From de4f0eb26b394f49abcc215badba443d3ab7922e Mon Sep 17 00:00:00 2001 From: Piotr Sikora Date: Thu, 1 Oct 2015 20:25:55 -0700 Subject: [PATCH] HTTP/2: fix indirect reprioritization. Previously, streams that were indirectly reprioritized (either because of a new exclusive dependency on their parent or because of removal of their parent from the dependency tree), didn't have their pointer to the parent node updated. This broke detection of circular dependencies and, as a result, nginx worker would crash due to stack overflow whenever such dependency was introduced. Found with afl-fuzz. Signed-off-by: Piotr Sikora --- src/http/v2/ngx_http_v2.c | 17 +++++++++++++---- 1 file changed, 13 insertions(+), 4 deletions(-) diff --git a/src/http/v2/ngx_http_v2.c b/src/http/v2/ngx_http_v2.c index 6cca2b9a3..51cf65a88 100644 --- a/src/http/v2/ngx_http_v2.c +++ b/src/http/v2/ngx_http_v2.c @@ -2914,11 +2914,14 @@ ngx_http_v2_get_closed_node(ngx_http_v2_connection_t *h2c) weight += child->weight; } + parent = node->parent; + for (q = ngx_queue_head(&node->children); q != ngx_queue_sentinel(&node->children); q = ngx_queue_next(q)) { child = ngx_queue_data(q, ngx_http_v2_node_t, queue); + child->parent = parent; child->weight = node->weight * child->weight / weight; if (child->weight == 0) { @@ -2926,8 +2929,6 @@ ngx_http_v2_get_closed_node(ngx_http_v2_connection_t *h2c) } } - parent = node->parent; - if (parent == NGX_HTTP_V2_ROOT) { node->rank = 0; node->rel_weight = 1.0; @@ -3940,8 +3941,8 @@ static void ngx_http_v2_set_dependency(ngx_http_v2_connection_t *h2c, ngx_http_v2_node_t *node, ngx_uint_t depend, ngx_uint_t exclusive) { - ngx_queue_t *children; - ngx_http_v2_node_t *parent, *next; + ngx_queue_t *children, *q; + ngx_http_v2_node_t *parent, *child, *next; parent = depend ? ngx_http_v2_get_node_by_id(h2c, depend, 0) : NULL; @@ -4003,6 +4004,14 @@ ngx_http_v2_set_dependency(ngx_http_v2_connection_t *h2c, } if (exclusive) { + for (q = ngx_queue_head(children); + q != ngx_queue_sentinel(children); + q = ngx_queue_next(q)) + { + child = ngx_queue_data(q, ngx_http_v2_node_t, queue); + child->parent = node; + } + ngx_queue_add(&node->children, children); ngx_queue_init(children); }