Home > Articles > Operating Systems, Server > Solaris

  • Print
  • + Share This
Like this article? We recommend

Labeled Processes

Generally a process' label is inherited from its parent process and remains constant. A few privileged launchers exist which can set a process label when executing a new process. These include the profiles shells (pfsh, pfksh, and pfcsh), the system shell (sysh), and the Internet daemon (inetd). Each of these processes interpret entries in the exec_attr database when executing programs.

All of the shells interpret the label keyword associated with a command when they execute a new process. inetd is able to launch servers at the same label as the requesting client. Such servers are said to be polyinstantiated, since a server instance can be launched corresponding to the label of each requesting client. The rules for determining the client's label are based on the contents of trusted networking databases that were discussed in the previous Sun BluePrints article1. In this article, we rely on inetd to polyinstantiate servers for ftp and telnet. Since this is the default behavior, no configuration changes are required.

The SMTP daemon, sendmail, has been modified in the Trusted Solaris OE to work in a polyinstantiated manner. It automatically forks off a process at the label of the requesting client. No special configuration is required, but a common configuration file is maintained by the service provider.

Creating a CGI Sandbox

Customers may want to develop and execute scripts on the server using the Common Gateway Interface (CGI) or Server Side Includes (SSI), so it is desirable to compartmentalize the web server and the CGI environment. Apache provides a small execution wrapper known as suEXEC, which allows scripts to be executed with a different user ID from the calling Web server. This concept can be extended to provide execution in a protected sandbox. By running the web server in the HTTP FTP compartment, and the CGI scripts in the CGI compartment, the environments are isolated from each other except for a pipe to the web server used for standard I/O.

Neither the web server nor the CGI scripts are able to modify any files with the C1 label because they are not permitted to write down, but each can read these files unless they are protected by DAC. In addition, the web server and the CGI scripts cannot read any files created in the other compartment because neither dominates the other. The CGI environment is also prevented from connecting to any remote systems since its label is outside the accreditation range of all network interfaces connected to the Internet (see section, "Associating Labels with Network Interfaces," on page -7).

The suEXEC program is Open Source, so it can be modified to switch its label compartments prior to executing a CGI script. The modification consists of a few lines of C added to file suexec.c which are executed between fork(2) and exec(2). Since the MAC policy for files is enforced when a file or pipe is opened, it is possible to pass open file descriptors to a child process even if its process label is changed. The following code fragment turns off the HTTP FTP compartment and turns on the CGI compartment (error handling is omitted for clarity).

#include <tsol/label.h>
bclabel_t label;
int p;
getcmwplabel(&label);              /* current label */
stobsl("- HTTP FTP", bcltosl(&label), 0, &p); /* HTTP, FTP off */
stobsl("+ CGI", bcltosl(&label), 0, &p);   /* CGI on    */
setcmwplabel(&label, SETCL_SL);        /* set new label */

The system call getcmwplabel(2) returns the initial process label of suEXEC, which is the same as the web server. The function stobsl(3) translates a string to a binary label. In these calls it adds or removes the compartment bits corresponding to a specified string. The label translation requires the privilege proc_setsl. The resulting label is then applied to the current process by the system call setcmwplabel(2), which requires the privilege proc_setsl. Since no change is made to the classification component of the label, this single change works for any of the customer labels described above. A modified version of the file suexec.c which incorporates this logic is included in the configuration files for this article.

The standard suEXEC program, which sets up the new user ID before executing the specified commands, requires the privilege proc_setid. These privileges are applied to the executable using the following commands:

# cd /usr/apache/bin
# setfpriv -s -a all -f proc_setid,sys_trans_label,proc_setsl suexec

The Apache documentation for suEXEC describes how to make it a setuid program by assigning it the permission bits 4711. Although the Trusted Solaris OE privilege policy does not require this setting, the Apache server refuses to communicate with suEXEC unless these permissions are set.

An alternative approach to modifying suEXEC is to write a privileged profile shell script wrapper around it. Such a wrapper would rely on the profile shell functionality to set the process label instead of suEXEC. However, the complexity of creating multiple profiles and the requirement to make the shell script wrapper a setuid program, make it a less attractive solution than modifying suEXEC directly.

Instantiating Servlets and JavaServer Pages™ Software

Another kind of web server application is a Java™ servlet container such as Apache's Tomcat server. A servlet container manages and invokes servlets on the behalf of users. The Tomcat servlet container described here is a combination of a web server plug-in and a Java container implementation that runs in a Java virtual achine or JVM™ software outside the web server. The web server plug-in and the Java servlet container JVM software communicate using TCP/IP sockets; therefore the servlet container can run on a backend machine, which is also running the Trusted Solaris OE. Unlike connections to the public Internet, the interfaces between these two systems are multilevel. That means that the respective interfaces can be used to communicate at any label within their accreditation ranges. We can use the Tomcat server's default port number, 8007, for all customers, since the port is polyinstantiated. Each Tomcat server will run in its own JVM software, and will only accept connections from a web server running with the same label.

NOTE

Adding backend servers is optional, but is consistent with the Trusted Solaris architecture since the compartmentalization provided by the MAC policy is enforced throughout the trusted network.

  • + Share This
  • 🔖 Save To Your Account

InformIT Promotional Mailings & Special Offers

I would like to receive exclusive offers and hear about products from InformIT and its family of brands. I can unsubscribe at any time.

Overview


Pearson Education, Inc., 221 River Street, Hoboken, New Jersey 07030, (Pearson) presents this site to provide information about products and services that can be purchased through this site.

This privacy notice provides an overview of our commitment to privacy and describes how we collect, protect, use and share personal information collected through this site. Please note that other Pearson websites and online products and services have their own separate privacy policies.

Collection and Use of Information


To conduct business and deliver products and services, Pearson collects and uses personal information in several ways in connection with this site, including:

Questions and Inquiries

For inquiries and questions, we collect the inquiry or question, together with name, contact details (email address, phone number and mailing address) and any other additional information voluntarily submitted to us through a Contact Us form or an email. We use this information to address the inquiry and respond to the question.

Online Store

For orders and purchases placed through our online store on this site, we collect order details, name, institution name and address (if applicable), email address, phone number, shipping and billing addresses, credit/debit card information, shipping options and any instructions. We use this information to complete transactions, fulfill orders, communicate with individuals placing orders or visiting the online store, and for related purposes.

Surveys

Pearson may offer opportunities to provide feedback or participate in surveys, including surveys evaluating Pearson products, services or sites. Participation is voluntary. Pearson collects information requested in the survey questions and uses the information to evaluate, support, maintain and improve products, services or sites, develop new products and services, conduct educational research and for other purposes specified in the survey.

Contests and Drawings

Occasionally, we may sponsor a contest or drawing. Participation is optional. Pearson collects name, contact information and other information specified on the entry form for the contest or drawing to conduct the contest or drawing. Pearson may collect additional personal information from the winners of a contest or drawing in order to award the prize and for tax reporting purposes, as required by law.

Newsletters

If you have elected to receive email newsletters or promotional mailings and special offers but want to unsubscribe, simply email information@informit.com.

Service Announcements

On rare occasions it is necessary to send out a strictly service related announcement. For instance, if our service is temporarily suspended for maintenance we might send users an email. Generally, users may not opt-out of these communications, though they can deactivate their account information. However, these communications are not promotional in nature.

Customer Service

We communicate with users on a regular basis to provide requested services and in regard to issues relating to their account we reply via email or phone in accordance with the users' wishes when a user submits their information through our Contact Us form.

Other Collection and Use of Information


Application and System Logs

Pearson automatically collects log data to help ensure the delivery, availability and security of this site. Log data may include technical information about how a user or visitor connected to this site, such as browser type, type of computer/device, operating system, internet service provider and IP address. We use this information for support purposes and to monitor the health of the site, identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents and appropriately scale computing resources.

Web Analytics

Pearson may use third party web trend analytical services, including Google Analytics, to collect visitor information, such as IP addresses, browser types, referring pages, pages visited and time spent on a particular site. While these analytical services collect and report information on an anonymous basis, they may use cookies to gather web trend information. The information gathered may enable Pearson (but not the third party web trend services) to link information with application and system log data. Pearson uses this information for system administration and to identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents, appropriately scale computing resources and otherwise support and deliver this site and its services.

Cookies and Related Technologies

This site uses cookies and similar technologies to personalize content, measure traffic patterns, control security, track use and access of information on this site, and provide interest-based messages and advertising. Users can manage and block the use of cookies through their browser. Disabling or blocking certain cookies may limit the functionality of this site.

Do Not Track

This site currently does not respond to Do Not Track signals.

Security


Pearson uses appropriate physical, administrative and technical security measures to protect personal information from unauthorized access, use and disclosure.

Children


This site is not directed to children under the age of 13.

Marketing


Pearson may send or direct marketing communications to users, provided that

  • Pearson will not use personal information collected or processed as a K-12 school service provider for the purpose of directed or targeted advertising.
  • Such marketing is consistent with applicable law and Pearson's legal obligations.
  • Pearson will not knowingly direct or send marketing communications to an individual who has expressed a preference not to receive marketing.
  • Where required by applicable law, express or implied consent to marketing exists and has not been withdrawn.

Pearson may provide personal information to a third party service provider on a restricted basis to provide marketing solely on behalf of Pearson or an affiliate or customer for whom Pearson is a service provider. Marketing preferences may be changed at any time.

Correcting/Updating Personal Information


If a user's personally identifiable information changes (such as your postal address or email address), we provide a way to correct or update that user's personal data provided to us. This can be done on the Account page. If a user no longer desires our service and desires to delete his or her account, please contact us at customer-service@informit.com and we will process the deletion of a user's account.

Choice/Opt-out


Users can always make an informed choice as to whether they should proceed with certain services offered by InformIT. If you choose to remove yourself from our mailing list(s) simply visit the following page and uncheck any communication you no longer want to receive: www.informit.com/u.aspx.

Sale of Personal Information


Pearson does not rent or sell personal information in exchange for any payment of money.

While Pearson does not sell personal information, as defined in Nevada law, Nevada residents may email a request for no sale of their personal information to NevadaDesignatedRequest@pearson.com.

Supplemental Privacy Statement for California Residents


California residents should read our Supplemental privacy statement for California residents in conjunction with this Privacy Notice. The Supplemental privacy statement for California residents explains Pearson's commitment to comply with California law and applies to personal information of California residents collected in connection with this site and the Services.

Sharing and Disclosure


Pearson may disclose personal information, as follows:

  • As required by law.
  • With the consent of the individual (or their parent, if the individual is a minor)
  • In response to a subpoena, court order or legal process, to the extent permitted or required by law
  • To protect the security and safety of individuals, data, assets and systems, consistent with applicable law
  • In connection the sale, joint venture or other transfer of some or all of its company or assets, subject to the provisions of this Privacy Notice
  • To investigate or address actual or suspected fraud or other illegal activities
  • To exercise its legal rights, including enforcement of the Terms of Use for this site or another contract
  • To affiliated Pearson companies and other companies and organizations who perform work for Pearson and are obligated to protect the privacy of personal information consistent with this Privacy Notice
  • To a school, organization, company or government agency, where Pearson collects or processes the personal information in a school setting or on behalf of such organization, company or government agency.

Links


This web site contains links to other sites. Please be aware that we are not responsible for the privacy practices of such other sites. We encourage our users to be aware when they leave our site and to read the privacy statements of each and every web site that collects Personal Information. This privacy statement applies solely to information collected by this web site.

Requests and Contact


Please contact us about this Privacy Notice or if you have any requests or questions relating to the privacy of your personal information.

Changes to this Privacy Notice


We may revise this Privacy Notice through an updated posting. We will identify the effective date of the revision in the posting. Often, updates are made to provide greater clarity or to comply with changes in regulatory requirements. If the updates involve material changes to the collection, protection, use or disclosure of Personal Information, Pearson will provide notice of the change through a conspicuous notice on this site or other appropriate way. Continued use of the site after the effective date of a posted revision evidences acceptance. Please contact us if you have questions or concerns about the Privacy Notice or any objection to any revisions.

Last Update: November 17, 2020