From: Vladislav Shpilevoy <v.shpilevoy@tarantool.org> To: tarantool-patches@freelists.org, Alexander Turenko <alexander.turenko@tarantool.org> Cc: AKhatskevich <avkhatskevich@tarantool.org> Subject: [tarantool-patches] Re: [PATCH v2 1/3] lua-yaml: verify arguments count Date: Fri, 25 Jan 2019 00:26:53 +0300 [thread overview] Message-ID: <04a54285-aa7c-2726-0077-64c14a40dde6@tarantool.org> (raw) In-Reply-To: <58ccdb031d0befd0e80d50a4684f5e7a59182062.1548123025.git.alexander.turenko@tarantool.org> Thanks for the patch! On 22/01/2019 05:12, Alexander Turenko wrote: > From: AKhatskevich <avkhatskevich@tarantool.org> > > Added arguments count check for yaml.encode() and decode.decode() Typo: 'decode.decode' -> 'yaml.decode'. > functions. > > Without these checks the functions could read garbage outside of a Lua > stack when called w/o arguments. Honestly, I do not understand how is it possible. Please, provide a test for both functions. See my 3 doubts below. > --- > third_party/lua-yaml/lyaml.cc | 7 ++++--- > 1 file changed, 4 insertions(+), 3 deletions(-) > > diff --git a/third_party/lua-yaml/lyaml.cc b/third_party/lua-yaml/lyaml.cc > index c6d118a79..9b07992d8 100644 > --- a/third_party/lua-yaml/lyaml.cc > +++ b/third_party/lua-yaml/lyaml.cc > @@ -400,7 +400,8 @@ static void load(struct lua_yaml_loader *loader) { > */ > static int l_load(lua_State *L) { > struct lua_yaml_loader loader; > - if (! lua_isstring(L, 1)) { > + int top = lua_gettop(L); > + if (!(top == 1 || top == 2) || !lua_isstring(L, 1)) { 1. How could the old code lead to a bug, if there was a check if the first argument is a string? The second argument is not used until the next hunk, about which see my next comment > usage_error: > return luaL_error(L, "Usage: yaml.decode(document, "\ > "[{tag_only = boolean}])"); > @@ -416,7 +417,7 @@ usage_error: > return luaL_error(L, OOM_ERRMSG); > yaml_parser_set_input_string(&loader.parser, (yaml_char_t *) document, len); > bool tag_only; > - if (lua_gettop(L) > 1) { > + if (lua_gettop(L) == 2) { 2. This function never touches anything beyond second value on the stack, so here lua_gettop(L) > 1 means the same as lua_gettop(L) == 2 - the second argument exist. Third and next values do not matter. > if (! lua_istable(L, 2)) > goto usage_error; > lua_getfield(L, 2, "tag_only"); > @@ -794,7 +795,7 @@ error: > static int l_dump(lua_State *L) { > struct luaL_serializer *serializer = luaL_checkserializer(L); > int top = lua_gettop(L); > - if (top > 2) { > + if (!(top == 1 || top == 2)) { 3. Here my reasoning is the same - the previous checking works as well. > usage_error: > return luaL_error(L, "Usage: encode(object, {tag_prefix = <string>, "\ > "tag_handle = <string>})"); >
next prev parent reply other threads:[~2019-01-24 21:27 UTC|newest] Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top 2019-01-22 2:12 [tarantool-patches] [PATCH v2 0/3] lua-yaml null/boolean fixes Alexander Turenko 2019-01-22 2:12 ` [tarantool-patches] [PATCH v2 1/3] lua-yaml: verify arguments count Alexander Turenko 2019-01-24 21:26 ` Vladislav Shpilevoy [this message] 2019-02-05 3:29 ` [tarantool-patches] " Alexander Turenko 2019-02-05 19:36 ` Vladislav Shpilevoy 2019-02-11 13:32 ` Alexander Turenko 2019-02-15 21:28 ` Vladislav Shpilevoy 2019-01-22 2:12 ` [tarantool-patches] [PATCH v2 2/3] lua-yaml: fix boolean/null representation in yaml Alexander Turenko 2019-01-24 21:26 ` [tarantool-patches] " Vladislav Shpilevoy 2019-01-24 21:32 ` Vladislav Shpilevoy 2019-02-05 3:29 ` Alexander Turenko 2019-02-05 19:36 ` Vladislav Shpilevoy 2019-02-15 21:06 ` Vladislav Shpilevoy 2019-02-15 21:23 ` Alexander Turenko 2019-02-18 18:55 ` Alexander Turenko 2019-02-22 15:14 ` Vladislav Shpilevoy 2019-01-22 2:12 ` [tarantool-patches] [PATCH v2 3/3] lua-yaml: treat an empty document/value as null Alexander Turenko 2019-01-24 21:26 ` [tarantool-patches] " Vladislav Shpilevoy 2019-02-05 3:30 ` Alexander Turenko 2019-01-24 21:26 ` [tarantool-patches] Re: [PATCH v2 0/3] lua-yaml null/boolean fixes Vladislav Shpilevoy 2019-02-25 11:27 ` Kirill Yukhin 2019-03-05 16:40 ` Alexander Turenko 2019-03-06 7:21 ` Kirill Yukhin
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