| Apache/2.4.7 (Ubuntu) Linux sman1baleendah 3.13.0-24-generic #46-Ubuntu SMP Thu Apr 10 19:11:08 UTC 2014 x86_64 uid=33(www-data) gid=33(www-data) groups=33(www-data) safemode : OFF MySQL: ON | Perl: ON | cURL: OFF | WGet: ON > / usr / share / doc / libcap2-bin / | server ip : 104.21.89.46 your ip : 172.69.17.86 H O M E |
| Filename | /usr/share/doc/libcap2-bin/README.Debian |
| Size | 1.12 kb |
| Permission | rw-r--r-- |
| Owner | root : root |
| Create time | 27-Apr-2025 09:50 |
| Last modified | 21-Feb-2014 07:30 |
| Last accessed | 06-Jul-2025 16:33 |
| Actions | edit | rename | delete | download (gzip) |
| View | text | code | image |
Please check http://www.friedhoff.org/posixfilecaps.html to get more
information on POSIX File Capabilities.
Example: how to remove the SUID root bit from /bin/ping?
--------------------------------------------------------
Make sure you have kernel 2.6.24 or newer you have
CONFIG_SECURITY_CAPABILITIES and CONFIG_SECURITY_FILE_CAPABILITIES
enabled. The Debian kernels are fine.
$ ls -l /bin/ping
-rwsr-xr-x 1 root root 30736 2007-01-31 00:10 /bin/ping
^
That is not good.
$ sudo chmod 755 /bin/ping
Or use dpkg-statoverride.
$ ls -l /bin/ping
-rwxr-xr-x 1 root root 30736 2007-01-31 00:10 /bin/ping
That is better but ping fails.
$ ping -c1 localhost
ping: icmp open socket: Operation not permitted
Now set the missing capability:
$ sudo setcap cap_net_raw+ep /bin/ping
... and ping will work again.
$ ping -c1 localhost
PING localhost (127.0.0.1) 56(84) bytes of data.
64 bytes from localhost (127.0.0.1): icmp_seq=1 ttl=64 time=0.026 ms
--- localhost ping statistics ---
1 packets transmitted, 1 received, 0% packet loss, time 0ms
rtt min/avg/max/mdev = 0.026/0.026/0.026/0.000 ms
Torsten Werner
information on POSIX File Capabilities.
Example: how to remove the SUID root bit from /bin/ping?
--------------------------------------------------------
Make sure you have kernel 2.6.24 or newer you have
CONFIG_SECURITY_CAPABILITIES and CONFIG_SECURITY_FILE_CAPABILITIES
enabled. The Debian kernels are fine.
$ ls -l /bin/ping
-rwsr-xr-x 1 root root 30736 2007-01-31 00:10 /bin/ping
^
That is not good.
$ sudo chmod 755 /bin/ping
Or use dpkg-statoverride.
$ ls -l /bin/ping
-rwxr-xr-x 1 root root 30736 2007-01-31 00:10 /bin/ping
That is better but ping fails.
$ ping -c1 localhost
ping: icmp open socket: Operation not permitted
Now set the missing capability:
$ sudo setcap cap_net_raw+ep /bin/ping
... and ping will work again.
$ ping -c1 localhost
PING localhost (127.0.0.1) 56(84) bytes of data.
64 bytes from localhost (127.0.0.1): icmp_seq=1 ttl=64 time=0.026 ms
--- localhost ping statistics ---
1 packets transmitted, 1 received, 0% packet loss, time 0ms
rtt min/avg/max/mdev = 0.026/0.026/0.026/0.000 ms
Torsten Werner