Fix CBOR tag handlers not recognizing tags 0-5 and 21-23 (#5331)

* Fix CBOR tag handlers not recognizing tags 0-5 and 21-23

The tagged-item switch in binary_reader::parse_cbor_internal() only handled
head bytes 0xC6-0xD4 and 0xD8-0xDB. Bytes 0xC0-0xC5 (tags 0-5: date/time,
epoch, bignum, decimal, bigfloat) and 0xD5-0xD7 (tags 21-23: base64url,
base64, base16 conversion hints) fell through to the default case and were
reported as invalid bytes, even under cbor_tag_handler_t::ignore and ::store,
despite being valid CBOR major-type-6 tags per RFC 8949.

Add the missing case labels so the full 0xC0-0xDB range is handled
uniformly. Extend the "Tagged values" test in unit-cbor.cpp to cover
0xC0-0xD7, and update the CBOR docs to state the corrected tag range.

Fixes #5315

Signed-off-by: sahilkamate03 <45514385+sahilkamate03@users.noreply.github.com>

* Fix stale CBOR tag docs and add store-mode binary-payload test

The "Incomplete mapping" warning still listed tags 0-5 (date/time,
bignum, decimal fraction, bigfloat) and 21-23 (expected conversions)
as unsupported, even though they now parse correctly under
cbor_tag_handler_t::ignore/store, same as 0xC6..0xD4/0xD8..0xDB.
Remove those five bullets and cross-reference the "Tagged items"
warning below, matching the equivalent docs fix landed independently
in PR #5367.

Also add a cbor_tag_handler_t::store test that wraps a binary
payload (not just a string) for every byte in 0xC0..0xD7, confirming
these tags are unwrapped the same way as 0xC6..0xD4 rather than
mistaken for the 0xD8..0xDB binary-subtype marker syntax, per review
feedback on #5331.

Signed-off-by: sahilkamate03 <45514385+sahilkamate03@users.noreply.github.com>

---------

Signed-off-by: sahilkamate03 <45514385+sahilkamate03@users.noreply.github.com>
This commit is contained in:
Sahil_Kamate
2026-08-19 20:19:47 +02:00
committed by GitHub
parent ce87157d4e
commit b5378e8deb
4 changed files with 36 additions and 10 deletions
@@ -773,7 +773,13 @@ class binary_reader
case 0xBF: // map (indefinite length)
return get_cbor_object(detail::unknown_size(), tag_handler);
case 0xC6: // tagged item
case 0xC0: // tagged item
case 0xC1:
case 0xC2:
case 0xC3:
case 0xC4:
case 0xC5:
case 0xC6:
case 0xC7:
case 0xC8:
case 0xC9:
@@ -788,6 +794,9 @@ class binary_reader
case 0xD2:
case 0xD3:
case 0xD4:
case 0xD5:
case 0xD6:
case 0xD7:
case 0xD8: // tagged item (1 byte follows)
case 0xD9: // tagged item (2 bytes follow)
case 0xDA: // tagged item (4 bytes follow)