Make the PHMAC integrity algorithm know to libcryptsetup.
The size of a key for PHMAC is not known, because PHMAC gets an opaque
blob as key, who's physical size has nothing to do with the cryptographic
size. Thus, let INTEGRITY_key_size() and crypt_parse_integrity_mode()
return the required_key_size as key size for PHMAC, or -EINVAL if
required_key_size is zero, to indicate that the size is unknown.
Signed-off-by: Ingo Franzki <ifranzki@linux.ibm.com>
NOTE: This is possibly an incompatible change as it changes text output.
Since the support of --sector-size option, the description "sectors"
became ambiguous as it usually means 512-byte sectors (device-mapper unit).
Major confusion occurs when the sector size is 4096 bytes while units display
is in 512-bytes.
Unfortunately, there is no clear compatible way, so this patch adds
[512-byte units] marker and also additional byte size value.
All other fields that display units are changed to use the "[units]" format.
The integrity format is also unified with the common style with ':' as a separator.
Fixes: #884.
For now, we used zeroed key for dm-integrity format, as there was not
data area. In future, there can be wrapped key scheme, that will require
to setup real key even in this situation.
This patch modifies the integrity format flow that the real key is used
during format.
Mostly based on code from Ingo Franzki <ifranzki@linux.ibm.com>
This patch add support for setting of integrity key size
for LUKS2 devices.
It adds new (optional) JSON "key_size" attribute in segment.integrity JSON object.
If not set, the code use hash length size (backward compatible).
For LUKS2, we do not allow smaller keys than 128 bits.
Mostly based on code from Ingo Franzki <ifranzki@linux.ibm.com>
This patch switches code to SPDX one-line license identifiers according to
https://spdx.dev/learn/handling-license-info/
and replacing long license text headers.
I used C++ format on the first line in style
// SPDX-License-Identifier: <id>
except exported libcryptsetup.h, when only C comments are used.
The only additional changes are:
- switch backend utf8.c from LGPL2+ to LGPL2.1+ (as in systemd)
- add some additional formatting lines.
This enables creating dm-integrity devices that
does not use all available space but only initial
part of the device.
This will be used with future hw-opal-crypt segment
where partion may be not aligned to locking range
alignment and needs to be reduced.
We dont't want to span dm-integrity device into
area not included in opal locking range.
Ths will allow automatic scan of known formats.
Errors are printed only if something is wrong with already detected metadata.
This change means that it is responsibility of the caller to print an error
message if needed.
Also fix some places without a message.
Fixes: #642
If cryptsetup/integritysetup tool is too old, it can happen that
kernel dm-integrity uses more recent version of dm-integrity metadata.
Print (and also traslate) better error in this case.
Fixes: #667
While the metadata device is detached header here, integrity
superblock is located on the data device.
For standalone integrity device it is diffferent
- data device contains only data and possible metadata device
contains integrity superblock and tag areas.
Fix it by checking metadata format.
Fixes: #609,#730
Fast xxhash64 algoritm can be used for integrity protection.
Add implicit tag size (so user do not need to use --tag-size),
mention it in man page and add a test.
Fixes: #632
If the provided key is NULL, we load it from the active device. This is
always available, since keyring keys are not supported in kernel for
integrity devices.
Attribute unused is useless and makes code imcomprehensible
when decorates internal functions not exposed via API.
Let's cleanup internal funtion prototypes whenever possible.
This patch adds support for Linux kernel (since version 5.11) dm-integrity
fixes that disables integrity recalculation if keyed algorithms (HMAC) is used.
Original dm-integrity superblock version <=4 is recalculation offset
field not protected by HMAC. An attacker can move this pointer and force
the kernel to recalculate the data area, ignoring original HMAC tags.
N.B. dm-integrity was not intended to protect against intentional changes.
Better use authenticated encryption (AEAD) in combination with dm-crypt.
It is designed to protect against random data corruption caused by hardware
or storage medium faults.
Despite that, we try to keep the system secure if keyed algorithms are used.
There are two possible keyed algorithms in dm-integrity - algorithm used
to protect journal and superblock (--journal-integrity) and algorithms
for protecting data (--integrity).
The dm-integrity superblock is guarded by --journal-integrity, so if you want
to protect data with HMAC, you should always also use HMAC for --journal-integrity.
The keys are independent. If HMAC is used for data but not for the journal,
recalculation is disabled by default.
For new kernel dm-integrity, the HMAC option also uses salt in superblock
to avoid an easy way to distinguish that the HMAC key is the same for two devices
(if data are the same).
The new HMAC and superblock are enabled automatically if the kernel supports it
(you can see superblock version 5 and fix_hmac flag in dump command).
If you need to use (insecure) backward compatibility, then two new integritysetup
options are introduced:
Use --integrity-legacy-recalc (instead of --integrity-recalc) to allow recalculation
on legacy devices.
Use --integrity-legacy-hmac in format action to force old insecure version
format (with HMAC).
Libcryptsetup API also introduces flags
CRYPT_COMPAT_LEGACY_INTEGRITY_HMAC and
CRYPT_COMPAT_LEGACY_INTEGRITY_RECALC
to set these through crypt_set_compatibility() call.
Some kernels show invalid dm-integrity table if suberblock
contains "recalculate" bit.
We can workaround that by setting recalculate option in table
(kernel uses bits from superblock anyway), so the table displayed
is always correct.
Fixes: #538
When integritysetup formats a device with hash or HMAC integrity checksums,
it requires explicitly tag size entry from a user (or default value).
This leads to confusion and shortened tags.
This patch calculates tag size according to real hash output, and
if tag size is specified, it warns if these values differ.
Fixes: #492.
The dump operation prints the fix_padding flag if set.
Also try to print warning if an old kernel is used and th edevice
cannot be activated because of missing fix padding support.
This patch adds support for fixed padding to cryptsetup.
* Cryptsetup will accept superblocks version 4.
* If the dm-integrity target version is greater than 1.4, cryptsetup will
add a flag "fix_padding" to the dm-integrity target arguments.
There is still one quirk: if we have an old libdm without
DM_DEVICE_GET_TARGET_VERSION and if dm-integrity module is not loaded,
cryptsetup will not detect that it can use the "fix_padding" option.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Support for multi-segment devices is requirement for online
reencryption to work. Introducing modififed dm backend that
splits data structures describing active device and individual
dm target (or segment).
Since the kernel 4.18 there is a possibility to speficy external
data device for dm-integrity that stores all integrity tags.
The new option --data-device in integritysetup uses this feature.
