From 587823eca162d063027faf1826ec3544f0a06e78 Mon Sep 17 00:00:00 2001 From: Andrew Cooper Date: Wed, 1 Feb 2023 11:27:42 +0000 Subject: [PATCH] tools/ocaml/libs: Fix memory/resource leaks with caml_alloc_custom() All caml_alloc_*() functions can throw exceptions, and longjump out of context. If this happens, we leak the xch/xce handle. Reorder the logic to allocate the the Ocaml object first. Fixes: 8b3c06a3e545 ("tools/ocaml/xenctrl: OCaml 5 support, fix use-after-free") Fixes: 22d5affdf0ce ("tools/ocaml/evtchn: OCaml 5 support, fix potential resource leak") Signed-off-by: Andrew Cooper Acked-by: Christian Lindig (cherry picked from commit d69ccf52ad467ccc22029172a8e61dc621187889) --- tools/ocaml/libs/eventchn/xeneventchn_stubs.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/tools/ocaml/libs/eventchn/xeneventchn_stubs.c b/tools/ocaml/libs/eventchn/xeneventchn_stubs.c index d7881ca95f..de2fc29292 100644 --- a/tools/ocaml/libs/eventchn/xeneventchn_stubs.c +++ b/tools/ocaml/libs/eventchn/xeneventchn_stubs.c @@ -63,6 +63,8 @@ CAMLprim value stub_eventchn_init(value cloexec) if ( !Bool_val(cloexec) ) flags |= XENEVTCHN_NO_CLOEXEC; + result = caml_alloc_custom(&xenevtchn_ops, sizeof(xce), 0, 1); + caml_enter_blocking_section(); xce = xenevtchn_open(NULL, flags); caml_leave_blocking_section(); @@ -70,7 +72,6 @@ CAMLprim value stub_eventchn_init(value cloexec) if (xce == NULL) caml_failwith("open failed"); - result = caml_alloc_custom(&xenevtchn_ops, sizeof(xce), 0, 1); *(xenevtchn_handle **)Data_custom_val(result) = xce; CAMLreturn(result); @@ -82,6 +83,8 @@ CAMLprim value stub_eventchn_fdopen(value fdval) CAMLlocal1(result); xenevtchn_handle *xce; + result = caml_alloc_custom(&xenevtchn_ops, sizeof(xce), 0, 1); + caml_enter_blocking_section(); xce = xenevtchn_fdopen(NULL, Int_val(fdval), 0); caml_leave_blocking_section(); @@ -89,7 +92,6 @@ CAMLprim value stub_eventchn_fdopen(value fdval) if (xce == NULL) caml_failwith("evtchn fdopen failed"); - result = caml_alloc_custom(&xenevtchn_ops, sizeof(xce), 0, 1); *(xenevtchn_handle **)Data_custom_val(result) = xce; CAMLreturn(result); -- 2.30.2