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fix(core/debug): separate buffer for debuglink to prevent BufferLock deadlocks

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This commit is contained in:
matejcik 2022-10-19 11:43:56 +02:00 committed by matejcik
parent d0f1095842
commit ac6936d65d
2 changed files with 57 additions and 79 deletions
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11
core/src/trezor/wire/__init__.py
View File

@ -136,6 +136,10 @@ PROTOBUF_BUFFER_SIZE = 8192
WIRE_BUFFER = bytearray(PROTOBUF_BUFFER_SIZE)
if __debug__:
PROTOBUF_BUFFER_SIZE_DEBUG = 1024
WIRE_BUFFER_DEBUG = bytearray(PROTOBUF_BUFFER_SIZE_DEBUG)
class Context:
def __init__(self, iface: WireInterface, sid: int, buffer: bytearray) -> None:
@ -381,7 +385,12 @@ async def _handle_single_message(
async def handle_session(
iface: WireInterface, session_id: int, is_debug_session: bool = False
) -> None:
ctx = Context(iface, session_id, WIRE_BUFFER)
if __debug__ and is_debug_session:
ctx_buffer = WIRE_BUFFER_DEBUG
else:
ctx_buffer = WIRE_BUFFER
ctx = Context(iface, session_id, ctx_buffer)
next_msg: codec_v1.Message | None = None
if __debug__ and is_debug_session:

125
core/src/trezor/wire/codec_v1.py
View File

@ -5,7 +5,6 @@ from typing import TYPE_CHECKING
from trezor import io, loop, utils
if TYPE_CHECKING:
from typing import Any
from trezorio import WireInterface
_REP_LEN = const(64)
@ -19,34 +18,6 @@ _REP_CONT_DATA = const(1) # offset of data in the continuation report
SESSION_ID = const(0)
INVALID_TYPE = const(-1)
# The wire buffer is shared between the main wire interface and debuglink
# (see __init__.py). There's no obvious guarantee that both interfaces won't
# use it at the same time, thus we check this at runtime in debug builds.
if __debug__:
class BufferLock: # type: ignore [Class declaration "BufferLock" is obscured by a declaration of the same name]
def __init__(self) -> None:
self.in_use = False
def __enter__(self) -> None:
assert not self.in_use, "global buffer already used by another context"
self.in_use = True
def __exit__(self, exc_type: Any, value: Any, traceback: Any) -> None:
self.in_use = False
else:
class BufferLock:
def __enter__(self) -> None:
pass
def __exit__(self, exc_type: Any, value: Any, traceback: Any) -> None:
pass
buffer_lock = BufferLock()
class CodecError(Exception):
pass
@ -71,32 +42,31 @@ async def read_message(iface: WireInterface, buffer: utils.BufferType) -> Messag
read_and_throw_away = False
with buffer_lock:
if msize > len(buffer):
# allocate a new buffer to fit the message
try:
mdata: utils.BufferType = bytearray(msize)
except MemoryError:
mdata = bytearray(_REP_LEN)
read_and_throw_away = True
if msize > len(buffer):
# allocate a new buffer to fit the message
try:
mdata: utils.BufferType = bytearray(msize)
except MemoryError:
mdata = bytearray(_REP_LEN)
read_and_throw_away = True
else:
# reuse a part of the supplied buffer
mdata = memoryview(buffer)[:msize]
# buffer the initial data
nread = utils.memcpy(mdata, 0, report, _REP_INIT_DATA)
while nread < msize:
# wait for continuation report
report = await read
if report[0] != _REP_MARKER:
raise CodecError("Invalid magic")
# buffer the continuation data
if read_and_throw_away:
nread += len(report) - 1
else:
# reuse a part of the supplied buffer
mdata = memoryview(buffer)[:msize]
# buffer the initial data
nread = utils.memcpy(mdata, 0, report, _REP_INIT_DATA)
while nread < msize:
# wait for continuation report
report = await read
if report[0] != _REP_MARKER:
raise CodecError("Invalid magic")
# buffer the continuation data
if read_and_throw_away:
nread += len(report) - 1
else:
nread += utils.memcpy(mdata, nread, report, _REP_CONT_DATA)
nread += utils.memcpy(mdata, nread, report, _REP_CONT_DATA)
if read_and_throw_away:
raise CodecError("Message too large")
@ -107,31 +77,30 @@ async def read_message(iface: WireInterface, buffer: utils.BufferType) -> Messag
async def write_message(iface: WireInterface, mtype: int, mdata: bytes) -> None:
write = loop.wait(iface.iface_num() | io.POLL_WRITE)
with buffer_lock:
# gather data from msg
msize = len(mdata)
# gather data from msg
msize = len(mdata)
# prepare the report buffer with header data
report = bytearray(_REP_LEN)
repofs = _REP_INIT_DATA
ustruct.pack_into(
_REP_INIT, report, 0, _REP_MARKER, _REP_MAGIC, _REP_MAGIC, mtype, msize
)
# prepare the report buffer with header data
report = bytearray(_REP_LEN)
repofs = _REP_INIT_DATA
ustruct.pack_into(
_REP_INIT, report, 0, _REP_MARKER, _REP_MAGIC, _REP_MAGIC, mtype, msize
)
nwritten = 0
nwritten = 0
while True:
# copy as much as possible to the report buffer
nwritten += utils.memcpy(report, repofs, mdata, nwritten)
# write the report
while True:
# copy as much as possible to the report buffer
nwritten += utils.memcpy(report, repofs, mdata, nwritten)
# write the report
while True:
await write
n = iface.write(report)
if n == len(report):
break
# if we have more data to write, use continuation reports for it
if nwritten < msize:
repofs = _REP_CONT_DATA
else:
await write
n = iface.write(report)
if n == len(report):
break
# if we have more data to write, use continuation reports for it
if nwritten < msize:
repofs = _REP_CONT_DATA
else:
break