getfattr $file,0)
 ])
+m4_define([AT_SELINUX_UTILS_PREREQ],[
+  file=$( mktemp -p . )
+  AT_CHECK_UTIL(chcon -h --user=unconfined_u $file,0)
+  rm -rf $file
+])
 m4_define([AT_ACLS_UTILS_PREREQ],[
   file=$( mktemp -p . )
   AT_CHECK_UTIL(setfacl -m u:$UID:rwx $file,0)
@@ -152,6 +157,14 @@ m4_define([AT_XATTRS_PREREQ],[
     AT_SKIP_TEST
   fi
 ])
+m4_define([AT_SELINUX_PREREQ],[
+  AT_XATTRS_UTILS_PREREQ
+  file=$( mktemp -p . )
+  err=$( tar --selinux -cf /dev/null $file 2>&1 >/dev/null | wc -l )
+  if test "$err" != "0"; then
+    AT_SKIP_TEST
+  fi
+])
 m4_define([AT_ACLS_PREREQ],[
   AT_XATTRS_UTILS_PREREQ
   file=$( mktemp -p . )
@@ -328,6 +341,9 @@ m4_include([xattr04.at])
 m4_include([acls01.at])
 m4_include([acls02.at])
 
+m4_include([selnx01.at])
+m4_include([selacl01.at])
+
 m4_include([capabs_raw01.at])
 
 m4_include([star/gtarfail.at])