Mercurial > hg > nginx
view src/stream/ngx_stream_split_clients_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 | 787dcc15b802 |
children |
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/* * Copyright (C) Igor Sysoev * Copyright (C) Nginx, Inc. */ #include <ngx_config.h> #include <ngx_core.h> #include <ngx_stream.h> typedef struct { uint32_t percent; ngx_stream_variable_value_t value; } ngx_stream_split_clients_part_t; typedef struct { ngx_stream_complex_value_t value; ngx_array_t parts; } ngx_stream_split_clients_ctx_t; static char *ngx_conf_split_clients_block(ngx_conf_t *cf, ngx_command_t *cmd, void *conf); static char *ngx_stream_split_clients(ngx_conf_t *cf, ngx_command_t *dummy, void *conf); static ngx_command_t ngx_stream_split_clients_commands[] = { { ngx_string("split_clients"), NGX_STREAM_MAIN_CONF|NGX_CONF_BLOCK|NGX_CONF_TAKE2, ngx_conf_split_clients_block, NGX_STREAM_MAIN_CONF_OFFSET, 0, NULL }, ngx_null_command }; static ngx_stream_module_t ngx_stream_split_clients_module_ctx = { NULL, /* preconfiguration */ NULL, /* postconfiguration */ NULL, /* create main configuration */ NULL, /* init main configuration */ NULL, /* create server configuration */ NULL /* merge server configuration */ }; ngx_module_t ngx_stream_split_clients_module = { NGX_MODULE_V1, &ngx_stream_split_clients_module_ctx, /* module context */ ngx_stream_split_clients_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 ngx_int_t ngx_stream_split_clients_variable(ngx_stream_session_t *s, ngx_stream_variable_value_t *v, uintptr_t data) { ngx_stream_split_clients_ctx_t *ctx = (ngx_stream_split_clients_ctx_t *) data; uint32_t hash; ngx_str_t val; ngx_uint_t i; ngx_stream_split_clients_part_t *part; *v = ngx_stream_variable_null_value; if (ngx_stream_complex_value(s, &ctx->value, &val) != NGX_OK) { return NGX_OK; } hash = ngx_murmur_hash2(val.data, val.len); part = ctx->parts.elts; for (i = 0; i < ctx->parts.nelts; i++) { ngx_log_debug2(NGX_LOG_DEBUG_STREAM, s->connection->log, 0, "stream split: %uD %uD", hash, part[i].percent); if (hash < part[i].percent || part[i].percent == 0) { *v = part[i].value; return NGX_OK; } } return NGX_OK; } static char * ngx_conf_split_clients_block(ngx_conf_t *cf, ngx_command_t *cmd, void *conf) { char *rv; uint32_t sum, last; ngx_str_t *value, name; ngx_uint_t i; ngx_conf_t save; ngx_stream_variable_t *var; ngx_stream_split_clients_ctx_t *ctx; ngx_stream_split_clients_part_t *part; ngx_stream_compile_complex_value_t ccv; ctx = ngx_pcalloc(cf->pool, sizeof(ngx_stream_split_clients_ctx_t)); if (ctx == NULL) { return NGX_CONF_ERROR; } value = cf->args->elts; ngx_memzero(&ccv, sizeof(ngx_stream_compile_complex_value_t)); ccv.cf = cf; ccv.value = &value[1]; ccv.complex_value = &ctx->value; if (ngx_stream_compile_complex_value(&ccv) != NGX_OK) { return NGX_CONF_ERROR; } name = value[2]; if (name.data[0] != '$') { ngx_conf_log_error(NGX_LOG_EMERG, cf, 0, "invalid variable name \"%V\"", &name); return NGX_CONF_ERROR; } name.len--; name.data++; var = ngx_stream_add_variable(cf, &name, NGX_STREAM_VAR_CHANGEABLE); if (var == NULL) { return NGX_CONF_ERROR; } var->get_handler = ngx_stream_split_clients_variable; var->data = (uintptr_t) ctx; if (ngx_array_init(&ctx->parts, cf->pool, 2, sizeof(ngx_stream_split_clients_part_t)) != NGX_OK) { return NGX_CONF_ERROR; } save = *cf; cf->ctx = ctx; cf->handler = ngx_stream_split_clients; cf->handler_conf = conf; rv = ngx_conf_parse(cf, NULL); *cf = save; if (rv != NGX_CONF_OK) { return rv; } sum = 0; last = 0; part = ctx->parts.elts; for (i = 0; i < ctx->parts.nelts; i++) { sum = part[i].percent ? sum + part[i].percent : 10000; if (sum > 10000) { ngx_conf_log_error(NGX_LOG_EMERG, cf, 0, "percent total is greater than 100%%"); return NGX_CONF_ERROR; } if (part[i].percent) { last += part[i].percent * (uint64_t) 0xffffffff / 10000; part[i].percent = last; } } return rv; } static char * ngx_stream_split_clients(ngx_conf_t *cf, ngx_command_t *dummy, void *conf) { ngx_int_t n; ngx_str_t *value; ngx_stream_split_clients_ctx_t *ctx; ngx_stream_split_clients_part_t *part; ctx = cf->ctx; value = cf->args->elts; part = ngx_array_push(&ctx->parts); if (part == NULL) { return NGX_CONF_ERROR; } if (value[0].len == 1 && value[0].data[0] == '*') { part->percent = 0; } else { if (value[0].len == 0 || value[0].data[value[0].len - 1] != '%') { goto invalid; } n = ngx_atofp(value[0].data, value[0].len - 1, 2); if (n == NGX_ERROR || n == 0) { goto invalid; } part->percent = (uint32_t) n; } part->value.len = value[1].len; part->value.valid = 1; part->value.no_cacheable = 0; part->value.not_found = 0; part->value.data = value[1].data; return NGX_CONF_OK; invalid: ngx_conf_log_error(NGX_LOG_EMERG, cf, 0, "invalid percent value \"%V\"", &value[0]); return NGX_CONF_ERROR; }