view src/http/modules/ngx_http_auth_basic_module.c @ 6075:7fcfe113827d stable-1.6

Fixed possible buffer overrun in "too long header line" logging. Additionally, ellipsis now always added to make it clear that the header logged is incomplete. Reported by Daniil Bondarev.
author Maxim Dounin <mdounin@mdounin.ru>
date Wed, 08 Oct 2014 17:16:04 +0400
parents c37f34bda5ea
children f01ab2dbcfdc
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>
#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: %d 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;
}