From 913fe0c316a6d024434e66f084acbb605293265a Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Mon, 10 Aug 2026 06:38:35 -0700 Subject: [PATCH] Return nulls honestly in aggregate "combine" functions. numeric_combine() and several other state-combining functions for aggregates cheated for the case of both inputs being NULL: they returned a null pointer without bothering to mark it as a SQL NULL. This was harmless in the expected usage where the result would be passed to the same combine function or a related aggregate final function. But it's bad news from a security standpoint, because now that value can be passed to an internal-accepting function even if said function is strict. While a previous patch prevented such queries from being issued, it seems like good defense-in-depth to expend the few additional lines of code needed to do this properly. Comparable functions such as array_agg_combine() already do so. Reported-by: Amy Burnett (OpenAI Codex Security) Author: Tom Lane Backpatch-through: 14 Security: CVE-2026-14680 --- src/backend/utils/adt/numeric.c | 32 ++++++++++++++++++++++++++++++++ 1 file changed, 32 insertions(+) diff --git a/src/backend/utils/adt/numeric.c b/src/backend/utils/adt/numeric.c index 0e1f2166847..8e932f0388d 100644 --- a/src/backend/utils/adt/numeric.c +++ b/src/backend/utils/adt/numeric.c @@ -4830,7 +4830,15 @@ numeric_combine(PG_FUNCTION_ARGS) state2 = PG_ARGISNULL(1) ? NULL : (NumericAggState *) PG_GETARG_POINTER(1); if (state2 == NULL) + { + /* + * NULL state2 is easy, just return state1, which we know is already + * in the agg_context + */ + if (state1 == NULL) + PG_RETURN_NULL(); PG_RETURN_POINTER(state1); + } /* manually copy all fields from state2 to state1 */ if (state1 == NULL) @@ -4922,7 +4930,15 @@ numeric_avg_combine(PG_FUNCTION_ARGS) state2 = PG_ARGISNULL(1) ? NULL : (NumericAggState *) PG_GETARG_POINTER(1); if (state2 == NULL) + { + /* + * NULL state2 is easy, just return state1, which we know is already + * in the agg_context + */ + if (state1 == NULL) + PG_RETURN_NULL(); PG_RETURN_POINTER(state1); + } /* manually copy all fields from state2 to state1 */ if (state1 == NULL) @@ -5445,7 +5461,15 @@ numeric_poly_combine(PG_FUNCTION_ARGS) state2 = PG_ARGISNULL(1) ? NULL : (PolyNumAggState *) PG_GETARG_POINTER(1); if (state2 == NULL) + { + /* + * NULL state2 is easy, just return state1, which we know is already + * in the agg_context + */ + if (state1 == NULL) + PG_RETURN_NULL(); PG_RETURN_POINTER(state1); + } /* manually copy all fields from state2 to state1 */ if (state1 == NULL) @@ -5672,7 +5696,15 @@ int8_avg_combine(PG_FUNCTION_ARGS) state2 = PG_ARGISNULL(1) ? NULL : (PolyNumAggState *) PG_GETARG_POINTER(1); if (state2 == NULL) + { + /* + * NULL state2 is easy, just return state1, which we know is already + * in the agg_context + */ + if (state1 == NULL) + PG_RETURN_NULL(); PG_RETURN_POINTER(state1); + } /* manually copy all fields from state2 to state1 */ if (state1 == NULL)