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fix: align OCB3 decrypt length checks with encrypt #774

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fix: align OCB3 decrypt length checks with encrypt #774

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98de513
fix: align OCB3 decrypt length checks with encrypt
radik878 Jan 23, 2026
4ddb1c0
add test
radik878 Jan 23, 2026
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2 changes: 1 addition & 1 deletion ocb3/src/lib.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -286,7 +286,7 @@ where
buffer: InOutBuf<'_, '_, u8>,
) -> aead::Result<aead::Tag<Self>> {
let max_len = 1 << (L_TABLE_SIZE + 4);
if (buffer.len() > max_len) || (associated_data.len() > max_len) {
if (buffer.len() >= max_len) || (associated_data.len() >= max_len) {
return Err(aead::Error);
}

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14 changes: 14 additions & 0 deletions ocb3/tests/len_check.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -22,3 +22,17 @@ fn ocb3_len_check() {
.encrypt_inout_detached(&nonce, &[], (&mut buf[..MAX_SIZE - 1]).into())
.unwrap();
}

#[test]
fn ocb3_len_check_decrypt() {
let key = hex!("000102030405060708090A0B0C0D0E0F").into();
let nonce = hex!("BBAA9988776655443322110F").into();
let cipher = Ocb3::<Aes128, U12, U16, L_SIZE>::new(&key);

// Buffer length equal to MAX_SIZE must be rejected with an error, not panic.
let mut buf = vec![0u8; MAX_SIZE];
let tag = aead::Tag::<Ocb3<Aes128, U12, U16, L_SIZE>>::default();
cipher
.decrypt_inout_detached(&nonce, &[], (&mut buf[..]).into(), &tag)
.unwrap_err();
}