1VERITYTAB(5)                       veritytab                      VERITYTAB(5)
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NAME

6       veritytab - Configuration for verity block devices
7

SYNOPSIS

9       /etc/veritytab
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DESCRIPTION

12       The /etc/veritytab file describes verity protected block devices that
13       are set up during system boot.
14
15       Empty lines and lines starting with the "#" character are ignored. Each
16       of the remaining lines describes one verity protected block device.
17       Fields are delimited by white space.
18
19       Each line is in the form
20
21           volume-name data-device hash-device roothash options
22
23       The first four fields are mandatory, the remaining one is optional.
24
25       The first field contains the name of the resulting verity volume; its
26       block device is set up below /dev/mapper/.
27
28       The second field contains a path to the underlying block data device,
29       or a specification of a block device via "UUID=" followed by the UUID.
30
31       The third field contains a path to the underlying block hash device, or
32       a specification of a block device via "UUID=" followed by the UUID.
33
34       The fourth field is the "roothash" in hexadecimal.
35
36       The fifth field, if present, is a comma-delimited list of options. The
37       following options are recognized:
38
39       ignore-corruption, restart-on-corruption, panic-on-corruption
40           Defines what to do if a data verity problem is detected (data
41           corruption). Without these options kernel fails the IO operation
42           with I/O error. With "--ignore-corruption" option the corruption is
43           only logged. With "--restart-on-corruption" or
44           "--panic-on-corruption" the kernel is restarted (panicked)
45           immediately. (You have to provide way how to avoid restart loops.)
46
47       ignore-zero-blocks
48           Instruct kernel to not verify blocks that are expected to contain
49           zeroes and always directly return zeroes instead. WARNING: Use this
50           option only in very specific cases. This option is available since
51           Linux kernel version 4.5.
52
53       check-at-most-once
54           Instruct kernel to verify blocks only the first time they are read
55           from the data device, rather than every time. WARNING: It provides
56           a reduced level of security because only offline tampering of the
57           data device's content will be detected, not online tampering. This
58           option is available since Linux kernel version 4.17.
59
60       root-hash-signature=PATH|base64:HEX
61           A base64 string encoding the root hash signature prefixed by
62           "base64:" or a path to roothash signature file used to verify the
63           root hash (in kernel). This feature requires Linux kernel version
64           5.4 or more recent.
65
66       _netdev
67           Marks this veritysetup device as requiring network. It will be
68           started after the network is available, similarly to
69           systemd.mount(5) units marked with _netdev. The service unit to set
70           up this device will be ordered between remote-fs-pre.target and
71           remote-veritysetup.target, instead of veritysetup-pre.target and
72           veritysetup.target.
73
74           Hint: if this device is used for a mount point that is specified in
75           fstab(5), the _netdev option should also be used for the mount
76           point. Otherwise, a dependency loop might be created where the
77           mount point will be pulled in by local-fs.target, while the service
78           to configure the network is usually only started after the local
79           file system has been mounted.
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81       noauto
82           This device will not be added to veritysetup.target. This means
83           that it will not be automatically enabled on boot, unless something
84           else pulls it in. In particular, if the device is used for a mount
85           point, it'll be enabled automatically during boot, unless the mount
86           point itself is also disabled with noauto.
87
88       nofail
89           This device will not be a hard dependency of veritysetup.target.
90           It'll still be pulled in and started, but the system will not wait
91           for the device to show up and be enabled, and boot will not fail if
92           this is unsuccessful. Note that other units that depend on the
93           enabled device may still fail. In particular, if the device is used
94           for a mount point, the mount point itself also needs to have the
95           nofail option, or the boot will fail if the device is not enabled
96           successfully.
97
98       x-initrd.attach
99           Setup this verity protected block device in the initramfs,
100           similarly to systemd.mount(5) units marked with x-initrd.mount.
101
102           Although it's not necessary to mark the mount entry for the root
103           file system with x-initrd.mount, x-initrd.attach is still
104           recommended with the verity protected block device containing the
105           root file system as otherwise systemd will attempt to detach the
106           device during the regular system shutdown while it's still in use.
107           With this option the device will still be detached but later after
108           the root file system is unmounted.
109
110           All other verity protected block devices that contain file systems
111           mounted in the initramfs should use this option.
112
113       At early boot and when the system manager configuration is reloaded,
114       this file is translated into native systemd units by systemd-
115       veritysetup-generator(8).
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EXAMPLES

118       Example 1. /etc/veritytab example
119
120       Set up two verity protected block devices. One using device blocks,
121       another using files.
122
123           usr  PARTUUID=783e45ae-7aa3-484a-beef-a80ff9c19cbb PARTUUID=21dc1dfe-4c33-8b48-98a9-918a22eb3e37 36e3f740ad502e2c25e2a23d9c7c17bf0fdad2300b7580842d4b7ec1fb0fa263 auto
124           data /etc/data /etc/hash a5ee4b42f70ae1f46a08a7c92c2e0a20672ad2f514792730f5d49d7606ab8fdf auto
125

SEE ALSO

127       systemd(1), systemd-veritysetup@.service(8), systemd-veritysetup-
128       generator(8), fstab(5), veritysetup(8),
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132systemd 251                                                       VERITYTAB(5)
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