Mercurial > hg > nginx
view src/http/modules/ngx_http_auth_basic_module.c @ 7060:1adc6b0d5eaa stable-1.12
Range filter: protect from total size overflows.
The overflow can be used to circumvent the restriction on total size of
ranges introduced in c2a91088b0c0 (1.1.2). Additionally, overflow
allows producing ranges with negative start (such ranges can be created
by using a suffix, "bytes=-100"; normally this results in 200 due to
the total size check). These can result in the following errors in logs:
[crit] ... pread() ... failed (22: Invalid argument)
[alert] ... sendfile() failed (22: Invalid argument)
When using cache, it can be also used to reveal cache file header.
It is believed that there are no other negative effects, at least with
standard nginx modules.
In theory, this can also result in memory disclosure and/or segmentation
faults if multiple ranges are allowed, and the response is returned in a
single in-memory buffer. This never happens with standard nginx modules
though, as well as known 3rd party modules.
Fix is to properly protect from possible overflow when incrementing size.
author | Maxim Dounin <mdounin@mdounin.ru> |
---|---|
date | Tue, 11 Jul 2017 16:06:23 +0300 |
parents | f01ab2dbcfdc |
children | 0cdee26605f3 |
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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_str_t passwd; } ngx_http_auth_basic_ctx_t; 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_http_auth_basic_ctx_t *ctx, 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_close(ngx_file_t *file); 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_ctx_t *ctx; 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; } ctx = ngx_http_get_module_ctx(r, ngx_http_auth_basic_module); if (ctx) { return ngx_http_auth_basic_crypt_handler(r, ctx, &ctx->passwd, &realm); } 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) { ngx_http_auth_basic_close(&file); return NGX_HTTP_INTERNAL_SERVER_ERROR; } 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'; ngx_http_auth_basic_close(&file); pwd.len = i - passwd; pwd.data = &buf[passwd]; return ngx_http_auth_basic_crypt_handler(r, NULL, &pwd, &realm); } 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; } ngx_http_auth_basic_close(&file); 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); return ngx_http_auth_basic_crypt_handler(r, NULL, &pwd, &realm); } ngx_log_error(NGX_LOG_ERR, r->connection->log, 0, "user \"%V\" was not found in \"%V\"", &r->headers_in.user, &user_file); return ngx_http_auth_basic_set_realm(r, &realm); } static ngx_int_t ngx_http_auth_basic_crypt_handler(ngx_http_request_t *r, ngx_http_auth_basic_ctx_t *ctx, 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) { 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); } if (rc == NGX_ERROR) { return NGX_HTTP_INTERNAL_SERVER_ERROR; } /* rc == NGX_AGAIN */ if (ctx == NULL) { ctx = ngx_palloc(r->pool, sizeof(ngx_http_auth_basic_ctx_t)); if (ctx == NULL) { return NGX_HTTP_INTERNAL_SERVER_ERROR; } ngx_http_set_ctx(r, ctx, ngx_http_auth_basic_module); ctx->passwd.len = passwd->len; passwd->len++; ctx->passwd.data = ngx_pstrdup(r->pool, passwd); if (ctx->passwd.data == NULL) { return NGX_HTTP_INTERNAL_SERVER_ERROR; } } /* TODO: add mutex event */ return rc; } 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) { 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_close(ngx_file_t *file) { if (ngx_close_file(file->fd) == NGX_FILE_ERROR) { ngx_log_error(NGX_LOG_ALERT, file->log, ngx_errno, ngx_close_file_n " \"%s\" failed", file->name.data); } } 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; }