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Raise ValueError if password is longer than 72 bytes (#1000)

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* move existing tests for long pws into a separate test to assert ValueError is raised

* add more tests for edge cases around the 72 byte length

* raise ValuError if the password passed to hashpw() is longer than 72 bytes

* improve error message

* update test_2a_wraparound_bug

* remove obsolete re-assignment of `password`

* remove obsolete tests

the "raise on passwords longer than 72 chars" behavior is already covered in `test_hashpw_raises_correctly_for_long_passwords`,
and the `test_2a_wraparound_bug` is not relevant anymore (this previously ensured truncation, which we do not do anymore)
This commit is contained in:
manu 2025-07-04 06:07:06 +02:00 committed by GitHub
parent c4d027ff2c
commit d50ab05b2b
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2 changed files with 29 additions and 28 deletions
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11
src/_bcrypt/src/lib.rs
View File

@ -77,7 +77,16 @@ fn hashpw<'p>(
// bytes on the updated prefix $2b$, but leaving $2a$ unchanged for
// compatibility. However, pyca/bcrypt 2.0.0 *did* correctly truncate inputs
// on $2a$, so we do it here to preserve compatibility with 2.0.0
let password = &password[..password.len().min(72)];
// Silent truncation is _probably_ not the best idea, even if the "original"
// OpenBSD implementation did/does this.
// We prefer to raise a ValueError in this case - if the user _wants_ to truncate,
// they can always do so manually by passing s[:72] instead of s into hashpw().
if password.len() > 72 {
return Err(pyo3::exceptions::PyValueError::new_err(
"password cannot be longer than 72 bytes, truncate manually if necessary (e.g. my_password[:72])",
));
}
// salt here is not just the salt bytes, but rather an encoded value
// containing a version number, number of rounds, and the salt.

46
tests/test_bcrypt.py
View File

@ -121,24 +121,6 @@ _test_vectors = [
b"$2a$05$XXXXXXXXXXXXXXXXXXXXXO",
b"$2a$05$XXXXXXXXXXXXXXXXXXXXXOAcXxm9kjPGEMsLznoKqmqw7tc8WCx4a",
),
(
b"0123456789abcdefghijklmnopqrstuvwxyz"
b"ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"
b"chars after 72 are ignored",
b"$2a$05$abcdefghijklmnopqrstuu",
b"$2a$05$abcdefghijklmnopqrstuu5s2v8.iXieOjg/.AySBTTZIIVFJeBui",
),
(
b"\xaa\xaa\xaa\xaa\xaa\xaa\xaa\xaa\xaa\xaa\xaa\xaa"
b"\xaa\xaa\xaa\xaa\xaa\xaa\xaa\xaa\xaa\xaa\xaa\xaa"
b"\xaa\xaa\xaa\xaa\xaa\xaa\xaa\xaa\xaa\xaa\xaa\xaa"
b"\xaa\xaa\xaa\xaa\xaa\xaa\xaa\xaa\xaa\xaa\xaa\xaa"
b"\xaa\xaa\xaa\xaa\xaa\xaa\xaa\xaa\xaa\xaa\xaa\xaa"
b"\xaa\xaa\xaa\xaa\xaa\xaa\xaa\xaa\xaa\xaa\xaa\xaa"
b"chars after 72 are ignored as usual",
b"$2a$05$/OK.fbVrR/bpIqNJ5ianF.",
b"$2a$05$/OK.fbVrR/bpIqNJ5ianF.swQOIzjOiJ9GHEPuhEkvqrUyvWhEMx6",
),
(
b"\xa3",
b"$2a$05$/OK.fbVrR/bpIqNJ5ianF.",
@ -252,6 +234,25 @@ def test_checkpw_2y_prefix(password, hashed, expected):
assert bcrypt.checkpw(password, hashed) is True
@pytest.mark.parametrize(
("pw_length", "should_raise"),
[
(71, False),
(72, False),
(73, True),
],
)
def test_hashpw_raises_correctly_for_long_passwords(pw_length, should_raise):
password = b"\xaa" * pw_length
salt = b"$2b$04$xnFVhJsTzsFBTeP3PpgbMe"
if should_raise:
with pytest.raises(ValueError):
bcrypt.hashpw(password, salt)
else:
bcrypt.hashpw(password, salt)
def test_hashpw_invalid():
with pytest.raises(ValueError):
bcrypt.hashpw(b"password", b"$2z$04$cVWp4XaNU8a4v1uMRum2SO")
@ -490,15 +491,6 @@ def test_invalid_params(password, salt, desired_key_bytes, rounds, error):
bcrypt.kdf(password, salt, desired_key_bytes, rounds)
def test_2a_wraparound_bug():
assert (
bcrypt.hashpw(
(b"0123456789" * 26)[:255], b"$2a$04$R1lJ2gkNaoPGdafE.H.16."
)
== b"$2a$04$R1lJ2gkNaoPGdafE.H.16.1MKHPvmKwryeulRe225LKProWYwt9Oi"
)
def test_multithreading():
def create_user(pw):
salt = bcrypt.gensalt(4)