Re: [Tarantool-patches] [PATCH v1 1/1] sql: fix assert when MP_EXT received via netbox

[Vladislav Shpilevoy via Tarantool-patches <tarantool-patches@dev.tarantool.org>]

Hi! Thanks for the patch!

See 4 comments below.

On 13.01.2022 10:37, imeevma@tarantool.org wrote:
> This patch fixes an assertion or segmentation fault when getting the
> value of MP_EXT via netbox.
> 
> Closes #6766
> ---
> https://github.com/tarantool/tarantool/issues/6766
> https://github.com/tarantool/tarantool/tree/imeevma/gh-6766-fix-assert-when-decoding-mp-ext
> 
>  src/box/bind.c                                | 30 ++++++++++++++++++-
>  test/sql-tap/engine.cfg                       |  1 +
>  .../gh-6766-fix-bind-for-mp-ext.test.lua      | 30 +++++++++++++++++++

1. Lets also add a changelog file.

>  3 files changed, 60 insertions(+), 1 deletion(-)
>  create mode 100755 test/sql-tap/gh-6766-fix-bind-for-mp-ext.test.lua
> 
> diff --git a/src/box/bind.c b/src/box/bind.c
> index 441c9f46f..6672d1271 100644
> --- a/src/box/bind.c
> +++ b/src/box/bind.c
> @@ -99,9 +101,35 @@ sql_bind_decode(struct sql_bind *bind, int i, const char **packet)
>  	case MP_BIN:
>  		bind->s = mp_decode_bin(packet, &bind->bytes);
>  		break;
> +	case MP_EXT: {
> +		int8_t ext_type;
> +		const char *svp = *packet;
> +		uint32_t size = mp_decode_extl(packet, &ext_type);
> +		if (ext_type != MP_UUID && ext_type != MP_DECIMAL) {
> +			bind->s = svp;
> +			*packet += size;
> +			bind->bytes = *packet - svp;
> +			break;

2. It might be better to move this below into 'else' branch after all
the type checks.

> +		}
> +		*packet = svp;
> +		if (ext_type == MP_UUID) {
> +			if (mp_decode_uuid(packet, &bind->uuid) == NULL) {

3. You already decoded the ext header. So you can call uuid_unpack().
Same below with decimal_unpack().

4. It still might be good to handle unknown MP_EXT values in sql_bind_column
or before it. Otherwise you will get a crash on any of them:

netbox = require('net.box')
msgpack = require('msgpack')
box.cfg{listen = 3313}
box.schema.user.grant('guest', 'super')

str = '\xc7\x00\x0f'
val = msgpack.object_from_raw(str)
con = netbox.connect(box.cfg.listen)
con:execute([[SELECT typeof(?);]], {val})

	Assertion failed: (p->ext_type == MP_UUID || p->ext_type == MP_DECIMAL),
	function sql_bind_column, file
	/Users/gerold/Work/Repositories/tarantool/src/box/bind.c, line 220.

Here I created a value of extension 15, which we don't support.