Re: git: b88df1e893c4 - main - Reapply "sbin/ping: allow normal users to specify larger packets"

  Hi Pedro,

let me help to explain you what Maxim is talking about.

ping(8) before your change:

# ping -c 1 -s 65507 10.1.10.1
PING 10.1.10.1 (10.1.10.1): 65507 data bytes
65515 bytes from 10.1.10.1: icmp_seq=0 ttl=64 time=2.078 ms

--- 10.1.10.1 ping statistics ---
1 packets transmitted, 1 packets received, 0.0% packet loss
round-trip min/avg/max/stddev = 2.078/2.078/2.078/0.000 ms

After your change:

# ping -s 65507 10.1.10.1
ping: packet size too large: 65507 > 65467

This is the regression Maxim is pointing you at.

Also, after your patch (running from non-root):
> ping -s 10000 10.1.10.1
PING 10.1.10.1 (10.1.10.1): 10000 data bytes
ping: sendto: Message too long

And this just shows that you didn't even fully achieve what you wanted.

To achieve what you want, you first need to fully revert your patch, and then
apply the attached patch.  It will consistently disable all the size checks
that _our_ ping has, instead of incorrectly and blindly applying a diff from
DragonflyBSD.

HOWEVER, PLEASE DO NOT COMMIT the attached patch! Please revert what you
already committed and start a normal review process on phabricator. You can use
my attached patch as a start.  Please put both the #network group and the
#secteam group.  This is a kind of sensitive change that can't be done by a
drive by commit.

P.S. If you are pinging FreeBSD host, the other side needs to have increased
maxfrag to reply:

# sysctl net.inet.ip.maxfragsperpacket=44

-- 
Gleb Smirnoff