From 08bdf0a4798bbbbc401bd951cd9553f3c6de2de7 Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Mon, 1 Apr 2024 15:15:03 -0400 Subject: [PATCH] Avoid possible longjmp-induced logic error in PLy_trigger_build_args. The "pltargs" variable wasn't marked volatile, which makes it unsafe to change its value within the PG_TRY block. It looks like the worst outcome would be to fail to release a refcount on Py_None during an (improbable) error exit, which would likely go unnoticed in the field. Still, it's a bug. A one-liner fix could be to mark pltargs volatile, but on the whole it seems cleaner to arrange things so that we don't change its value within PG_TRY. Per report from Xing Guo. This has been there for quite awhile, so back-patch to all supported branches. Discussion: https://postgr.es/m/CACpMh+DLrk=fDv07MNpBT4J413fDAm+gmMXgi8cjPONE+jvzuw@mail.gmail.com --- src/pl/plpython/plpy_exec.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) diff --git a/src/pl/plpython/plpy_exec.c b/src/pl/plpython/plpy_exec.c index 993a4e2ea9..953c2d4819 100644 --- a/src/pl/plpython/plpy_exec.c +++ b/src/pl/plpython/plpy_exec.c @@ -691,7 +691,7 @@ PLy_trigger_build_args(FunctionCallInfo fcinfo, PLyProcedure *proc, HeapTuple *r *pltrelid, *plttablename, *plttableschema, - *pltargs = NULL, + *pltargs, *pytnew, *pytold, *pltdata; @@ -715,6 +715,11 @@ PLy_trigger_build_args(FunctionCallInfo fcinfo, PLyProcedure *proc, HeapTuple *r return NULL; } } + else + { + Py_INCREF(Py_None); + pltargs = Py_None; + } PG_TRY(); { @@ -858,7 +863,7 @@ PLy_trigger_build_args(FunctionCallInfo fcinfo, PLyProcedure *proc, HeapTuple *r PyObject *pltarg; /* pltargs should have been allocated before the PG_TRY block. */ - Assert(pltargs); + Assert(pltargs && pltargs != Py_None); for (i = 0; i < tdata->tg_trigger->tgnargs; i++) { @@ -872,8 +877,7 @@ PLy_trigger_build_args(FunctionCallInfo fcinfo, PLyProcedure *proc, HeapTuple *r } else { - Py_INCREF(Py_None); - pltargs = Py_None; + Assert(pltargs == Py_None); } PyDict_SetItemString(pltdata, "args", pltargs); Py_DECREF(pltargs);