dd5ae4c36c
When dbus client connects to systemd-bus-proxyd through
Unix domain socket proxy takes client's smack label and sets for itself.
It is done before and independent of dropping privileges.
The reason of such soluton is fact that tests of access rights
performed by lsm may take place inside kernel, not only
in userspace of recipient of message.
The bus-proxyd needs CAP_MAC_ADMIN to manipulate its label.
In case of systemd running in system mode, CAP_MAC_ADMIN
should be added to CapabilityBoundingSet in service file of bus-proxyd.
In case of systemd running in user mode ('systemd --user')
it can be achieved by addition
Capabilities=cap_mac_admin=i and SecureBits=keep-caps
to user@.service file
and setting cap_mac_admin+ei on bus-proxyd binary.
23 lines
903 B
Plaintext
23 lines
903 B
Plaintext
# This file is part of systemd.
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#
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# systemd is free software; you can redistribute it and/or modify it
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# under the terms of the GNU Lesser General Public License as published by
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# the Free Software Foundation; either version 2.1 of the License, or
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# (at your option) any later version.
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[Unit]
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Description=Legacy D-Bus Protocol Compatibility Daemon
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[Service]
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# The first argument will be replaced by the service by information on
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# the process requesting the proxy, we need a placeholder to keep the
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# space available for this.
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ExecStart=@rootlibexecdir@/systemd-bus-proxyd --drop-privileges --address=kernel:path=/sys/fs/kdbus/0-system/bus xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
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NotifyAccess=main
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CapabilityBoundingSet=CAP_IPC_OWNER CAP_SETUID CAP_SETGID CAP_SETPCAP m4_ifdef(`HAVE_SMACK', CAP_MAC_ADMIN )
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PrivateTmp=yes
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PrivateDevices=yes
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PrivateNetwork=yes
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ProtectSystem=full
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ProtectHome=yes
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