Mercurial > hg > nginx
view src/stream/ngx_stream_return_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 | 56fc55e32f23 |
children |
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/* * Copyright (C) Roman Arutyunyan * Copyright (C) Nginx, Inc. */ #include <ngx_config.h> #include <ngx_core.h> #include <ngx_stream.h> typedef struct { ngx_stream_complex_value_t text; } ngx_stream_return_srv_conf_t; typedef struct { ngx_chain_t *out; } ngx_stream_return_ctx_t; static void ngx_stream_return_handler(ngx_stream_session_t *s); static void ngx_stream_return_write_handler(ngx_event_t *ev); static void *ngx_stream_return_create_srv_conf(ngx_conf_t *cf); static char *ngx_stream_return(ngx_conf_t *cf, ngx_command_t *cmd, void *conf); static ngx_command_t ngx_stream_return_commands[] = { { ngx_string("return"), NGX_STREAM_SRV_CONF|NGX_CONF_TAKE1, ngx_stream_return, NGX_STREAM_SRV_CONF_OFFSET, 0, NULL }, ngx_null_command }; static ngx_stream_module_t ngx_stream_return_module_ctx = { NULL, /* preconfiguration */ NULL, /* postconfiguration */ NULL, /* create main configuration */ NULL, /* init main configuration */ ngx_stream_return_create_srv_conf, /* create server configuration */ NULL /* merge server configuration */ }; ngx_module_t ngx_stream_return_module = { NGX_MODULE_V1, &ngx_stream_return_module_ctx, /* module context */ ngx_stream_return_commands, /* module directives */ NGX_STREAM_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 void ngx_stream_return_handler(ngx_stream_session_t *s) { ngx_str_t text; ngx_buf_t *b; ngx_connection_t *c; ngx_stream_return_ctx_t *ctx; ngx_stream_return_srv_conf_t *rscf; c = s->connection; c->log->action = "returning text"; rscf = ngx_stream_get_module_srv_conf(s, ngx_stream_return_module); if (ngx_stream_complex_value(s, &rscf->text, &text) != NGX_OK) { ngx_stream_finalize_session(s, NGX_STREAM_INTERNAL_SERVER_ERROR); return; } ngx_log_debug1(NGX_LOG_DEBUG_STREAM, c->log, 0, "stream return text: \"%V\"", &text); if (text.len == 0) { ngx_stream_finalize_session(s, NGX_STREAM_OK); return; } ctx = ngx_pcalloc(c->pool, sizeof(ngx_stream_return_ctx_t)); if (ctx == NULL) { ngx_stream_finalize_session(s, NGX_STREAM_INTERNAL_SERVER_ERROR); return; } ngx_stream_set_ctx(s, ctx, ngx_stream_return_module); b = ngx_calloc_buf(c->pool); if (b == NULL) { ngx_stream_finalize_session(s, NGX_STREAM_INTERNAL_SERVER_ERROR); return; } b->memory = 1; b->pos = text.data; b->last = text.data + text.len; b->last_buf = 1; ctx->out = ngx_alloc_chain_link(c->pool); if (ctx->out == NULL) { ngx_stream_finalize_session(s, NGX_STREAM_INTERNAL_SERVER_ERROR); return; } ctx->out->buf = b; ctx->out->next = NULL; c->write->handler = ngx_stream_return_write_handler; ngx_stream_return_write_handler(c->write); } static void ngx_stream_return_write_handler(ngx_event_t *ev) { ngx_connection_t *c; ngx_stream_session_t *s; ngx_stream_return_ctx_t *ctx; c = ev->data; s = c->data; if (ev->timedout) { ngx_connection_error(c, NGX_ETIMEDOUT, "connection timed out"); ngx_stream_finalize_session(s, NGX_STREAM_OK); return; } ctx = ngx_stream_get_module_ctx(s, ngx_stream_return_module); if (ngx_stream_top_filter(s, ctx->out, 1) == NGX_ERROR) { ngx_stream_finalize_session(s, NGX_STREAM_INTERNAL_SERVER_ERROR); return; } ctx->out = NULL; if (!c->buffered) { ngx_log_debug0(NGX_LOG_DEBUG_STREAM, c->log, 0, "stream return done sending"); ngx_stream_finalize_session(s, NGX_STREAM_OK); return; } if (ngx_handle_write_event(ev, 0) != NGX_OK) { ngx_stream_finalize_session(s, NGX_STREAM_INTERNAL_SERVER_ERROR); return; } ngx_add_timer(ev, 5000); } static void * ngx_stream_return_create_srv_conf(ngx_conf_t *cf) { ngx_stream_return_srv_conf_t *conf; conf = ngx_pcalloc(cf->pool, sizeof(ngx_stream_return_srv_conf_t)); if (conf == NULL) { return NULL; } return conf; } static char * ngx_stream_return(ngx_conf_t *cf, ngx_command_t *cmd, void *conf) { ngx_stream_return_srv_conf_t *rscf = conf; ngx_str_t *value; ngx_stream_core_srv_conf_t *cscf; ngx_stream_compile_complex_value_t ccv; if (rscf->text.value.data) { return "is duplicate"; } value = cf->args->elts; ngx_memzero(&ccv, sizeof(ngx_stream_compile_complex_value_t)); ccv.cf = cf; ccv.value = &value[1]; ccv.complex_value = &rscf->text; if (ngx_stream_compile_complex_value(&ccv) != NGX_OK) { return NGX_CONF_ERROR; } cscf = ngx_stream_conf_get_module_srv_conf(cf, ngx_stream_core_module); cscf->handler = ngx_stream_return_handler; return NGX_CONF_OK; }