Re: [edk2-devel] [PATCH 1/1] NetworkPkg: Fix possible infinite loop in HTTP msg body parser

["Maciej Rabeda" <maciej.rabeda@linux.intel.com>]

Hi Vladimir,

Functionally the patch is fine.
However, from coding standard perspective, !PortionLen is not allowed - 
such structure is used only for BOOLEAN type values.
Reference: Table 10, 
https://edk2-docs.gitbook.io/edk-ii-c-coding-standards-specification/5_source_files/57_c_programming#5-7-2-2-a-comparison-of-any-pointer-to-zero-must-be-done-via-the-null-type

Do not submit v2, I will correct that upon merging. On terms CS issue is 
addressed, I am giving:
Reviewed-by: Maciej Rabeda <maciej.rabeda@linux.intel.com>

Thanks,
Maciej

On 01-Oct-20 17:25, Vladimir Olovyannikov wrote:
> Hi Maciej,
>
> Thank you for looking into this.
>
> Vladimir
>> -----Original Message-----
>> From: Rabeda, Maciej <maciej.rabeda@linux.intel.com>
>> Sent: Wednesday, September 30, 2020 2:57 AM
>> To: devel@edk2.groups.io; vladimir.olovyannikov@broadcom.com
>> Cc: Jiaxin Wu <jiaxin.wu@intel.com>; Siyuan Fu <siyuan.fu@intel.com>;
>> Laszlo Ersek <lersek@redhat.com>
>> Subject: Re: [edk2-devel] [PATCH 1/1] NetworkPkg: Fix possible infinite
>> loop
>> in HTTP msg body parser
>>
>> Hi Vladimir,
>>
>> Yes, this must have go past my radar, sorry. Things are becoming more and
>> more busy out here :/ I will take a look at it by the end of week.
>>
>> On 24-Sep-20 23:57, Vladimir Olovyannikov via groups.io wrote:
>>> Hi Maciej,
>>>
>>> Can you please review this patch?
>>> It is sitting there for a while, looks like it slipped through the
>>> cracks.
>>>
>>> Thank you,
>>> Vladimir
>>>> -----Original Message-----
>>>> From: Vladimir Olovyannikov <vladimir.olovyannikov@broadcom.com>
>>>> Sent: Friday, August 28, 2020 11:17 AM
>>>> To: devel@edk2.groups.io
>>>> Cc: Vladimir Olovyannikov <vladimir.olovyannikov@broadcom.com>;
>>>> Maciej Rabeda <maciej.rabeda@linux.intel.com>; Jiaxin Wu
>>>> <jiaxin.wu@intel.com>; Siyuan Fu <siyuan.fu@intel.com>
>>>> Subject: [PATCH 1/1] NetworkPkg: Fix possible infinite loop in HTTP
>>>> msg
>>> body
>>>> parser
>>>>
>>>> When an HTTP server sends a non-chunked body data with no Content-
>>>> Length header, the HttpParserMessageBody in DxeHttpLib gets confused
>>>> and never sets the Char pointer beyond the body start.
>>>> This causes "for" loop to never break because the condition of "Char
>>>>> =
>>> Body
>>>> + BodyLength" is never satisfied.
>>>> Use BodyLength as the ContentLength for the parser when
>> ContentLength
>>>> is absent in HTTP response headers.
>>>> BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=2941
>>>>
>>>> Signed-off-by: Vladimir Olovyannikov
>>>> <vladimir.olovyannikov@broadcom.com>
>>>> Cc: Maciej Rabeda <maciej.rabeda@linux.intel.com>
>>>> Cc: Jiaxin Wu <jiaxin.wu@intel.com>
>>>> Cc: Siyuan Fu <siyuan.fu@intel.com>
>>>> ---
>>>>    NetworkPkg/Library/DxeHttpLib/DxeHttpLib.c | 19 ++++++++++++++++-
>> --
>>>>    1 file changed, 16 insertions(+), 3 deletions(-)
>>>>
>>>> diff --git a/NetworkPkg/Library/DxeHttpLib/DxeHttpLib.c
>>>> b/NetworkPkg/Library/DxeHttpLib/DxeHttpLib.c
>>>> index 180d9321025a..e550c9962dc1 100644
>>>> --- a/NetworkPkg/Library/DxeHttpLib/DxeHttpLib.c
>>>> +++ b/NetworkPkg/Library/DxeHttpLib/DxeHttpLib.c
>>>> @@ -1122,6 +1122,7 @@ HttpParseMessageBody (
>>>>      CHAR8                 *Char;
>>>>      UINTN                 RemainderLengthInThis;
>>>>      UINTN                 LengthForCallback;
>>>> +  UINTN                 PortionLength;
>>>>      EFI_STATUS            Status;
>>>>      HTTP_BODY_PARSER      *Parser;
>>>>
>>>> @@ -1173,19 +1174,31 @@ HttpParseMessageBody (
>>>>          //
>>>>          // Identity transfer-coding, just notify user to save the
>>>> body
>>> data.
>>>>          //
>>>> +      PortionLength = MIN (
>>>> +                        BodyLength,
>>>> +                        Parser->ContentLength -
>>> Parser->ParsedBodyLength
>>>> +                        );
>>>> +      if (!PortionLength) {
>>>> +        //
>>>> +        // Got BodyLength, but no ContentLength. Use BodyLength.
>>>> +        //
>>>> +        PortionLength = BodyLength;
>>>> +        Parser->ContentLength = PortionLength;
>>>> +      }
>>>> +
>>>>          if (Parser->Callback != NULL) {
>>>>            Status = Parser->Callback (
>>>>                               BodyParseEventOnData,
>>>>                               Char,
>>>> -                           MIN (BodyLength, Parser->ContentLength -
>>> Parser-
>>>>> ParsedBodyLength),
>>>> +                           PortionLength,
>>>>                               Parser->Context
>>>>                               );
>>>>            if (EFI_ERROR (Status)) {
>>>>              return Status;
>>>>            }
>>>>          }
>>>> -      Char += MIN (BodyLength, Parser->ContentLength - Parser-
>>>>> ParsedBodyLength);
>>>> -      Parser->ParsedBodyLength += MIN (BodyLength, Parser-
>>>>> ContentLength - Parser->ParsedBodyLength);
>>>> +      Char += PortionLength;
>>>> +      Parser->ParsedBodyLength += PortionLength;
>>>>          if (Parser->ParsedBodyLength == Parser->ContentLength) {
>>>>            Parser->State = BodyParserComplete;
>>>>            if (Parser->Callback != NULL) {
>>>> --
>>>> 2.26.2.266.ge870325ee8
>>> 
>>>
>>>