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mp4-rust/src/mp4box/edts.rs
oftheforest 7cfdffbd71
Fix several overflows in box and track processing (#94)
* Fix several overflows in box and track processing

* Use size_of::<Type>() instead of magic numbers

* Fix a panic in Mp4Track::read_sample() for one-past-the-end

This appears to be a bug unmasked by other changes. read_sample() calls
sample_offset() then sample_size(), and assumes that if the former returns Ok
then the latter does as well. However, if the sample_id is one past the end,
sample_offset() might succeed (it only checks samples _up to_ the given
sample_id but not _including_ it) while sample_size() fails (because the sample
doesn't exist). read_sample() will then panic.

Fix this by duplicating the error propagation (that is currently done for
sample_offset) for sample_size, instead of unwrapping. This is a cautious
change that fixes the bug; alternatively, having sample_offset() call
sample_size() on the given sample_id and propagate any error might also work.

* Account for header size in box processing overflow fixes

* Ensure that boxes aren't bigger than their containers

Together with the entry_count checks, this eliminates several OOMs when reading
incorrect mp4 files.

* Fix order of arithmetic operations

This was due to an incorrect transcription when switching to checked
arithmetic, and fixes a bug that could cause attempted lookups of the wrong
chunk_id.
2023-02-18 11:46:51 -08:00

86 lines
1.9 KiB
Rust

use serde::Serialize;
use std::io::{Read, Seek, Write};
use crate::mp4box::elst::ElstBox;
use crate::mp4box::*;
#[derive(Debug, Clone, PartialEq, Eq, Default, Serialize)]
pub struct EdtsBox {
pub elst: Option<ElstBox>,
}
impl EdtsBox {
pub(crate) fn new() -> EdtsBox {
Default::default()
}
pub fn get_type(&self) -> BoxType {
BoxType::EdtsBox
}
pub fn get_size(&self) -> u64 {
let mut size = HEADER_SIZE;
if let Some(ref elst) = self.elst {
size += elst.box_size();
}
size
}
}
impl Mp4Box for EdtsBox {
fn box_type(&self) -> BoxType {
self.get_type()
}
fn box_size(&self) -> u64 {
self.get_size()
}
fn to_json(&self) -> Result<String> {
Ok(serde_json::to_string(&self).unwrap())
}
fn summary(&self) -> Result<String> {
let s = String::new();
Ok(s)
}
}
impl<R: Read + Seek> ReadBox<&mut R> for EdtsBox {
fn read_box(reader: &mut R, size: u64) -> Result<Self> {
let start = box_start(reader)?;
let mut edts = EdtsBox::new();
let header = BoxHeader::read(reader)?;
let BoxHeader { name, size: s } = header;
if s > size {
return Err(Error::InvalidData(
"edts box contains a box with a larger size than it",
));
}
if let BoxType::ElstBox = name {
let elst = ElstBox::read_box(reader, s)?;
edts.elst = Some(elst);
}
skip_bytes_to(reader, start + size)?;
Ok(edts)
}
}
impl<W: Write> WriteBox<&mut W> for EdtsBox {
fn write_box(&self, writer: &mut W) -> Result<u64> {
let size = self.box_size();
BoxHeader::new(self.box_type(), size).write(writer)?;
if let Some(ref elst) = self.elst {
elst.write_box(writer)?;
}
Ok(size)
}
}