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Update patch fixing a segfault caused by possible invalid frees

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Björn Esser 2017-12-14 18:54:42 +01:00
parent 9c657adefe
commit d86ebd42ff
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2 changed files with 20 additions and 17 deletions
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32
json-c-0.13_json_object_avoid_invalid_free.patch
View File

@ -1,26 +1,26 @@
From 1c1c14271eadeb35dc2fb38e199bde2e90ff4ea3 Mon Sep 17 00:00:00 2001
From 9aca3b6a087a396a81d7e26f4557eb97fecc1386 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bj=C3=B6rn=20Esser?= <besser82@fedoraproject.org>
Date: Wed, 13 Dec 2017 19:22:52 +0100
Subject: [PATCH] json_object: Avoid double free (and thus a segfault) when
Subject: [PATCH] json_object: Avoid invalid free (and thus a segfault) when
ref_count gets < 0
---
json_object.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
json_object.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/json_object.c b/json_object.c
index 042477a71b..b94b9e222a 100644
index 042477a71b..7c7438d8ea 100644
--- a/json_object.c
+++ b/json_object.c
@@ -189,9 +189,9 @@ int json_object_put(struct json_object *jso)
* as that can result in the thread that loses the race to 0
* operating on an already-freed object.
*/
- if (__sync_sub_and_fetch(&jso->_ref_count, 1) > 0) return 0;
+ if (__sync_sub_and_fetch(&jso->_ref_count, 1) != 0) return 0;
#else
- if (--jso->_ref_count > 0) return 0;
+ if (--jso->_ref_count != 0) return 0;
#endif
@@ -182,6 +182,11 @@ int json_object_put(struct json_object *jso)
{
if(!jso) return 0;
if (jso->_user_delete)
+ /* Avoid invalid free and crash explicitly instead of (silently)
+ * segfaulting.
+ */
+ assert(jso->_ref_count > 0);
+
#if defined(HAVE_ATOMIC_BUILTINS) && defined(ENABLE_THREADING)
/* Note: this only allow the refcount to remain correct
* when multiple threads are adjusting it. It is still an error

5
json-c.spec
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@ -16,7 +16,7 @@
Name: json-c
Version: 0.13
Release: 4%{?dist}
Release: 5%{?dist}
Summary: JSON implementation in C
License: MIT
@ -176,6 +176,9 @@ end
%changelog
* Thu Dec 14 2017 Björn Esser <besser82@fedoraproject.org> - 0.13-5
- Update patch fixing a segfault caused by possible invalid frees
* Wed Dec 13 2017 Björn Esser <besser82@fedoraproject.org> - 0.13-4
- Add upstream patch fixing invalid free in some cases