This commit is contained in:
crusader 2018-10-04 14:43:21 +09:00
commit e18767b858
3 changed files with 71 additions and 1 deletions

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#! /bin/bash
#
# Unfortunately, macOS's devfs is based on the old FreeBSD
# one, not the current one, so there's no way to configure it
# to create BPF devices with particular owners or groups. BPF
# devices on macOS are also non-cloning, that is they can
# be created on demand at any time. This startup item will
# pre-create a number of BPF devices, then make them owned by
# the access_bpf group, with permissions rw-rw----, so that
# anybody in the access_bpf group can use programs that capture
# or send raw packets.
#
# Change this as appropriate for your site, e.g. to make
# it owned by a particular user without changing the permissions,
# so only that user and the super-user can capture or send raw
# packets, or give it the permissions rw-r-----, so that
# only the super-user can send raw packets but anybody in the
# admin group can capture packets.
#
# Pre-create BPF devices. Set to 0 to disable.
FORCE_CREATE_BPF_MAX=256
SYSCTL_MAX=$( sysctl -n debug.bpf_maxdevices )
if [ "$FORCE_CREATE_BPF_MAX" -gt "$SYSCTL_MAX" ] ; then
FORCE_CREATE_BPF_MAX=$SYSCTL_MAX
fi
syslog -s -l notice "ChmodBPF: Forcing creation and setting permissions for /dev/bpf*"
CUR_DEV=0
while [ "$CUR_DEV" -lt "$FORCE_CREATE_BPF_MAX" ] ; do
# Try to do the minimum necessary to trigger the next device.
read -n 0 < /dev/bpf$CUR_DEV > /dev/null 2>&1
CUR_DEV=$(( $CUR_DEV + 1 ))
done
chgrp access_bpf /dev/bpf*
chmod g+rw /dev/bpf*

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<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple Computer//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
<key>Label</key>
<string>com.loafle.overflow.scanner.ChmodBPF</string>
<key>RunAtLoad</key>
<true/>
<key>Program</key>
<string>/Library/Application Support/overFlow-NetworkScanner/ChmodBPF/ChmodBPF</string>
</dict>
</plist>

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#!/bin/sh
exit 0
CHMOD_BPF="/Library/LaunchDaemons/com.loafle.overflow.scanner.ChmodBPF.plist"
BPF_GROUP="access_bpf"
BPF_GROUP_NAME="BPF device access ACL"
dscl . -read /Groups/"$BPF_GROUP" > /dev/null 2>&1 || \
dseditgroup -q -o create "$BPF_GROUP"
dseditgroup -q -o edit -a "$USER" -t user "$BPF_GROUP"
cp "/Library/Application Support/overFlow-NetworkScanner/ChmodBPF/com.loafle.overflow.scanner.ChmodBPF.plist" \
"$CHMOD_BPF"
chmod 755 "$CHMOD_BPF"
chown root:wheel "$CHMOD_BPF"
rm -rf /Library/StartupItems/ChmodBPF
launchctl load "$CHMOD_BPF"
exit 0