With GB18030, prevent SIGSEGV from reading past end of allocation. With GB18030 as source encoding, applications could crash the server via SQL functions convert() or convert_from(). Applications themselves could crash after passing unterminated GB18030 input to libpq functions PQescapeLiteral(), PQescapeIdentifier(), PQescapeStringConn(), or PQescapeString(). Extension code could crash by passing unterminated GB18030 input to jsonapi.h functions. All those functions have been intended to handle untrusted, unterminated input safely.
A crash required allocating the input such that the last byte of the allocation was the last byte of a virtual memory page. Some malloc() implementations take measures against that, making the SIGSEGV hard to reach. Back-patch to v13 (all supported versions). Author: Noah Misch <n...@leadboat.com> Author: Andres Freund <and...@anarazel.de> Reviewed-by: Masahiko Sawada <sawada.m...@gmail.com> Backpatch-through: 13 Security: CVE-2025-4207 Branch ------ REL_15_STABLE Details ------- https://git.postgresql.org/pg/commitdiff/44ba3f55f552b56b2fbefae028fcf3ea5b53461d Modified Files -------------- src/backend/utils/mb/mbutils.c | 18 ++++-- src/common/jsonapi.c | 7 ++- src/common/wchar.c | 51 +++++++++++++-- src/include/mb/pg_wchar.h | 2 + src/interfaces/libpq/fe-exec.c | 6 +- src/interfaces/libpq/fe-misc.c | 15 ++--- src/test/modules/test_escape/test_escape.c | 99 ++++++++++++++++++++++++++++++ src/test/regress/expected/conversion.out | 13 ++-- src/test/regress/sql/conversion.sql | 7 ++- 9 files changed, 188 insertions(+), 30 deletions(-)
