377c25d322
json_lex_string() relies on pg_encoding_mblen_bounded() to point to the end of a JSON string when generating an error message, and the input it uses is not guaranteed to be null-terminated. It was possible to walk off the end of the input buffer by a few bytes when the last bytes consist of an incomplete multi-byte sequence, as token_terminator would point to a location defined by pg_encoding_mblen_bounded() rather than the end of the input. This commit switches token_terminator so as the error uses data up to the end of the JSON input. More work should be done so as this code could rely on an equivalent of report_invalid_encoding() so as incorrect byte sequences can show in error messages in a readable form. This requires work for at least two cases in the JSON parsing API: an incomplete token and an invalid escape sequence. A more complete solution may be too invasive for a backpatch, so this is left as a future improvement, taking care of the overread first. A test is added on HEAD as test_json_parser makes this issue straight-forward to check. Note that pg_encoding_mblen_bounded() no longer has any callers. This will be removed on HEAD with a separate commit, as this is proving to encourage unsafe coding. Author: Jacob Champion Discussion: https://postgr.es/m/CAOYmi+ncM7pwLS3AnKCSmoqqtpjvA8wmCdoBtKA3ZrB2hZG6zA@mail.gmail.com Backpatch-through: 13
PostgreSQL Database Management System ===================================== This directory contains the source code distribution of the PostgreSQL database management system. PostgreSQL is an advanced object-relational database management system that supports an extended subset of the SQL standard, including transactions, foreign keys, subqueries, triggers, user-defined types and functions. This distribution also contains C language bindings. PostgreSQL has many language interfaces, many of which are listed here: https://www.postgresql.org/download/ See the file INSTALL for instructions on how to build and install PostgreSQL. That file also lists supported operating systems and hardware platforms and contains information regarding any other software packages that are required to build or run the PostgreSQL system. Copyright and license information can be found in the file COPYRIGHT. A comprehensive documentation set is included in this distribution; it can be read as described in the installation instructions. The latest version of this software may be obtained at https://www.postgresql.org/download/. For more information look at our web site located at https://www.postgresql.org/.