Mercurial > hg > nginx-quic
view src/http/modules/ngx_http_index_module.c @ 7977:7731c710796f
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 | e55e28e6998f |
children |
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/* * Copyright (C) Igor Sysoev * Copyright (C) Nginx, Inc. */ #include <ngx_config.h> #include <ngx_core.h> #include <ngx_http.h> typedef struct { ngx_str_t name; ngx_array_t *lengths; ngx_array_t *values; } ngx_http_index_t; typedef struct { ngx_array_t *indices; /* array of ngx_http_index_t */ size_t max_index_len; } ngx_http_index_loc_conf_t; #define NGX_HTTP_DEFAULT_INDEX "index.html" static ngx_int_t ngx_http_index_test_dir(ngx_http_request_t *r, ngx_http_core_loc_conf_t *clcf, u_char *path, u_char *last); static ngx_int_t ngx_http_index_error(ngx_http_request_t *r, ngx_http_core_loc_conf_t *clcf, u_char *file, ngx_err_t err); static ngx_int_t ngx_http_index_init(ngx_conf_t *cf); static void *ngx_http_index_create_loc_conf(ngx_conf_t *cf); static char *ngx_http_index_merge_loc_conf(ngx_conf_t *cf, void *parent, void *child); static char *ngx_http_index_set_index(ngx_conf_t *cf, ngx_command_t *cmd, void *conf); static ngx_command_t ngx_http_index_commands[] = { { ngx_string("index"), NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_1MORE, ngx_http_index_set_index, NGX_HTTP_LOC_CONF_OFFSET, 0, NULL }, ngx_null_command }; static ngx_http_module_t ngx_http_index_module_ctx = { NULL, /* preconfiguration */ ngx_http_index_init, /* postconfiguration */ NULL, /* create main configuration */ NULL, /* init main configuration */ NULL, /* create server configuration */ NULL, /* merge server configuration */ ngx_http_index_create_loc_conf, /* create location configuration */ ngx_http_index_merge_loc_conf /* merge location configuration */ }; ngx_module_t ngx_http_index_module = { NGX_MODULE_V1, &ngx_http_index_module_ctx, /* module context */ ngx_http_index_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 }; /* * Try to open/test the first index file before the test of directory * existence because valid requests should prevail over invalid ones. * If open()/stat() of a file will fail then stat() of a directory * should be faster because kernel may have already cached some data. * Besides, Win32 may return ERROR_PATH_NOT_FOUND (NGX_ENOTDIR) at once. * Unix has ENOTDIR error; however, it's less helpful than Win32's one: * it only indicates that path points to a regular file, not a directory. */ static ngx_int_t ngx_http_index_handler(ngx_http_request_t *r) { u_char *p, *name; size_t len, root, reserve, allocated; ngx_int_t rc; ngx_str_t path, uri; ngx_uint_t i, dir_tested; ngx_http_index_t *index; ngx_open_file_info_t of; ngx_http_script_code_pt code; ngx_http_script_engine_t e; ngx_http_core_loc_conf_t *clcf; ngx_http_index_loc_conf_t *ilcf; ngx_http_script_len_code_pt lcode; if (r->uri.data[r->uri.len - 1] != '/') { return NGX_DECLINED; } if (!(r->method & (NGX_HTTP_GET|NGX_HTTP_HEAD|NGX_HTTP_POST))) { return NGX_DECLINED; } ilcf = ngx_http_get_module_loc_conf(r, ngx_http_index_module); clcf = ngx_http_get_module_loc_conf(r, ngx_http_core_module); allocated = 0; root = 0; dir_tested = 0; name = NULL; /* suppress MSVC warning */ path.data = NULL; index = ilcf->indices->elts; for (i = 0; i < ilcf->indices->nelts; i++) { if (index[i].lengths == NULL) { if (index[i].name.data[0] == '/') { return ngx_http_internal_redirect(r, &index[i].name, &r->args); } reserve = ilcf->max_index_len; len = index[i].name.len; } else { ngx_memzero(&e, sizeof(ngx_http_script_engine_t)); e.ip = index[i].lengths->elts; e.request = r; e.flushed = 1; /* 1 is for terminating '\0' as in static names */ len = 1; while (*(uintptr_t *) e.ip) { lcode = *(ngx_http_script_len_code_pt *) e.ip; len += lcode(&e); } /* 16 bytes are preallocation */ reserve = len + 16; } if (reserve > allocated) { name = ngx_http_map_uri_to_path(r, &path, &root, reserve); if (name == NULL) { return NGX_HTTP_INTERNAL_SERVER_ERROR; } allocated = path.data + path.len - name; } if (index[i].values == NULL) { /* index[i].name.len includes the terminating '\0' */ ngx_memcpy(name, index[i].name.data, index[i].name.len); path.len = (name + index[i].name.len - 1) - path.data; } else { e.ip = index[i].values->elts; e.pos = name; while (*(uintptr_t *) e.ip) { code = *(ngx_http_script_code_pt *) e.ip; code((ngx_http_script_engine_t *) &e); } if (*name == '/') { uri.len = len - 1; uri.data = name; return ngx_http_internal_redirect(r, &uri, &r->args); } path.len = e.pos - path.data; *e.pos = '\0'; } ngx_log_debug1(NGX_LOG_DEBUG_HTTP, r->connection->log, 0, "open index \"%V\"", &path); ngx_memzero(&of, sizeof(ngx_open_file_info_t)); of.read_ahead = clcf->read_ahead; of.directio = clcf->directio; of.valid = clcf->open_file_cache_valid; of.min_uses = clcf->open_file_cache_min_uses; of.test_only = 1; of.errors = clcf->open_file_cache_errors; of.events = clcf->open_file_cache_events; if (ngx_http_set_disable_symlinks(r, clcf, &path, &of) != NGX_OK) { return NGX_HTTP_INTERNAL_SERVER_ERROR; } if (ngx_open_cached_file(clcf->open_file_cache, &path, &of, r->pool) != NGX_OK) { if (of.err == 0) { return NGX_HTTP_INTERNAL_SERVER_ERROR; } ngx_log_debug2(NGX_LOG_DEBUG_HTTP, r->connection->log, of.err, "%s \"%s\" failed", of.failed, path.data); #if (NGX_HAVE_OPENAT) if (of.err == NGX_EMLINK || of.err == NGX_ELOOP) { return NGX_HTTP_FORBIDDEN; } #endif if (of.err == NGX_ENOTDIR || of.err == NGX_ENAMETOOLONG || of.err == NGX_EACCES) { return ngx_http_index_error(r, clcf, path.data, of.err); } if (!dir_tested) { rc = ngx_http_index_test_dir(r, clcf, path.data, name - 1); if (rc != NGX_OK) { return rc; } dir_tested = 1; } if (of.err == NGX_ENOENT) { continue; } ngx_log_error(NGX_LOG_CRIT, r->connection->log, of.err, "%s \"%s\" failed", of.failed, path.data); return NGX_HTTP_INTERNAL_SERVER_ERROR; } uri.len = r->uri.len + len - 1; if (!clcf->alias) { uri.data = path.data + root; } else { uri.data = ngx_pnalloc(r->pool, uri.len); if (uri.data == NULL) { return NGX_HTTP_INTERNAL_SERVER_ERROR; } p = ngx_copy(uri.data, r->uri.data, r->uri.len); ngx_memcpy(p, name, len - 1); } return ngx_http_internal_redirect(r, &uri, &r->args); } return NGX_DECLINED; } static ngx_int_t ngx_http_index_test_dir(ngx_http_request_t *r, ngx_http_core_loc_conf_t *clcf, u_char *path, u_char *last) { u_char c; ngx_str_t dir; ngx_open_file_info_t of; c = *last; if (c != '/' || path == last) { /* "alias" without trailing slash */ c = *(++last); } *last = '\0'; dir.len = last - path; dir.data = path; ngx_log_debug1(NGX_LOG_DEBUG_HTTP, r->connection->log, 0, "http index check dir: \"%V\"", &dir); ngx_memzero(&of, sizeof(ngx_open_file_info_t)); of.test_dir = 1; of.test_only = 1; of.valid = clcf->open_file_cache_valid; of.errors = clcf->open_file_cache_errors; if (ngx_http_set_disable_symlinks(r, clcf, &dir, &of) != NGX_OK) { return NGX_HTTP_INTERNAL_SERVER_ERROR; } if (ngx_open_cached_file(clcf->open_file_cache, &dir, &of, r->pool) != NGX_OK) { if (of.err) { #if (NGX_HAVE_OPENAT) if (of.err == NGX_EMLINK || of.err == NGX_ELOOP) { return NGX_HTTP_FORBIDDEN; } #endif if (of.err == NGX_ENOENT) { *last = c; return ngx_http_index_error(r, clcf, dir.data, NGX_ENOENT); } if (of.err == NGX_EACCES) { *last = c; /* * ngx_http_index_test_dir() is called after the first index * file testing has returned an error distinct from NGX_EACCES. * This means that directory searching is allowed. */ return NGX_OK; } ngx_log_error(NGX_LOG_CRIT, r->connection->log, of.err, "%s \"%s\" failed", of.failed, dir.data); } return NGX_HTTP_INTERNAL_SERVER_ERROR; } *last = c; if (of.is_dir) { return NGX_OK; } ngx_log_error(NGX_LOG_ALERT, r->connection->log, 0, "\"%s\" is not a directory", dir.data); return NGX_HTTP_INTERNAL_SERVER_ERROR; } static ngx_int_t ngx_http_index_error(ngx_http_request_t *r, ngx_http_core_loc_conf_t *clcf, u_char *file, ngx_err_t err) { if (err == NGX_EACCES) { ngx_log_error(NGX_LOG_ERR, r->connection->log, err, "\"%s\" is forbidden", file); return NGX_HTTP_FORBIDDEN; } if (clcf->log_not_found) { ngx_log_error(NGX_LOG_ERR, r->connection->log, err, "\"%s\" is not found", file); } return NGX_HTTP_NOT_FOUND; } static void * ngx_http_index_create_loc_conf(ngx_conf_t *cf) { ngx_http_index_loc_conf_t *conf; conf = ngx_palloc(cf->pool, sizeof(ngx_http_index_loc_conf_t)); if (conf == NULL) { return NULL; } conf->indices = NULL; conf->max_index_len = 0; return conf; } static char * ngx_http_index_merge_loc_conf(ngx_conf_t *cf, void *parent, void *child) { ngx_http_index_loc_conf_t *prev = parent; ngx_http_index_loc_conf_t *conf = child; ngx_http_index_t *index; if (conf->indices == NULL) { conf->indices = prev->indices; conf->max_index_len = prev->max_index_len; } if (conf->indices == NULL) { conf->indices = ngx_array_create(cf->pool, 1, sizeof(ngx_http_index_t)); if (conf->indices == NULL) { return NGX_CONF_ERROR; } index = ngx_array_push(conf->indices); if (index == NULL) { return NGX_CONF_ERROR; } index->name.len = sizeof(NGX_HTTP_DEFAULT_INDEX); index->name.data = (u_char *) NGX_HTTP_DEFAULT_INDEX; index->lengths = NULL; index->values = NULL; conf->max_index_len = sizeof(NGX_HTTP_DEFAULT_INDEX); return NGX_CONF_OK; } return NGX_CONF_OK; } static ngx_int_t ngx_http_index_init(ngx_conf_t *cf) { ngx_http_handler_pt *h; ngx_http_core_main_conf_t *cmcf; cmcf = ngx_http_conf_get_module_main_conf(cf, ngx_http_core_module); h = ngx_array_push(&cmcf->phases[NGX_HTTP_CONTENT_PHASE].handlers); if (h == NULL) { return NGX_ERROR; } *h = ngx_http_index_handler; return NGX_OK; } /* TODO: warn about duplicate indices */ static char * ngx_http_index_set_index(ngx_conf_t *cf, ngx_command_t *cmd, void *conf) { ngx_http_index_loc_conf_t *ilcf = conf; ngx_str_t *value; ngx_uint_t i, n; ngx_http_index_t *index; ngx_http_script_compile_t sc; if (ilcf->indices == NULL) { ilcf->indices = ngx_array_create(cf->pool, 2, sizeof(ngx_http_index_t)); if (ilcf->indices == NULL) { return NGX_CONF_ERROR; } } value = cf->args->elts; for (i = 1; i < cf->args->nelts; i++) { if (value[i].data[0] == '/' && i != cf->args->nelts - 1) { ngx_conf_log_error(NGX_LOG_WARN, cf, 0, "only the last index in \"index\" directive " "should be absolute"); } if (value[i].len == 0) { ngx_conf_log_error(NGX_LOG_EMERG, cf, 0, "index \"%V\" in \"index\" directive is invalid", &value[1]); return NGX_CONF_ERROR; } index = ngx_array_push(ilcf->indices); if (index == NULL) { return NGX_CONF_ERROR; } index->name.len = value[i].len; index->name.data = value[i].data; index->lengths = NULL; index->values = NULL; n = ngx_http_script_variables_count(&value[i]); if (n == 0) { if (ilcf->max_index_len < index->name.len) { ilcf->max_index_len = index->name.len; } if (index->name.data[0] == '/') { continue; } /* include the terminating '\0' to the length to use ngx_memcpy() */ index->name.len++; continue; } ngx_memzero(&sc, sizeof(ngx_http_script_compile_t)); sc.cf = cf; sc.source = &value[i]; sc.lengths = &index->lengths; sc.values = &index->values; sc.variables = n; sc.complete_lengths = 1; sc.complete_values = 1; if (ngx_http_script_compile(&sc) != NGX_OK) { return NGX_CONF_ERROR; } } return NGX_CONF_OK; }