lua: Security fix for CVE-2019-6706

Source: lua.org
MR: 97553
Type: Security Fix
Disposition: Backport from http://lua.2524044.n2.nabble.com/CVE-2019-6706-use-after-free-in-lua-upvaluejoin-function-tc7685575.html
ChangeID: c939b7edcb54274ab0aeebcb7e3dc9f17cc09c2d
Description:

Affects < 5.3.5
Fixes:
CVE-2019-6706

Signed-off-by: Armin Kuster <akuster808@gmail.com>

meta-oe/recipes-devtools/lua/lua/CVE-2019-6706.patch

@@ -0,0 +1,32 @@
+CVE-2019-6706: use-after-free in lua_upvaluejoin function 
+
+Upstream-Status: Backport
+http://lua.2524044.n2.nabble.com/CVE-2019-6706-use-after-free-in-lua-upvaluejoin-function-tc7685575.html
+CVE: CVE-2019-6706
+Affects < 5.3.5
+Signed-off-by: Armin Kuster <akuster@mvista.com>
+
+Index: lua-5.3.4/src/lapi.c
+===================================================================
+--- lua-5.3.4.orig/src/lapi.c
++++ lua-5.3.4/src/lapi.c
+@@ -1285,14 +1285,14 @@ LUA_API void *lua_upvalueid (lua_State *
+ 
+ LUA_API void lua_upvaluejoin (lua_State *L, int fidx1, int n1,
+                                             int fidx2, int n2) {
+-  LClosure *f1;
+-  UpVal **up1 = getupvalref(L, fidx1, n1, &f1);
++  UpVal **up1 = getupvalref(L, fidx1, n1, NULL); /* the last parameter not needed */
+   UpVal **up2 = getupvalref(L, fidx2, n2, NULL);
++  if (*up1 == *up2) return; /* Already joined */
++  (*up2)->refcount++;
++  if (upisopen(*up2)) (*up2)->u.open.touched = 1;
++  luaC_upvalbarrier(L, *up2);
+   luaC_upvdeccount(L, *up1);
+   *up1 = *up2;
+-  (*up1)->refcount++;
+-  if (upisopen(*up1)) (*up1)->u.open.touched = 1;
+-  luaC_upvalbarrier(L, *up1);
+ }
+ 
+ 

meta-oe/recipes-devtools/lua/lua_5.3.4.bb

@@ -7,6 +7,7 @@ HOMEPAGE = "http://www.lua.org/"
 DEPENDS = "readline"
 SRC_URI = "http://www.lua.org/ftp/lua-${PV}.tar.gz;name=tarballsrc \
            file://lua.pc.in \
+           file://CVE-2019-6706.patch \
            "
 SRC_URI += "${@bb.utils.contains('DISTRO_FEATURES', 'ptest', \
            'http://www.lua.org/tests/lua-${PV}-tests.tar.gz;name=tarballtest \