diff -rupN cryptsetup-2.3.7.old/man/cryptsetup.8 cryptsetup-2.3.7/man/cryptsetup.8

--- cryptsetup-2.3.7.old/man/cryptsetup.8	2022-02-24 15:58:37.968167423 +0100

+++ cryptsetup-2.3.7/man/cryptsetup.8	2022-02-24 17:06:25.326217548 +0100

@@ -321,7 +321,7 @@ the command prompts for it interactively

 \-\-keyfile\-size, \-\-readonly, \-\-test\-passphrase,

 \-\-allow\-discards, \-\-header, \-\-key-slot, \-\-master\-key\-file, \-\-token\-id,

 \-\-token\-only, \-\-disable\-keyring, \-\-disable\-locks, \-\-type, \-\-refresh,

-\-\-serialize\-memory\-hard\-pbkdf].

+\-\-serialize\-memory\-hard\-pbkdf, \-\-unbound].

 .PP

 \fIluksSuspend\fR <name>

 .IP

@@ -1409,10 +1409,14 @@ aligned to page size and page-cache init

 integrity tag.

 .TP

 .B "\-\-unbound"

-

 Creates new or dumps existing LUKS2 unbound keyslot. See \fIluksAddKey\fR or

 \fIluksDump\fR actions for more details.

+When used in \fIluksOpen\fR action (allowed only together with

+\-\-test\-passphrase parameter), it allows to test passphrase for unbound LUKS2

+keyslot. Otherwise, unbound keyslot passphrase can be tested only when specific

+keyslot is selected via \-\-key\-slot parameter.

+

 .TP

 .B "\-\-tcrypt\-hidden"

 .B "\-\-tcrypt\-system"

diff -rupN cryptsetup-2.3.7.old/src/cryptsetup.c cryptsetup-2.3.7/src/cryptsetup.c

--- cryptsetup-2.3.7.old/src/cryptsetup.c	2022-02-24 15:58:37.969167429 +0100

+++ cryptsetup-2.3.7/src/cryptsetup.c	2022-02-24 17:10:30.947561638 +0100

@@ -230,7 +230,7 @@ static void _set_activation_flags(uint32

 		*flags |= CRYPT_ACTIVATE_IGNORE_PERSISTENT;

 	/* Only for LUKS2 but ignored elsewhere */

-	if (opt_test_passphrase)

+	if (opt_test_passphrase && (opt_unbound || (opt_key_slot != CRYPT_ANY_SLOT)))

 		*flags |= CRYPT_ACTIVATE_ALLOW_UNBOUND_KEY;

 	if (opt_serialize_memory_hard_pbkdf)

@@ -4021,6 +4021,17 @@ int main(int argc, const char **argv)

 		_("Option --tcrypt-hidden, --tcrypt-system or --tcrypt-backup is supported only for TCRYPT device."),

 		poptGetInvocationName(popt_context));

+	if (opt_unbound && !strcmp(aname, "open") && device_type &&

+	    strncmp(device_type, "luks", 4))

+		usage(popt_context, EXIT_FAILURE,

+		_("Option --unbound is allowed only for open of luks device."),

+		poptGetInvocationName(popt_context));

+

+	if (opt_unbound && !opt_test_passphrase && !strcmp(aname, "open"))

+		usage(popt_context, EXIT_FAILURE,

+		_("Option --unbound cannot be used without --test-passphrase."),

+		poptGetInvocationName(popt_context));

+

 	if (opt_tcrypt_hidden && opt_allow_discards)

 		usage(popt_context, EXIT_FAILURE,

 		_("Option --tcrypt-hidden cannot be combined with --allow-discards."),

@@ -4103,9 +4114,9 @@ int main(int argc, const char **argv)

 		      _("Keyslot specification is required."),

 		      poptGetInvocationName(popt_context));

-	if (opt_unbound && strcmp(aname, "luksAddKey") && strcmp(aname, "luksDump"))

+	if (opt_unbound && strcmp(aname, "luksAddKey") && strcmp(aname, "luksDump") && strcmp(aname, "open"))

 		usage(popt_context, EXIT_FAILURE,

-		      _("Option --unbound may be used only with luksAddKey and luksDump actions."),

+		      _("Option --unbound may be used only with luksAddKey, luksDump and open actions."),

 		      poptGetInvocationName(popt_context));

 	if (opt_refresh && strcmp(aname, "open"))

diff -rupN cryptsetup-2.3.7.old/tests/compat-test2 cryptsetup-2.3.7/tests/compat-test2

--- cryptsetup-2.3.7.old/tests/compat-test2	2022-02-24 15:58:38.013167680 +0100

+++ cryptsetup-2.3.7/tests/compat-test2	2022-02-24 17:23:23.035760517 +0100

@@ -696,7 +696,7 @@ $CRYPTSETUP luksOpen -S 5 -d $KEY1 $LOOP

 # otoh it should be allowed to test for proper passphrase

 prepare "" new

 echo $PWD1 | $CRYPTSETUP open -S1 --test-passphrase $HEADER_KEYU || fail

-echo $PWD1 | $CRYPTSETUP open --test-passphrase $HEADER_KEYU || fail

+echo $PWD1 | $CRYPTSETUP open --unbound --test-passphrase $HEADER_KEYU || fail

 echo $PWD1 | $CRYPTSETUP open -S1 $HEADER_KEYU $DEV_NAME 2>/dev/null && fail

 [ -b /dev/mapper/$DEV_NAME ] && fail

 echo $PWD1 | $CRYPTSETUP open $HEADER_KEYU $DEV_NAME 2>/dev/null && fail

@@ -705,7 +705,7 @@ echo $PWD0 | $CRYPTSETUP open -S1 --test

 $CRYPTSETUP luksKillSlot -q $HEADER_KEYU 0

 $CRYPTSETUP luksDump $HEADER_KEYU | grep -q "0: luks2" && fail

 echo $PWD1 | $CRYPTSETUP open -S1 --test-passphrase $HEADER_KEYU || fail

-echo $PWD1 | $CRYPTSETUP open --test-passphrase $HEADER_KEYU || fail

+echo $PWD1 | $CRYPTSETUP open --unbound --test-passphrase $HEADER_KEYU || fail

 echo $PWD1 | $CRYPTSETUP open -S1 $HEADER_KEYU $DEV_NAME 2>/dev/null && fail

 prepare "[28] Detached LUKS header" wipe

@@ -952,11 +952,9 @@ echo $PWD3 | $CRYPTSETUP -q luksAddKey -

 # do not allow to replace keyslot by unbound slot

 echo $PWD1 | $CRYPTSETUP -q luksAddKey -S5 --unbound -s 32 $LOOPDEV 2>/dev/null && fail

 echo $PWD2 | $CRYPTSETUP -q open $LOOPDEV $DEV_NAME 2> /dev/null && fail

-echo $PWD2 | $CRYPTSETUP -q open $LOOPDEV --test-passphrase || fail

 echo $PWD2 | $CRYPTSETUP -q open -S2 $LOOPDEV $DEV_NAME 2> /dev/null && fail

 echo $PWD2 | $CRYPTSETUP -q open -S2 $LOOPDEV --test-passphrase || fail

 echo $PWD1 | $CRYPTSETUP -q open $LOOPDEV $DEV_NAME 2> /dev/null && fail

-echo $PWD1 | $CRYPTSETUP -q open $LOOPDEV --test-passphrase || fail

 # check we're able to change passphrase for unbound keyslot

 echo -e "$PWD2\n$PWD3" | $CRYPTSETUP luksChangeKey $FAST_PBKDF_OPT -S 2 $LOOPDEV || fail

 echo $PWD3 | $CRYPTSETUP open --test-passphrase $FAST_PBKDF_OPT -S 2 $LOOPDEV || fail