cryptsetup mistakenly includes newline character in passphrase

cryptsetup mistakenly includes newline character in passphrase

[doffloster]

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Hi cryptsetup/LUKS Team,

I noticed a potential bug in cryptsetup:

When feeding the passphrase via stdin, then cryptsetup includes the newline
character ('\n') in the passphrase.
This behavior contradicts the manual of cryptsetup:
Under title "NOTES ON PASSPHRASE PROCESSING FOR LUKS" it is written as
follows:
"From stdin: LUKS will read passphrases from stdin up to the first newline
character or the compiled-in maximum key file length."

I've written a script which reproduces the bug (attached, file
"commands_reproduce.sh"), executed it and provided its output (attached,
file "log.txt").

Please check this issue.

Best regards,
David.

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[-- Attachment #2: log.txt --]
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Format device with LUKS container:
# cryptsetup 2.4.3 processing "cryptsetup --verbose --debug --hash sha512 --iter-time=50 --key-size 256 --type=luks2 luksFormat /dev/sda5 -"
# Running command luksFormat.
# Locking memory.
# Installing SIGINT/SIGTERM handler.
# Unblocking interruption on signal.
# Allocating context for crypt device /dev/sda5.
# Trying to open and read device /dev/sda5 with direct-io.
# Initialising device-mapper backend library.
WARNING: Device /dev/sda5 already contains a 'crypto_LUKS' superblock signature.
# STDIN descriptor passphrase entry requested.
# Crypto backend (OpenSSL 3.0.2 15 Mar 2022 [default][legacy]) initialized in cryptsetup library version 2.4.3.
# Detected kernel Linux 5.15.0-43-generic x86_64.
# PBKDF argon2id, time_ms 50 (iterations 0), max_memory_kb 1048576, parallel_threads 4.
Existing 'crypto_LUKS' superblock signature on device /dev/sda5 will be wiped.
Existing 'crypto_LUKS' superblock signature on device /dev/sda5 will be wiped.
# Formatting device /dev/sda5 as type LUKS2.
# Auto-detected optimal encryption sector size for device /dev/sda5 is 512 bytes.
# Topology: IO (512/0), offset = 0; Required alignment is 1048576 bytes.
# Checking if cipher aes-xts-plain64 is usable.
# Using userspace crypto wrapper to access keyslot area.
# Formatting LUKS2 with JSON metadata area 12288 bytes and keyslots area 16744448 bytes.
# Creating new digest 0 (pbkdf2).
# Setting PBKDF2 type key digest 0.
# Running pbkdf2(sha512) benchmark.
# PBKDF benchmark: memory cost = 0, iterations = 1724631, threads = 0 (took 19 ms)
# PBKDF benchmark: memory cost = 0, iterations = 1765279, threads = 0 (took 297 ms)
# PBKDF benchmark: memory cost = 0, iterations = 1774240, threads = 0 (took 591 ms)
# Benchmark returns pbkdf2(sha512) 1774240 iterations, 0 memory, 0 threads (for 256-bits key).
# Segment 0 assigned to digest 0.
# Wiping LUKS areas (0x000000 - 0x1000000) with zeroes.
# Wiping keyslots area (0x008000 - 0x1000000) with random data.
# Reusing open rw fd on device /dev/sda5
# Device size 115964116992, offset 16777216.
# Acquiring write lock for device /dev/sda5.
# Opening lock resource file /run/cryptsetup/L_8:5
# Verifying lock handle for /dev/sda5.
# Device /dev/sda5 WRITE lock taken.
# Trying to write LUKS2 header (16384 bytes) at offset 0.
# Reusing open rw fd on device /dev/sda5
# Checksum:ffa3de155faa7b6c391a287250c4ee9910c73e688815e906afa1b15c280e7f36 (in-memory)
# Trying to write LUKS2 header (16384 bytes) at offset 16384.
# Reusing open rw fd on device /dev/sda5
# Checksum:221fcd31672fb3c669910598eb77e9c0f7413a2708a187a3440c1026be868d07 (in-memory)
# Device /dev/sda5 WRITE lock released.
# Adding new keyslot -1 using volume key.
# Adding new keyslot -1 with volume key assigned to a crypt segment.
# Selected keyslot 0.
# Keyslot 0 assigned to digest 0.
# Trying to allocate LUKS2 keyslot 0.
# Found area 32768 -> 163840
# Running argon2id() benchmark.
# PBKDF benchmark: memory cost = 65536, iterations = 4, threads = 4 (took 57 ms)
# PBKDF benchmark: memory cost = 287438, iterations = 4, threads = 4 (took 240 ms)
# PBKDF benchmark: memory cost = 299414, iterations = 4, threads = 4 (took 249 ms)
# PBKDF benchmark: memory cost = 300616, iterations = 4, threads = 4 (took 249 ms)
# PBKDF benchmark: memory cost = 301823, iterations = 4, threads = 4 (took 249 ms)
# PBKDF benchmark: memory cost = 303035, iterations = 4, threads = 4 (took 252 ms)
# Benchmark returns argon2id() 4 iterations, 65536 memory, 4 threads (for 256-bits key).
# Calculating attributes for LUKS2 keyslot 0.
# Acquiring write lock for device /dev/sda5.
# Opening lock resource file /run/cryptsetup/L_8:5
# Verifying lock handle for /dev/sda5.
# Device /dev/sda5 WRITE lock taken.
# Checking context sequence id matches value stored on disk.
# Reusing open ro fd on device /dev/sda5
# Running keyslot key derivation.
# Updating keyslot area [0x8000].
# Reusing open rw fd on device /dev/sda5
# Device size 115964116992, offset 16777216.
# Device /dev/sda5 WRITE lock already held.
# Trying to write LUKS2 header (16384 bytes) at offset 0.
# Reusing open rw fd on device /dev/sda5
# Checksum:932f1402012b950c0209021ad63efa2bee0f6d4794465e28187b4cd39f349d09 (in-memory)
# Trying to write LUKS2 header (16384 bytes) at offset 16384.
# Reusing open rw fd on device /dev/sda5
# Checksum:6444e4480d67748d9fa3b3f636300cf9405cc7fa27727a02972e992e248eef0c (in-memory)
# Device /dev/sda5 WRITE lock released.
Key slot 0 created.
# Releasing crypt device /dev/sda5 context.
# Releasing device-mapper backend.
# Closing read only fd for /dev/sda5.
# Closing read write fd for /dev/sda5.
# Unlocking memory.
Command successful.



Try to open without a newline (should fail):
No key available with this passphrase.
# cryptsetup 2.4.3 processing "cryptsetup --verbose --debug --key-file - open /dev/sda5 debug_open"
# Running command open.
# Locking memory.
# Installing SIGINT/SIGTERM handler.
# Unblocking interruption on signal.
# Allocating context for crypt device /dev/sda5.
# Trying to open and read device /dev/sda5 with direct-io.
# Initialising device-mapper backend library.
# Trying to load any crypt type from device /dev/sda5.
# Crypto backend (OpenSSL 3.0.2 15 Mar 2022 [default][legacy]) initialized in cryptsetup library version 2.4.3.
# Detected kernel Linux 5.15.0-43-generic x86_64.
# Loading LUKS2 header (repair disabled).
# Acquiring read lock for device /dev/sda5.
# Opening lock resource file /run/cryptsetup/L_8:5
# Verifying lock handle for /dev/sda5.
# Device /dev/sda5 READ lock taken.
# Trying to read primary LUKS2 header at offset 0x0.
# Opening locked device /dev/sda5
# Verifying locked device handle (bdev)
# LUKS2 header version 2 of size 16384 bytes, checksum sha256.
# Checksum:932f1402012b950c0209021ad63efa2bee0f6d4794465e28187b4cd39f349d09 (on-disk)
# Checksum:932f1402012b950c0209021ad63efa2bee0f6d4794465e28187b4cd39f349d09 (in-memory)
# Trying to read secondary LUKS2 header at offset 0x4000.
# Reusing open ro fd on device /dev/sda5
# LUKS2 header version 2 of size 16384 bytes, checksum sha256.
# Checksum:6444e4480d67748d9fa3b3f636300cf9405cc7fa27727a02972e992e248eef0c (on-disk)
# Checksum:6444e4480d67748d9fa3b3f636300cf9405cc7fa27727a02972e992e248eef0c (in-memory)
# Device size 115964116992, offset 16777216.
# Device /dev/sda5 READ lock released.
# PBKDF argon2id, time_ms 2000 (iterations 0), max_memory_kb 1048576, parallel_threads 4.
# Activating volume debug_open using token (any type) -1.
# dm version   [ opencount flush ]   [16384] (*1)
# dm versions   [ opencount flush ]   [16384] (*1)
# Detected dm-ioctl version 4.45.0.
# Detected dm-crypt version 1.23.0.
# Device-mapper backend running with UDEV support enabled.
# dm status debug_open  [ opencount noflush ]   [16384] (*1)
No usable token is available.
# STDIN descriptor passphrase entry requested.
# Activating volume debug_open [keyslot -1] using passphrase.
# dm versions   [ opencount flush ]   [16384] (*1)
# dm status debug_open  [ opencount noflush ]   [16384] (*1)
# Keyslot 0 priority 1 != 2 (required), skipped.
# Trying to open LUKS2 keyslot 0.
# Running keyslot key derivation.
# Reading keyslot area [0x8000].
# Acquiring read lock for device /dev/sda5.
# Opening lock resource file /run/cryptsetup/L_8:5
# Verifying lock handle for /dev/sda5.
# Device /dev/sda5 READ lock taken.
# Reusing open ro fd on device /dev/sda5
# Device /dev/sda5 READ lock released.
# Verifying key from keyslot 0, digest 0.
# Digest 0 (pbkdf2) verify failed with -1.
# Releasing crypt device /dev/sda5 context.
# Releasing device-mapper backend.
# Closing read only fd for /dev/sda5.
# Unlocking memory.
Command failed with code -2 (no permission or bad passphrase).



Try to open with a newline (should succeed):
# cryptsetup 2.4.3 processing "cryptsetup --verbose --debug --key-file - open /dev/sda5 debug_open"
# Running command open.
# Locking memory.
# Installing SIGINT/SIGTERM handler.
# Unblocking interruption on signal.
# Allocating context for crypt device /dev/sda5.
# Trying to open and read device /dev/sda5 with direct-io.
# Initialising device-mapper backend library.
# Trying to load any crypt type from device /dev/sda5.
# Crypto backend (OpenSSL 3.0.2 15 Mar 2022 [default][legacy]) initialized in cryptsetup library version 2.4.3.
# Detected kernel Linux 5.15.0-43-generic x86_64.
# Loading LUKS2 header (repair disabled).
# Acquiring read lock for device /dev/sda5.
# Opening lock resource file /run/cryptsetup/L_8:5
# Verifying lock handle for /dev/sda5.
# Device /dev/sda5 READ lock taken.
# Trying to read primary LUKS2 header at offset 0x0.
# Opening locked device /dev/sda5
# Verifying locked device handle (bdev)
# LUKS2 header version 2 of size 16384 bytes, checksum sha256.
# Checksum:932f1402012b950c0209021ad63efa2bee0f6d4794465e28187b4cd39f349d09 (on-disk)
# Checksum:932f1402012b950c0209021ad63efa2bee0f6d4794465e28187b4cd39f349d09 (in-memory)
# Trying to read secondary LUKS2 header at offset 0x4000.
# Reusing open ro fd on device /dev/sda5
# LUKS2 header version 2 of size 16384 bytes, checksum sha256.
# Checksum:6444e4480d67748d9fa3b3f636300cf9405cc7fa27727a02972e992e248eef0c (on-disk)
# Checksum:6444e4480d67748d9fa3b3f636300cf9405cc7fa27727a02972e992e248eef0c (in-memory)
# Device size 115964116992, offset 16777216.
# Device /dev/sda5 READ lock released.
# PBKDF argon2id, time_ms 2000 (iterations 0), max_memory_kb 1048576, parallel_threads 4.
# Activating volume debug_open using token (any type) -1.
# dm version   [ opencount flush ]   [16384] (*1)
# dm versions   [ opencount flush ]   [16384] (*1)
# Detected dm-ioctl version 4.45.0.
# Detected dm-crypt version 1.23.0.
# Device-mapper backend running with UDEV support enabled.
# dm status debug_open  [ opencount noflush ]   [16384] (*1)
No usable token is available.
# STDIN descriptor passphrase entry requested.
# Activating volume debug_open [keyslot -1] using passphrase.
# dm versions   [ opencount flush ]   [16384] (*1)
# dm status debug_open  [ opencount noflush ]   [16384] (*1)
# Keyslot 0 priority 1 != 2 (required), skipped.
# Trying to open LUKS2 keyslot 0.
# Running keyslot key derivation.
# Reading keyslot area [0x8000].
# Acquiring read lock for device /dev/sda5.
# Opening lock resource file /run/cryptsetup/L_8:5
# Verifying lock handle for /dev/sda5.
# Device /dev/sda5 READ lock taken.
# Reusing open ro fd on device /dev/sda5
# Device /dev/sda5 READ lock released.
# Verifying key from keyslot 0, digest 0.
# Loading key (32 bytes, type logon) in thread keyring.
# dm versions   [ opencount flush ]   [16384] (*1)
# dm status debug_open  [ opencount noflush ]   [16384] (*1)
# Calculated device size is 226459648 sectors (RW), offset 32768.
# DM-UUID is CRYPT-LUKS2-cc3cebb890834b69955810730a1abc5d-debug_open
# Udev cookie 0xd4d962d (semid 2) created
# Udev cookie 0xd4d962d (semid 2) incremented to 1
# Udev cookie 0xd4d962d (semid 2) incremented to 2
# Udev cookie 0xd4d962d (semid 2) assigned to CREATE task(0) with flags DISABLE_LIBRARY_FALLBACK         (0x20)
# dm create debug_open CRYPT-LUKS2-cc3cebb890834b69955810730a1abc5d-debug_open [ opencount flush ]   [16384] (*1)
# dm reload   (253:0) [ opencount flush securedata ]   [16384] (*1)
# dm resume debug_open  [ opencount flush securedata ]   [16384] (*1)
# debug_open: Stacking NODE_ADD (253,0) 0:6 0660 [trust_udev]
# debug_open: Stacking NODE_READ_AHEAD 256 (flags=1)
# Udev cookie 0xd4d962d (semid 2) decremented to 1
# Udev cookie 0xd4d962d (semid 2) waiting for zero
# Udev cookie 0xd4d962d (semid 2) destroyed
# debug_open: Skipping NODE_ADD (253,0) 0:6 0660 [trust_udev]
# debug_open: Processing NODE_READ_AHEAD 256 (flags=1)
# debug_open (253:0): read ahead is 256
# debug_open: retaining kernel read ahead of 256 (requested 256)
Key slot 0 unlocked.
# Releasing crypt device /dev/sda5 context.
# Releasing device-mapper backend.
# Closing read only fd for /dev/sda5.
# Unlocking memory.
Command successful.

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Re: cryptsetup mistakenly includes newline character in passphrase

[Christoph Anton Mitterer]

Hey.

In your script, you create the volume via:
> printf "%s\n" "${PASSPHRASE}" | cryptsetup "${cmd_cryptsetup_params[@]}" --type=luks2 luksFormat ${DEVP}5 -

With the "-" in the end meaning "read the key file from stdin"... so it
takes up everything presented (up to some compiled-in maximum).

There you have a trailing "\n" in the printf.


When opening you also read a keyfile from stdin, but you don't give a
trailing "\n":
> printf "%s" "${PASSPHRASE}" | cryptsetup --verbose --debug --key-file - open ${DEVP}5 debug_open


Cheers,
Chris.

Re: cryptsetup mistakenly includes newline character in passphrase

[doffloster]

Hi Christoph,

I understand.
Then it seems that I got confused.

Thanks.

Best regards,
David.


On Wed, Sep 7, 2022 at 7:03 PM Christoph Anton Mitterer
<calestyo@scientia.org> wrote:
>
> Hey.
>
> In your script, you create the volume via:
> > printf "%s\n" "${PASSPHRASE}" | cryptsetup "${cmd_cryptsetup_params[@]}" --type=luks2 luksFormat ${DEVP}5 -
>
> With the "-" in the end meaning "read the key file from stdin"... so it
> takes up everything presented (up to some compiled-in maximum).
>
> There you have a trailing "\n" in the printf.
>
>
> When opening you also read a keyfile from stdin, but you don't give a
> trailing "\n":
> > printf "%s" "${PASSPHRASE}" | cryptsetup --verbose --debug --key-file - open ${DEVP}5 debug_open
>
>
> Cheers,
> Chris.



-- 

Best regards,
David.