From: Sergey Bronnikov via Tarantool-patches <tarantool-patches@dev.tarantool.org> To: Sergey Kaplun <skaplun@tarantool.org>, Maxim Kokryashkin <m.kokryashkin@tarantool.org> Cc: tarantool-patches@dev.tarantool.org Subject: Re: [Tarantool-patches] [PATCH luajit 5/6] FFI: Fix dangling reference to CType. Improve checks. Date: Wed, 29 Nov 2023 18:41:29 +0300 [thread overview] Message-ID: <9faa1bde-fd48-4dd2-8760-25c308b743a8@tarantool.org> (raw) In-Reply-To: <a963238df9c76a9db9908f89deb4df6ab093e1bd.1698049570.git.skaplun@tarantool.org> Hello, Sergey thanks for the patch! See comments below On 10/23/23 12:22, Sergey Kaplun wrote: > From: Mike Pall <mike> > > Reported by elmknot. > > (cherry-picked from commit cc96ab9d513582703f8663a8775a935b56db32b7) > > During the recording of an arithmetic operation with a cdata function > object and some cdata value in `recff_cdata_arith()`, reallocation of > `cts->tab` in `lj_ctype_intern()` may occur. In that case, the reference > to the first `CType` object (`s[0]`) becomes invalid. This patch saves > the `CTypeID` of this object and gets its `CType` again after possible > reallocation. > > Also, this commit fills `cts->tab` memory with zeros before being freed > when `-DLUAJIT_CTYPE_CHECK_ANCHOR` is defined. It helps to observe > assertion failures in case this memory is used after free. failed to reproduce a bug with reverted fix and LuaJIT built with a flag: $ CMAKE_C_FLAGS=-DLUAJIT_CTYPE_CHECK_ANCHOR CFLAGS=-DLUAJIT_CTYPE_CHECK_ANCHOR cmake -S . -B build -DCMAKE_BUILD_TYPE=Debug -DLUA_USE_ASSERT=ON -DLUAJIT_USE_ASAN=ON $ ./build/src/luajit test/tarantool-tests/lj-920-fix-dangling-reference-to-ctype.test.lua TAP version 13 1..1 ok - no heap-use-after-free in recff_cdata_arith > > Sergey Kaplun: > * added the description and the test for the problem > > Part of tarantool/tarantool#9145 > --- > src/lj_crecord.c | 4 + > src/lj_ctype.c | 12 +++ > ...0-fix-dangling-reference-to-ctype.test.lua | 77 +++++++++++++++++++ > 3 files changed, 93 insertions(+) > create mode 100644 test/tarantool-tests/lj-920-fix-dangling-reference-to-ctype.test.lua > > diff --git a/src/lj_crecord.c b/src/lj_crecord.c > index 10d1dc70..e17e512f 100644 > --- a/src/lj_crecord.c > +++ b/src/lj_crecord.c > @@ -1502,9 +1502,13 @@ void LJ_FASTCALL recff_cdata_arith(jit_State *J, RecordFFData *rd) > if (ctype_isenum(ct->info)) ct = ctype_child(cts, ct); > goto ok; > } else if (ctype_isfunc(ct->info)) { > + CTypeID id0 = i ? ctype_typeid(cts, s[0]) : 0; > tr = emitir(IRT(IR_FLOAD, IRT_PTR), tr, IRFL_CDATA_PTR); > ct = ctype_get(cts, > lj_ctype_intern(cts, CTINFO(CT_PTR, CTALIGN_PTR|id), CTSIZE_PTR)); > + if (i) { > + s[0] = ctype_get(cts, id0); /* cts->tab may have been reallocated. */ > + } > goto ok; > } else { > tr = emitir(IRT(IR_ADD, IRT_PTR), tr, lj_ir_kintp(J, sizeof(GCcdata))); > diff --git a/src/lj_ctype.c b/src/lj_ctype.c > index a42e3d60..0874fa61 100644 > --- a/src/lj_ctype.c > +++ b/src/lj_ctype.c > @@ -191,8 +191,20 @@ CTypeID lj_ctype_intern(CTState *cts, CTInfo info, CTSize size) > } > id = cts->top; > if (LJ_UNLIKELY(id >= cts->sizetab)) { > +#ifdef LUAJIT_CTYPE_CHECK_ANCHOR > + CType *ct; > +#endif > if (id >= CTID_MAX) lj_err_msg(cts->L, LJ_ERR_TABOV); > +#ifdef LUAJIT_CTYPE_CHECK_ANCHOR > + ct = lj_mem_newvec(cts->L, id+1, CType); > + memcpy(ct, cts->tab, id*sizeof(CType)); > + memset(cts->tab, 0, id*sizeof(CType)); > + lj_mem_freevec(cts->g, cts->tab, cts->sizetab, CType); > + cts->tab = ct; > + cts->sizetab = id+1; > +#else > lj_mem_growvec(cts->L, cts->tab, cts->sizetab, CTID_MAX, CType); > +#endif > } > cts->top = id+1; > cts->tab[id].info = info; > diff --git a/test/tarantool-tests/lj-920-fix-dangling-reference-to-ctype.test.lua b/test/tarantool-tests/lj-920-fix-dangling-reference-to-ctype.test.lua > new file mode 100644 > index 00000000..a7e35888 > --- /dev/null > +++ b/test/tarantool-tests/lj-920-fix-dangling-reference-to-ctype.test.lua > @@ -0,0 +1,77 @@ > +local tap = require('tap') > +local ffi = require('ffi') > +local test = tap.test('lj-920-fix-dangling-reference-to-ctype'):skipcond({ > + ['Test requires JIT enabled'] = not jit.status(), > + -- luacheck: no global > + ['Impossible to predict the value of cts->top'] = _TARANTOOL, Let's declare _TARANTOOL as global in .luacheckrc instead of suppressing warning inline every time. About 7 tests suppress it. > +}) > + > +test:plan(1) > + > +-- This test demonstrates LuaJIT's incorrect behaviour when the > +-- reallocation of `cts->tab` strikes during the recording of the > +-- cdata metamethod arithmetic. > +-- The test fails under ASAN. > + > +-- XXX: Just some C functions to be casted. There is no need to > +-- declare their prototypes correctly. > +ffi.cdef[[ > + int malloc(void); > + int fprintf(void); > + int printf(void); > + int memset(void); > + int memcpy(void); > + int memmove(void); > + int getppid(void); > +]] > + > +local cfunc_type = ffi.metatype(ffi.typeof('struct {int a;}'), { > + -- Just some metatable with reloaded arithmetic operator. > + __add = function(o1, _) return o1 end > +}) > +-- Just some cdata with metamethod. > +local test_value = cfunc_type(1) > + > +-- XXX: structure to set `cts->top` to 112. > +local _ = ffi.new('struct {int a; long b; float c; double d;}', 0) > + > +-- Anchor table to prevent cdata objects from being collected. > +local anchor = {} > +-- Each call to this function grows `cts->top` by 3. > +local function save_new_func(func) > + anchor[#anchor + 1] = ffi.cast('void (*)(void)', func) > +end > + > +save_new_func(ffi.C.fprintf) -- `cts->top` = 112 > +save_new_func(ffi.C.printf) -- `cts->top` = 115 > +save_new_func(ffi.C.memset) -- `cts->top` = 118 > +save_new_func(ffi.C.memcpy) -- `cts->top` = 121 > +save_new_func(ffi.C.malloc) -- `cts->top` = 124 > + > +-- Assertions to check the `cts->top` value and step between > +-- calls. > +assert(ffi.typeinfo(124), 'cts->top >= 124') > +assert(not ffi.typeinfo(125), 'cts->top < 125') > + > +save_new_func(ffi.C.memmove) -- `cts->top` = 127 > + > +jit.opt.start('hotloop=1') > + > +-- Just some function to record trace and cause reallocation. > +local function recorded_func(func_arg) > + local res = test_value + func_arg > + return res > +end > +recorded_func(ffi.C.malloc) > + > +assert(ffi.typeinfo(127), 'cts->top >= 127') > +assert(not ffi.typeinfo(128), 'cts->top < 128') > + > +-- Last call to grow `cts->top` up to 129, so this causes > +-- `cts->tab` reallocation. Need to use different functions as > +-- an argument. > +recorded_func(ffi.C.getppid) > + > +test:ok(true, 'no heap-use-after-free in recff_cdata_arith') > + > +test:done(true)
next prev parent reply other threads:[~2023-11-29 15:41 UTC|newest] Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top 2023-10-23 9:22 [Tarantool-patches] [PATCH luajit 0/6] FFI fixes Sergey Kaplun via Tarantool-patches 2023-10-23 9:22 ` [Tarantool-patches] [PATCH luajit 1/6] Abstract out on-demand loading of FFI library Sergey Kaplun via Tarantool-patches 2023-10-24 14:38 ` Maxim Kokryashkin via Tarantool-patches 2023-11-29 14:35 ` Sergey Bronnikov via Tarantool-patches 2023-10-23 9:22 ` [Tarantool-patches] [PATCH luajit 2/6] FFI: Fix missing cts->L initialization in argv2ctype() Sergey Kaplun via Tarantool-patches 2023-10-24 14:49 ` Maxim Kokryashkin via Tarantool-patches 2023-10-25 10:19 ` Sergey Kaplun via Tarantool-patches 2023-11-29 14:39 ` Sergey Bronnikov via Tarantool-patches 2023-10-23 9:22 ` [Tarantool-patches] [PATCH luajit 3/6] FFI: Ensure returned string is alive in ffi.typeinfo() Sergey Kaplun via Tarantool-patches 2023-10-24 21:33 ` Maxim Kokryashkin via Tarantool-patches 2023-11-29 14:48 ` Sergey Bronnikov via Tarantool-patches 2023-10-23 9:22 ` [Tarantool-patches] [PATCH luajit 4/6] FFI: Fix dangling reference to CType Sergey Kaplun via Tarantool-patches 2023-10-25 7:48 ` Maxim Kokryashkin via Tarantool-patches 2023-10-25 10:43 ` Sergey Kaplun via Tarantool-patches 2023-10-25 11:42 ` Maxim Kokryashkin via Tarantool-patches 2023-10-25 8:06 ` Maxim Kokryashkin via Tarantool-patches 2023-11-29 15:00 ` Sergey Bronnikov via Tarantool-patches 2023-10-23 9:22 ` [Tarantool-patches] [PATCH luajit 5/6] FFI: Fix dangling reference to CType. Improve checks Sergey Kaplun via Tarantool-patches 2023-10-25 8:05 ` Maxim Kokryashkin via Tarantool-patches 2023-10-25 10:46 ` Sergey Kaplun via Tarantool-patches 2023-10-25 11:42 ` Maxim Kokryashkin via Tarantool-patches 2023-11-29 15:41 ` Sergey Bronnikov via Tarantool-patches [this message] 2023-11-30 7:25 ` Sergey Kaplun via Tarantool-patches 2023-12-19 10:55 ` Sergey Bronnikov via Tarantool-patches 2023-10-23 9:22 ` [Tarantool-patches] [PATCH luajit 6/6] FFI: Fix dangling reference to CType in carith_checkarg() Sergey Kaplun via Tarantool-patches 2023-10-25 8:07 ` Maxim Kokryashkin via Tarantool-patches 2023-10-25 10:48 ` Sergey Kaplun via Tarantool-patches 2023-10-25 11:42 ` Maxim Kokryashkin via Tarantool-patches 2023-12-19 10:59 ` Sergey Bronnikov via Tarantool-patches 2023-12-19 11:01 ` [Tarantool-patches] [PATCH luajit 0/6] FFI fixes Sergey Bronnikov via Tarantool-patches 2024-01-10 8:53 ` Igor Munkin via Tarantool-patches
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