From f2393f8feff45835c0b612c1871afa015361637c Mon Sep 17 00:00:00 2001 From: Piotr Sikora Date: Sun, 26 Mar 2017 01:25:04 -0700 Subject: HTTP/2: fix flow control with padded DATA frames. Previously, flow control didn't account for padding in DATA frames, which meant that its view of the world could drift from peer's view by up to 256 bytes per received padded DATA frame, which could lead to a deadlock. Signed-off-by: Piotr Sikora --- src/http/v2/ngx_http_v2.c | 22 ++++++++++++---------- 1 file changed, 12 insertions(+), 10 deletions(-) (limited to 'src') diff --git a/src/http/v2/ngx_http_v2.c b/src/http/v2/ngx_http_v2.c index f3050f1db..e17af9ac4 100644 --- a/src/http/v2/ngx_http_v2.c +++ b/src/http/v2/ngx_http_v2.c @@ -783,9 +783,12 @@ ngx_http_v2_state_head(ngx_http_v2_connection_t *h2c, u_char *pos, u_char *end) static u_char * ngx_http_v2_state_data(ngx_http_v2_connection_t *h2c, u_char *pos, u_char *end) { + size_t size; ngx_http_v2_node_t *node; ngx_http_v2_stream_t *stream; + size = h2c->state.length; + if (h2c->state.flags & NGX_HTTP_V2_PADDED_FLAG) { if (h2c->state.length == 0) { @@ -802,33 +805,32 @@ ngx_http_v2_state_data(ngx_http_v2_connection_t *h2c, u_char *pos, u_char *end) } h2c->state.padding = *pos++; - h2c->state.length--; - if (h2c->state.padding > h2c->state.length) { + if (h2c->state.padding >= size) { ngx_log_error(NGX_LOG_INFO, h2c->connection->log, 0, "client sent padded DATA frame " "with incorrect length: %uz, padding: %uz", - h2c->state.length, h2c->state.padding); + size, h2c->state.padding); return ngx_http_v2_connection_error(h2c, NGX_HTTP_V2_SIZE_ERROR); } - h2c->state.length -= h2c->state.padding; + h2c->state.length -= 1 + h2c->state.padding; } ngx_log_debug0(NGX_LOG_DEBUG_HTTP, h2c->connection->log, 0, "http2 DATA frame"); - if (h2c->state.length > h2c->recv_window) { + if (size > h2c->recv_window) { ngx_log_error(NGX_LOG_INFO, h2c->connection->log, 0, "client violated connection flow control: " "received DATA frame length %uz, available window %uz", - h2c->state.length, h2c->recv_window); + size, h2c->recv_window); return ngx_http_v2_connection_error(h2c, NGX_HTTP_V2_FLOW_CTRL_ERROR); } - h2c->recv_window -= h2c->state.length; + h2c->recv_window -= size; if (h2c->recv_window < NGX_HTTP_V2_MAX_WINDOW / 4) { @@ -854,11 +856,11 @@ ngx_http_v2_state_data(ngx_http_v2_connection_t *h2c, u_char *pos, u_char *end) stream = node->stream; - if (h2c->state.length > stream->recv_window) { + if (size > stream->recv_window) { ngx_log_error(NGX_LOG_INFO, h2c->connection->log, 0, "client violated flow control for stream %ui: " "received DATA frame length %uz, available window %uz", - node->id, h2c->state.length, stream->recv_window); + node->id, size, stream->recv_window); if (ngx_http_v2_terminate_stream(h2c, stream, NGX_HTTP_V2_FLOW_CTRL_ERROR) @@ -871,7 +873,7 @@ ngx_http_v2_state_data(ngx_http_v2_connection_t *h2c, u_char *pos, u_char *end) return ngx_http_v2_state_skip_padded(h2c, pos, end); } - stream->recv_window -= h2c->state.length; + stream->recv_window -= size; if (stream->no_flow_control && stream->recv_window < NGX_HTTP_V2_MAX_WINDOW / 4) -- cgit