From: Igor Munkin via Tarantool-patches <tarantool-patches@dev.tarantool.org> To: Sergey Kaplun <skaplun@tarantool.org> Cc: tarantool-patches@dev.tarantool.org Subject: Re: [Tarantool-patches] [PATCH luajit] FFI: Fix pragma push stack limit check and throw on overflow. Date: Wed, 8 Nov 2023 18:39:59 +0000 [thread overview] Message-ID: <ZUvV_5Zf8FqdIm7f@tarantool.org> (raw) In-Reply-To: <20231108084044.6654-1-skaplun@tarantool.org> Sergey, Thanks for the patch! LGTM, with a single nit below. On 08.11.23, Sergey Kaplun wrote: > From: Mike Pall <mike> > > Reported by Sergey Kaplun. > > (cherry-picked from commit 433d7e8d8d182f44e88b5cfdc4b2d3026469dfb7) > > `cp->packstack` is the array of size `CPARSE_MAX_PACKSTACK` (7). Before > the patch, `cp->curpack` is checked to be less than > `CPARSE_MAX_PACKSTACK`, but then `cp->packstack` is accessed at > `cp->curpack + 1`, which is out of bounds, so `cp->curpack` value is > overwritten. > > This patch fixes a condition and also adds the error throw when counter > is overflow (instead of rewriting a top `cp->packstack` value). > > Sergey Kaplun: > * added the description and the test for the problem > > Resolves tarantool/tarantool#9339 > Part of tarantool/tarantool#9145 > --- > > Branch: https://github.com/tarantool/luajit/tree/skaplun/lj-1114-ffi-pragma-pack > Tarantool PR: https://github.com/tarantool/tarantool/pull/9342 > Relate issues: > * https://github.com/LuaJIT/LuaJIT/issues/1114 > * https://github.com/tarantool/tarantool/issues/9339 > * https://github.com/tarantool/tarantool/issues/9145 > > src/lj_cparse.c | 4 +- > .../lj-1114-ffi-pragma-pack.test.lua | 44 +++++++++++++++++++ > 2 files changed, 47 insertions(+), 1 deletion(-) > create mode 100644 test/tarantool-tests/lj-1114-ffi-pragma-pack.test.lua > <snipped> > diff --git a/test/tarantool-tests/lj-1114-ffi-pragma-pack.test.lua b/test/tarantool-tests/lj-1114-ffi-pragma-pack.test.lua > new file mode 100644 > index 00000000..e5642828 > --- /dev/null > +++ b/test/tarantool-tests/lj-1114-ffi-pragma-pack.test.lua > @@ -0,0 +1,44 @@ > +local tap = require('tap') > + > +-- Test file to demonstrate LuaJIT incorrect parsing of `#pragma` > +-- directive via FFI. > +-- See also: https://github.com/LuaJIT/LuaJIT/issues/1114. > + > +local test = tap.test('lj-1114-ffi-pragma-pack') > +local ffi = require 'ffi' Please use parantheses here too. > + > +test:plan(2) > + > +-- `cp->packstack` is the array of size `CPARSE_MAX_PACKSTACK` > +-- (7). Before the patch, `cp->curpack` is checked to be less than > +-- `CPARSE_MAX_PACKSTACK`, but then `cp->packstack` is accessed at > +-- `cp->curpack + 1`, which is out of bounds, so `cp->curpack` > +-- value is overwritten. > +-- As a result, the incorrect pack value (1) is chosen after pop. > +-- After the patch, the error is thrown in the case of overflow > +-- (instead of rewriting the top pack slot value), so we use the > +-- wrapper to catch the error. > +local function ffi_cdef_wp() > + ffi.cdef[[ > + #pragma pack(push, 1) > + #pragma pack(push, 1) > + #pragma pack(push, 1) > + #pragma pack(push, 1) > + #pragma pack(push, 8) > + #pragma pack(push, 8) > + #pragma pack(push, 8) > + #pragma pack(pop) > + struct aligned_struct {uint64_t a; uint8_t b;}; > + ]] > + > + -- Got 9 in case of buffer overflow. > + return ffi.sizeof(ffi.new('struct aligned_struct')) > +end > + > +local err, msg = pcall(ffi_cdef_wp) > + > +test:ok(not err, 'the error is thrown when couner overflows') > +test:like(msg, 'chunk has too many syntax levels', > + 'the error message is correct') > + > +test:done(true) > -- > 2.42.0 > -- Best regards, IM
next prev parent reply other threads:[~2023-11-08 18:42 UTC|newest] Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top 2023-11-08 8:40 Sergey Kaplun via Tarantool-patches 2023-11-08 18:39 ` Igor Munkin via Tarantool-patches [this message] 2023-11-08 18:59 ` Maxim Kokryashkin via Tarantool-patches 2023-11-09 5:57 ` Sergey Kaplun via Tarantool-patches 2023-11-23 6:31 ` Igor Munkin via Tarantool-patches
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