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Recreate upgrade headers for websocket request #1592

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merged 4 commits into from
Mar 18, 2022
Merged

Recreate upgrade headers for websocket request #1592

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b3e04fe
Recreate upgrade headers for websocket request
ttaym Mar 5, 2022
23d3e9b
fixup! Recreate upgrade headers for websocket request
ttaym Mar 17, 2022
73f894c
fixup! Recreate upgrade headers for websocket request
ttaym Mar 17, 2022
1ce0b5d
Update fw/http.c
ttaym Mar 18, 2022
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58 changes: 54 additions & 4 deletions fw/http.c
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Original file line number Diff line number Diff line change
Expand Up @@ -2572,6 +2572,33 @@ tfw_http_set_hdr_date(TfwHttpMsg *hm)
return r;
}

/*
* Add 'Upgrade:' header for websocket upgrade messages
*/
static int
tfw_http_set_hdr_upgrade(TfwHttpMsg *hm, bool is_resp)
{
int r = 0;

if (test_bit(TFW_HTTP_B_UPGRADE_WEBSOCKET, hm->flags)) {
if (is_resp && ((TfwHttpResp *)hm)->status == 101
&& test_bit(TFW_HTTP_B_UPGRADE_EXTRA, hm->flags))
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I'm not sure if I understand this. It seems this is about https://datatracker.ietf.org/doc/html/rfc7230#section-6.7

A server that sends a 101 (Switching Protocols) response MUST send an
Upgrade header field to indicate the new protocol(s) to which the
connection is being switched; if multiple protocol layers are being
switched, the sender MUST list the protocols in layer-ascending
order. A server MUST NOT switch to a protocol that was not indicated
by the client in the corresponding request's Upgrade header field.

This piece of code is for response with something extra plus to websocket in Upgrader header. Since we can only generate Upgrade: websocket in adjusted client request and server MUST NOT add anything non-requested, then what could be in the response for the extra? Can't we just always send Upgrade: websocket from the server to the client?

If I'm wrong, then a good comment with the RFC cite is required in the place.

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@ttaym ttaym Mar 17, 2022 •
edited
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My intention was as follows:

We always strip upgrade header from response and re-add it when needed. So we do not just pass it through tempesta as is. But when we recreate headers would be beneficially to do simple sane check because we essentially hide backend and act on behalf on it.

Imaging erroneous backend that we on our discretion silently transform into compliant backend. That would be destructive if you ask me.

But this intention is, i understand, subtle and subjective. It is up to you if we need just alway send Upgrade: websocket.

{
T_ERR("Unable to add uncompliant Upgrade: header "
"to msg [%p]\n", hm);
return -EINVAL;
}
r = tfw_http_msg_hdr_xfrm(hm, "upgrade", SLEN("upgrade"),
"websocket", SLEN("websocket"),
TFW_HTTP_HDR_UPGRADE, 0);
if (r)
T_ERR("Unable to add Upgrade: header to msg [%p]\n", hm);
else
T_DBG2("Added Upgrade: header to msg [%p]\n", hm);
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}
return r;
}

/*
* Expand HTTP response with 'Date:' header field.
*/
Expand Down Expand Up @@ -2677,23 +2704,38 @@ tfw_http_expand_hbh(TfwHttpResp *resp, unsigned short status)
static int
tfw_http_set_hdr_connection(TfwHttpMsg *hm, unsigned long conn_flg)
{
int r;
BUILD_BUG_ON(BIT_WORD(__TFW_HTTP_MSG_M_CONN) != 0);
if (((hm->flags[0] & __TFW_HTTP_MSG_M_CONN) == conn_flg)
&& (!TFW_STR_EMPTY(&hm->h_tbl->tbl[TFW_HTTP_HDR_CONNECTION]))
&& !test_bit(TFW_HTTP_B_CONN_EXTRA, hm->flags))
&& !test_bit(TFW_HTTP_B_CONN_EXTRA, hm->flags)
&& !test_bit(TFW_HTTP_B_CONN_UPGRADE, hm->flags))
{
return 0;
}

switch (conn_flg) {
case BIT(TFW_HTTP_B_CONN_CLOSE):
return TFW_HTTP_MSG_HDR_XFRM(hm, "Connection", "close",
TFW_HTTP_HDR_CONNECTION, 0);
case BIT(TFW_HTTP_B_CONN_KA):
return TFW_HTTP_MSG_HDR_XFRM(hm, "Connection", "keep-alive",
TFW_HTTP_HDR_CONNECTION, 0);
r = TFW_HTTP_MSG_HDR_XFRM(hm, "Connection", "keep-alive",
TFW_HTTP_HDR_CONNECTION, 0);
break;
default:
return TFW_HTTP_MSG_HDR_DEL(hm, "Connection",
r = TFW_HTTP_MSG_HDR_DEL(hm, "Connection",
TFW_HTTP_HDR_CONNECTION);
}

if (r < 0)
return r;

if (test_bit(TFW_HTTP_B_UPGRADE_WEBSOCKET, hm->flags)
&& test_bit(TFW_HTTP_B_CONN_UPGRADE, hm->flags))
r = TFW_HTTP_MSG_HDR_XFRM(hm, "Connection", "upgrade",
TFW_HTTP_HDR_CONNECTION, 1);
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Headers modification is a heavy operation, probably involving memory allocations and skb frarmentation (see #1103), so it'd be more beneficial to do bit more complex condition and call do only one transformation call.

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That make sense. I'll fix it.


return r;
}

/**
Expand Down Expand Up @@ -3072,6 +3114,10 @@ tfw_h1_adjust_req(TfwHttpReq *req)
if (r < 0)
return r;

r = tfw_http_set_hdr_upgrade(hm, false);
if (r < 0)
return r;

r = tfw_h1_set_loc_hdrs(hm, false, false);
if (r < 0)
return r;
Expand Down Expand Up @@ -3642,6 +3688,10 @@ tfw_http_adjust_resp(TfwHttpResp *resp)
if (r < 0)
return r;

r = tfw_http_set_hdr_upgrade(hm, true);
if (r < 0)
return r;

r = tfw_http_set_hdr_keep_alive(hm, conn_flg);
if (r < 0)
return r;
Expand Down
4 changes: 3 additions & 1 deletion fw/http.h
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Original file line number Diff line number Diff line change
Expand Up @@ -242,8 +242,10 @@ enum {
TFW_HTTP_B_CONN_KA,
TFW_HTTP_B_CONN_UPGRADE,
TFW_HTTP_B_CONN_EXTRA,
/* Request is a websocket upgrade request */
/* Message is a websocket upgrade request */
TFW_HTTP_B_UPGRADE_WEBSOCKET,
/* Message upgrade header contains extra fields */
TFW_HTTP_B_UPGRADE_EXTRA,
/* Chunked is last transfer encoding. */
TFW_HTTP_B_CHUNKED,
/* Chunked in the middle of applied transfer encodings. */
Expand Down
35 changes: 31 additions & 4 deletions fw/http_parser.c
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Original file line number Diff line number Diff line change
Expand Up @@ -3348,7 +3348,7 @@ STACK_FRAME_NON_STANDARD(__parse_pragma);
* __FSM_I_MOVE_fixup()/__FSM_I_MATCH_fixup()/TRY_STR_fixup() everywhere.
*/
static int
__req_parse_upgrade(TfwHttpMsg *hm, unsigned char *data, size_t len)
__parse_upgrade(TfwHttpMsg *hm, unsigned char *data, size_t len)
{
int r = CSTR_NEQ;
__FSM_DECLARE_VARS(hm);
Expand Down Expand Up @@ -3382,6 +3382,8 @@ __req_parse_upgrade(TfwHttpMsg *hm, unsigned char *data, size_t len)
*/
return CSTR_NEQ;
}

__set_bit(TFW_HTTP_B_UPGRADE_EXTRA, msg->flags);
__FSM_I_JMP(I_UpgradeProtocolEnd);
}

Expand All @@ -3398,6 +3400,8 @@ __req_parse_upgrade(TfwHttpMsg *hm, unsigned char *data, size_t len)
__set_bit(TFW_HTTP_B_UPGRADE_WEBSOCKET,
msg->flags);
}
} else {
__set_bit(TFW_HTTP_B_UPGRADE_EXTRA, msg->flags);
}

__FSM_I_JMP(I_UpgradeProtocolEnd);
Expand Down Expand Up @@ -3437,7 +3441,6 @@ __req_parse_upgrade(TfwHttpMsg *hm, unsigned char *data, size_t len)
* At this state we know that we saw at least one character in
* protocol version and now we can pass zero length token.
*/

__FSM_STATE(I_UpgradeVersion) {
__FSM_I_MATCH_MOVE_fixup(token, I_UpgradeVersion,
TFW_STR_VALUE);
Expand Down Expand Up @@ -3477,7 +3480,7 @@ __req_parse_upgrade(TfwHttpMsg *hm, unsigned char *data, size_t len)
done:
return r;
}
STACK_FRAME_NON_STANDARD(__req_parse_upgrade);
STACK_FRAME_NON_STANDARD(__parse_upgrade);

static int
__req_parse_user_agent(TfwHttpMsg *hm, unsigned char *data, size_t len)
Expand Down Expand Up @@ -4479,7 +4482,7 @@ tfw_http_parse_req(void *req_data, unsigned char *data, size_t len,
TFW_HTTP_HDR_USER_AGENT);

/* 'Upgrade:*OWS' is read, process field-value. */
__TFW_HTTP_PARSE_SPECHDR_VAL(Req_HdrUpgradeV, msg,__req_parse_upgrade,
__TFW_HTTP_PARSE_SPECHDR_VAL(Req_HdrUpgradeV, msg, __parse_upgrade,
TFW_HTTP_HDR_UPGRADE, 0);

/* 'Cookie:*OWS' is read, process field-value. */
Expand Down Expand Up @@ -10057,6 +10060,17 @@ tfw_http_parse_resp(void *resp_data, unsigned char *data, size_t len,
__FSM_MOVE_hdr_fixup(RGen_LWS, 1);
}
__FSM_MOVE(Resp_HdrT);
case 'u':
if (likely(__data_available(p, 8)
&& C4_INT_LCM(p, 'u', 'p', 'g', 'r')
&& C4_INT3_LCM(p + 4, 'a', 'd', 'e', ':')))
{
__msg_hdr_chunk_fixup(data, __data_off(p + 7));
parser->_i_st = &&Resp_HdrUpgradeV;
p += 7;
__FSM_MOVE_hdr_fixup(RGen_LWS, 1);
}
__FSM_MOVE(Resp_HdrU);
case 'v':
if (likely(__data_available(p, 5)
&& C4_INT3_LCM(p + 1, 'a', 'r', 'y', ':')))
Expand Down Expand Up @@ -10229,6 +10243,10 @@ tfw_http_parse_resp(void *resp_data, unsigned char *data, size_t len,
/* 'Pragma:*OWS' is read, process field-value. */
__TFW_HTTP_PARSE_RAWHDR_VAL(Resp_HdrPragmaV, msg, __parse_pragma, 0);

/* 'Upgrade:*OWS' is read, process field-value. */
__TFW_HTTP_PARSE_SPECHDR_VAL(Resp_HdrUpgradeV, msg, __parse_upgrade,
TFW_HTTP_HDR_UPGRADE, 0);

/* 'Server:*OWS' is read, process field-value. */
TFW_HTTP_PARSE_SPECHDR_VAL(Resp_HdrServerV, resp, __resp_parse_server,
TFW_HTTP_HDR_SERVER);
Expand Down Expand Up @@ -10744,6 +10762,15 @@ tfw_http_parse_resp(void *resp_data, unsigned char *data, size_t len,
__FSM_TX_AF(Resp_HdrWWW_Authenticat, 'e', Resp_HdrWWW_Authenticate);
__FSM_TX_AF_OWS_HP(Resp_HdrWWW_Authenticate, RGen_HdrOtherV, 61);

/* Upgrade header processing. */
__FSM_TX_AF(Resp_HdrU, 'p', Resp_HdrUp);
__FSM_TX_AF(Resp_HdrUp, 'g', Resp_HdrUpg);
__FSM_TX_AF(Resp_HdrUpg, 'r', Resp_HdrUpgr);
__FSM_TX_AF(Resp_HdrUpgr, 'a', Resp_HdrUpgra);
__FSM_TX_AF(Resp_HdrUpgra, 'd', Resp_HdrUpgrad);
__FSM_TX_AF(Resp_HdrUpgrad, 'e', Resp_HdrUpgrade);
__FSM_TX_AF_OWS(Resp_HdrUpgrade, Resp_HdrUpgradeV);

__FSM_FINISH(resp);

return r;
Expand Down