On Mon, Oct 18, 2021 at 03:48:28PM +0300, Roman Arutyunyan wrote:
> # HG changeset patch
> # User Roman Arutyunyan <arut@nginx.com>
> # Date 1634559753 -10800
> # Mon Oct 18 15:22:33 2021 +0300
> # Branch quic
> # Node ID 8739f475583031399879ef0af2eb5af76008449e
> # Parent 404de224517e33f685613d6425dcdb3c8ef5b97e
> HTTP/3: adjusted QUIC connection finalization.
>
> When an HTTP/3 function returns an error in context of a QUIC stream, it's
> this function's responsibility now to finalize the entire QUIC connection
> with the right code, if required. Previously, QUIC connection finalization
> could be done both outside and inside such functions. The new rule follows
> a similar rule for logging, leads to cleaner code, and allows to provide more
> details about the error.
>
> While here, a few error cases are no longer treated as fatal and QUIC connection
> is no longer finalized in these cases. A few other cases now lead to
> stream reset instead of connection finalization.
>
> diff --git a/src/http/v3/ngx_http_v3.c b/src/http/v3/ngx_http_v3.c
> --- a/src/http/v3/ngx_http_v3.c
> +++ b/src/http/v3/ngx_http_v3.c
> @@ -33,7 +33,7 @@ ngx_http_v3_init_session(ngx_connection_
>
> h3c = ngx_pcalloc(pc->pool, sizeof(ngx_http_v3_session_t));
> if (h3c == NULL) {
> - return NGX_ERROR;
> + goto failed;
> }
>
> h3c->max_push_id = (uint64_t) -1;
> @@ -49,7 +49,7 @@ ngx_http_v3_init_session(ngx_connection_
>
> cln = ngx_pool_cleanup_add(pc->pool, 0);
> if (cln == NULL) {
> - return NGX_ERROR;
> + goto failed;
> }
>
> cln->handler = ngx_http_v3_cleanup_session;
> @@ -58,6 +58,14 @@ ngx_http_v3_init_session(ngx_connection_
> hc->v3_session = h3c;
>
> return ngx_http_v3_send_settings(c);
> +
> +failed:
> +
> + ngx_log_error(NGX_LOG_ERR, c->log, 0, "failed to create http3 session");
> +
> + ngx_http_v3_finalize_connection(c, NGX_HTTP_V3_ERR_INTERNAL_ERROR,
> + "failed to create http3 session");
> + return NGX_ERROR;
> }
>
>
> diff --git a/src/http/v3/ngx_http_v3_request.c b/src/http/v3/ngx_http_v3_request.c
> --- a/src/http/v3/ngx_http_v3_request.c
> +++ b/src/http/v3/ngx_http_v3_request.c
> @@ -65,8 +65,6 @@ ngx_http_v3_init(ngx_connection_t *c)
> ngx_http_core_srv_conf_t *cscf;
>
> if (ngx_http_v3_init_session(c) != NGX_OK) {
> - ngx_http_v3_finalize_connection(c, NGX_HTTP_V3_ERR_INTERNAL_ERROR,
> - "internal error");
> ngx_http_close_connection(c);
> return;
> }
> @@ -110,8 +108,6 @@ ngx_http_v3_init(ngx_connection_t *c)
> h3c->goaway = 1;
>
> if (ngx_http_v3_send_goaway(c, (n + 1) << 2) != NGX_OK) {
> - ngx_http_v3_finalize_connection(c, NGX_HTTP_V3_ERR_INTERNAL_ERROR,
> - "goaway error");
> ngx_http_close_connection(c);
> return;
> }
> @@ -287,15 +283,14 @@ ngx_http_v3_process_request(ngx_event_t
> rc = ngx_http_v3_parse_headers(c, st, b);
>
> if (rc > 0) {
> - ngx_http_v3_finalize_connection(c, rc,
> - "could not parse request headers");
> + ngx_quic_reset_stream(c, rc);
> + ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
> + "client sent invalid header");
> ngx_http_finalize_request(r, NGX_HTTP_BAD_REQUEST);
> break;
> }
>
> if (rc == NGX_ERROR) {
> - ngx_http_v3_finalize_connection(c, NGX_HTTP_V3_ERR_INTERNAL_ERROR,
> - "internal error");
> ngx_http_close_request(r, NGX_HTTP_INTERNAL_SERVER_ERROR);
> break;
> }
> @@ -1167,17 +1162,13 @@ ngx_http_v3_request_body_filter(ngx_http
> }
>
> if (rc > 0) {
> - ngx_http_v3_finalize_connection(r->connection, rc,
> - "client sent invalid body");
> + ngx_quic_reset_stream(r->connection, rc);
> ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
> "client sent invalid body");
> return NGX_HTTP_BAD_REQUEST;
> }
>
> if (rc == NGX_ERROR) {
> - ngx_http_v3_finalize_connection(r->connection,
> - NGX_HTTP_V3_ERR_INTERNAL_ERROR,
> - "internal error");
> return NGX_HTTP_INTERNAL_SERVER_ERROR;
> }
>
> diff --git a/src/http/v3/ngx_http_v3_streams.c b/src/http/v3/ngx_http_v3_streams.c
> --- a/src/http/v3/ngx_http_v3_streams.c
> +++ b/src/http/v3/ngx_http_v3_streams.c
> @@ -283,7 +283,7 @@ ngx_http_v3_create_push_stream(ngx_conne
>
> sc = ngx_quic_open_stream(c, 0);
> if (sc == NULL) {
> - return NULL;
> + goto failed;
> }
>
> p = buf;
> @@ -318,7 +318,13 @@ ngx_http_v3_create_push_stream(ngx_conne
>
> failed:
>
> - ngx_http_v3_close_uni_stream(sc);
> + ngx_log_error(NGX_LOG_ERR, c->log, 0, "failed to create push stream");
> +
> + ngx_http_v3_finalize_connection(c, NGX_HTTP_V3_ERR_STREAM_CREATION_ERROR,
> + "failed to create push stream");
> + if (sc) {
> + ngx_http_v3_close_uni_stream(sc);
> + }
>
> return NULL;
> }
> @@ -368,7 +374,7 @@ ngx_http_v3_get_uni_stream(ngx_connectio
>
> sc = ngx_quic_open_stream(c, 0);
> if (sc == NULL) {
> - return NULL;
> + goto failed;
> }
>
> sc->quic->cancelable = 1;
> @@ -405,7 +411,13 @@ ngx_http_v3_get_uni_stream(ngx_connectio
>
> failed:
>
> - ngx_http_v3_close_uni_stream(sc);
> + ngx_log_error(NGX_LOG_ERR, c->log, 0, "failed to create server stream");
> +
> + ngx_http_v3_finalize_connection(c, NGX_HTTP_V3_ERR_STREAM_CREATION_ERROR,
> + "failed to create server stream");
> + if (sc) {
> + ngx_http_v3_close_uni_stream(sc);
> + }
>
> return NULL;
> }
> @@ -424,7 +436,7 @@ ngx_http_v3_send_settings(ngx_connection
>
> cc = ngx_http_v3_get_uni_stream(c, NGX_HTTP_V3_STREAM_CONTROL);
> if (cc == NULL) {
> - return NGX_DECLINED;
> + return NGX_ERROR;
> }
>
> h3scf = ngx_http_v3_get_module_srv_conf(c, ngx_http_v3_module);
> @@ -457,6 +469,10 @@ ngx_http_v3_send_settings(ngx_connection
>
> failed:
>
> + ngx_log_error(NGX_LOG_ERR, c->log, 0, "failed to send settings");
> +
> + ngx_http_v3_finalize_connection(c, NGX_HTTP_V3_ERR_EXCESSIVE_LOAD,
> + "failed to send settings");
> ngx_http_v3_close_uni_stream(cc);
>
> return NGX_ERROR;
> @@ -475,7 +491,7 @@ ngx_http_v3_send_goaway(ngx_connection_t
>
> cc = ngx_http_v3_get_uni_stream(c, NGX_HTTP_V3_STREAM_CONTROL);
> if (cc == NULL) {
> - return NGX_DECLINED;
> + return NGX_ERROR;

This case now misses sending CONNECTION_CLOSE (no further stream processing),
Instead, the last allowed stream connection is now closed while initializing
with sending FIN with off:0 in its cleanup function which confuses clients
due to H3_FRAME_UNEXPECTED. It probably needs to be converted to goto failed
with conditional uni stream close.

Same in ngx_http_v3_send_settings() around ngx_http_v3_get_uni_stream(), but
there it just leads to control stream silent closure with no visible effects
on the wire. Yet, with teh 2nd patch applied that updates stream reset logic,
the error causes to emit RESET_STREAM(H3_INTERNAL_ERROR), which is a protocol
violation when operating on a critical (control) stream.

> }
>
> n = ngx_http_v3_encode_varlen_int(NULL, id);
> @@ -495,6 +511,10 @@ ngx_http_v3_send_goaway(ngx_connection_t
>
> failed:
>
> + ngx_log_error(NGX_LOG_ERR, c->log, 0, "failed to send goaway");
> +
> + ngx_http_v3_finalize_connection(c, NGX_HTTP_V3_ERR_EXCESSIVE_LOAD,
> + "failed to send goaway");
> ngx_http_v3_close_uni_stream(cc);
>
> return NGX_ERROR;
> @@ -510,7 +530,7 @@ ngx_http_v3_send_ack_section(ngx_connect
> ngx_http_v3_session_t *h3c;
>
> ngx_log_debug1(NGX_LOG_DEBUG_HTTP, c->log, 0,
> - "http3 client ack section %ui", stream_id);
> + "http3 send section acknowledgement %ui", stream_id);
>
> dc = ngx_http_v3_get_uni_stream(c, NGX_HTTP_V3_STREAM_DECODER);
> if (dc == NULL) {
> @@ -524,11 +544,21 @@ ngx_http_v3_send_ack_section(ngx_connect
> h3c->total_bytes += n;
>
> if (dc->send(dc, buf, n) != (ssize_t) n) {
> - ngx_http_v3_close_uni_stream(dc);
> - return NGX_ERROR;
> + goto failed;
> }
>
> return NGX_OK;
> +
> +failed:
> +
> + ngx_log_error(NGX_LOG_ERR, c->log, 0,
> + "failed to send section acknowledgement");
> +
> + ngx_http_v3_finalize_connection(c, NGX_HTTP_V3_ERR_EXCESSIVE_LOAD,
> + "failed to send section acknowledgement");
> + ngx_http_v3_close_uni_stream(dc);
> +
> + return NGX_ERROR;
> }
>
>
> @@ -541,7 +571,7 @@ ngx_http_v3_send_cancel_stream(ngx_conne
> ngx_http_v3_session_t *h3c;
>
> ngx_log_debug1(NGX_LOG_DEBUG_HTTP, c->log, 0,
> - "http3 client cancel stream %ui", stream_id);
> + "http3 send stream cancellation %ui", stream_id);
>
> dc = ngx_http_v3_get_uni_stream(c, NGX_HTTP_V3_STREAM_DECODER);
> if (dc == NULL) {
> @@ -555,11 +585,20 @@ ngx_http_v3_send_cancel_stream(ngx_conne
> h3c->total_bytes += n;
>
> if (dc->send(dc, buf, n) != (ssize_t) n) {
> - ngx_http_v3_close_uni_stream(dc);
> - return NGX_ERROR;
> + goto failed;
> }
>
> return NGX_OK;
> +
> +failed:
> +
> + ngx_log_error(NGX_LOG_ERR, c->log, 0, "failed to send stream cancellation");
> +
> + ngx_http_v3_finalize_connection(c, NGX_HTTP_V3_ERR_EXCESSIVE_LOAD,
> + "failed to send stream cancellation");
> + ngx_http_v3_close_uni_stream(dc);
> +
> + return NGX_ERROR;
> }
>
>
> @@ -572,7 +611,7 @@ ngx_http_v3_send_inc_insert_count(ngx_co
> ngx_http_v3_session_t *h3c;
>
> ngx_log_debug1(NGX_LOG_DEBUG_HTTP, c->log, 0,
> - "http3 client increment insert count %ui", inc);
> + "http3 send insert count increment %ui", inc);
>
> dc = ngx_http_v3_get_uni_stream(c, NGX_HTTP_V3_STREAM_DECODER);
> if (dc == NULL) {
> @@ -586,11 +625,21 @@ ngx_http_v3_send_inc_insert_count(ngx_co
> h3c->total_bytes += n;
>
> if (dc->send(dc, buf, n) != (ssize_t) n) {
> - ngx_http_v3_close_uni_stream(dc);
> - return NGX_ERROR;
> + goto failed;
> }
>
> return NGX_OK;
> +
> +failed:
> +
> + ngx_log_error(NGX_LOG_ERR, c->log, 0,
> + "failed to send insert count increment");
> +
> + ngx_http_v3_finalize_connection(c, NGX_HTTP_V3_ERR_EXCESSIVE_LOAD,
> + "failed to send insert count increment");
> + ngx_http_v3_close_uni_stream(dc);
> +
> + return NGX_ERROR;
> }
>
>
> diff --git a/src/http/v3/ngx_http_v3_tables.c b/src/http/v3/ngx_http_v3_tables.c
> --- a/src/http/v3/ngx_http_v3_tables.c
> +++ b/src/http/v3/ngx_http_v3_tables.c
> @@ -589,6 +589,10 @@ ngx_http_v3_check_insert_count(ngx_conne
> if (h3c->nblocked == h3scf->max_blocked_streams) {
> ngx_log_error(NGX_LOG_INFO, c->log, 0,
> "client exceeded http3_max_blocked_streams limit");
> +
> + ngx_http_v3_finalize_connection(c,
> + NGX_HTTP_V3_ERR_DECOMPRESSION_FAILED,
> + "too many blocked streams");
> return NGX_HTTP_V3_ERR_DECOMPRESSION_FAILED;
> }
>
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