Re: [Qemu-devel] [PATCH] io: ignore case when matching websockets HTTP headers

["Daniel P. Berrange" <berrange@redhat.com>]

On Tue, Feb 28, 2017 at 01:58:38PM +0300, Denis V. Lunev wrote:
> On 02/28/2017 01:54 PM, Denis V. Lunev wrote:
> > On 02/28/2017 01:48 PM, Daniel P. Berrange wrote:
> >> On Mon, Feb 27, 2017 at 08:14:56PM +0000, Daniel P. Berrange wrote:
> >>> According to RFC7230 Section 3.2, header field name is case-insensitive.
> >>> Convert the header data into all lowercase before doing string matching
> >>> on the headers.
> >>>
> >>> Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
> >>> ---
> >>>  io/channel-websock.c | 14 +++++++++-----
> >>>  1 file changed, 9 insertions(+), 5 deletions(-)
> >>>
> >>> diff --git a/io/channel-websock.c b/io/channel-websock.c
> >>> index a06a4a8..32b7f37 100644
> >>> --- a/io/channel-websock.c
> >>> +++ b/io/channel-websock.c
> >>> @@ -33,9 +33,9 @@
> >>>  #define QIO_CHANNEL_WEBSOCK_GUID "258EAFA5-E914-47DA-95CA-C5AB0DC85B11"
> >>>  #define QIO_CHANNEL_WEBSOCK_GUID_LEN strlen(QIO_CHANNEL_WEBSOCK_GUID)
> >>>  
> >>> -#define QIO_CHANNEL_WEBSOCK_HEADER_PROTOCOL "Sec-WebSocket-Protocol"
> >>> -#define QIO_CHANNEL_WEBSOCK_HEADER_VERSION "Sec-WebSocket-Version"
> >>> -#define QIO_CHANNEL_WEBSOCK_HEADER_KEY "Sec-WebSocket-Key"
> >>> +#define QIO_CHANNEL_WEBSOCK_HEADER_PROTOCOL "sec-websocket-protocol"
> >>> +#define QIO_CHANNEL_WEBSOCK_HEADER_VERSION "sec-websocket-version"
> >>> +#define QIO_CHANNEL_WEBSOCK_HEADER_KEY "sec-websocket-key"
> >>>  
> >>>  #define QIO_CHANNEL_WEBSOCK_PROTOCOL_BINARY "binary"
> >>>  
> >>> @@ -223,7 +223,7 @@ static int qio_channel_websock_handshake_process(QIOChannelWebsock *ioc,
> >>>  static int qio_channel_websock_handshake_read(QIOChannelWebsock *ioc,
> >>>                                                Error **errp)
> >>>  {
> >>> -    char *handshake_end;
> >>> +    char *handshake_end, *tmp;
> >>>      ssize_t ret;
> >>>      /* Typical HTTP headers from novnc are 512 bytes, so limiting
> >>>       * total header size to 4096 is easily enough. */
> >>> @@ -249,9 +249,13 @@ static int qio_channel_websock_handshake_read(QIOChannelWebsock *ioc,
> >>>          }
> >>>      }
> >>>  
> >>> +    for (tmp = (char *)ioc->encinput.buffer; tmp < handshake_end; tmp++) {
> >>> +        *tmp = g_ascii_tolower(*tmp);
> >>> +    }
> >>> +
> >> self-nack - this does not in fact work - while it is fine to lowercase
> >> the header keys, we must not touch the header values as some data is
> >> case-sensitive
> >>
> >> Regards,
> >> Daniel
> > g-ascii-tolower() will help
> >
> > Den
> ah, sorry, wrong copy/paste. I meant 'g_ascii_strdown ()'

That would still lowercase both the key & value part of the headers.
We need to only lowercase the key, ie text between start of line
and first ':'. This requires properly parsing the HTTP header.

Regards,
Daniel
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