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fido_u2f: parse and serialize keypath as LE

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This commit is contained in:
Jan Pochyla 2018-07-24 13:06:56 +02:00
parent 9d4e38bd4c
commit 934b32707c
1 changed files with 9 additions and 4 deletions
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13
src/apps/fido_u2f/__init__.py
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@ -565,7 +565,7 @@ def msg_register_sign(challenge: bytes, app_id: bytes) -> bytes:
pubkey = nist256p1.publickey(node.private_key(), False)
# first half of keyhandle is keypath
keybuf = ustruct.pack(">8L", *keypath)
keybuf = ustruct.pack("<8L", *keypath)
# second half of keyhandle is a hmac of app_id and keypath
keybase = hmac.Hmac(node.private_key(), app_id, hashlib.sha256)
@ -626,7 +626,12 @@ def msg_authenticate(req: Msg, state: ConfirmState) -> Cmd:
auth = overlay_struct(req.data, req_cmd_authenticate(khlen))
# check the keyHandle and generate the signing key
node = msg_authenticate_genkey(auth.appId, auth.keyHandle)
node = msg_authenticate_genkey(auth.appId, auth.keyHandle, "<8L")
if node is None:
# prior to firmware version 2.0.8, keypath was serialized in a
# big-endian manner, instead of little endian, like in trezor-mcu.
# try to parse it as big-endian now and check the HMAC.
node = msg_authenticate_genkey(auth.appId, auth.keyHandle, ">8L")
if node is None:
# specific error logged in msg_authenticate_genkey
return msg_error(req.cid, _SW_WRONG_DATA)
@ -665,12 +670,12 @@ def msg_authenticate(req: Msg, state: ConfirmState) -> Cmd:
return Cmd(req.cid, _CMD_MSG, buf)
def msg_authenticate_genkey(app_id: bytes, keyhandle: bytes):
def msg_authenticate_genkey(app_id: bytes, keyhandle: bytes, pathformat: str):
from apps.common import seed
# unpack the keypath from the first half of keyhandle
keybuf = keyhandle[:32]
keypath = ustruct.unpack(">8L", keybuf)
keypath = ustruct.unpack(pathformat, keybuf)
# check high bit for hardened keys
for i in keypath: