view src/http/modules/ngx_http_static_module.c @ 5356:acd51b0f6fd4

Disable symlinks: use O_PATH to open path components. It was introduced in Linux 2.6.39, glibc 2.14 and allows to obtain file descriptors without actually opening files. Thus made it possible to traverse path with openat() syscalls without the need to have read permissions for path components. It is effectively emulates O_SEARCH which is missing on Linux. O_PATH is used in combination with O_RDONLY. The last one is ignored if O_PATH is used, but it allows nginx to not fail when it was built on modern system (i.e. glibc 2.14+) and run with a kernel older than 2.6.39. Then O_PATH is unknown to the kernel and ignored, while O_RDONLY is used. Sadly, fstat() is not working with O_PATH descriptors till Linux 3.6. As a workaround we fallback to fstatat() with the AT_EMPTY_PATH flag that was introduced at the same time as O_PATH.
author Valentin Bartenev <vbart@nginx.com>
date Mon, 02 Sep 2013 08:07:59 +0400
parents 192f54280a7a
children b1858fc47e3b
line wrap: on
line source


/*
 * Copyright (C) Igor Sysoev
 * Copyright (C) Nginx, Inc.
 */


#include <ngx_config.h>
#include <ngx_core.h>
#include <ngx_http.h>


static ngx_int_t ngx_http_static_handler(ngx_http_request_t *r);
static ngx_int_t ngx_http_static_init(ngx_conf_t *cf);


ngx_http_module_t  ngx_http_static_module_ctx = {
    NULL,                                  /* preconfiguration */
    ngx_http_static_init,                  /* postconfiguration */

    NULL,                                  /* create main configuration */
    NULL,                                  /* init main configuration */

    NULL,                                  /* create server configuration */
    NULL,                                  /* merge server configuration */

    NULL,                                  /* create location configuration */
    NULL                                   /* merge location configuration */
};


ngx_module_t  ngx_http_static_module = {
    NGX_MODULE_V1,
    &ngx_http_static_module_ctx,           /* module context */
    NULL,                                  /* 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_static_handler(ngx_http_request_t *r)
{
    u_char                    *last, *location;
    size_t                     root, len;
    ngx_str_t                  path;
    ngx_int_t                  rc;
    ngx_uint_t                 level;
    ngx_log_t                 *log;
    ngx_buf_t                 *b;
    ngx_chain_t                out;
    ngx_open_file_info_t       of;
    ngx_http_core_loc_conf_t  *clcf;

    if (!(r->method & (NGX_HTTP_GET|NGX_HTTP_HEAD|NGX_HTTP_POST))) {
        return NGX_HTTP_NOT_ALLOWED;
    }

    if (r->uri.data[r->uri.len - 1] == '/') {
        return NGX_DECLINED;
    }

    log = r->connection->log;

    /*
     * ngx_http_map_uri_to_path() allocates memory for terminating '\0'
     * so we do not need to reserve memory for '/' for possible redirect
     */

    last = ngx_http_map_uri_to_path(r, &path, &root, 0);
    if (last == NULL) {
        return NGX_HTTP_INTERNAL_SERVER_ERROR;
    }

    path.len = last - path.data;

    ngx_log_debug1(NGX_LOG_DEBUG_HTTP, log, 0,
                   "http filename: \"%s\"", path.data);

    clcf = ngx_http_get_module_loc_conf(r, ngx_http_core_module);

    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.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)
    {
        switch (of.err) {

        case 0:
            return NGX_HTTP_INTERNAL_SERVER_ERROR;

        case NGX_ENOENT:
        case NGX_ENOTDIR:
        case NGX_ENAMETOOLONG:

            level = NGX_LOG_ERR;
            rc = NGX_HTTP_NOT_FOUND;
            break;

        case NGX_EACCES:
#if (NGX_HAVE_OPENAT)
        case NGX_EMLINK:
        case NGX_ELOOP:
#endif

            level = NGX_LOG_ERR;
            rc = NGX_HTTP_FORBIDDEN;
            break;

        default:

            level = NGX_LOG_CRIT;
            rc = NGX_HTTP_INTERNAL_SERVER_ERROR;
            break;
        }

        if (rc != NGX_HTTP_NOT_FOUND || clcf->log_not_found) {
            ngx_log_error(level, log, of.err,
                          "%s \"%s\" failed", of.failed, path.data);
        }

        return rc;
    }

    r->root_tested = !r->error_page;

    ngx_log_debug1(NGX_LOG_DEBUG_HTTP, log, 0, "http static fd: %d", of.fd);

    if (of.is_dir) {

        ngx_log_debug0(NGX_LOG_DEBUG_HTTP, log, 0, "http dir");

        ngx_http_clear_location(r);

        r->headers_out.location = ngx_palloc(r->pool, sizeof(ngx_table_elt_t));
        if (r->headers_out.location == NULL) {
            return NGX_HTTP_INTERNAL_SERVER_ERROR;
        }

        len = r->uri.len + 1;

        if (!clcf->alias && clcf->root_lengths == NULL && r->args.len == 0) {
            location = path.data + clcf->root.len;

            *last = '/';

        } else {
            if (r->args.len) {
                len += r->args.len + 1;
            }

            location = ngx_pnalloc(r->pool, len);
            if (location == NULL) {
                return NGX_HTTP_INTERNAL_SERVER_ERROR;
            }

            last = ngx_copy(location, r->uri.data, r->uri.len);

            *last = '/';

            if (r->args.len) {
                *++last = '?';
                ngx_memcpy(++last, r->args.data, r->args.len);
            }
        }

        /*
         * we do not need to set the r->headers_out.location->hash and
         * r->headers_out.location->key fields
         */

        r->headers_out.location->value.len = len;
        r->headers_out.location->value.data = location;

        return NGX_HTTP_MOVED_PERMANENTLY;
    }

#if !(NGX_WIN32) /* the not regular files are probably Unix specific */

    if (!of.is_file) {
        ngx_log_error(NGX_LOG_CRIT, log, 0,
                      "\"%s\" is not a regular file", path.data);

        return NGX_HTTP_NOT_FOUND;
    }

#endif

    if (r->method & NGX_HTTP_POST) {
        return NGX_HTTP_NOT_ALLOWED;
    }

    rc = ngx_http_discard_request_body(r);

    if (rc != NGX_OK) {
        return rc;
    }

    log->action = "sending response to client";

    r->headers_out.status = NGX_HTTP_OK;
    r->headers_out.content_length_n = of.size;
    r->headers_out.last_modified_time = of.mtime;

    if (ngx_http_set_etag(r) != NGX_OK) {
        return NGX_HTTP_INTERNAL_SERVER_ERROR;
    }

    if (ngx_http_set_content_type(r) != NGX_OK) {
        return NGX_HTTP_INTERNAL_SERVER_ERROR;
    }

    if (r != r->main && of.size == 0) {
        return ngx_http_send_header(r);
    }

    r->allow_ranges = 1;

    /* we need to allocate all before the header would be sent */

    b = ngx_pcalloc(r->pool, sizeof(ngx_buf_t));
    if (b == NULL) {
        return NGX_HTTP_INTERNAL_SERVER_ERROR;
    }

    b->file = ngx_pcalloc(r->pool, sizeof(ngx_file_t));
    if (b->file == NULL) {
        return NGX_HTTP_INTERNAL_SERVER_ERROR;
    }

    rc = ngx_http_send_header(r);

    if (rc == NGX_ERROR || rc > NGX_OK || r->header_only) {
        return rc;
    }

    b->file_pos = 0;
    b->file_last = of.size;

    b->in_file = b->file_last ? 1: 0;
    b->last_buf = (r == r->main) ? 1: 0;
    b->last_in_chain = 1;

    b->file->fd = of.fd;
    b->file->name = path;
    b->file->log = log;
    b->file->directio = of.is_directio;

    out.buf = b;
    out.next = NULL;

    return ngx_http_output_filter(r, &out);
}


static ngx_int_t
ngx_http_static_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_static_handler;

    return NGX_OK;
}