From 7c67ff73634acde729ceb151110f8db10322a33e Mon Sep 17 00:00:00 2001 From: Maxim Dounin Date: Wed, 23 Sep 2020 19:50:49 +0300 Subject: [PATCH] HTTP/2: fixed segfault on DATA frames after 400 errors. If 400 errors were redirected to an upstream server using the error_page directive, DATA frames from the client might cause segmentation fault due to null pointer dereference. The bug had appeared in 6989:2c4dbcd6f2e4 (1.13.0). Fix is to skip such frames in ngx_http_v2_state_read_data() (similarly to 7561:9f1f9d6e056a). With the fix, behaviour of 400 errors in HTTP/2 is now similar to one in HTTP/1.x, that is, nginx doesn't try to read the request body. Note that proxying 400 errors, as well as other early stage errors, to upstream servers might not be a good idea anyway. These errors imply that reading and processing of the request (and the request headers) wasn't complete, and proxying of such incomplete request might lead to various errors. Reported by Chenglong Zhang. --- src/http/v2/ngx_http_v2.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/src/http/v2/ngx_http_v2.c b/src/http/v2/ngx_http_v2.c index 1037e9d15..9c994b8a3 100644 --- a/src/http/v2/ngx_http_v2.c +++ b/src/http/v2/ngx_http_v2.c @@ -1084,6 +1084,13 @@ ngx_http_v2_state_read_data(ngx_http_v2_connection_t *h2c, u_char *pos, return ngx_http_v2_state_skip_padded(h2c, pos, end); } + if (r->headers_in.content_length_n < 0 && !r->headers_in.chunked) { + ngx_log_debug0(NGX_LOG_DEBUG_HTTP, h2c->connection->log, 0, + "skipping http2 DATA frame"); + + return ngx_http_v2_state_skip_padded(h2c, pos, end); + } + size = end - pos; if (size >= h2c->state.length) {