Re: [PATCH] ls - colorize files with capabilities

[Jim Meyering]

Kamil Dudka <address@hidden> wrote:
> On Friday 25 July 2008 12:40:25 you wrote:
>> On what type of system did the new test succeed for you?
>> On rawhide, capget appears to malfunction:
>>
>>   # rm t;>t;strace -e capget setcap cap_net_bind_service=ep t 2>&1|cut
>> -c-78 capget(0x20071026, 0, NULL)             = -1 EFAULT (Bad address)
>> capget(0x20071026, 0,
>> {CAP_CHOWN|CAP_DAC_OVERRIDE|CAP_DAC_READ_SEARCH|CAP_FOWN capget(0x20071026,
>> 0, NULL)             = -1 EFAULT (Bad address) Failed to set capabilities
>> on file `t' (Operation not permitted) usage: setcap [-q] (-r|-|<caps>)
>> <filename> [ ... (-r|-|<capsN>) <filenameN> ]
>>
>>    Note <filename> must be a regular (non-symlink) file.
>>
>> Considering the test doesn't pass anywhere I've tried, I'm in
>> no hurry to apply it.
> I have not my own rawhide testing machine, but it is disabled even on F-9. It
> helped to me allow it manually (using audit2allow):
> # echo "module local 1.0;
>   require {
>         type unconfined_t;
>         class capability setfcap;
>   }
>   allow unconfined_t self:capability setfcap;
>   " > local.te
> # checkmodule -M -m -o local.mod local.te
> # semodule_package -o local.pp -m local.mod
> # semodule -i local.pp

Thanks for the additional details.
With that, the test did pass for me.

> This is easy way to enable setting of file capabilities on SELinux, but it is
> still disabled by default. So I think the best solution is to skip the test
> if setcap fails (as it was in my 1st version of test), because this is not
> failure of ls.

I agree, and have made the corresponding change.

Here's what I've just pushed:

>From 84f6abfe00b4ab533145623638b417a2221f9c75 Mon Sep 17 00:00:00 2001
From: Kamil Dudka <address@hidden>
Date: Fri, 1 Aug 2008 19:33:45 +0200
Subject: [PATCH] ls: --color now highlights files with capabilities, too

* src/ls.c: [HAVE_CAP] Include <sys/capability.h>.
(has_capability): New function for capability detection.
(print_color_indicator): Colorize file with capability.
* m4/jm-macro.m4: New configure option: --disable-libcap.
Check for libcap usability.
* src/Makefile.am (dir_LDADD, ls_LDADD, ...): Append $(LIB_CAP).
* src/dircolors.c: Update color lists.
* src/dircolors.hin: Mention new CAPABILITY color attribute.
* tests/ls/capability: Test for ls - colorize file with capability.
* tests/Makefile.am (root_tests): Add ls/capability.
* NEWS: Mention the change.
---
 NEWS                |    2 ++
 m4/jm-macros.m4     |   13 +++++++++++++
 src/Makefile.am     |    6 +++---
 src/dircolors.c     |    4 ++--
 src/dircolors.hin   |    1 +
 src/ls.c            |   42 ++++++++++++++++++++++++++++++++++++++++--
 tests/Makefile.am   |    1 +
 tests/ls/capability |   43 +++++++++++++++++++++++++++++++++++++++++++
 8 files changed, 105 insertions(+), 7 deletions(-)
 create mode 100755 tests/ls/capability

diff --git a/NEWS b/NEWS
index bcbabb1..dfe893c 100644
--- a/NEWS
+++ b/NEWS
@@ -34,6 +34,8 @@ GNU coreutils NEWS                                    -*- 
outline -*-
   represents the maximum number of inputs that will be merged at once.
   When processing more than NMERGE inputs, sort uses temporary files.

+  ls now colorizes files with capabilities if libcap is available
+
 ** Bug fixes

   chcon --verbose now prints a newline after each message
diff --git a/m4/jm-macros.m4 b/m4/jm-macros.m4
index 062737b..a691d95 100644
--- a/m4/jm-macros.m4
+++ b/m4/jm-macros.m4
@@ -82,6 +82,19 @@ AC_DEFUN([coreutils_MACROS],
     AC_CHECK_FUNCS(fdatasync)
   LIBS=$coreutils_saved_libs

+  # Check whether libcap is usable -- for ls --color support
+  AC_ARG_ENABLE([libcap],
+    AC_HELP_STRING([--disable-libcap], [disable libcap support]),
+    AC_MSG_WARN([libcap support disabled by user]),
+    [AC_CHECK_LIB([cap], [cap_get_file],
+      [AC_CHECK_HEADER([sys/capability.h],
+        [LIB_CAP=-lcap AC_DEFINE([HAVE_CAP], 1, [libcap usability])],
+        [AC_MSG_WARN([header sys/capability.h was not found, support for 
libcap will not be built])]
+      )],
+      [AC_MSG_WARN([libcap library was not found or not usable, support for 
libcap will not be built])])
+    ])
+  AC_SUBST([LIB_CAP])
+
   # See if linking `seq' requires -lm.
   # It does on nearly every system.  The single exception (so far) is
   # BeOS which has all the math functions in the normal runtime library
diff --git a/src/Makefile.am b/src/Makefile.am
index f464a70..7410653 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -101,15 +101,15 @@ __LDADD = $(LDADD) $(LIB_EACCESS)

 # for clock_gettime and fdatasync
 dd_LDADD = $(LDADD) $(LIB_GETHRXTIME) $(LIB_FDATASYNC)
-dir_LDADD = $(LDADD) $(LIB_CLOCK_GETTIME) $(LIB_SELINUX)
+dir_LDADD = $(LDADD) $(LIB_CLOCK_GETTIME) $(LIB_SELINUX) $(LIB_CAP)
 id_LDADD = $(LDADD) $(LIB_SELINUX)
-ls_LDADD = $(LDADD) $(LIB_CLOCK_GETTIME) $(LIB_SELINUX)
+ls_LDADD = $(LDADD) $(LIB_CLOCK_GETTIME) $(LIB_SELINUX) $(LIB_CAP)
 mktemp_LDADD = $(LDADD) $(LIB_GETHRXTIME)
 pr_LDADD = $(LDADD) $(LIB_CLOCK_GETTIME)
 shred_LDADD = $(LDADD) $(LIB_GETHRXTIME) $(LIB_FDATASYNC)
 shuf_LDADD = $(LDADD) $(LIB_GETHRXTIME)
 tac_LDADD = $(LDADD) $(LIB_CLOCK_GETTIME)
-vdir_LDADD = $(LDADD) $(LIB_CLOCK_GETTIME) $(LIB_SELINUX)
+vdir_LDADD = $(LDADD) $(LIB_CLOCK_GETTIME) $(LIB_SELINUX) $(LIB_CAP)

 ## If necessary, add -lm to resolve use of pow in lib/strtod.c.
 sort_LDADD = $(LDADD) $(POW_LIB) $(LIB_GETHRXTIME)
diff --git a/src/dircolors.c b/src/dircolors.c
index 56194f7..79109b9 100644
--- a/src/dircolors.c
+++ b/src/dircolors.c
@@ -63,14 +63,14 @@ static const char *const slack_codes[] =
   "SYMLINK", "ORPHAN", "MISSING", "FIFO", "PIPE", "SOCK", "BLK", "BLOCK",
   "CHR", "CHAR", "DOOR", "EXEC", "LEFT", "LEFTCODE", "RIGHT", "RIGHTCODE",
   "END", "ENDCODE", "SUID", "SETUID", "SGID", "SETGID", "STICKY",
-  "OTHER_WRITABLE", "OWR", "STICKY_OTHER_WRITABLE", "OWT", NULL
+  "OTHER_WRITABLE", "OWR", "STICKY_OTHER_WRITABLE", "OWT", "CAPABILITY", NULL
 };

 static const char *const ls_codes[] =
 {
   "no", "no", "fi", "rs", "di", "ln", "ln", "ln", "or", "mi", "pi", "pi",
   "so", "bd", "bd", "cd", "cd", "do", "ex", "lc", "lc", "rc", "rc", "ec", "ec",
-  "su", "su", "sg", "sg", "st", "ow", "ow", "tw", "tw", NULL
+  "su", "su", "sg", "sg", "st", "ow", "ow", "tw", "tw", "ca", NULL
 };
 #define array_len(Array) (sizeof (Array) / sizeof *(Array))
 verify (array_len (slack_codes) == array_len (ls_codes));
diff --git a/src/dircolors.hin b/src/dircolors.hin
index 38914c8..5137cc6 100644
--- a/src/dircolors.hin
+++ b/src/dircolors.hin
@@ -77,6 +77,7 @@ CHR 40;33;01  # character device driver
 ORPHAN 40;31;01 # symlink to nonexistent file, or non-stat'able file
 SETUID 37;41   # file that is setuid (u+s)
 SETGID 30;43   # file that is setgid (g+s)
+CAPABILITY 30;41       # file with capability
 STICKY_OTHER_WRITABLE 30;42 # dir that is sticky and other-writable (+t,o+w)
 OTHER_WRITABLE 34;42 # dir that is other-writable (o+w) and not sticky
 STICKY 37;44   # dir with the sticky bit set (+t) and not other-writable
diff --git a/src/ls.c b/src/ls.c
index a661c06..fd32730 100644
--- a/src/ls.c
+++ b/src/ls.c
@@ -38,6 +38,10 @@
 #include <config.h>
 #include <sys/types.h>

+#ifdef HAVE_CAP
+# include <sys/capability.h>
+#endif
+
 #if HAVE_TERMIOS_H
 # include <termios.h>
 #endif
@@ -513,14 +517,14 @@ enum indicator_no
     C_LEFT, C_RIGHT, C_END, C_RESET, C_NORM, C_FILE, C_DIR, C_LINK,
     C_FIFO, C_SOCK,
     C_BLK, C_CHR, C_MISSING, C_ORPHAN, C_EXEC, C_DOOR, C_SETUID, C_SETGID,
-    C_STICKY, C_OTHER_WRITABLE, C_STICKY_OTHER_WRITABLE
+    C_STICKY, C_OTHER_WRITABLE, C_STICKY_OTHER_WRITABLE, C_CAP
   };

 static const char *const indicator_name[]=
   {
     "lc", "rc", "ec", "rs", "no", "fi", "di", "ln", "pi", "so",
     "bd", "cd", "mi", "or", "ex", "do", "su", "sg", "st",
-    "ow", "tw", NULL
+    "ow", "tw", "ca", NULL
   };

 struct color_ext_type
@@ -553,6 +557,7 @@ static struct bin_str color_indicator[] =
     { LEN_STR_PAIR ("37;44") },                /* st: sticky: black on blue */
     { LEN_STR_PAIR ("34;42") },                /* ow: other-writable: blue on 
green */
     { LEN_STR_PAIR ("30;42") },                /* tw: ow w/ sticky: black on 
green */
+    { LEN_STR_PAIR ("30;41") },                /* capability: black on red */
   };

 /* FIXME: comment  */
@@ -3910,6 +3915,37 @@ print_type_indicator (bool stat_ok, mode_t mode, enum 
filetype type)
     DIRED_PUTCHAR (c);
 }

+#ifdef HAVE_CAP
+/* Return true if NAME has a capability (see linux/capability.h) */
+static bool
+has_capability (char const *name)
+{
+  char *result;
+  bool has_cap;
+
+  cap_t cap_d = cap_get_file (name);
+  if (cap_d == NULL)
+    return false;
+
+  result = cap_to_text (cap_d, NULL);
+  cap_free (cap_d);
+  if (!result)
+    return false;
+
+  /* check if human-readable capability string is empty */
+  has_cap = !!*result;
+
+  cap_free (result);
+  return has_cap;
+}
+#else
+static bool
+has_capability (char const *name)
+{
+  return false;
+}
+#endif
+
 /* Returns whether any color sequence was printed. */
 static bool
 print_color_indicator (const char *name, mode_t mode, int linkok,
@@ -3937,6 +3973,8 @@ print_color_indicator (const char *name, mode_t mode, int 
linkok,
            type = C_SETUID;
          else if ((mode & S_ISGID) != 0)
            type = C_SETGID;
+         else if (has_capability (name))
+           type = C_CAP;
          else if ((mode & S_IXUGO) != 0)
            type = C_EXEC;
        }
diff --git a/tests/Makefile.am b/tests/Makefile.am
index c2da630..7bdf88a 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -25,6 +25,7 @@ root_tests =                                  \
   cp/cp-a-selinux                              \
   cp/preserve-gid                              \
   cp/special-bits                              \
+  ls/capability                                        \
   ls/nameless-uid                              \
   misc/chcon                                   \
   misc/selinux                                 \
diff --git a/tests/ls/capability b/tests/ls/capability
new file mode 100755
index 0000000..fcd3c2a
--- /dev/null
+++ b/tests/ls/capability
@@ -0,0 +1,43 @@
+#!/bin/sh
+# Ensure "ls --color" properly colorizes file with capability.
+
+# 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
+
+. $srcdir/test-lib.sh
+require_root_
+
+(setcap --help) 2>&1 |grep 'usage: setcap' > /dev/null \
+  || skip_test_ "setcap utility not found"
+fail=0
+
+# Don't let a different umask perturb the results.
+umask 22
+
+touch test
+setcap cap_net_bind_service=ep test \
+  || skip_test_ "setcap doesn't work"
+code='30;41'
+LS_COLORS="ca=$code" \
+  ls --color=always test > out || fail=1
+printf "\033[0m\033[${code}mtest\033[0m\n\033[m" > out_ok || fail=1
+compare out out_ok || fail=1
+
+(exit $fail); exit $fail
--
1.6.0.rc1.36.g5ff70