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Secure Payload length fixes

This commit is contained in:
Alexey 2026-02-23 02:38:25 +03:00
parent 8c1d66a03e
commit d4d867156a
No known key found for this signature in database
1 changed files with 8 additions and 16 deletions
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24
src/protocol/constants.rs
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@ -162,21 +162,12 @@ pub fn is_valid_secure_payload_len(data_len: usize) -> bool {
} }
/// Compute Secure Intermediate payload length from wire length. /// Compute Secure Intermediate payload length from wire length.
/// /// Secure mode strips up to 3 random tail bytes by truncating to 4-byte boundary.
/// Returns `None` for invalid Secure lengths (e.g. divisible by 4).
pub fn secure_payload_len_from_wire_len(wire_len: usize) -> Option<usize> { pub fn secure_payload_len_from_wire_len(wire_len: usize) -> Option<usize> {
if wire_len < 4 { if wire_len < 4 {
return None; return None;
} }
let padding_len = wire_len % 4; Some(wire_len - (wire_len % 4))
if padding_len == 0 || wire_len < padding_len {
return None;
}
let payload_len = wire_len - padding_len;
if !is_valid_secure_payload_len(payload_len) {
return None;
}
Some(payload_len)
} }
/// Generate padding length for Secure Intermediate protocol. /// Generate padding length for Secure Intermediate protocol.
@ -383,7 +374,7 @@ mod tests {
#[test] #[test]
fn secure_wire_len_roundtrip_for_aligned_payload() { fn secure_wire_len_roundtrip_for_aligned_payload() {
for payload_len in (4..4096).step_by(4) { for payload_len in (4..4096).step_by(4) {
for padding in 1..=3usize { for padding in 0..=3usize {
let wire_len = payload_len + padding; let wire_len = payload_len + padding;
let recovered = secure_payload_len_from_wire_len(wire_len); let recovered = secure_payload_len_from_wire_len(wire_len);
assert_eq!(recovered, Some(payload_len)); assert_eq!(recovered, Some(payload_len));
@ -392,9 +383,10 @@ mod tests {
} }
#[test] #[test]
fn secure_wire_len_rejects_aligned_totals() { fn secure_wire_len_rejects_too_short_frames() {
for wire_len in (0..1024).step_by(4) { assert_eq!(secure_payload_len_from_wire_len(0), None);
assert_eq!(secure_payload_len_from_wire_len(wire_len), None); assert_eq!(secure_payload_len_from_wire_len(1), None);
} assert_eq!(secure_payload_len_from_wire_len(2), None);
assert_eq!(secure_payload_len_from_wire_len(3), None);
} }
} }