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src/backup/data_blob.rs - CryptReader/CryptWriter: fix buffer size handling

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This commit is contained in:
Dietmar Maurer 2019-08-13 15:23:15 +02:00
parent 548c9489d7
commit 6082216343
1 changed files with 61 additions and 21 deletions
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82
src/backup/data_blob.rs
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@ -311,6 +311,7 @@ use std::io::{Read, BufRead, BufReader, Write, Seek, SeekFrom};
struct CryptReader<R> {
reader: R,
small_read_buf: Vec<u8>,
block_size: usize,
crypter: openssl::symm::Crypter,
finalized: bool,
@ -319,13 +320,14 @@ struct CryptReader<R> {
impl <R: BufRead> CryptReader<R> {
fn new(reader: R, iv: [u8; 16], tag: [u8; 16], config: &CryptConfig) -> Result<Self, Error> {
let block_size = config.cipher().block_size();
if block_size.count_ones() != 1 || block_size > 1024 {
let block_size = config.cipher().block_size(); // Note: block size is normally 1 byte for stream ciphers
if block_size.count_ones() != 1 || block_size > 512 {
bail!("unexpected Cipher block size {}", block_size);
}
let mut crypter = config.data_crypter(&iv, openssl::symm::Mode::Decrypt)?;
crypter.set_tag(&tag)?;
Ok(Self { reader, crypter, block_size, finalized: false })
Ok(Self { reader, crypter, block_size, finalized: false, small_read_buf: Vec::new() })
}
fn finish(self) -> Result<R, Error> {
@ -339,30 +341,63 @@ impl <R: BufRead> CryptReader<R> {
impl <R: BufRead> Read for CryptReader<R> {
fn read(&mut self, buf: &mut [u8]) -> Result<usize, std::io::Error> {
if buf.len() <= 2*self.block_size {
panic!("CryptReader read buffer too small!");
if self.small_read_buf.len() > 0 {
let max = if self.small_read_buf.len() > buf.len() { buf.len() } else { self.small_read_buf.len() };
let rest = self.small_read_buf.split_off(max);
buf[..max].copy_from_slice(&self.small_read_buf);
self.small_read_buf = rest;
return Ok(max);
}
let data = self.reader.fill_buf()?;
if data.len() == 0 { // EOF
let rest = self.crypter.finalize(buf)?;
self.finalized = true;
Ok(rest)
} else {
let mut read_size = buf.len() - self.block_size;
if read_size > data.len() {
read_size = data.len();
// handle small read buffers
if buf.len() <= 2*self.block_size {
let mut outbuf = [0u8; 1024];
let count = if data.len() == 0 { // EOF
let written = self.crypter.finalize(&mut outbuf)?;
self.finalized = true;
written
} else {
let mut read_size = outbuf.len() - self.block_size;
if read_size > data.len() {
read_size = data.len();
}
let written = self.crypter.update(&data[..read_size], &mut outbuf)?;
self.reader.consume(read_size);
written
};
if count > buf.len() {
buf.copy_from_slice(&outbuf[..buf.len()]);
self.small_read_buf = outbuf[buf.len()..count].to_vec();
return Ok(buf.len());
} else {
buf[..count].copy_from_slice(&outbuf[..count]);
return Ok(count);
}
} else {
if data.len() == 0 { // EOF
let rest = self.crypter.finalize(buf)?;
self.finalized = true;
return Ok(rest)
} else {
let mut read_size = buf.len() - self.block_size;
if read_size > data.len() {
read_size = data.len();
}
let count = self.crypter.update(&data[..read_size], buf)?;
self.reader.consume(read_size);
return Ok(count)
}
let count = self.crypter.update(&data[..read_size], buf)?;
self.reader.consume(read_size);
Ok(count)
}
}
}
struct CryptWriter<W> {
writer: W,
block_size: usize,
encr_buf: [u8; 64*1024],
iv: [u8; 16],
crypter: openssl::symm::Crypter,
@ -373,10 +408,11 @@ impl <W: Write> CryptWriter<W> {
fn new(writer: W, config: &CryptConfig) -> Result<Self, Error> {
let mut iv = [0u8; 16];
proxmox::sys::linux::fill_with_random_data(&mut iv)?;
let block_size = config.cipher().block_size();
let crypter = config.data_crypter(&iv, openssl::symm::Mode::Encrypt)?;
Ok(Self { writer, iv, crypter, encr_buf: [0u8; 64*1024] })
Ok(Self { writer, iv, crypter, block_size, encr_buf: [0u8; 64*1024] })
}
fn finish(mut self) -> Result<(W, [u8; 16], [u8; 16]), Error> {
@ -397,7 +433,11 @@ impl <W: Write> CryptWriter<W> {
impl <W: Write> Write for CryptWriter<W> {
fn write(&mut self, buf: &[u8]) -> Result<usize, std::io::Error> {
let count = self.crypter.update(buf, &mut self.encr_buf)
let mut write_size = buf.len();
if write_size > (self.encr_buf.len() - self.block_size) {
write_size = self.encr_buf.len() - self.block_size;
}
let count = self.crypter.update(&buf[..write_size], &mut self.encr_buf)
.map_err(|err| {
std::io::Error::new(
std::io::ErrorKind::Other,
@ -406,7 +446,7 @@ impl <W: Write> Write for CryptWriter<W> {
self.writer.write_all(&self.encr_buf[..count])?;
Ok(count)
Ok(write_size)
}
fn flush(&mut self) -> Result<(), std::io::Error> {
@ -801,7 +841,7 @@ impl <'a, R: Read> DataBlobReader<'a, R> {
reader.read_exact(&mut iv)?;
reader.read_exact(&mut expected_tag)?;
let csum_reader = ChecksumReader::new(reader, None);
let decrypt_reader = CryptReader::new(BufReader::with_capacity(64*1024,csum_reader), iv, expected_tag, config.unwrap())?;
let decrypt_reader = CryptReader::new(BufReader::with_capacity(64*1024, csum_reader), iv, expected_tag, config.unwrap())?;
Ok(Self { state: BlobReaderState::Encrypted { expected_crc, decrypt_reader }})
}
ENCR_COMPR_BLOB_MAGIC_1_0 => {
@ -811,7 +851,7 @@ impl <'a, R: Read> DataBlobReader<'a, R> {
reader.read_exact(&mut iv)?;
reader.read_exact(&mut expected_tag)?;
let csum_reader = ChecksumReader::new(reader, None);
let decrypt_reader = CryptReader::new(BufReader::with_capacity(64*1024,csum_reader), iv, expected_tag, config.unwrap())?;
let decrypt_reader = CryptReader::new(BufReader::with_capacity(64*1024, csum_reader), iv, expected_tag, config.unwrap())?;
let decompr = zstd::stream::read::Decoder::new(decrypt_reader)?;
Ok(Self { state: BlobReaderState::EncryptedCompressed { expected_crc, decompr }})
}