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Re: [Qemu-devel] [PATCH] io: ignore case when matching websockets HTTP h
From: |
Daniel P. Berrange |
Subject: |
Re: [Qemu-devel] [PATCH] io: ignore case when matching websockets HTTP headers |
Date: |
Tue, 28 Feb 2017 10:09:07 +0000 |
User-agent: |
Mutt/1.7.1 (2016-10-04) |
On Mon, Feb 27, 2017 at 03:20:37PM -0600, Eric Blake wrote:
> On 02/27/2017 02:14 PM, 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 <address@hidden>
> > ---
> > io/channel-websock.c | 14 +++++++++-----
> > 1 file changed, 9 insertions(+), 5 deletions(-)
> >
>
> > @@ -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. */
>
> Drive-by grammar nit: s/easily/easy/
>
> > @@ -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);
> > + }
> > +
> > if (qio_channel_websock_handshake_process(ioc,
> > (char *)ioc->encinput.buffer,
> > - ioc->encinput.offset,
> > + handshake_end - (char
> > *)ioc->encinput.buffer,
>
> I'm not sure why this change is here; nothing else in the patch changed
> ioc->encinput.offset.
It is a related bug. The ioc->encinput buffer contains upto 4096
bytes, but that data may cover both the header & payload. The
handshake_end pointer refers to the end of the header region.
So if we just pass encinput.offset, then handshake_process()
will be searching part of the payload as well as the header.
This might cause it do match the wrong data. I guess I should
have made that clear in the commit, or even tput it in a
separate commit
Regards,
Daniel
--
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