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introduce-new-04-frame-unmasking.patch

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Signed-off-by: Andy Green <andy@warmcat.com>
This commit is contained in:
Andy Green 2011-01-18 18:14:26 +00:00
parent f85e830f7b
commit 3e5eb78490
2 changed files with 64 additions and 1 deletions
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56
lib/parsers.c
View file

@ -192,11 +192,21 @@ int libwebsocket_parse(struct libwebsocket *wsi, unsigned char c)
return 0;
}
static unsigned char inline
unmask(struct libwebsocket *wsi, unsigned char c)
{
c ^= wsi->masking_key_04[wsi->frame_mask_index++];
if (wsi->frame_mask_index == 20)
wsi->frame_mask_index = 0;
return c;
}
static int libwebsocket_rx_sm(struct libwebsocket *wsi, unsigned char c)
{
int n;
unsigned char buf[2];
unsigned char buf[20 + 4];
switch (wsi->lws_rx_parse_state) {
case LWS_RXPS_NEW:
@ -208,6 +218,8 @@ static int libwebsocket_rx_sm(struct libwebsocket *wsi, unsigned char c)
wsi->lws_rx_parse_state = LWS_RXPS_SEEN_76_FF;
break;
case 4:
wsi->frame_masking_nonce_04[0] = c;
wsi->lws_rx_parse_state = LWS_RXPS_04_MASK_NONCE_1;
break;
}
@ -216,6 +228,48 @@ static int libwebsocket_rx_sm(struct libwebsocket *wsi, unsigned char c)
wsi->rx_user_buffer_head = 0;
}
break;
case LWS_RXPS_04_MASK_NONCE_1:
wsi->frame_masking_nonce_04[1] = c;
wsi->lws_rx_parse_state = LWS_RXPS_04_MASK_NONCE_2;
break;
case LWS_RXPS_04_MASK_NONCE_2:
wsi->frame_masking_nonce_04[2] = c;
wsi->lws_rx_parse_state = LWS_RXPS_04_MASK_NONCE_3;
break;
case LWS_RXPS_04_MASK_NONCE_3:
wsi->frame_masking_nonce_04[3] = c;
/*
* we are able to compute the frame key now
* it's a SHA1 of ( frame nonce we were just sent, concatenated
* with the connection masking key we computed at handshake
* time ) -- yeah every frame from the client invokes a SHA1
* for no real reason so much for lightweight.
*/
buf[0] = wsi->frame_masking_nonce_04[0];
buf[1] = wsi->frame_masking_nonce_04[1];
buf[2] = wsi->frame_masking_nonce_04[2];
buf[3] = wsi->frame_masking_nonce_04[3];
memcpy(buf + 4, wsi->masking_key_04, 20);
/*
* wsi->frame_mask_04 is our recirculating 20-byte XOR key
* for this frame
*/
SHA1((unsigned char *)buf, 4 + 20, wsi->frame_mask_04);
/*
* start from the zero'th byte in the XOR key buffer since
* this is the start of a frame with a new key
*/
wsi->frame_mask_index = 0;
wsi->lws_rx_parse_state = LWS_RXPS_04_FRAME_HDR_1;
break;
case LWS_RXPS_EAT_UNTIL_76_FF:
if (c == 0xff) {
wsi->lws_rx_parse_state = LWS_RXPS_NEW;

9
lib/private-libwebsockets.h
View file

@ -116,6 +116,12 @@ enum lws_rx_parse_state {
LWS_RXPS_PULLING_76_LENGTH,
LWS_RXPS_EAT_UNTIL_76_FF,
LWS_RXPS_04_MASK_NONCE_1,
LWS_RXPS_04_MASK_NONCE_2,
LWS_RXPS_04_MASK_NONCE_3,
LWS_RXPS_04_FRAME_HDR_1,
LWS_RXPS_PAYLOAD_UNTIL_LENGTH_EXHAUSTED
};
@ -154,6 +160,9 @@ struct libwebsocket {
struct lws_tokens utf8_token[WSI_TOKEN_COUNT];
int ietf_spec_revision;
unsigned char masking_key_04[20];
unsigned char frame_mask_04[20];
unsigned char frame_masking_nonce_04[4];
unsigned char frame_mask_index;
char rx_user_buffer[LWS_SEND_BUFFER_PRE_PADDING + MAX_USER_RX_BUFFER +
LWS_SEND_BUFFER_POST_PADDING];
int rx_user_buffer_head;