Thread: pgsql: Avoid memory size overflow when allocating backend activity buff
Avoid memory size overflow when allocating backend activity buffer The code in charge of copying the contents of PgBackendStatus to local memory could fail on memory allocation because of an overflow on the amount of memory to use. The overflow can happen when combining a high value track_activity_query_size (max at 1MB) with a large max_connections, when both multiplied get higher than INT32_MAX as both parameters treated as signed integers. This could for example trigger with the following functions, all calling pgstat_read_current_status(): - pg_stat_get_backend_subxact() - pg_stat_get_backend_idset() - pg_stat_get_progress_info() - pg_stat_get_activity() - pg_stat_get_db_numbackends() The change to use MemoryContextAllocHuge() has been introduced in 8d0ddccec636, so backpatch down to 12. Author: Jakub Wartak Discussion: https://postgr.es/m/CAKZiRmw8QSNVw2qNK-dznsatQqz+9DkCquxP0GHbbv1jMkGHMA@mail.gmail.com Backpatch-through: 12 Branch ------ REL_13_STABLE Details ------- https://git.postgresql.org/pg/commitdiff/a0b0136259080c0441f4ff1c7d65d8a9d08360cf Modified Files -------------- src/backend/postmaster/pgstat.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)