Mercurial > hg > nginx
view src/http/modules/ngx_http_stub_status_module.c @ 7674:7731c710796f
Memcached: protect from too long responses.
If a memcached response was followed by a correct trailer, and then
the NUL character followed by some extra data - this was accepted by
the trailer checking code. This in turn resulted in ctx->rest underflow
and caused negative size buffer on the next reading from the upstream,
followed by the "negative size buf in writer" alert.
Fix is to always check for too long responses, so a correct trailer cannot
be followed by extra data.
author | Maxim Dounin <mdounin@mdounin.ru> |
---|---|
date | Mon, 06 Jul 2020 18:36:17 +0300 |
parents | 2a288909abc6 |
children | 43a0a9e988be |
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/* * Copyright (C) Igor Sysoev * Copyright (C) Nginx, Inc. */ #include <ngx_config.h> #include <ngx_core.h> #include <ngx_http.h> static ngx_int_t ngx_http_stub_status_handler(ngx_http_request_t *r); static ngx_int_t ngx_http_stub_status_variable(ngx_http_request_t *r, ngx_http_variable_value_t *v, uintptr_t data); static ngx_int_t ngx_http_stub_status_add_variables(ngx_conf_t *cf); static char *ngx_http_set_stub_status(ngx_conf_t *cf, ngx_command_t *cmd, void *conf); static ngx_command_t ngx_http_status_commands[] = { { ngx_string("stub_status"), NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_NOARGS|NGX_CONF_TAKE1, ngx_http_set_stub_status, 0, 0, NULL }, ngx_null_command }; static ngx_http_module_t ngx_http_stub_status_module_ctx = { ngx_http_stub_status_add_variables, /* preconfiguration */ NULL, /* postconfiguration */ NULL, /* create main configuration */ NULL, /* init main configuration */ NULL, /* create server configuration */ NULL, /* merge server configuration */ NULL, /* create location configuration */ NULL /* merge location configuration */ }; ngx_module_t ngx_http_stub_status_module = { NGX_MODULE_V1, &ngx_http_stub_status_module_ctx, /* module context */ ngx_http_status_commands, /* module directives */ NGX_HTTP_MODULE, /* module type */ NULL, /* init master */ NULL, /* init module */ NULL, /* init process */ NULL, /* init thread */ NULL, /* exit thread */ NULL, /* exit process */ NULL, /* exit master */ NGX_MODULE_V1_PADDING }; static ngx_http_variable_t ngx_http_stub_status_vars[] = { { ngx_string("connections_active"), NULL, ngx_http_stub_status_variable, 0, NGX_HTTP_VAR_NOCACHEABLE, 0 }, { ngx_string("connections_reading"), NULL, ngx_http_stub_status_variable, 1, NGX_HTTP_VAR_NOCACHEABLE, 0 }, { ngx_string("connections_writing"), NULL, ngx_http_stub_status_variable, 2, NGX_HTTP_VAR_NOCACHEABLE, 0 }, { ngx_string("connections_waiting"), NULL, ngx_http_stub_status_variable, 3, NGX_HTTP_VAR_NOCACHEABLE, 0 }, ngx_http_null_variable }; static ngx_int_t ngx_http_stub_status_handler(ngx_http_request_t *r) { size_t size; ngx_int_t rc; ngx_buf_t *b; ngx_chain_t out; ngx_atomic_int_t ap, hn, ac, rq, rd, wr, wa; if (!(r->method & (NGX_HTTP_GET|NGX_HTTP_HEAD))) { return NGX_HTTP_NOT_ALLOWED; } rc = ngx_http_discard_request_body(r); if (rc != NGX_OK) { return rc; } r->headers_out.content_type_len = sizeof("text/plain") - 1; ngx_str_set(&r->headers_out.content_type, "text/plain"); r->headers_out.content_type_lowcase = NULL; if (r->method == NGX_HTTP_HEAD) { r->headers_out.status = NGX_HTTP_OK; rc = ngx_http_send_header(r); if (rc == NGX_ERROR || rc > NGX_OK || r->header_only) { return rc; } } size = sizeof("Active connections: \n") + NGX_ATOMIC_T_LEN + sizeof("server accepts handled requests\n") - 1 + 6 + 3 * NGX_ATOMIC_T_LEN + sizeof("Reading: Writing: Waiting: \n") + 3 * NGX_ATOMIC_T_LEN; b = ngx_create_temp_buf(r->pool, size); if (b == NULL) { return NGX_HTTP_INTERNAL_SERVER_ERROR; } out.buf = b; out.next = NULL; ap = *ngx_stat_accepted; hn = *ngx_stat_handled; ac = *ngx_stat_active; rq = *ngx_stat_requests; rd = *ngx_stat_reading; wr = *ngx_stat_writing; wa = *ngx_stat_waiting; b->last = ngx_sprintf(b->last, "Active connections: %uA \n", ac); b->last = ngx_cpymem(b->last, "server accepts handled requests\n", sizeof("server accepts handled requests\n") - 1); b->last = ngx_sprintf(b->last, " %uA %uA %uA \n", ap, hn, rq); b->last = ngx_sprintf(b->last, "Reading: %uA Writing: %uA Waiting: %uA \n", rd, wr, wa); r->headers_out.status = NGX_HTTP_OK; r->headers_out.content_length_n = b->last - b->pos; b->last_buf = (r == r->main) ? 1 : 0; b->last_in_chain = 1; rc = ngx_http_send_header(r); if (rc == NGX_ERROR || rc > NGX_OK || r->header_only) { return rc; } return ngx_http_output_filter(r, &out); } static ngx_int_t ngx_http_stub_status_variable(ngx_http_request_t *r, ngx_http_variable_value_t *v, uintptr_t data) { u_char *p; ngx_atomic_int_t value; p = ngx_pnalloc(r->pool, NGX_ATOMIC_T_LEN); if (p == NULL) { return NGX_ERROR; } switch (data) { case 0: value = *ngx_stat_active; break; case 1: value = *ngx_stat_reading; break; case 2: value = *ngx_stat_writing; break; case 3: value = *ngx_stat_waiting; break; /* suppress warning */ default: value = 0; break; } v->len = ngx_sprintf(p, "%uA", value) - p; v->valid = 1; v->no_cacheable = 0; v->not_found = 0; v->data = p; return NGX_OK; } static ngx_int_t ngx_http_stub_status_add_variables(ngx_conf_t *cf) { ngx_http_variable_t *var, *v; for (v = ngx_http_stub_status_vars; v->name.len; v++) { var = ngx_http_add_variable(cf, &v->name, v->flags); if (var == NULL) { return NGX_ERROR; } var->get_handler = v->get_handler; var->data = v->data; } return NGX_OK; } static char * ngx_http_set_stub_status(ngx_conf_t *cf, ngx_command_t *cmd, void *conf) { ngx_http_core_loc_conf_t *clcf; clcf = ngx_http_conf_get_module_loc_conf(cf, ngx_http_core_module); clcf->handler = ngx_http_stub_status_handler; return NGX_CONF_OK; }