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52 lines
1.7 KiB
Diff
52 lines
1.7 KiB
Diff
From 89aee84cbc9224f638f3b7951b306d2ee8ecb71e Mon Sep 17 00:00:00 2001
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From: Roberto Ierusalimschy <roberto@inf.puc-rio.br>
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Date: Wed, 27 Mar 2019 14:30:12 -0300
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Subject: [PATCH] Fixed bug in 'lua_upvaluejoin'
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Bug-fix: joining an upvalue with itself could cause a use-after-free
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crash.
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---
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src/lapi.c | 12 +++++------
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1 file changed, 41 insertions(+), 39 deletions(-)
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--- a/src/lapi.c
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+++ b/src/lapi.c
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@@ -1254,13 +1254,12 @@ LUA_API const char *lua_setupvalue (lua_
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}
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-static UpVal **getupvalref (lua_State *L, int fidx, int n, LClosure **pf) {
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+static UpVal **getupvalref (lua_State *L, int fidx, int n) {
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LClosure *f;
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StkId fi = index2addr(L, fidx);
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api_check(L, ttisLclosure(fi), "Lua function expected");
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f = clLvalue(fi);
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api_check(L, (1 <= n && n <= f->p->sizeupvalues), "invalid upvalue index");
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- if (pf) *pf = f;
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return &f->upvals[n - 1]; /* get its upvalue pointer */
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}
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@@ -1269,7 +1268,7 @@ LUA_API void *lua_upvalueid (lua_State *
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StkId fi = index2addr(L, fidx);
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switch (ttype(fi)) {
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case LUA_TLCL: { /* lua closure */
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- return *getupvalref(L, fidx, n, NULL);
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+ return *getupvalref(L, fidx, n);
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}
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case LUA_TCCL: { /* C closure */
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CClosure *f = clCvalue(fi);
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@@ -1286,9 +1285,10 @@ LUA_API void *lua_upvalueid (lua_State *
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LUA_API void lua_upvaluejoin (lua_State *L, int fidx1, int n1,
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int fidx2, int n2) {
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- LClosure *f1;
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- UpVal **up1 = getupvalref(L, fidx1, n1, &f1);
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- UpVal **up2 = getupvalref(L, fidx2, n2, NULL);
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+ UpVal **up1 = getupvalref(L, fidx1, n1);
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+ UpVal **up2 = getupvalref(L, fidx2, n2);
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+ if (*up1 == *up2)
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+ return;
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luaC_upvdeccount(L, *up1);
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*up1 = *up2;
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(*up1)->refcount++;
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