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view src/http/modules/ngx_http_browser_module.c @ 7760:83c4622053b0

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Upstream: fixed zero size buf alerts on extra data (ticket #2117). After 7675:9afa45068b8f and 7678:bffcc5af1d72 (1.19.1), during non-buffered simple proxying, responses with extra data might result in zero size buffers being generated and "zero size buf" alerts in writer. This bug is similar to the one with FastCGI proxying fixed in 7689:da8d758aabeb. In non-buffered mode, normally the filter function is not called if u->length is already 0, since u->length is checked after each call of the filter function. There is a case when this can happen though: if the response length is 0, and there are pre-read response body data left after reading response headers. As such, a check for u->length is needed at the start of non-buffered filter functions, similar to the one for p->length present in buffered filter functions. Appropriate checks added to the existing non-buffered copy filters in the upstream (used by scgi and uwsgi proxying) and proxy modules.
author Maxim Dounin <mdounin@mdounin.ru>
date Tue, 12 Jan 2021 16:59:31 +0300
parents 2a288909abc6
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>


/*
 * The module can check browser versions conforming to the following formats:
 * X, X.X, X.X.X, and X.X.X.X.  The maximum values of each format may be
 * 4000, 4000.99, 4000.99.99, and 4000.99.99.99.
 */


#define  NGX_HTTP_MODERN_BROWSER   0
#define  NGX_HTTP_ANCIENT_BROWSER  1


typedef struct {
    u_char                      browser[12];
    size_t                      skip;
    size_t                      add;
    u_char                      name[12];
} ngx_http_modern_browser_mask_t;


typedef struct {
    ngx_uint_t                  version;
    size_t                      skip;
    size_t                      add;
    u_char                      name[12];
} ngx_http_modern_browser_t;


typedef struct {
    ngx_array_t                *modern_browsers;
    ngx_array_t                *ancient_browsers;
    ngx_http_variable_value_t  *modern_browser_value;
    ngx_http_variable_value_t  *ancient_browser_value;

    unsigned                    modern_unlisted_browsers:1;
    unsigned                    netscape4:1;
} ngx_http_browser_conf_t;


static ngx_int_t ngx_http_msie_variable(ngx_http_request_t *r,
    ngx_http_variable_value_t *v, uintptr_t data);
static ngx_int_t ngx_http_browser_variable(ngx_http_request_t *r,
    ngx_http_variable_value_t *v, uintptr_t data);

static ngx_uint_t ngx_http_browser(ngx_http_request_t *r,
    ngx_http_browser_conf_t *cf);

static ngx_int_t ngx_http_browser_add_variables(ngx_conf_t *cf);
static void *ngx_http_browser_create_conf(ngx_conf_t *cf);
static char *ngx_http_browser_merge_conf(ngx_conf_t *cf, void *parent,
    void *child);
static int ngx_libc_cdecl ngx_http_modern_browser_sort(const void *one,
    const void *two);
static char *ngx_http_modern_browser(ngx_conf_t *cf, ngx_command_t *cmd,
    void *conf);
static char *ngx_http_ancient_browser(ngx_conf_t *cf, ngx_command_t *cmd,
    void *conf);
static char *ngx_http_modern_browser_value(ngx_conf_t *cf, ngx_command_t *cmd,
    void *conf);
static char *ngx_http_ancient_browser_value(ngx_conf_t *cf, ngx_command_t *cmd,
    void *conf);


static ngx_command_t  ngx_http_browser_commands[] = {

    { ngx_string("modern_browser"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE12,
      ngx_http_modern_browser,
      NGX_HTTP_LOC_CONF_OFFSET,
      0,
      NULL },

    { ngx_string("ancient_browser"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_1MORE,
      ngx_http_ancient_browser,
      NGX_HTTP_LOC_CONF_OFFSET,
      0,
      NULL },

    { ngx_string("modern_browser_value"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1,
      ngx_http_modern_browser_value,
      NGX_HTTP_LOC_CONF_OFFSET,
      0,
      NULL },

    { ngx_string("ancient_browser_value"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1,
      ngx_http_ancient_browser_value,
      NGX_HTTP_LOC_CONF_OFFSET,
      0,
      NULL },

      ngx_null_command
};


static ngx_http_module_t  ngx_http_browser_module_ctx = {
    ngx_http_browser_add_variables,        /* preconfiguration */
    NULL,                                  /* postconfiguration */

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

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

    ngx_http_browser_create_conf,          /* create location configuration */
    ngx_http_browser_merge_conf            /* merge location configuration */
};


ngx_module_t  ngx_http_browser_module = {
    NGX_MODULE_V1,
    &ngx_http_browser_module_ctx,          /* module context */
    ngx_http_browser_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_http_modern_browser_mask_t  ngx_http_modern_browser_masks[] = {

    /* Opera must be the first browser to check */

    /*
     * "Opera/7.50 (X11; FreeBSD i386; U)  [en]"
     * "Mozilla/5.0 (X11; FreeBSD i386; U) Opera 7.50  [en]"
     * "Mozilla/4.0 (compatible; MSIE 6.0; X11; FreeBSD i386) Opera 7.50  [en]"
     * "Opera/8.0 (Windows NT 5.1; U; ru)"
     * "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.0; en) Opera 8.0"
     * "Opera/9.01 (X11; FreeBSD 6 i386; U; en)"
     */

    { "opera",
      0,
      sizeof("Opera ") - 1,
      "Opera"},

    /* "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1)" */

    { "msie",
      sizeof("Mozilla/4.0 (compatible; ") - 1,
      sizeof("MSIE ") - 1,
      "MSIE "},

    /*
     * "Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.0.0) Gecko/20020610"
     * "Mozilla/5.0 (Windows; U; Windows NT 5.1; ru-RU; rv:1.5) Gecko/20031006"
     * "Mozilla/5.0 (Windows; U; Windows NT 5.1; ru-RU; rv:1.6) Gecko/20040206
     *              Firefox/0.8"
     * "Mozilla/5.0 (Windows; U; Windows NT 5.1; ru-RU; rv:1.7.8)
     *              Gecko/20050511 Firefox/1.0.4"
     * "Mozilla/5.0 (X11; U; FreeBSD i386; en-US; rv:1.8.0.5) Gecko/20060729
     *              Firefox/1.5.0.5"
     */

    { "gecko",
      sizeof("Mozilla/5.0 (") - 1,
      sizeof("rv:") - 1,
      "rv:"},

    /*
     * "Mozilla/5.0 (Macintosh; U; PPC Mac OS X; ru-ru) AppleWebKit/125.2
     *              (KHTML, like Gecko) Safari/125.7"
     * "Mozilla/5.0 (SymbianOS/9.1; U; en-us) AppleWebKit/413
     *              (KHTML, like Gecko) Safari/413"
     * "Mozilla/5.0 (Macintosh; U; PPC Mac OS X; en) AppleWebKit/418
     *              (KHTML, like Gecko) Safari/417.9.3"
     * "Mozilla/5.0 (Macintosh; U; PPC Mac OS X; ru-ru) AppleWebKit/418.8
     *              (KHTML, like Gecko) Safari/419.3"
     */

    { "safari",
      sizeof("Mozilla/5.0 (") - 1,
      sizeof("Safari/") - 1,
      "Safari/"},

    /*
     * "Mozilla/5.0 (compatible; Konqueror/3.1; Linux)"
     * "Mozilla/5.0 (compatible; Konqueror/3.4; Linux) KHTML/3.4.2 (like Gecko)"
     * "Mozilla/5.0 (compatible; Konqueror/3.5; FreeBSD) KHTML/3.5.1
     *              (like Gecko)"
     */

    { "konqueror",
      sizeof("Mozilla/5.0 (compatible; ") - 1,
      sizeof("Konqueror/") - 1,
      "Konqueror/"},

    { "", 0, 0, "" }

};


static ngx_http_variable_t  ngx_http_browser_vars[] = {

    { ngx_string("msie"), NULL, ngx_http_msie_variable,
      0, NGX_HTTP_VAR_CHANGEABLE, 0 },

    { ngx_string("modern_browser"), NULL, ngx_http_browser_variable,
      NGX_HTTP_MODERN_BROWSER, NGX_HTTP_VAR_CHANGEABLE, 0 },

    { ngx_string("ancient_browser"), NULL, ngx_http_browser_variable,
      NGX_HTTP_ANCIENT_BROWSER, NGX_HTTP_VAR_CHANGEABLE, 0 },

      ngx_http_null_variable
};


static ngx_int_t
ngx_http_browser_variable(ngx_http_request_t *r, ngx_http_variable_value_t *v,
    uintptr_t data)
{
    ngx_uint_t                rc;
    ngx_http_browser_conf_t  *cf;

    cf = ngx_http_get_module_loc_conf(r, ngx_http_browser_module);

    rc = ngx_http_browser(r, cf);

    if (data == NGX_HTTP_MODERN_BROWSER && rc == NGX_HTTP_MODERN_BROWSER) {
        *v = *cf->modern_browser_value;
        return NGX_OK;
    }

    if (data == NGX_HTTP_ANCIENT_BROWSER && rc == NGX_HTTP_ANCIENT_BROWSER) {
        *v = *cf->ancient_browser_value;
        return NGX_OK;
    }

    *v = ngx_http_variable_null_value;
    return NGX_OK;
}


static ngx_uint_t
ngx_http_browser(ngx_http_request_t *r, ngx_http_browser_conf_t *cf)
{
    size_t                      len;
    u_char                     *name, *ua, *last, c;
    ngx_str_t                  *ancient;
    ngx_uint_t                  i, version, ver, scale;
    ngx_http_modern_browser_t  *modern;

    if (r->headers_in.user_agent == NULL) {
        if (cf->modern_unlisted_browsers) {
            return NGX_HTTP_MODERN_BROWSER;
        }

        return NGX_HTTP_ANCIENT_BROWSER;
    }

    ua = r->headers_in.user_agent->value.data;
    len = r->headers_in.user_agent->value.len;
    last = ua + len;

    if (cf->modern_browsers) {
        modern = cf->modern_browsers->elts;

        for (i = 0; i < cf->modern_browsers->nelts; i++) {
            name = ua + modern[i].skip;

            if (name >= last) {
                continue;
            }

            name = (u_char *) ngx_strstr(name, modern[i].name);

            if (name == NULL) {
                continue;
            }

            ngx_log_debug1(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                           "browser: \"%s\"", name);

            name += modern[i].add;

            if (name >= last) {
                continue;
            }

            ngx_log_debug2(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                           "version: \"%ui\" \"%s\"", modern[i].version, name);

            version = 0;
            ver = 0;
            scale = 1000000;

            while (name < last) {

                c = *name++;

                if (c >= '0' && c <= '9') {
                    ver = ver * 10 + (c - '0');
                    continue;
                }

                if (c == '.') {
                    version += ver * scale;

                    ngx_log_debug2(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                                   "version: \"%ui\" \"%ui\"",
                                   modern[i].version, version);

                    if (version > modern[i].version) {
                        return NGX_HTTP_MODERN_BROWSER;
                    }

                    ver = 0;
                    scale /= 100;
                    continue;
                }

                break;
            }

            version += ver * scale;

            ngx_log_debug2(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                           "version: \"%ui\" \"%ui\"",
                           modern[i].version, version);

            if (version >= modern[i].version) {
                return NGX_HTTP_MODERN_BROWSER;
            }

            return NGX_HTTP_ANCIENT_BROWSER;
        }

        if (!cf->modern_unlisted_browsers) {
            return NGX_HTTP_ANCIENT_BROWSER;
        }
    }

    if (cf->netscape4) {
        if (len > sizeof("Mozilla/4.72 ") - 1
            && ngx_strncmp(ua, "Mozilla/", sizeof("Mozilla/") - 1) == 0
            && ua[8] > '0' && ua[8] < '5')
        {
            return NGX_HTTP_ANCIENT_BROWSER;
        }
    }

    if (cf->ancient_browsers) {
        ancient = cf->ancient_browsers->elts;

        for (i = 0; i < cf->ancient_browsers->nelts; i++) {
            if (len >= ancient[i].len
                && ngx_strstr(ua, ancient[i].data) != NULL)
            {
                return NGX_HTTP_ANCIENT_BROWSER;
            }
        }
    }

    if (cf->modern_unlisted_browsers) {
        return NGX_HTTP_MODERN_BROWSER;
    }

    return NGX_HTTP_ANCIENT_BROWSER;
}


static ngx_int_t
ngx_http_msie_variable(ngx_http_request_t *r, ngx_http_variable_value_t *v,
    uintptr_t data)
{
    if (r->headers_in.msie) {
        *v = ngx_http_variable_true_value;
        return NGX_OK;
    }

    *v = ngx_http_variable_null_value;
    return NGX_OK;
}


static ngx_int_t
ngx_http_browser_add_variables(ngx_conf_t *cf)
{
    ngx_http_variable_t  *var, *v;

    for (v = ngx_http_browser_vars; v->name.len; v++) {

        var = ngx_http_add_variable(cf, &v->name, v->flags);
        if (var == NULL) {
            return NGX_ERROR;
        }

        var->get_handler = v->get_handler;
        var->data = v->data;
    }

    return NGX_OK;
}


static void *
ngx_http_browser_create_conf(ngx_conf_t *cf)
{
    ngx_http_browser_conf_t  *conf;

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

    /*
     * set by ngx_pcalloc():
     *
     *     conf->modern_browsers = NULL;
     *     conf->ancient_browsers = NULL;
     *     conf->modern_browser_value = NULL;
     *     conf->ancient_browser_value = NULL;
     *
     *     conf->modern_unlisted_browsers = 0;
     *     conf->netscape4 = 0;
     */

    return conf;
}


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

    ngx_uint_t                  i, n;
    ngx_http_modern_browser_t  *browsers, *opera;

    /*
     * At the merge the skip field is used to store the browser slot,
     * it will be used in sorting and then will overwritten
     * with a real skip value.  The zero value means Opera.
     */

    if (conf->modern_browsers == NULL && conf->modern_unlisted_browsers == 0) {
        conf->modern_browsers = prev->modern_browsers;
        conf->modern_unlisted_browsers = prev->modern_unlisted_browsers;

    } else if (conf->modern_browsers != NULL) {
        browsers = conf->modern_browsers->elts;

        for (i = 0; i < conf->modern_browsers->nelts; i++) {
            if (browsers[i].skip == 0) {
                goto found;
            }
        }

        /*
         * Opera may contain MSIE string, so if Opera was not enumerated
         * as modern browsers, then add it and set a unreachable version
         */

        opera = ngx_array_push(conf->modern_browsers);
        if (opera == NULL) {
            return NGX_CONF_ERROR;
        }

        opera->skip = 0;
        opera->version = 4001000000U;

        browsers = conf->modern_browsers->elts;

found:

        ngx_qsort(browsers, (size_t) conf->modern_browsers->nelts,
                  sizeof(ngx_http_modern_browser_t),
                  ngx_http_modern_browser_sort);

        for (i = 0; i < conf->modern_browsers->nelts; i++) {
             n = browsers[i].skip;

             browsers[i].skip = ngx_http_modern_browser_masks[n].skip;
             browsers[i].add = ngx_http_modern_browser_masks[n].add;
             (void) ngx_cpystrn(browsers[i].name,
                                ngx_http_modern_browser_masks[n].name, 12);
        }
    }

    if (conf->ancient_browsers == NULL && conf->netscape4 == 0) {
        conf->ancient_browsers = prev->ancient_browsers;
        conf->netscape4 = prev->netscape4;
    }

    if (conf->modern_browser_value == NULL) {
        conf->modern_browser_value = prev->modern_browser_value;
    }

    if (conf->modern_browser_value == NULL) {
        conf->modern_browser_value = &ngx_http_variable_true_value;
    }

    if (conf->ancient_browser_value == NULL) {
        conf->ancient_browser_value = prev->ancient_browser_value;
    }

    if (conf->ancient_browser_value == NULL) {
        conf->ancient_browser_value = &ngx_http_variable_true_value;
    }

    return NGX_CONF_OK;
}


static int ngx_libc_cdecl
ngx_http_modern_browser_sort(const void *one, const void *two)
{
    ngx_http_modern_browser_t *first = (ngx_http_modern_browser_t *) one;
    ngx_http_modern_browser_t *second = (ngx_http_modern_browser_t *) two;

    return (first->skip - second->skip);
}


static char *
ngx_http_modern_browser(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
{
    ngx_http_browser_conf_t *bcf = conf;

    u_char                           c;
    ngx_str_t                       *value;
    ngx_uint_t                       i, n, version, ver, scale;
    ngx_http_modern_browser_t       *browser;
    ngx_http_modern_browser_mask_t  *mask;

    value = cf->args->elts;

    if (cf->args->nelts == 2) {
        if (ngx_strcmp(value[1].data, "unlisted") == 0) {
            bcf->modern_unlisted_browsers = 1;
            return NGX_CONF_OK;
        }

        return NGX_CONF_ERROR;
    }

    if (bcf->modern_browsers == NULL) {
        bcf->modern_browsers = ngx_array_create(cf->pool, 5,
                                            sizeof(ngx_http_modern_browser_t));
        if (bcf->modern_browsers == NULL) {
            return NGX_CONF_ERROR;
        }
    }

    browser = ngx_array_push(bcf->modern_browsers);
    if (browser == NULL) {
        return NGX_CONF_ERROR;
    }

    mask = ngx_http_modern_browser_masks;

    for (n = 0; mask[n].browser[0] != '\0'; n++) {
        if (ngx_strcasecmp(mask[n].browser, value[1].data) == 0) {
            goto found;
        }
    }

    ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
                       "unknown browser name \"%V\"", &value[1]);

    return NGX_CONF_ERROR;

found:

    /*
     * at this stage the skip field is used to store the browser slot,
     * it will be used in sorting in merge stage and then will overwritten
     * with a real value
     */

    browser->skip = n;

    version = 0;
    ver = 0;
    scale = 1000000;

    for (i = 0; i < value[2].len; i++) {

        c = value[2].data[i];

        if (c >= '0' && c <= '9') {
            ver = ver * 10 + (c - '0');
            continue;
        }

        if (c == '.') {
            version += ver * scale;
            ver = 0;
            scale /= 100;
            continue;
        }

        ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
                           "invalid browser version \"%V\"", &value[2]);

        return NGX_CONF_ERROR;
    }

    version += ver * scale;

    browser->version = version;

    return NGX_CONF_OK;
}


static char *
ngx_http_ancient_browser(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
{
    ngx_http_browser_conf_t *bcf = conf;

    ngx_str_t   *value, *browser;
    ngx_uint_t   i;

    value = cf->args->elts;

    for (i = 1; i < cf->args->nelts; i++) {
        if (ngx_strcmp(value[i].data, "netscape4") == 0) {
            bcf->netscape4 = 1;
            continue;
        }

        if (bcf->ancient_browsers == NULL) {
            bcf->ancient_browsers = ngx_array_create(cf->pool, 4,
                                                     sizeof(ngx_str_t));
            if (bcf->ancient_browsers == NULL) {
                return NGX_CONF_ERROR;
            }
        }

        browser = ngx_array_push(bcf->ancient_browsers);
        if (browser == NULL) {
            return NGX_CONF_ERROR;
        }

        *browser = value[i];
    }

    return NGX_CONF_OK;
}


static char *
ngx_http_modern_browser_value(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
{
    ngx_http_browser_conf_t *bcf = conf;

    ngx_str_t  *value;

    bcf->modern_browser_value = ngx_palloc(cf->pool,
                                           sizeof(ngx_http_variable_value_t));
    if (bcf->modern_browser_value == NULL) {
        return NGX_CONF_ERROR;
    }

    value = cf->args->elts;

    bcf->modern_browser_value->len = value[1].len;
    bcf->modern_browser_value->valid = 1;
    bcf->modern_browser_value->no_cacheable = 0;
    bcf->modern_browser_value->not_found = 0;
    bcf->modern_browser_value->data = value[1].data;

    return NGX_CONF_OK;
}


static char *
ngx_http_ancient_browser_value(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
{
    ngx_http_browser_conf_t *bcf = conf;

    ngx_str_t  *value;

    bcf->ancient_browser_value = ngx_palloc(cf->pool,
                                            sizeof(ngx_http_variable_value_t));
    if (bcf->ancient_browser_value == NULL) {
        return NGX_CONF_ERROR;
    }

    value = cf->args->elts;

    bcf->ancient_browser_value->len = value[1].len;
    bcf->ancient_browser_value->valid = 1;
    bcf->ancient_browser_value->no_cacheable = 0;
    bcf->ancient_browser_value->not_found = 0;
    bcf->ancient_browser_value->data = value[1].data;

    return NGX_CONF_OK;
}