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https://chromium.googlesource.com/crosvm/crosvm
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eb1640e301
Impose a limit on the maximum nesting of file formats that can open more files. For example, a qcow2 file can have a backing file, which could be another qcow2 file with a backing file (or even the same file as the original), potentially causing unbounded recursion. BUG=b:198326611 TEST=cros_fuzz Change-Id: I2f8573a7c71c6d8b310f2c2a75a240f2f8f0c9b1 Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/crosvm/+/3146214 Tested-by: kokoro <noreply+kokoro@google.com> Reviewed-by: Cody Schuffelen <schuffelen@google.com> Reviewed-by: Chirantan Ekbote <chirantan@chromium.org> Commit-Queue: Daniel Verkamp <dverkamp@chromium.org>
39 lines
1.2 KiB
Rust
39 lines
1.2 KiB
Rust
// Copyright 2019 The Chromium OS Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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#![no_main]
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use cros_fuzz::fuzz_target;
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use disk::QcowFile;
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use tempfile;
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use std::io::{Cursor, Read, Seek, SeekFrom, Write};
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use std::mem::size_of;
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// Take the first 64 bits of data as an address and the next 64 bits as data to
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// store there. The rest of the data is used as a qcow image.
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fuzz_target!(|bytes| {
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if bytes.len() < 16 {
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// Need an address and data, each are 8 bytes.
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return;
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}
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let mut disk_image = Cursor::new(bytes);
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let addr = read_u64(&mut disk_image);
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let value = read_u64(&mut disk_image);
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let max_nesting_depth = 10;
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let mut disk_file = tempfile::tempfile().unwrap();
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disk_file.write_all(&bytes[16..]).unwrap();
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disk_file.seek(SeekFrom::Start(0)).unwrap();
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if let Ok(mut qcow) = QcowFile::from(disk_file, max_nesting_depth) {
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if qcow.seek(SeekFrom::Start(addr)).is_ok() {
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let _ = qcow.write_all(&value.to_le_bytes());
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}
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}
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});
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fn read_u64<T: Read>(readable: &mut T) -> u64 {
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let mut buf = [0u8; size_of::<u64>()];
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readable.read_exact(&mut buf[..]).unwrap();
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u64::from_le_bytes(buf)
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}
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