parquet/encryption/
ciphers.rs

1// Licensed to the Apache Software Foundation (ASF) under one
2// or more contributor license agreements.  See the NOTICE file
3// distributed with this work for additional information
4// regarding copyright ownership.  The ASF licenses this file
5// to you under the Apache License, Version 2.0 (the
6// "License"); you may not use this file except in compliance
7// with the License.  You may obtain a copy of the License at
8//
9//   http://www.apache.org/licenses/LICENSE-2.0
10//
11// Unless required by applicable law or agreed to in writing,
12// software distributed under the License is distributed on an
13// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
14// KIND, either express or implied.  See the License for the
15// specific language governing permissions and limitations
16// under the License.
17
18use crate::errors::ParquetError;
19use crate::errors::ParquetError::General;
20use crate::errors::Result;
21use crate::file::metadata::HeapSize;
22use ring::aead::{AES_128_GCM, AES_256_GCM, Aad, LessSafeKey, NonceSequence, UnboundKey};
23use ring::rand::{SecureRandom, SystemRandom};
24use std::fmt::Debug;
25
26const RIGHT_TWELVE: u128 = 0x0000_0000_ffff_ffff_ffff_ffff_ffff_ffff;
27pub(crate) const NONCE_LEN: usize = 12;
28pub(crate) const TAG_LEN: usize = 16;
29pub(crate) const SIZE_LEN: usize = 4;
30
31pub(crate) trait BlockDecryptor: Debug + Send + Sync + HeapSize {
32    fn decrypt(&self, length_and_ciphertext: &[u8], aad: &[u8]) -> Result<Vec<u8>>;
33
34    fn compute_plaintext_tag(&self, aad: &[u8], plaintext: &[u8]) -> Result<Vec<u8>>;
35}
36
37#[derive(Debug, Clone)]
38pub(crate) struct RingGcmBlockDecryptor {
39    key: LessSafeKey,
40}
41
42impl RingGcmBlockDecryptor {
43    /// Create a new `RingGcmBlockDecryptor` with a given key.
44    pub(crate) fn new(key_bytes: &[u8]) -> Result<Self> {
45        let algorithm = if key_bytes.len() == AES_128_GCM.key_len() {
46            &AES_128_GCM
47        } else if key_bytes.len() == AES_256_GCM.key_len() {
48            &AES_256_GCM
49        } else {
50            return Err(general_err!(
51                "Error creating RingGcmBlockDecryptor with unsupported key length: {}",
52                key_bytes.len()
53            ));
54        };
55        let key = UnboundKey::new(algorithm, key_bytes)
56            .map_err(|_| general_err!("Failed to create {:?} key", algorithm))?;
57
58        Ok(Self {
59            key: LessSafeKey::new(key),
60        })
61    }
62}
63
64impl HeapSize for RingGcmBlockDecryptor {
65    fn heap_size(&self) -> usize {
66        // Ring's LessSafeKey doesn't allocate on the heap
67        0
68    }
69}
70
71impl BlockDecryptor for RingGcmBlockDecryptor {
72    fn decrypt(&self, length_and_ciphertext: &[u8], aad: &[u8]) -> Result<Vec<u8>> {
73        let mut result = Vec::with_capacity(length_and_ciphertext.len() - SIZE_LEN - NONCE_LEN);
74        result.extend_from_slice(&length_and_ciphertext[SIZE_LEN + NONCE_LEN..]);
75
76        let nonce = ring::aead::Nonce::try_assume_unique_for_key(
77            &length_and_ciphertext[SIZE_LEN..SIZE_LEN + NONCE_LEN],
78        )?;
79
80        self.key.open_in_place(nonce, Aad::from(aad), &mut result)?;
81
82        // Truncate result to remove the tag
83        result.resize(result.len() - TAG_LEN, 0u8);
84        Ok(result)
85    }
86
87    fn compute_plaintext_tag(&self, aad: &[u8], plaintext: &[u8]) -> Result<Vec<u8>> {
88        let mut plaintext = plaintext.to_vec();
89        let nonce = &plaintext[plaintext.len() - NONCE_LEN - TAG_LEN..plaintext.len() - TAG_LEN];
90        let nonce = ring::aead::Nonce::try_assume_unique_for_key(nonce)?;
91        let plaintext_end = plaintext.len() - NONCE_LEN - TAG_LEN;
92        let tag = self.key.seal_in_place_separate_tag(
93            nonce,
94            Aad::from(aad),
95            &mut plaintext[..plaintext_end],
96        )?;
97        Ok(tag.as_ref().to_vec())
98    }
99}
100
101pub(crate) trait BlockEncryptor: Debug + Send + Sync {
102    fn encrypt(&mut self, plaintext: &[u8], aad: &[u8]) -> Result<Vec<u8>>;
103}
104
105#[derive(Debug, Clone)]
106struct CounterNonce {
107    start: u128,
108    counter: u128,
109}
110
111impl CounterNonce {
112    pub fn new(rng: &SystemRandom) -> Result<Self> {
113        let mut buf = [0; 16];
114        rng.fill(&mut buf)?;
115
116        // Since this is a random seed value, endianness doesn't matter at all,
117        // and we can use whatever is platform-native.
118        let start = u128::from_ne_bytes(buf) & RIGHT_TWELVE;
119        let counter = start.wrapping_add(1);
120
121        Ok(Self { start, counter })
122    }
123
124    /// One accessor for the nonce bytes to avoid potentially flipping endianness
125    #[inline]
126    pub fn get_bytes(&self) -> [u8; NONCE_LEN] {
127        self.counter.to_le_bytes()[0..NONCE_LEN].try_into().unwrap()
128    }
129}
130
131impl NonceSequence for CounterNonce {
132    fn advance(&mut self) -> Result<ring::aead::Nonce, ring::error::Unspecified> {
133        // If we've wrapped around, we've exhausted this nonce sequence
134        if (self.counter & RIGHT_TWELVE) == (self.start & RIGHT_TWELVE) {
135            Err(ring::error::Unspecified)
136        } else {
137            // Otherwise, just advance and return the new value
138            let buf: [u8; NONCE_LEN] = self.get_bytes();
139            self.counter = self.counter.wrapping_add(1);
140            Ok(ring::aead::Nonce::assume_unique_for_key(buf))
141        }
142    }
143}
144
145#[derive(Debug, Clone)]
146pub(crate) struct RingGcmBlockEncryptor {
147    key: LessSafeKey,
148    nonce_sequence: CounterNonce,
149}
150
151impl RingGcmBlockEncryptor {
152    /// Create a new `RingGcmBlockEncryptor` with a given key and random nonce.
153    /// The nonce will advance appropriately with each block encryption and
154    /// return an error if it wraps around.
155    pub(crate) fn new(key_bytes: &[u8]) -> Result<Self> {
156        let rng = SystemRandom::new();
157        let algorithm = if key_bytes.len() == AES_128_GCM.key_len() {
158            &AES_128_GCM
159        } else if key_bytes.len() == AES_256_GCM.key_len() {
160            &AES_256_GCM
161        } else {
162            return Err(general_err!(
163                "Error creating RingGcmBlockEncryptor with unsupported key length: {}",
164                key_bytes.len()
165            ));
166        };
167
168        let key = UnboundKey::new(algorithm, key_bytes)
169            .map_err(|e| general_err!("Error creating {:?} key: {}", algorithm, e))?;
170        let nonce = CounterNonce::new(&rng)?;
171
172        Ok(Self {
173            key: LessSafeKey::new(key),
174            nonce_sequence: nonce,
175        })
176    }
177}
178
179impl BlockEncryptor for RingGcmBlockEncryptor {
180    fn encrypt(&mut self, plaintext: &[u8], aad: &[u8]) -> Result<Vec<u8>> {
181        // Create encrypted buffer.
182        // Format is: [ciphertext size, nonce, ciphertext, authentication tag]
183        let ciphertext_length: u32 = (NONCE_LEN + plaintext.len() + TAG_LEN)
184            .try_into()
185            .map_err(|err| General(format!("Plaintext data too long. {err:?}")))?;
186        // Not checking for overflow here because we've already checked for it with ciphertext_length
187        let mut ciphertext = Vec::with_capacity(SIZE_LEN + ciphertext_length as usize);
188        ciphertext.extend((ciphertext_length).to_le_bytes());
189
190        let nonce = self.nonce_sequence.advance()?;
191        ciphertext.extend(nonce.as_ref());
192        ciphertext.extend(plaintext);
193
194        let tag = self.key.seal_in_place_separate_tag(
195            nonce,
196            Aad::from(aad),
197            &mut ciphertext[SIZE_LEN + NONCE_LEN..],
198        )?;
199
200        ciphertext.extend(tag.as_ref());
201
202        debug_assert_eq!(SIZE_LEN + ciphertext_length as usize, ciphertext.len());
203
204        Ok(ciphertext)
205    }
206}
207
208#[cfg(test)]
209mod tests {
210    use super::*;
211
212    #[test]
213    fn test_round_trip() {
214        let key = [0u8; 16];
215        let mut encryptor = RingGcmBlockEncryptor::new(&key).unwrap();
216        let decryptor = RingGcmBlockDecryptor::new(&key).unwrap();
217
218        let plaintext = b"hello, world!";
219        let aad = b"some aad";
220
221        let ciphertext = encryptor.encrypt(plaintext, aad).unwrap();
222        let decrypted = decryptor.decrypt(&ciphertext, aad).unwrap();
223
224        assert_eq!(plaintext, decrypted.as_slice());
225    }
226}
parquet/encryption/ciphers.rs

parquet/encryption/
ciphers.rs
