Mercurial > hg > nginx-quic
view src/http/modules/ngx_http_auth_basic_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 | 0cb942c1c1aa |
children | bdd4d89370a7 |
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/* * Copyright (C) Igor Sysoev * Copyright (C) Nginx, Inc. */ #include <ngx_config.h> #include <ngx_core.h> #include <ngx_http.h> #include <ngx_crypt.h> #define NGX_HTTP_AUTH_BUF_SIZE 2048 typedef struct { ngx_http_complex_value_t *realm; ngx_http_complex_value_t user_file; } ngx_http_auth_basic_loc_conf_t; static ngx_int_t ngx_http_auth_basic_handler(ngx_http_request_t *r); static ngx_int_t ngx_http_auth_basic_crypt_handler(ngx_http_request_t *r, ngx_str_t *passwd, ngx_str_t *realm); static ngx_int_t ngx_http_auth_basic_set_realm(ngx_http_request_t *r, ngx_str_t *realm); static void *ngx_http_auth_basic_create_loc_conf(ngx_conf_t *cf); static char *ngx_http_auth_basic_merge_loc_conf(ngx_conf_t *cf, void *parent, void *child); static ngx_int_t ngx_http_auth_basic_init(ngx_conf_t *cf); static char *ngx_http_auth_basic_user_file(ngx_conf_t *cf, ngx_command_t *cmd, void *conf); static ngx_command_t ngx_http_auth_basic_commands[] = { { ngx_string("auth_basic"), NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_HTTP_LMT_CONF |NGX_CONF_TAKE1, ngx_http_set_complex_value_slot, NGX_HTTP_LOC_CONF_OFFSET, offsetof(ngx_http_auth_basic_loc_conf_t, realm), NULL }, { ngx_string("auth_basic_user_file"), NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_HTTP_LMT_CONF |NGX_CONF_TAKE1, ngx_http_auth_basic_user_file, NGX_HTTP_LOC_CONF_OFFSET, offsetof(ngx_http_auth_basic_loc_conf_t, user_file), NULL }, ngx_null_command }; static ngx_http_module_t ngx_http_auth_basic_module_ctx = { NULL, /* preconfiguration */ ngx_http_auth_basic_init, /* postconfiguration */ NULL, /* create main configuration */ NULL, /* init main configuration */ NULL, /* create server configuration */ NULL, /* merge server configuration */ ngx_http_auth_basic_create_loc_conf, /* create location configuration */ ngx_http_auth_basic_merge_loc_conf /* merge location configuration */ }; ngx_module_t ngx_http_auth_basic_module = { NGX_MODULE_V1, &ngx_http_auth_basic_module_ctx, /* module context */ ngx_http_auth_basic_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_int_t ngx_http_auth_basic_handler(ngx_http_request_t *r) { off_t offset; ssize_t n; ngx_fd_t fd; ngx_int_t rc; ngx_err_t err; ngx_str_t pwd, realm, user_file; ngx_uint_t i, level, login, left, passwd; ngx_file_t file; ngx_http_auth_basic_loc_conf_t *alcf; u_char buf[NGX_HTTP_AUTH_BUF_SIZE]; enum { sw_login, sw_passwd, sw_skip } state; alcf = ngx_http_get_module_loc_conf(r, ngx_http_auth_basic_module); if (alcf->realm == NULL || alcf->user_file.value.data == NULL) { return NGX_DECLINED; } if (ngx_http_complex_value(r, alcf->realm, &realm) != NGX_OK) { return NGX_ERROR; } if (realm.len == 3 && ngx_strncmp(realm.data, "off", 3) == 0) { return NGX_DECLINED; } rc = ngx_http_auth_basic_user(r); if (rc == NGX_DECLINED) { ngx_log_error(NGX_LOG_INFO, r->connection->log, 0, "no user/password was provided for basic authentication"); return ngx_http_auth_basic_set_realm(r, &realm); } if (rc == NGX_ERROR) { return NGX_HTTP_INTERNAL_SERVER_ERROR; } if (ngx_http_complex_value(r, &alcf->user_file, &user_file) != NGX_OK) { return NGX_ERROR; } fd = ngx_open_file(user_file.data, NGX_FILE_RDONLY, NGX_FILE_OPEN, 0); if (fd == NGX_INVALID_FILE) { err = ngx_errno; if (err == NGX_ENOENT) { level = NGX_LOG_ERR; rc = NGX_HTTP_FORBIDDEN; } else { level = NGX_LOG_CRIT; rc = NGX_HTTP_INTERNAL_SERVER_ERROR; } ngx_log_error(level, r->connection->log, err, ngx_open_file_n " \"%s\" failed", user_file.data); return rc; } ngx_memzero(&file, sizeof(ngx_file_t)); file.fd = fd; file.name = user_file; file.log = r->connection->log; state = sw_login; passwd = 0; login = 0; left = 0; offset = 0; for ( ;; ) { i = left; n = ngx_read_file(&file, buf + left, NGX_HTTP_AUTH_BUF_SIZE - left, offset); if (n == NGX_ERROR) { rc = NGX_HTTP_INTERNAL_SERVER_ERROR; goto cleanup; } if (n == 0) { break; } for (i = left; i < left + n; i++) { switch (state) { case sw_login: if (login == 0) { if (buf[i] == '#' || buf[i] == CR) { state = sw_skip; break; } if (buf[i] == LF) { break; } } if (buf[i] != r->headers_in.user.data[login]) { state = sw_skip; break; } if (login == r->headers_in.user.len) { state = sw_passwd; passwd = i + 1; } login++; break; case sw_passwd: if (buf[i] == LF || buf[i] == CR || buf[i] == ':') { buf[i] = '\0'; pwd.len = i - passwd; pwd.data = &buf[passwd]; rc = ngx_http_auth_basic_crypt_handler(r, &pwd, &realm); goto cleanup; } break; case sw_skip: if (buf[i] == LF) { state = sw_login; login = 0; } break; } } if (state == sw_passwd) { left = left + n - passwd; ngx_memmove(buf, &buf[passwd], left); passwd = 0; } else { left = 0; } offset += n; } if (state == sw_passwd) { pwd.len = i - passwd; pwd.data = ngx_pnalloc(r->pool, pwd.len + 1); if (pwd.data == NULL) { return NGX_HTTP_INTERNAL_SERVER_ERROR; } ngx_cpystrn(pwd.data, &buf[passwd], pwd.len + 1); rc = ngx_http_auth_basic_crypt_handler(r, &pwd, &realm); goto cleanup; } ngx_log_error(NGX_LOG_ERR, r->connection->log, 0, "user \"%V\" was not found in \"%s\"", &r->headers_in.user, user_file.data); rc = ngx_http_auth_basic_set_realm(r, &realm); cleanup: if (ngx_close_file(file.fd) == NGX_FILE_ERROR) { ngx_log_error(NGX_LOG_ALERT, r->connection->log, ngx_errno, ngx_close_file_n " \"%s\" failed", user_file.data); } ngx_explicit_memzero(buf, NGX_HTTP_AUTH_BUF_SIZE); return rc; } static ngx_int_t ngx_http_auth_basic_crypt_handler(ngx_http_request_t *r, ngx_str_t *passwd, ngx_str_t *realm) { ngx_int_t rc; u_char *encrypted; rc = ngx_crypt(r->pool, r->headers_in.passwd.data, passwd->data, &encrypted); ngx_log_debug3(NGX_LOG_DEBUG_HTTP, r->connection->log, 0, "rc: %i user: \"%V\" salt: \"%s\"", rc, &r->headers_in.user, passwd->data); if (rc != NGX_OK) { return NGX_HTTP_INTERNAL_SERVER_ERROR; } if (ngx_strcmp(encrypted, passwd->data) == 0) { return NGX_OK; } ngx_log_debug1(NGX_LOG_DEBUG_HTTP, r->connection->log, 0, "encrypted: \"%s\"", encrypted); ngx_log_error(NGX_LOG_ERR, r->connection->log, 0, "user \"%V\": password mismatch", &r->headers_in.user); return ngx_http_auth_basic_set_realm(r, realm); } static ngx_int_t ngx_http_auth_basic_set_realm(ngx_http_request_t *r, ngx_str_t *realm) { size_t len; u_char *basic, *p; r->headers_out.www_authenticate = ngx_list_push(&r->headers_out.headers); if (r->headers_out.www_authenticate == NULL) { return NGX_HTTP_INTERNAL_SERVER_ERROR; } len = sizeof("Basic realm=\"\"") - 1 + realm->len; basic = ngx_pnalloc(r->pool, len); if (basic == NULL) { r->headers_out.www_authenticate->hash = 0; r->headers_out.www_authenticate = NULL; return NGX_HTTP_INTERNAL_SERVER_ERROR; } p = ngx_cpymem(basic, "Basic realm=\"", sizeof("Basic realm=\"") - 1); p = ngx_cpymem(p, realm->data, realm->len); *p = '"'; r->headers_out.www_authenticate->hash = 1; ngx_str_set(&r->headers_out.www_authenticate->key, "WWW-Authenticate"); r->headers_out.www_authenticate->value.data = basic; r->headers_out.www_authenticate->value.len = len; return NGX_HTTP_UNAUTHORIZED; } static void * ngx_http_auth_basic_create_loc_conf(ngx_conf_t *cf) { ngx_http_auth_basic_loc_conf_t *conf; conf = ngx_pcalloc(cf->pool, sizeof(ngx_http_auth_basic_loc_conf_t)); if (conf == NULL) { return NULL; } return conf; } static char * ngx_http_auth_basic_merge_loc_conf(ngx_conf_t *cf, void *parent, void *child) { ngx_http_auth_basic_loc_conf_t *prev = parent; ngx_http_auth_basic_loc_conf_t *conf = child; if (conf->realm == NULL) { conf->realm = prev->realm; } if (conf->user_file.value.data == NULL) { conf->user_file = prev->user_file; } return NGX_CONF_OK; } static ngx_int_t ngx_http_auth_basic_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_ACCESS_PHASE].handlers); if (h == NULL) { return NGX_ERROR; } *h = ngx_http_auth_basic_handler; return NGX_OK; } static char * ngx_http_auth_basic_user_file(ngx_conf_t *cf, ngx_command_t *cmd, void *conf) { ngx_http_auth_basic_loc_conf_t *alcf = conf; ngx_str_t *value; ngx_http_compile_complex_value_t ccv; if (alcf->user_file.value.data) { return "is duplicate"; } value = cf->args->elts; ngx_memzero(&ccv, sizeof(ngx_http_compile_complex_value_t)); ccv.cf = cf; ccv.value = &value[1]; ccv.complex_value = &alcf->user_file; ccv.zero = 1; ccv.conf_prefix = 1; if (ngx_http_compile_complex_value(&ccv) != NGX_OK) { return NGX_CONF_ERROR; } return NGX_CONF_OK; }