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view src/http/modules/ngx_http_referer_module.c @ 7985:ec2e6893caaa

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Simplified sendfile(SF_NODISKIO) usage. Starting with FreeBSD 11, there is no need to use AIO operations to preload data into cache for sendfile(SF_NODISKIO) to work. Instead, sendfile() handles non-blocking loading data from disk by itself. It still can, however, return EBUSY if a page is already being loaded (for example, by a different process). If this happens, we now post an event for the next event loop iteration, so sendfile() is retried "after a short period", as manpage recommends. The limit of the number of EBUSY tolerated without any progress is preserved, but now it does not result in an alert, since on an idle system event loop iteration might be very short and EBUSY can happen many times in a row. Instead, SF_NODISKIO is simply disabled for one call once the limit is reached. With this change, sendfile(SF_NODISKIO) is now used automatically as long as sendfile() is enabled, and no longer requires "aio on;".
author Maxim Dounin <mdounin@mdounin.ru>
date Mon, 27 Dec 2021 19:48:33 +0300
parents 7564a919d333
children
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>


#define NGX_HTTP_REFERER_NO_URI_PART  ((void *) 4)


typedef struct {
    ngx_hash_combined_t      hash;

#if (NGX_PCRE)
    ngx_array_t             *regex;
    ngx_array_t             *server_name_regex;
#endif

    ngx_flag_t               no_referer;
    ngx_flag_t               blocked_referer;
    ngx_flag_t               server_names;

    ngx_hash_keys_arrays_t  *keys;

    ngx_uint_t               referer_hash_max_size;
    ngx_uint_t               referer_hash_bucket_size;
} ngx_http_referer_conf_t;


static ngx_int_t ngx_http_referer_add_variables(ngx_conf_t *cf);
static void * ngx_http_referer_create_conf(ngx_conf_t *cf);
static char * ngx_http_referer_merge_conf(ngx_conf_t *cf, void *parent,
    void *child);
static char *ngx_http_valid_referers(ngx_conf_t *cf, ngx_command_t *cmd,
    void *conf);
static ngx_int_t ngx_http_add_referer(ngx_conf_t *cf,
    ngx_hash_keys_arrays_t *keys, ngx_str_t *value, ngx_str_t *uri);
static ngx_int_t ngx_http_add_regex_referer(ngx_conf_t *cf,
    ngx_http_referer_conf_t *rlcf, ngx_str_t *name);
#if (NGX_PCRE)
static ngx_int_t ngx_http_add_regex_server_name(ngx_conf_t *cf,
    ngx_http_referer_conf_t *rlcf, ngx_http_regex_t *regex);
#endif
static int ngx_libc_cdecl ngx_http_cmp_referer_wildcards(const void *one,
    const void *two);


static ngx_command_t  ngx_http_referer_commands[] = {

    { ngx_string("valid_referers"),
      NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_1MORE,
      ngx_http_valid_referers,
      NGX_HTTP_LOC_CONF_OFFSET,
      0,
      NULL },

    { ngx_string("referer_hash_max_size"),
      NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1,
      ngx_conf_set_num_slot,
      NGX_HTTP_LOC_CONF_OFFSET,
      offsetof(ngx_http_referer_conf_t, referer_hash_max_size),
      NULL },

    { ngx_string("referer_hash_bucket_size"),
      NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1,
      ngx_conf_set_num_slot,
      NGX_HTTP_LOC_CONF_OFFSET,
      offsetof(ngx_http_referer_conf_t, referer_hash_bucket_size),
      NULL },

      ngx_null_command
};


static ngx_http_module_t  ngx_http_referer_module_ctx = {
    ngx_http_referer_add_variables,        /* preconfiguration */
    NULL,                                  /* postconfiguration */

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

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

    ngx_http_referer_create_conf,          /* create location configuration */
    ngx_http_referer_merge_conf            /* merge location configuration */
};


ngx_module_t  ngx_http_referer_module = {
    NGX_MODULE_V1,
    &ngx_http_referer_module_ctx,          /* module context */
    ngx_http_referer_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_str_t  ngx_http_invalid_referer_name = ngx_string("invalid_referer");


static ngx_int_t
ngx_http_referer_variable(ngx_http_request_t *r, ngx_http_variable_value_t *v,
    uintptr_t data)
{
    u_char                    *p, *ref, *last;
    size_t                     len;
    ngx_str_t                 *uri;
    ngx_uint_t                 i, key;
    ngx_http_referer_conf_t   *rlcf;
    u_char                     buf[256];
#if (NGX_PCRE)
    ngx_int_t                  rc;
    ngx_str_t                  referer;
#endif

    rlcf = ngx_http_get_module_loc_conf(r, ngx_http_referer_module);

    if (rlcf->hash.hash.buckets == NULL
        && rlcf->hash.wc_head == NULL
        && rlcf->hash.wc_tail == NULL
#if (NGX_PCRE)
        && rlcf->regex == NULL
        && rlcf->server_name_regex == NULL
#endif
       )
    {
        goto valid;
    }

    if (r->headers_in.referer == NULL) {
        if (rlcf->no_referer) {
            goto valid;
        }

        goto invalid;
    }

    len = r->headers_in.referer->value.len;
    ref = r->headers_in.referer->value.data;

    if (len >= sizeof("http://i.ru") - 1) {
        last = ref + len;

        if (ngx_strncasecmp(ref, (u_char *) "http://", 7) == 0) {
            ref += 7;
            len -= 7;
            goto valid_scheme;

        } else if (ngx_strncasecmp(ref, (u_char *) "https://", 8) == 0) {
            ref += 8;
            len -= 8;
            goto valid_scheme;
        }
    }

    if (rlcf->blocked_referer) {
        goto valid;
    }

    goto invalid;

valid_scheme:

    i = 0;
    key = 0;

    for (p = ref; p < last; p++) {
        if (*p == '/' || *p == ':') {
            break;
        }

        if (i == 256) {
            goto invalid;
        }

        buf[i] = ngx_tolower(*p);
        key = ngx_hash(key, buf[i++]);
    }

    uri = ngx_hash_find_combined(&rlcf->hash, key, buf, p - ref);

    if (uri) {
        goto uri;
    }

#if (NGX_PCRE)

    if (rlcf->server_name_regex) {
        referer.len = p - ref;
        referer.data = buf;

        rc = ngx_regex_exec_array(rlcf->server_name_regex, &referer,
                                  r->connection->log);

        if (rc == NGX_OK) {
            goto valid;
        }

        if (rc == NGX_ERROR) {
            return rc;
        }

        /* NGX_DECLINED */
    }

    if (rlcf->regex) {
        referer.len = len;
        referer.data = ref;

        rc = ngx_regex_exec_array(rlcf->regex, &referer, r->connection->log);

        if (rc == NGX_OK) {
            goto valid;
        }

        if (rc == NGX_ERROR) {
            return rc;
        }

        /* NGX_DECLINED */
    }

#endif

invalid:

    *v = ngx_http_variable_true_value;

    return NGX_OK;

uri:

    for ( /* void */ ; p < last; p++) {
        if (*p == '/') {
            break;
        }
    }

    len = last - p;

    if (uri == NGX_HTTP_REFERER_NO_URI_PART) {
        goto valid;
    }

    if (len < uri->len || ngx_strncmp(uri->data, p, uri->len) != 0) {
        goto invalid;
    }

valid:

    *v = ngx_http_variable_null_value;

    return NGX_OK;
}


static ngx_int_t
ngx_http_referer_add_variables(ngx_conf_t *cf)
{
    ngx_http_variable_t  *var;

    var = ngx_http_add_variable(cf, &ngx_http_invalid_referer_name,
                                NGX_HTTP_VAR_CHANGEABLE);
    if (var == NULL) {
        return NGX_ERROR;
    }

    var->get_handler = ngx_http_referer_variable;

    return NGX_OK;
}


static void *
ngx_http_referer_create_conf(ngx_conf_t *cf)
{
    ngx_http_referer_conf_t  *conf;

    conf = ngx_pcalloc(cf->pool, sizeof(ngx_http_referer_conf_t));
    if (conf == NULL) {
        return NULL;
    }

    /*
     * set by ngx_pcalloc():
     *
     *     conf->hash = { NULL };
     *     conf->server_names = 0;
     *     conf->keys = NULL;
     */

#if (NGX_PCRE)
    conf->regex = NGX_CONF_UNSET_PTR;
    conf->server_name_regex = NGX_CONF_UNSET_PTR;
#endif

    conf->no_referer = NGX_CONF_UNSET;
    conf->blocked_referer = NGX_CONF_UNSET;
    conf->referer_hash_max_size = NGX_CONF_UNSET_UINT;
    conf->referer_hash_bucket_size = NGX_CONF_UNSET_UINT;

    return conf;
}


static char *
ngx_http_referer_merge_conf(ngx_conf_t *cf, void *parent, void *child)
{
    ngx_http_referer_conf_t *prev = parent;
    ngx_http_referer_conf_t *conf = child;

    ngx_uint_t                 n;
    ngx_hash_init_t            hash;
    ngx_http_server_name_t    *sn;
    ngx_http_core_srv_conf_t  *cscf;

    if (conf->keys == NULL) {
        conf->hash = prev->hash;

#if (NGX_PCRE)
        ngx_conf_merge_ptr_value(conf->regex, prev->regex, NULL);
        ngx_conf_merge_ptr_value(conf->server_name_regex,
                                 prev->server_name_regex, NULL);
#endif
        ngx_conf_merge_value(conf->no_referer, prev->no_referer, 0);
        ngx_conf_merge_value(conf->blocked_referer, prev->blocked_referer, 0);
        ngx_conf_merge_uint_value(conf->referer_hash_max_size,
                                  prev->referer_hash_max_size, 2048);
        ngx_conf_merge_uint_value(conf->referer_hash_bucket_size,
                                  prev->referer_hash_bucket_size, 64);

        return NGX_CONF_OK;
    }

    if (conf->server_names == 1) {
        cscf = ngx_http_conf_get_module_srv_conf(cf, ngx_http_core_module);

        sn = cscf->server_names.elts;
        for (n = 0; n < cscf->server_names.nelts; n++) {

#if (NGX_PCRE)
            if (sn[n].regex) {

                if (ngx_http_add_regex_server_name(cf, conf, sn[n].regex)
                    != NGX_OK)
                {
                    return NGX_CONF_ERROR;
                }

                continue;
            }
#endif

            if (ngx_http_add_referer(cf, conf->keys, &sn[n].name, NULL)
                != NGX_OK)
            {
                return NGX_CONF_ERROR;
            }
        }
    }

    if ((conf->no_referer == 1 || conf->blocked_referer == 1)
        && conf->keys->keys.nelts == 0
        && conf->keys->dns_wc_head.nelts == 0
        && conf->keys->dns_wc_tail.nelts == 0)
    {
        ngx_log_error(NGX_LOG_EMERG, cf->log, 0,
                      "the \"none\" or \"blocked\" referers are specified "
                      "in the \"valid_referers\" directive "
                      "without any valid referer");
        return NGX_CONF_ERROR;
    }

    ngx_conf_merge_uint_value(conf->referer_hash_max_size,
                              prev->referer_hash_max_size, 2048);
    ngx_conf_merge_uint_value(conf->referer_hash_bucket_size,
                              prev->referer_hash_bucket_size, 64);
    conf->referer_hash_bucket_size = ngx_align(conf->referer_hash_bucket_size,
                                               ngx_cacheline_size);

    hash.key = ngx_hash_key_lc;
    hash.max_size = conf->referer_hash_max_size;
    hash.bucket_size = conf->referer_hash_bucket_size;
    hash.name = "referer_hash";
    hash.pool = cf->pool;

    if (conf->keys->keys.nelts) {
        hash.hash = &conf->hash.hash;
        hash.temp_pool = NULL;

        if (ngx_hash_init(&hash, conf->keys->keys.elts, conf->keys->keys.nelts)
            != NGX_OK)
        {
            return NGX_CONF_ERROR;
        }
    }

    if (conf->keys->dns_wc_head.nelts) {

        ngx_qsort(conf->keys->dns_wc_head.elts,
                  (size_t) conf->keys->dns_wc_head.nelts,
                  sizeof(ngx_hash_key_t),
                  ngx_http_cmp_referer_wildcards);

        hash.hash = NULL;
        hash.temp_pool = cf->temp_pool;

        if (ngx_hash_wildcard_init(&hash, conf->keys->dns_wc_head.elts,
                                   conf->keys->dns_wc_head.nelts)
            != NGX_OK)
        {
            return NGX_CONF_ERROR;
        }

        conf->hash.wc_head = (ngx_hash_wildcard_t *) hash.hash;
    }

    if (conf->keys->dns_wc_tail.nelts) {

        ngx_qsort(conf->keys->dns_wc_tail.elts,
                  (size_t) conf->keys->dns_wc_tail.nelts,
                  sizeof(ngx_hash_key_t),
                  ngx_http_cmp_referer_wildcards);

        hash.hash = NULL;
        hash.temp_pool = cf->temp_pool;

        if (ngx_hash_wildcard_init(&hash, conf->keys->dns_wc_tail.elts,
                                   conf->keys->dns_wc_tail.nelts)
            != NGX_OK)
        {
            return NGX_CONF_ERROR;
        }

        conf->hash.wc_tail = (ngx_hash_wildcard_t *) hash.hash;
    }

#if (NGX_PCRE)
    ngx_conf_merge_ptr_value(conf->regex, prev->regex, NULL);
    ngx_conf_merge_ptr_value(conf->server_name_regex, prev->server_name_regex,
                             NULL);
#endif

    if (conf->no_referer == NGX_CONF_UNSET) {
        conf->no_referer = 0;
    }

    if (conf->blocked_referer == NGX_CONF_UNSET) {
        conf->blocked_referer = 0;
    }

    conf->keys = NULL;

    return NGX_CONF_OK;
}


static char *
ngx_http_valid_referers(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
{
    ngx_http_referer_conf_t  *rlcf = conf;

    u_char      *p;
    ngx_str_t   *value, uri;
    ngx_uint_t   i;

    if (rlcf->keys == NULL) {
        rlcf->keys = ngx_pcalloc(cf->temp_pool, sizeof(ngx_hash_keys_arrays_t));
        if (rlcf->keys == NULL) {
            return NGX_CONF_ERROR;
        }

        rlcf->keys->pool = cf->pool;
        rlcf->keys->temp_pool = cf->pool;

        if (ngx_hash_keys_array_init(rlcf->keys, NGX_HASH_SMALL) != NGX_OK) {
            return NGX_CONF_ERROR;
        }
    }

    value = cf->args->elts;

    for (i = 1; i < cf->args->nelts; i++) {
        if (value[i].len == 0) {
            ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
                               "invalid referer \"%V\"", &value[i]);
            return NGX_CONF_ERROR;
        }

        if (ngx_strcmp(value[i].data, "none") == 0) {
            rlcf->no_referer = 1;
            continue;
        }

        if (ngx_strcmp(value[i].data, "blocked") == 0) {
            rlcf->blocked_referer = 1;
            continue;
        }

        if (ngx_strcmp(value[i].data, "server_names") == 0) {
            rlcf->server_names = 1;
            continue;
        }

        if (value[i].data[0] == '~') {
            if (ngx_http_add_regex_referer(cf, rlcf, &value[i]) != NGX_OK) {
                return NGX_CONF_ERROR;
            }

            continue;
        }

        ngx_str_null(&uri);

        p = (u_char *) ngx_strchr(value[i].data, '/');

        if (p) {
            uri.len = (value[i].data + value[i].len) - p;
            uri.data = p;
            value[i].len = p - value[i].data;
        }

        if (ngx_http_add_referer(cf, rlcf->keys, &value[i], &uri) != NGX_OK) {
            return NGX_CONF_ERROR;
        }
    }

    return NGX_CONF_OK;
}


static ngx_int_t
ngx_http_add_referer(ngx_conf_t *cf, ngx_hash_keys_arrays_t *keys,
    ngx_str_t *value, ngx_str_t *uri)
{
    ngx_int_t   rc;
    ngx_str_t  *u;

    if (uri == NULL || uri->len == 0) {
        u = NGX_HTTP_REFERER_NO_URI_PART;

    } else {
        u = ngx_palloc(cf->pool, sizeof(ngx_str_t));
        if (u == NULL) {
            return NGX_ERROR;
        }

        *u = *uri;
    }

    rc = ngx_hash_add_key(keys, value, u, NGX_HASH_WILDCARD_KEY);

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

    if (rc == NGX_DECLINED) {
        ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
                           "invalid hostname or wildcard \"%V\"", value);
    }

    if (rc == NGX_BUSY) {
        ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
                           "conflicting parameter \"%V\"", value);
    }

    return NGX_ERROR;
}


static ngx_int_t
ngx_http_add_regex_referer(ngx_conf_t *cf, ngx_http_referer_conf_t *rlcf,
    ngx_str_t *name)
{
#if (NGX_PCRE)
    ngx_regex_elt_t      *re;
    ngx_regex_compile_t   rc;
    u_char                errstr[NGX_MAX_CONF_ERRSTR];

    if (name->len == 1) {
        ngx_conf_log_error(NGX_LOG_EMERG, cf, 0, "empty regex in \"%V\"", name);
        return NGX_ERROR;
    }

    if (rlcf->regex == NGX_CONF_UNSET_PTR) {
        rlcf->regex = ngx_array_create(cf->pool, 2, sizeof(ngx_regex_elt_t));
        if (rlcf->regex == NULL) {
            return NGX_ERROR;
        }
    }

    re = ngx_array_push(rlcf->regex);
    if (re == NULL) {
        return NGX_ERROR;
    }

    name->len--;
    name->data++;

    ngx_memzero(&rc, sizeof(ngx_regex_compile_t));

    rc.pattern = *name;
    rc.pool = cf->pool;
    rc.options = NGX_REGEX_CASELESS;
    rc.err.len = NGX_MAX_CONF_ERRSTR;
    rc.err.data = errstr;

    if (ngx_regex_compile(&rc) != NGX_OK) {
        ngx_conf_log_error(NGX_LOG_EMERG, cf, 0, "%V", &rc.err);
        return NGX_ERROR;
    }

    re->regex = rc.regex;
    re->name = name->data;

    return NGX_OK;

#else

    ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
                       "the using of the regex \"%V\" requires PCRE library",
                       name);

    return NGX_ERROR;

#endif
}


#if (NGX_PCRE)

static ngx_int_t
ngx_http_add_regex_server_name(ngx_conf_t *cf, ngx_http_referer_conf_t *rlcf,
    ngx_http_regex_t *regex)
{
    ngx_regex_elt_t  *re;

    if (rlcf->server_name_regex == NGX_CONF_UNSET_PTR) {
        rlcf->server_name_regex = ngx_array_create(cf->pool, 2,
                                                   sizeof(ngx_regex_elt_t));
        if (rlcf->server_name_regex == NULL) {
            return NGX_ERROR;
        }
    }

    re = ngx_array_push(rlcf->server_name_regex);
    if (re == NULL) {
        return NGX_ERROR;
    }

    re->regex = regex->regex;
    re->name = regex->name.data;

    return NGX_OK;
}

#endif


static int ngx_libc_cdecl
ngx_http_cmp_referer_wildcards(const void *one, const void *two)
{
    ngx_hash_key_t  *first, *second;

    first = (ngx_hash_key_t *) one;
    second = (ngx_hash_key_t *) two;

    return ngx_dns_strcmp(first->key.data, second->key.data);
}