ping socket: Permission denied

I am root.
ping 127.0.0.1 and return error;

root@sam-PC:~# ping 127.0.0.1
socket: Permission denied
root@sam-PC:~# ifconfig
eth0 Link encap:Ethernet HWaddr 00:00:ff:ff:00:00 inet addr:192.168.100.104 Bcast:192.168.100.255 Mask:255.255.255.0 inet6 addr: fe80::200:ffff:feff:0/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:36 errors:0 dropped:0 overruns:0 frame:0 TX packets:7 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:2220 (2.2 KB) TX bytes:524 (524.0 B)
lo Link encap:Local Loopback inet addr:127.0.0.1 Mask:255.0.0.0 inet6 addr: ::1/128 Scope:Host UP LOOPBACK RUNNING MTU:16436 Metric:1 RX packets:40 errors:0 dropped:0 overruns:0 frame:0 TX packets:40 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:3160 (3.1 KB) TX bytes:3160 (3.1 KB)
root@sam-PC:~# ping 192.168.100.100
socket: Permission denied

who knows why?

4

3 Answers

For this problem, we should add the following lines to /etc/group:

inet:x:3003:root
net_raw:x:3004:root

1

The underlying ping is using sock_raw. To create such a socket, you must have root privileges.

int main(void) { rawsock = socket(AF_INET, SOCK_RAW, protocol->p_proto); if(rawsock < 0){ perror("socket"); return -1; }
}

If the owner of the ping is not root, the error will not be fixed. Using the linux capability mechanism can't solve the problem.

1

The OP is executing ping as root, so this isn't an answer to them, more an extended comment on the answer from @leesagacious. In my situation, on CentOS Stream 8, so doubly inappropriate for askubuntu... unless it happens there too, the Linux capability mechanism does appear to the the answer, kudos :

[manager@smu-centos8-daily-test ~]$ ping -c 1 8.8.8.8
ping: socket: Operation not permitted
[manager@smu-centos8-daily-test ~]$ getcap /usr/bin/ping
[manager@smu-centos8-daily-test ~]$ sudo setcap cap_net_raw+p /usr/bin/ping
[manager@smu-centos8-daily-test ~]$ ping -c 1 8.8.8.8
PING 8.8.8.8 (8.8.8.8) 56(84) bytes of data.
64 bytes from 8.8.8.8: icmp_seq=1 ttl=117 time=4.57 ms
--- 8.8.8.8 ping statistics ---
1 packets transmitted, 1 received, 0% packet loss, time 0ms
rtt min/avg/max/mdev = 4.567/4.567/4.567/0.000 ms
[manager@smu-centos8-daily-test ~]$ getcap /usr/bin/ping
/usr/bin/ping = cap_net_raw+p
[manager@smu-centos8-daily-test ~]$ sudo setcap -r /usr/bin/ping
[manager@smu-centos8-daily-test ~]$ getcap /usr/bin/ping
[manager@smu-centos8-daily-test ~]$ ping -c 1 8.8.8.8
ping: socket: Operation not permitted
[manager@smu-centos8-daily-test ~]$ 

I don't think that the owner of ping, as opposed to the uid of the process executing ping, would be relevant, except back in the days when ping was setuid.

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