From 604409b67d55102c38ff5e735817c115e0073cc7 Mon Sep 17 00:00:00 2001 From: Aleksander Alekseev Date: Tue, 16 Jun 2026 14:45:51 +0300 Subject: [PATCH v1 1/2] jsonb_plperl, jsonb_plpython: Add missing check_stack_depth() calls The functions responsible for converting JSONB to and from Perl and Python values recurse mutually: Jsonb_to_SV() calls JsonbValue_to_SV() which may call Jsonb_to_SV() again, and similarly SV_to_JsonbValue() calls AV_to_JsonbValue() or HV_to_JsonbValue() which call SV_to_JsonbValue() back. Likewise in jsonb_plpython.c. Without a stack depth check, converting a deeply nested JSONB value would cause a stack overflow and crash the backend process with SIGSEGV. Add check_stack_depth() at the start of the entry function for each recursion cycle so that an informative error is raised instead. Note that while the JSON text parser already calls check_stack_depth() during parsing, that protection does not cover JSONB values built via jsonb_build_object() or other means that bypass the text parser. Author: Aleksander Alekseev Reviewed-by: TODO FIXME Discussion: TODO FIXME --- contrib/jsonb_plperl/jsonb_plperl.c | 5 +++++ contrib/jsonb_plpython/jsonb_plpython.c | 5 +++++ 2 files changed, 10 insertions(+) diff --git a/contrib/jsonb_plperl/jsonb_plperl.c b/contrib/jsonb_plperl/jsonb_plperl.c index f8e4a584fdd..fdcec7760da 100644 --- a/contrib/jsonb_plperl/jsonb_plperl.c +++ b/contrib/jsonb_plperl/jsonb_plperl.c @@ -3,6 +3,7 @@ #include #include "fmgr.h" +#include "miscadmin.h" #include "plperl.h" #include "utils/fmgrprotos.h" #include "utils/jsonb.h" @@ -66,6 +67,8 @@ Jsonb_to_SV(JsonbContainer *jsonb) JsonbIterator *it; JsonbIteratorToken r; + check_stack_depth(); + it = JsonbIteratorInit(jsonb); r = JsonbIteratorNext(&it, &v, true); @@ -179,6 +182,8 @@ SV_to_JsonbValue(SV *in, JsonbInState *jsonb_state, bool is_elem) dTHX; JsonbValue out; /* result */ + check_stack_depth(); + /* Dereference references recursively. */ while (SvROK(in)) in = SvRV(in); diff --git a/contrib/jsonb_plpython/jsonb_plpython.c b/contrib/jsonb_plpython/jsonb_plpython.c index 4de75a04e76..f6eddb81c48 100644 --- a/contrib/jsonb_plpython/jsonb_plpython.c +++ b/contrib/jsonb_plpython/jsonb_plpython.c @@ -1,5 +1,6 @@ #include "postgres.h" +#include "miscadmin.h" #include "plpy_elog.h" #include "plpy_typeio.h" #include "plpy_util.h" @@ -143,6 +144,8 @@ PLyObject_FromJsonbContainer(JsonbContainer *jsonb) JsonbIterator *it; PyObject *result; + check_stack_depth(); + it = JsonbIteratorInit(jsonb); r = JsonbIteratorNext(&it, &v, true); @@ -410,6 +413,8 @@ PLyObject_ToJsonbValue(PyObject *obj, JsonbInState *jsonb_state, bool is_elem) { JsonbValue *out; + check_stack_depth(); + if (!PyUnicode_Check(obj)) { if (PySequence_Check(obj)) -- 2.43.0