From a5dbca460ace7e89a607d43e206973efaee0ed19 Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Mon, 6 Jun 2022 11:20:21 -0400 Subject: [PATCH] Don't fail on libpq-generated error reports in ecpg_raise_backend(). An error PGresult generated by libpq itself, such as a report of connection loss, won't have broken-down error fields. ecpg_raise_backend() blithely assumed that PG_DIAG_MESSAGE_PRIMARY would always be present, and would end up passing a NULL string pointer to snprintf when it isn't. That would typically crash before 3779ac62d, and it would fail to provide a useful error report in any case. Best practice is to substitute PQerrorMessage(conn) in such cases, so do that. Per bug #17421 from Masayuki Hirose. Back-patch to all supported branches. Discussion: https://postgr.es/m/17421-790ff887e3188874@postgresql.org --- src/interfaces/ecpg/ecpglib/error.c | 19 +++++++++---------- 1 file changed, 9 insertions(+), 10 deletions(-) diff --git a/src/interfaces/ecpg/ecpglib/error.c b/src/interfaces/ecpg/ecpglib/error.c index cd6c6a6819..26fdcdb69e 100644 --- a/src/interfaces/ecpg/ecpglib/error.c +++ b/src/interfaces/ecpg/ecpglib/error.c @@ -229,18 +229,17 @@ ecpg_raise_backend(int line, PGresult *result, PGconn *conn, int compat) return; } - if (result) - { - sqlstate = PQresultErrorField(result, PG_DIAG_SQLSTATE); - if (sqlstate == NULL) - sqlstate = ECPG_SQLSTATE_ECPG_INTERNAL_ERROR; - message = PQresultErrorField(result, PG_DIAG_MESSAGE_PRIMARY); - } - else - { + /* + * PQresultErrorField will return NULL if "result" is NULL, or if there is + * no such field, which will happen for libpq-generated errors. Fall back + * to PQerrorMessage in such cases. + */ + sqlstate = PQresultErrorField(result, PG_DIAG_SQLSTATE); + if (sqlstate == NULL) sqlstate = ECPG_SQLSTATE_ECPG_INTERNAL_ERROR; + message = PQresultErrorField(result, PG_DIAG_MESSAGE_PRIMARY); + if (message == NULL) message = PQerrorMessage(conn); - } if (strcmp(sqlstate, ECPG_SQLSTATE_ECPG_INTERNAL_ERROR) == 0) {