Re: [Tarantool-patches] [PATCH v2] base64: Properly ignore invalid characters

[Leonid Vasiliev <lvasiliev@tarantool.org>]

Hi!
Just to be clear. Perhaps before I have not clearly expressed my
opinion.
If you ok with 29 instead
```
+    plan(28
+         + 1 /* invalid chars test */
+         );
```
then LGTM.

On 17.12.2020 17:52, Leonid Vasiliev via Tarantool-patches wrote:
> Hi!
> 
> On 17.12.2020 16:04, Sergey Nikiforov wrote:
>> Hi!
>>
>> On 17.12.2020 12:41, Leonid Vasiliev wrote:
>>> Hi! Thank you for the patch.
>>> Generally LGTM.
>>> See some comments below:
>>>
>>> According to 
>>> https://github.com/tarantool/tarantool/wiki/Code-review-procedure#commit-message 
>>>
>>> "Description is what the patch does, started from lowercase letter,
>>> without a dot in the end, in the imperative mood."
>>> ("properly...").
>>> I could be wrong, but it seems like <description> is not written in an
>>> imperative mood.
>>
>> Mmm. I am not that great in English, but how "Properly ignore..." is 
>> not "imperative mood"? What would you suggest?
>> I should, however, use lowercase (alas, force of habit).
> 
> I will refer to my phrase:"I could be wrong") Leave it as is.
> 
>>
>>> On 15.12.2020 17:25, Sergey Nikiforov wrote:
>>>> Not all invalid characters were ignored by base64 decoder
>>>> causing data corruption and reads beyond decode table
>>>> (faults under ASAN).
>>>>
>>>> Added corresponding check into base64 unit test.
>>>>
>>>> Fixes: #5627
>>>> ---
>>>>
>>>> Branch: 
>>>> https://github.com/tarantool/tarantool/tree/void234/gh-5627-fix-base64-invalid-chars-processing 
>>>>
>>>> Issue: https://github.com/tarantool/tarantool/issues/5627
>>>>
>>>>   test/unit/base64.c      | 23 ++++++++++++++++++++++-
>>>>   test/unit/base64.result |  5 ++++-
>>>>   third_party/base64.c    |  3 ++-
>>>>   3 files changed, 28 insertions(+), 3 deletions(-)
>>>>
>>>> diff --git a/test/unit/base64.c b/test/unit/base64.c
>>>> index ada497adf..c0f53a5e1 100644
>>>> --- a/test/unit/base64.c
>>>> +++ b/test/unit/base64.c
>>>> @@ -58,9 +58,28 @@ base64_nowrap_test(const char *str)
>>>>       base64_test(str, BASE64_NOWRAP, symbols, lengthof(symbols));
>>>>   }
>>>> +static void
>>>> +base64_invalid_chars_test(void)
>>>> +{
>>>> +    /* Upper bit must be cleared */
>>>> +    const char invalid_data[] = { '\x7b', '\x7c', '\x7d', '\x7e' };
>>>> +    char outbuf[8];
>>>> +
>>>> +    plan(1);
>>>
>>> Usually `plan ()` is called as the first call in a function. It's just
>>> easier to see how many checks there will be. I don't know any rule about
>>> this. So, it's up to you.
>>
>> I would move it if you like (if there would be another patch 
>> revision). I have just tried to be C89-friendly. Force of habit 
>> (useful one).
>>
> 
> Ok.
> 
>>>> +
>>>> +    /* Invalid chars should be ignored, not decoded into garbage */
>>>> +    is(base64_decode(invalid_data, sizeof(invalid_data),
>>>> +                     outbuf, sizeof(outbuf)),
>>>> +       0, "ignoring invalid chars");
>>>> +
>>>> +    check_plan();
>>>> +}
>>>> +
>>>>   int main(int argc, char *argv[])
>>>>   {
>>>> -    plan(28);
>>>> +    plan(28
>>>> +         + 1 /* invalid chars test */
>>>> +         );
>>>
>>> I agree with Vlad. Why `+ 1` and not just 29?
>>
>> Using "magic" values without explanation is a bad idea for 
>> readability. Should I "decode" how 28 was calculated as well (using 
>> constants where appropriate) or no one bothers so much with tests?
> 
> AFAIK in `plan()` we always just write the "total" number of checks.
> 
>>
>>>>       header();
>>>>       const char *option_tests[] = {
>>>> @@ -78,6 +97,8 @@ int main(int argc, char *argv[])
>>>>           base64_nowrap_test(option_tests[i]);
>>>>       }
>>>> +    base64_invalid_chars_test();
>>>> +
>>>>       footer();
>>>>       return check_plan();
>>>>   }
>>>> diff --git a/test/unit/base64.result b/test/unit/base64.result
>>>> index cd1f2b3f6..3bc2c2275 100644
>>>> --- a/test/unit/base64.result
>>>> +++ b/test/unit/base64.result
>>>> @@ -1,4 +1,4 @@
>>>> -1..28
>>>> +1..29
>>>>       *** main ***
>>>>       1..3
>>>>       ok 1 - length
>>>> @@ -175,4 +175,7 @@ ok 27 - subtests
>>>>       ok 3 - decode length ok
>>>>       ok 4 - encode/decode
>>>>   ok 28 - subtests
>>>> +    1..1
>>>> +    ok 1 - ignoring invalid chars
>>>> +ok 29 - subtests
>>>>       *** main: done ***
>>>> diff --git a/third_party/base64.c b/third_party/base64.c
>>>> index 8ecab23eb..7c69315ea 100644
>>>> --- a/third_party/base64.c
>>>> +++ b/third_party/base64.c
>>>> @@ -222,7 +222,8 @@ base64_decode_value(int value)
>>>>           32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43,
>>>>           44, 45, 46, 47, 48, 49, 50, 51
>>>>       };
>>>> -    static const int decoding_size = sizeof(decoding);
>>>> +    static const int decoding_size =
>>>> +        sizeof(decoding) / sizeof(decoding[0]);
>>>>       int codepos = value;
>>>>       codepos -= 43;
>>>>       if (codepos < 0 || codepos >= decoding_size)
>>>>