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[WIP] pkcs5: add back support for using AES-GCM in PBES2 #2313

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[WIP] pkcs5: add back support for using AES-GCM in PBES2 #2313

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64 changes: 64 additions & 0 deletions Cargo.lock
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3 changes: 2 additions & 1 deletion pkcs5/Cargo.toml
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Original file line number Diff line number Diff line change
Expand Up @@ -21,6 +21,7 @@ spki = "0.8"

# optional dependencies
aes = { version = "0.9", optional = true, default-features = false }
aes-gcm = { version = "0.11.0-rc.3", optional = true, default-features = false, features = ["aes"] }
cbc = { version = "0.2", optional = true }
des = { version = "0.9", optional = true, default-features = false }
pbkdf2 = { version = "0.13", optional = true, default-features = false, features = ["hmac"] }
Expand All @@ -39,7 +40,7 @@ alloc = []
3des = ["dep:des", "pbes2"]
des-insecure = ["dep:des", "pbes2"]
getrandom = ["dep:getrandom", "rand_core"]
pbes2 = ["dep:aes", "dep:cbc", "dep:pbkdf2", "dep:scrypt", "dep:sha2"]
pbes2 = ["dep:aes", "dep:aes-gcm", "dep:cbc", "dep:pbkdf2", "dep:scrypt", "dep:sha2"]
rand_core = ["dep:rand_core"]
sha1-insecure = ["dep:sha1", "pbes2"]

Expand Down
78 changes: 78 additions & 0 deletions pkcs5/src/pbes2.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -39,6 +39,14 @@ pub const AES_192_CBC_OID: ObjectIdentifier =
pub const AES_256_CBC_OID: ObjectIdentifier =
ObjectIdentifier::new_unwrap("2.16.840.1.101.3.4.1.42");

/// 128-bit Advanced Encryption Standard (AES) algorithm with Galois Counter Mode
pub const AES_128_GCM_OID: ObjectIdentifier =
ObjectIdentifier::new_unwrap("2.16.840.1.101.3.4.1.6");

/// 256-bit Advanced Encryption Standard (AES) algorithm with Galois Counter Mode
pub const AES_256_GCM_OID: ObjectIdentifier =
ObjectIdentifier::new_unwrap("2.16.840.1.101.3.4.1.46");

/// DES operating in CBC mode
#[cfg(feature = "des-insecure")]
pub const DES_CBC_OID: ObjectIdentifier = ObjectIdentifier::new_unwrap("1.3.14.3.2.7");
Expand All @@ -55,6 +63,12 @@ pub const PBES2_OID: ObjectIdentifier = ObjectIdentifier::new_unwrap("1.2.840.11
/// AES cipher block size
const AES_BLOCK_SIZE: usize = 16;

/// GCM nonce size
///
/// We could use any value here but GCM is most efficient
/// with 96 bit nonces
const GCM_NONCE_SIZE: usize = 12;

/// DES / Triple DES block size
#[cfg(any(feature = "3des", feature = "des-insecure"))]
const DES_BLOCK_SIZE: usize = 8;
Expand Down Expand Up @@ -255,6 +269,46 @@ impl Parameters {
Ok(Self { kdf, encryption })
}

/// Initialize PBES2 parameters using scrypt as the password-based
/// key derivation function and AES-128-GCM as the symmetric cipher.
///
/// For more information on scrypt parameters, see documentation for the
/// [`scrypt::Params`] struct.
///
/// # Errors
/// Propagates errors from [`ScryptParams::from_params_and_salt`].
// TODO(tarcieri): encapsulate `scrypt::Params`?
#[cfg(feature = "pbes2")]
pub fn scrypt_aes128gcm(
params: scrypt::Params,
salt: &[u8],
gcm_nonce: [u8; GCM_NONCE_SIZE],
) -> Result<Self> {
let kdf = ScryptParams::from_params_and_salt(params, salt)?.into();
let encryption = EncryptionScheme::Aes128Gcm { nonce: gcm_nonce };
Ok(Self { kdf, encryption })
}

/// Initialize PBES2 parameters using scrypt as the password-based
/// key derivation function and AES-256-GCM as the symmetric cipher.
///
/// For more information on scrypt parameters, see documentation for the
/// [`scrypt::Params`] struct.
///
/// # Errors
/// Propagates errors from [`ScryptParams::from_params_and_salt`].
// TODO(tarcieri): encapsulate `scrypt::Params`?
#[cfg(feature = "pbes2")]
pub fn scrypt_aes256gcm(
params: scrypt::Params,
salt: &[u8],
gcm_nonce: [u8; GCM_NONCE_SIZE],
) -> Result<Self> {
let kdf = ScryptParams::from_params_and_salt(params, salt)?.into();
let encryption = EncryptionScheme::Aes256Gcm { nonce: gcm_nonce };
Ok(Self { kdf, encryption })
}

/// Attempt to decrypt the given ciphertext, allocating and returning a
/// byte vector containing the plaintext.
///
Expand Down Expand Up @@ -387,6 +441,18 @@ pub enum EncryptionScheme {
iv: [u8; AES_BLOCK_SIZE],
},

/// AES-128 in CBC mode
Aes128Gcm {
/// GCM nonce
nonce: [u8; GCM_NONCE_SIZE],
},

/// AES-256 in GCM mode
Aes256Gcm {
/// GCM nonce
nonce: [u8; GCM_NONCE_SIZE],
},

/// 3-Key Triple DES in CBC mode
#[cfg(feature = "3des")]
DesEde3Cbc {
Expand All @@ -410,6 +476,8 @@ impl EncryptionScheme {
Self::Aes128Cbc { .. } => 16,
Self::Aes192Cbc { .. } => 24,
Self::Aes256Cbc { .. } => 32,
Self::Aes128Gcm { .. } => 16,
Self::Aes256Gcm { .. } => 32,
#[cfg(feature = "des-insecure")]
Self::DesCbc { .. } => 8,
#[cfg(feature = "3des")]
Expand All @@ -424,6 +492,8 @@ impl EncryptionScheme {
Self::Aes128Cbc { .. } => AES_128_CBC_OID,
Self::Aes192Cbc { .. } => AES_192_CBC_OID,
Self::Aes256Cbc { .. } => AES_256_CBC_OID,
Self::Aes128Gcm { .. } => AES_128_GCM_OID,
Self::Aes256Gcm { .. } => AES_256_GCM_OID,
#[cfg(feature = "des-insecure")]
Self::DesCbc { .. } => DES_CBC_OID,
#[cfg(feature = "3des")]
Expand Down Expand Up @@ -468,6 +538,12 @@ impl TryFrom<AlgorithmIdentifierRef<'_>> for EncryptionScheme {
AES_256_CBC_OID => Ok(Self::Aes256Cbc {
iv: iv.try_into().map_err(|_| Tag::OctetString.value_error())?,
}),
AES_128_GCM_OID => Ok(Self::Aes128Gcm {
nonce: iv.try_into().map_err(|_| Tag::OctetString.value_error())?,
}),
AES_256_GCM_OID => Ok(Self::Aes256Gcm {
nonce: iv.try_into().map_err(|_| Tag::OctetString.value_error())?,
}),
#[cfg(feature = "des-insecure")]
DES_CBC_OID => Ok(Self::DesCbc {
iv: iv[0..DES_BLOCK_SIZE]
Expand All @@ -493,6 +569,8 @@ impl<'a> TryFrom<&'a EncryptionScheme> for AlgorithmIdentifierRef<'a> {
EncryptionScheme::Aes128Cbc { iv } => iv.as_slice(),
EncryptionScheme::Aes192Cbc { iv } => iv.as_slice(),
EncryptionScheme::Aes256Cbc { iv } => iv.as_slice(),
EncryptionScheme::Aes128Gcm { nonce } => nonce.as_slice(),
EncryptionScheme::Aes256Gcm { nonce } => nonce.as_slice(),
#[cfg(feature = "des-insecure")]
EncryptionScheme::DesCbc { iv } => iv.as_slice(),
#[cfg(feature = "3des")]
Expand Down
74 changes: 73 additions & 1 deletion pkcs5/src/pbes2/encryption.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -2,6 +2,7 @@

use super::{EncryptionScheme, Kdf, Parameters, Pbkdf2Params, Pbkdf2Prf, ScryptParams};
use crate::{Error, Result};
use aes_gcm::{KeyInit as GcmKeyInit, Nonce, Tag, aead::AeadInOut};
use cbc::cipher::{
BlockCipherDecrypt, BlockCipherEncrypt, BlockModeDecrypt, BlockModeEncrypt, KeyInit, KeyIvInit,
block_padding::Pkcs7,
Expand All @@ -12,7 +13,7 @@ use pbkdf2::{
digest::{
FixedOutput, HashMarker, Update,
block_api::BlockSizeUser,
typenum::{IsLess, NonZero, True, U256},
typenum::{IsLess, NonZero, True, U12, U16, U256},
},
},
pbkdf2_hmac,
Expand Down Expand Up @@ -47,6 +48,65 @@ fn cbc_decrypt<'a, C: BlockCipherDecrypt + KeyInit>(
.map_err(|_| Error::DecryptFailed)
}

fn gcm_encrypt<C, NonceSize, TagSize>(
es: EncryptionScheme,
key: EncryptionKey,
nonce: Nonce<NonceSize>,
buffer: &mut [u8],
pos: usize,
) -> Result<&[u8]>
where
C: BlockSizeUser<BlockSize = U16> + GcmKeyInit + BlockCipherEncrypt,
aes_gcm::AesGcm<C, NonceSize, TagSize>: GcmKeyInit,
TagSize: aes_gcm::TagSize,
NonceSize: aes::cipher::array::ArraySize,
{
if buffer.len() < TagSize::USIZE + pos {
return Err(Error::EncryptFailed);
}
let gcm =
<aes_gcm::AesGcm<C, NonceSize, TagSize> as GcmKeyInit>::new_from_slice(key.as_slice())
.map_err(|_| es.to_alg_params_invalid())?;
let tag = gcm
.encrypt_inout_detached(&nonce, &[], (&mut buffer[..pos]).into())
.map_err(|_| Error::EncryptFailed)?;
buffer[pos..].copy_from_slice(tag.as_ref());
Ok(&buffer[0..pos + TagSize::USIZE])
}

fn gcm_decrypt<C, NonceSize, TagSize>(
es: EncryptionScheme,
key: EncryptionKey,
nonce: Nonce<NonceSize>,
buffer: &mut [u8],
) -> Result<&[u8]>
where
C: BlockSizeUser<BlockSize = U16> + GcmKeyInit + BlockCipherEncrypt,
aes_gcm::AesGcm<C, NonceSize, TagSize>: GcmKeyInit,
TagSize: aes_gcm::TagSize,
NonceSize: aes::cipher::array::ArraySize,
{
let msg_len = buffer
.len()
.checked_sub(TagSize::USIZE)
.ok_or(Error::DecryptFailed)?;

let gcm =
<aes_gcm::AesGcm<C, NonceSize, TagSize> as GcmKeyInit>::new_from_slice(key.as_slice())
.map_err(|_| es.to_alg_params_invalid())?;

let tag = Tag::try_from(&buffer[msg_len..]).map_err(|_| Error::DecryptFailed)?;

if gcm
.decrypt_inout_detached(&nonce, &[], (&mut buffer[..msg_len]).into(), &tag)
.is_err()
{
return Err(Error::DecryptFailed);
}

Ok(&buffer[..msg_len])
}

pub fn encrypt_in_place<'b>(
params: &Parameters,
password: impl AsRef<[u8]>,
Expand All @@ -64,6 +124,12 @@ pub fn encrypt_in_place<'b>(
EncryptionScheme::Aes128Cbc { iv } => cbc_encrypt::<aes::Aes128Enc>(es, key, &iv, buf, pos),
EncryptionScheme::Aes192Cbc { iv } => cbc_encrypt::<aes::Aes192Enc>(es, key, &iv, buf, pos),
EncryptionScheme::Aes256Cbc { iv } => cbc_encrypt::<aes::Aes256Enc>(es, key, &iv, buf, pos),
EncryptionScheme::Aes128Gcm { nonce } => {
gcm_encrypt::<aes::Aes128Enc, U12, U16>(es, key, Nonce::from(nonce), buf, pos)
}
EncryptionScheme::Aes256Gcm { nonce } => {
gcm_encrypt::<aes::Aes256Enc, U12, U16>(es, key, Nonce::from(nonce), buf, pos)
}
#[cfg(feature = "3des")]
EncryptionScheme::DesEde3Cbc { iv } => cbc_encrypt::<des::TdesEde3>(es, key, &iv, buf, pos),
#[cfg(feature = "des-insecure")]
Expand All @@ -86,6 +152,12 @@ pub fn decrypt_in_place<'a>(
EncryptionScheme::Aes128Cbc { iv } => cbc_decrypt::<aes::Aes128Dec>(es, key, &iv, buf),
EncryptionScheme::Aes192Cbc { iv } => cbc_decrypt::<aes::Aes192Dec>(es, key, &iv, buf),
EncryptionScheme::Aes256Cbc { iv } => cbc_decrypt::<aes::Aes256Dec>(es, key, &iv, buf),
EncryptionScheme::Aes128Gcm { nonce } => {
gcm_decrypt::<aes::Aes128Enc, U12, U16>(es, key, Nonce::from(nonce), buf)
}
EncryptionScheme::Aes256Gcm { nonce } => {
gcm_decrypt::<aes::Aes256Enc, U12, U16>(es, key, Nonce::from(nonce), buf)
}
#[cfg(feature = "3des")]
EncryptionScheme::DesEde3Cbc { iv } => cbc_decrypt::<des::TdesEde3>(es, key, &iv, buf),
#[cfg(feature = "des-insecure")]
Expand Down
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