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harden ember-persistence — safe u32 length casts in format layer #104

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Merged
kacy merged 1 commit into from
Feb 12, 2026
Merged

harden ember-persistence — safe u32 length casts in format layer #104

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20 changes: 10 additions & 10 deletions crates/ember-persistence/src/aof.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -216,15 +216,15 @@ impl AofRecord {
AofRecord::LPush { key, values } => {
format::write_u8(&mut buf, TAG_LPUSH)?;
format::write_bytes(&mut buf, key.as_bytes())?;
format::write_u32(&mut buf, values.len() as u32)?;
format::write_len(&mut buf, values.len())?;
for v in values {
format::write_bytes(&mut buf, v)?;
}
}
AofRecord::RPush { key, values } => {
format::write_u8(&mut buf, TAG_RPUSH)?;
format::write_bytes(&mut buf, key.as_bytes())?;
format::write_u32(&mut buf, values.len() as u32)?;
format::write_len(&mut buf, values.len())?;
for v in values {
format::write_bytes(&mut buf, v)?;
}
Expand All @@ -240,7 +240,7 @@ impl AofRecord {
AofRecord::ZAdd { key, members } => {
format::write_u8(&mut buf, TAG_ZADD)?;
format::write_bytes(&mut buf, key.as_bytes())?;
format::write_u32(&mut buf, members.len() as u32)?;
format::write_len(&mut buf, members.len())?;
for (score, member) in members {
format::write_f64(&mut buf, *score)?;
format::write_bytes(&mut buf, member.as_bytes())?;
Expand All @@ -249,7 +249,7 @@ impl AofRecord {
AofRecord::ZRem { key, members } => {
format::write_u8(&mut buf, TAG_ZREM)?;
format::write_bytes(&mut buf, key.as_bytes())?;
format::write_u32(&mut buf, members.len() as u32)?;
format::write_len(&mut buf, members.len())?;
for member in members {
format::write_bytes(&mut buf, member.as_bytes())?;
}
Expand All @@ -274,7 +274,7 @@ impl AofRecord {
AofRecord::HSet { key, fields } => {
format::write_u8(&mut buf, TAG_HSET)?;
format::write_bytes(&mut buf, key.as_bytes())?;
format::write_u32(&mut buf, fields.len() as u32)?;
format::write_len(&mut buf, fields.len())?;
for (field, value) in fields {
format::write_bytes(&mut buf, field.as_bytes())?;
format::write_bytes(&mut buf, value)?;
Expand All @@ -283,7 +283,7 @@ impl AofRecord {
AofRecord::HDel { key, fields } => {
format::write_u8(&mut buf, TAG_HDEL)?;
format::write_bytes(&mut buf, key.as_bytes())?;
format::write_u32(&mut buf, fields.len() as u32)?;
format::write_len(&mut buf, fields.len())?;
for field in fields {
format::write_bytes(&mut buf, field.as_bytes())?;
}
Expand All @@ -297,15 +297,15 @@ impl AofRecord {
AofRecord::SAdd { key, members } => {
format::write_u8(&mut buf, TAG_SADD)?;
format::write_bytes(&mut buf, key.as_bytes())?;
format::write_u32(&mut buf, members.len() as u32)?;
format::write_len(&mut buf, members.len())?;
for member in members {
format::write_bytes(&mut buf, member.as_bytes())?;
}
}
AofRecord::SRem { key, members } => {
format::write_u8(&mut buf, TAG_SREM)?;
format::write_bytes(&mut buf, key.as_bytes())?;
format::write_u32(&mut buf, members.len() as u32)?;
format::write_len(&mut buf, members.len())?;
for member in members {
format::write_bytes(&mut buf, member.as_bytes())?;
}
Expand Down Expand Up @@ -343,7 +343,7 @@ impl AofRecord {
format::write_u8(&mut buf, TAG_VADD)?;
format::write_bytes(&mut buf, key.as_bytes())?;
format::write_bytes(&mut buf, element.as_bytes())?;
format::write_u32(&mut buf, vector.len() as u32)?;
format::write_len(&mut buf, vector.len())?;
for &v in vector {
format::write_f32(&mut buf, v)?;
}
Expand Down Expand Up @@ -653,7 +653,7 @@ impl AofWriter {
if let Some(ref key) = self.encryption_key {
let (nonce, ciphertext) = crate::encryption::encrypt_record(key, &payload)?;
self.writer.write_all(&nonce)?;
format::write_u32(&mut self.writer, ciphertext.len() as u32)?;
format::write_len(&mut self.writer, ciphertext.len())?;
self.writer.write_all(&ciphertext)?;
return Ok(());
}
Expand Down
21 changes: 20 additions & 1 deletion crates/ember-persistence/src/format.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -94,9 +94,28 @@ pub fn write_f64(w: &mut impl Write, val: f64) -> io::Result<()> {
w.write_all(&val.to_le_bytes())
}

/// Writes a collection length as u32, returning an error if it exceeds `u32::MAX`.
pub fn write_len(w: &mut impl Write, len: usize) -> io::Result<()> {
let len = u32::try_from(len).map_err(|_| {
io::Error::new(
io::ErrorKind::InvalidInput,
format!("collection length {len} exceeds u32::MAX"),
)
})?;
write_u32(w, len)
}

/// Writes a length-prefixed byte slice: `[len: u32][data]`.
///
/// Returns an error if the data length exceeds `u32::MAX`.
pub fn write_bytes(w: &mut impl Write, data: &[u8]) -> io::Result<()> {
write_u32(w, data.len() as u32)?;
let len = u32::try_from(data.len()).map_err(|_| {
io::Error::new(
io::ErrorKind::InvalidInput,
format!("data length {} exceeds u32::MAX", data.len()),
)
})?;
write_u32(w, len)?;
w.write_all(data)
}

Expand Down
20 changes: 13 additions & 7 deletions crates/ember-persistence/src/snapshot.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -280,30 +280,30 @@ impl SnapshotWriter {
}
SnapValue::List(deque) => {
format::write_u8(&mut buf, TYPE_LIST)?;
format::write_u32(&mut buf, deque.len() as u32)?;
format::write_len(&mut buf, deque.len())?;
for item in deque {
format::write_bytes(&mut buf, item)?;
}
}
SnapValue::SortedSet(members) => {
format::write_u8(&mut buf, TYPE_SORTED_SET)?;
format::write_u32(&mut buf, members.len() as u32)?;
format::write_len(&mut buf, members.len())?;
for (score, member) in members {
format::write_f64(&mut buf, *score)?;
format::write_bytes(&mut buf, member.as_bytes())?;
}
}
SnapValue::Hash(map) => {
format::write_u8(&mut buf, TYPE_HASH)?;
format::write_u32(&mut buf, map.len() as u32)?;
format::write_len(&mut buf, map.len())?;
for (field, value) in map {
format::write_bytes(&mut buf, field.as_bytes())?;
format::write_bytes(&mut buf, value)?;
}
}
SnapValue::Set(set) => {
format::write_u8(&mut buf, TYPE_SET)?;
format::write_u32(&mut buf, set.len() as u32)?;
format::write_len(&mut buf, set.len())?;
for member in set {
format::write_bytes(&mut buf, member.as_bytes())?;
}
Expand All @@ -323,7 +323,7 @@ impl SnapshotWriter {
format::write_u32(&mut buf, *connectivity)?;
format::write_u32(&mut buf, *expansion_add)?;
format::write_u32(&mut buf, *dim)?;
format::write_u32(&mut buf, elements.len() as u32)?;
format::write_len(&mut buf, elements.len())?;
for (name, vector) in elements {
format::write_bytes(&mut buf, name.as_bytes())?;
for &v in vector {
Expand All @@ -343,13 +343,19 @@ impl SnapshotWriter {
#[cfg(feature = "encryption")]
if let Some(ref key) = self.encryption_key {
let (nonce, ciphertext) = crate::encryption::encrypt_record(key, &buf)?;
let ct_len = u32::try_from(ciphertext.len()).map_err(|_| {
io::Error::new(
io::ErrorKind::InvalidInput,
"encrypted record exceeds u32::MAX bytes",
)
})?;
// footer CRC covers the encrypted envelope
self.hasher.update(&nonce);
let ct_len_bytes = (ciphertext.len() as u32).to_le_bytes();
let ct_len_bytes = ct_len.to_le_bytes();
self.hasher.update(&ct_len_bytes);
self.hasher.update(&ciphertext);
self.writer.write_all(&nonce)?;
format::write_u32(&mut self.writer, ciphertext.len() as u32)?;
format::write_u32(&mut self.writer, ct_len)?;
self.writer.write_all(&ciphertext)?;
self.count += 1;
return Ok(());
Expand Down