pg_stat_statements: Fix potential use-after-free of PlannedStmt pgss_ProcessUtility() included a reference to a portion of a PlannedStmt after the point where this data's structure could have been freed, causing an incorrect memory access. There was a comment documenting this requirement, missed in 3357471cf9f5.
This commit includes a test able to make valgrind complain with a PlannedStmt freed by an internal ROLLBACK query. Similarly to what is mentioned in 495e73c2079e, this can be triggered by using the extended query protocol, something that can be now tested thanks to the recent meta-command additions in psql. This commit mentions potential other cases, but as far as I can see the extended protocol case with an internal ROLLBACK is the only problematic pattern reachable in practice. Issue introduced by 3357471cf9f5, gone unnoticed due to a lack of test coverage. The fix is authored by Chao, my contribution being the new test. Author: Chao Li <[email protected]> Co-authored-by: Michael Paquier <[email protected]> Discussion: https://postgr.es/m/[email protected] Branch ------ master Details ------- https://git.postgresql.org/pg/commitdiff/8268e41aca23ae3414360b0a1dc6ae99ea7b43f4 Modified Files -------------- contrib/pg_stat_statements/expected/plancache.out | 38 +++++++++++++++++++++++ contrib/pg_stat_statements/pg_stat_statements.c | 3 +- contrib/pg_stat_statements/sql/plancache.sql | 19 ++++++++++++ 3 files changed, 59 insertions(+), 1 deletion(-)
