details: http://hg.nginx.org/nginx/rev/052305810ca4 branches: changeset: 6954:052305810ca4 user: Piotr Sikora <piotrsik...@google.com> date: Sun Mar 26 01:25:04 2017 -0700 description: 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 <piotrsik...@google.com> diffstat: src/http/v2/ngx_http_v2.c | 24 +++++++++++++----------- 1 files changed, 13 insertions(+), 11 deletions(-) diffs (80 lines): diff -r 663e6a48bfcb -r 052305810ca4 src/http/v2/ngx_http_v2.c --- a/src/http/v2/ngx_http_v2.c Sun Mar 26 01:25:03 2017 -0700 +++ b/src/http/v2/ngx_http_v2.c Sun Mar 26 01:25:04 2017 -0700 @@ -783,9 +783,12 @@ ngx_http_v2_state_head(ngx_http_v2_conne 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_conne } 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_conne 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_conne 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) _______________________________________________ nginx-devel mailing list nginx-devel@nginx.org http://mailman.nginx.org/mailman/listinfo/nginx-devel