* 🐛 fix BSON conformance issue
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
* 🐛 fix BSON conformance issue
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
* 🐛 reject ill-formed UTF-8 in CBOR/MessagePack/BSON text strings at decode time (#5531)
from_cbor()/from_msgpack()/from_bson() copied the raw bytes of a decoded
text string into the resulting json value without any UTF-8 validation,
even though RFC 8949 §3.1 (CBOR) and the MessagePack/BSON specifications
all require text strings to be valid UTF-8. Malformed input only failed
later, if the value was dump()'d, with a type_error.316 - so the
allow_exceptions=false pattern used specifically to get a discarded
sentinel instead of an exception did not discard this category of
malformed input, unlike every other kind of malformed binary input this
library rejects at decode time (see #5529).
Fix this at the single choke point shared by BSON/CBOR/MessagePack/UBJSON
string reads, binary_reader::get_string(): validate the bytes with the
UTF-8 DFA right after they are read, and report failures the same way as
every other binary_reader error (parse_error.113), so allow_exceptions
and strict discarding behave consistently. get_binary()/binary blob reads
are untouched and still accept arbitrary bytes, since only text strings
are required to be UTF-8.
There were two independent implementations of a UTF-8 validator: the
lexer's streaming scanner, and the serializer's Hoehrmann DFA used by
dump_escaped_impl(). Rather than write a third, the serializer's decode()
function, its utf8d table and the UTF8_ACCEPT/UTF8_REJECT constants are
extracted into detail/string_utils.hpp (a low-level header already
included before both detail/input/ and detail/output/), alongside a new
is_valid_utf8() helper built on the same decode() step. serializer.hpp's
dump_escaped_impl() now calls the shared decode(), so there is exactly
one UTF-8 validator in the codebase; dump()'s exact type_error.316
messages and byte-index reporting are unchanged (see the added
regression-guard test in unit-serialization.cpp).
Claude-Session: https://claude.ai/code/session_01N4RQ1Ahan5YAGbnAQGjZTY
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
Co-authored-by: Claude Sonnet 5 <noreply@anthropic.com>
* ⚡ validate only newly read bytes of binary-format strings
get_string() validated the whole result after each call, but get_bytes()
appends to it and CBOR indefinite-length strings collect all chunks in
the same result, so every chunk re-validated everything read before it.
An input of many small chunks took quadratic time (80000 one-byte chunks,
160 KB of input, took about 7 seconds). Only the newly read bytes are
validated now, which also matches RFC 8949's requirement that every
chunk is valid UTF-8 on its own.
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
---------
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
Co-authored-by: Claude Sonnet 5 <noreply@anthropic.com>
- warn about BSON marker 0x11 interoperability in both directions
- explain subtype-less binary normalization to subtype 0x00
- add a round-trip test for binary values without a subtype
Signed-off-by: YingqiDuan <141370165+YingqiDuan@users.noreply.github.com>
