Secure Programming for Linux and Unix HOWTO

• Index
• Introduction
• Background
• History of Unix, Linux, and Open Source / Free Software
• Security Principles
• Why do Programmers Write Insecure Code?
• Is Open Source Good for Security?
• Types of Secure Programs
• Paranoia is a Virtue
• Why Did I Write This Document?
• Sources of Design and Implementation Guidelines
• Other Sources of Security Information
• Document Conventions
• Summary of Linux and Unix Security Features
• Processes
• Files
• System V IPC
• Sockets and Network Connections
• Signals
• Quotas and Limits
• Dynamically Linked Libraries
• Audit
• PAM
• Specialized Security Extensions for Unix-like Systems
• Security Requirements
• Common Criteria Introduction
• Security Environment and Objectives
• Security Functionality Requirements
• Security Assurance Measure Requirements
• Validate All Input
• Command line
• Environment Variables
• File Descriptors
• File Names
• File Contents
• Web-Based Application Inputs (Especially CGI Scripts)
• Other Inputs
• Human Language (Locale) Selection
• Character Encoding
• Prevent Cross-site Malicious Content on Input
• Filter HTML/URIs That May Be Re-presented
• Forbid HTTP GET To Perform Non-Queries
• Counter SPAM
• Limit Valid Input Time and Load Level
• Avoid Buffer Overflow
• Dangers in C/C++
• Library Solutions in C/C++
• Compilation Solutions in C/C++
• Other Languages
• Structure Program Internals and Approach
• Follow Good Software Engineering Principles for Secure Programs
• Secure the Interface
• Separate Data and Control
• Minimize Privileges
• Minimize the Functionality of a Component
• Avoid Creating Setuid/Setgid Scripts
• Configure Safely and Use Safe Defaults
• Load Initialization Values Safely
• Fail Safe
• Avoid Race Conditions
• Trust Only Trustworthy Channels
• Set up a Trusted Path
• Use Internal Consistency-Checking Code
• Self-limit Resources
• Prevent Cross-Site (XSS) Malicious Content
• Foil Semantic Attacks
• Be Careful with Data Types
• Carefully Call Out to Other Resources
• Call Only Safe Library Routines
• Limit Call-outs to Valid Values
• Handle Metacharacters
• Call Only Interfaces Intended for Programmers
• Check All System Call Returns
• Avoid Using vfork(2)
• Counter Web Bugs When Retrieving Embedded Content
• Hide Sensitive Information
• Send Information Back Judiciously
• Minimize Feedback
• Don't Include Comments
• Handle Full/Unresponsive Output
• Control Data Formatting (Format Strings/Formatation)
• Control Character Encoding in Output
• Prevent Include/Configuration File Access
• Language-Specific Issues
• C/C++
• Perl
• Python
• Shell Scripting Languages (sh and csh Derivatives)
• Ada
• Java
• Tcl
• PHP
• Special Topics
• Passwords
• Authenticating on the Web
• Random Numbers
• Specially Protect Secrets (Passwords and Keys) in User Memory
• Cryptographic Algorithms and Protocols
• Using PAM
• Tools
• Windows CE
• Write Audit Records
• Physical Emissions
• Miscellaneous
• Conclusion
• Bibliography
• History
• Acknowledgements
• About the Documentation License
• GNU Free Documentation License
• Endorsements
• About the Author
• Legal notice