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10 SP1 EAL4
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Figure 5-79: System x SLE
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10 SP1 EAL4
Contents
3
Table of Contents
13
1 Introduction
1.1 Purpose of this document
1.2 Document overview
1.3 Conventions used in this document
1.4 Terminology
14
2 System Overview
Figure 2-1: Series of TOE systems connected by a physically protected LAN
15
2.1 Product history
2.1.1 SUSE Linux Enterprise Server
2.1.2 eServer systems
2.2 High-level product overview
16
2.2.1 eServer host computer structure
Figure 2-2: Overall structure of the TOE
18
2.2.2 eServer system structure
2.2.3 TOE services
19
2.2.4 Security policy
Figure 2-3: Local and network services provided by SLES
20
2.2.5 Operation and administration
2.2.6 TSF interfaces
21
2.3 Approach to TSF identification
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3 Hardware architecture
3.1 System x
3.1.1 System x hardware overview
3.1.2 System x hardware architecture
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3.2 System p
3.2.1 System p hardware overview
3.2.2 System p hardware architecture
26
3.3 System z
3.3.1 System z hardware overview
3.3.2 System z hardware architecture
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3.4 eServer 326
Figure 3-1: z/VM as hypervisor
3.4.1 eServer 326 hardware overview
3.4.2 eServer 326 hardware architecture
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Figure 3-2: AMD x86-64 architecture in compatibility mode
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4 Software architecture
4.1 Hardware and software privilege
4.1.1 Hardware privilege
4.1.1.1 Privilege level
31
Figure 4-1: Levels of Privilege
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4.1.2 Software privilege
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4.1.2.1 DAC
4.1.2.1.1 Subjects and objects
4.1.2.1.2 Attributes
4.1.2.1.3 Access control rules
4.1.2.1.4 Software privilege
4.1.2.2 AppArmor
4.1.2.3 Programs with software privilege
34
4.2 TOE Security Functions software structure
Figure 4-2: TSF and non-TSF software
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4.2.1 Kernel TSF software
4.2.1.1 Logical components
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Figure 4-3: Logical kernel subsystems and their interactions
4.2.1.2 Execution components
37
Figure 4-4: Kernel execution components
4.2.1.2.1 Base kernel
4.2.1.2.2 Kernel threads
4.2.1.2.3 Kernel modules and device drivers
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4.2.2 Non-kernel TSF software
40
4.3 TSF databases
4.4 Definition of subsystems for the CC evaluation
41
4.4.1 Hardware
4.4.2 Firmware
4.4.3 Kernel subsystems
4.4.4 Trusted process subsystems
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4.4.5 User-level audit subsystem
44
5 Functional descriptions
5.1 File and I/O management
Figure 5-1: File and I/O subsystem and its interaction with other subsystems
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5.1.1 Virtual File System
Figure 5-2: ext3 and CD-ROM file systems before mounting
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Figure 5-3: ext3 and CD-ROM file systems after mounting
Figure 5-4: Virtual file system
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5.1.1.1 Pathname translation
5.1.1.2 open()
49
Figure 5-6: VFS data structures and their relationships with each other
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5.1.1.3 write()
5.1.1.4 mount()
5.1.1.5 Shared subtrees
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5.1.2 Disk-based file systems
5.1.2.1 Ext3 file system
5.1.2.1.1 Extended Attributes
5.1.2.1.2 Data structures
52
Figure 5-7: Security attributes, extended security attributes, and data blocks for the ext3 inode
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Figure 5-9: Access control on ext3 file system
5.1.2.2 ISO 9660 file system for CD-ROM
5.1.2.2.1 Data structures and algorithms
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5.1.3 Pseudo file systems
Figure 5-10: File lookup on CD-ROM file system
5.1.3.1 procfs
5.1.3.2 tmpfs
57
5.1.3.3 sysfs
5.1.3.4 devpts
5.1.3.5 rootfs
5.1.3.6 binfmt_misc
5.1.3.7 securityfs
5.1.3.8 configfs
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5.1.4 inotify
5.1.5 Discretionary Access Control (DAC)
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5.1.5.1 Permission bits
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5.1.5.2 Access Control Lists
5.1.5.2.1 Types of ACL tags
5.1.5.2.2 ACL qualifier
61
5.1.5.2.3 ACL permissions
5.1.5.2.4 Relationship to file permission bits
5.1.5.2.5 ACL_MASK
5.1.5.2.6 Default ACLs and ACL inheritance
5.1.5.2.7 ACL representations and interfaces
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5.1.5.2.8 ACL enforcement
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5.1.6 Asynchronous I/O
5.1.7 I/O scheduler
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5.1.7.1 Deadline I/O scheduler
5.1.7.2 Anticipatory I/O scheduler
5.1.7.3 Completely Fair Queuing scheduler
5.1.7.4 Noop I/O scheduler
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5.1.8 I/O interrupts
5.1.8.1 Top halves
5.1.8.2 Bottom halves
5.1.8.3 Softirqs
5.1.8.4 Tasklets
5.1.8.5 Work queue
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5.1.9 Processor interrupts
5.1.10 Machine check
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5.2 Process control and management
Figure 5-11: Process subsystem and its interaction with other subsystems
5.2.1 Data structures
Figure 5-12: The task structure
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5.2.2 Process creation and destruction
5.2.2.1 Control of child processes
5.2.2.2 DAC controls 5.2.2.2.1 setuid()and setgid()
5.2.2.2.2 seteuid()and setegid()
5.2.2.2.3 setreuid()and setregid()
5.2.2.2.4 setresuid()and setresgid()
5.2.2.3 execve()
5.2.2.4 do_exit()
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5.2.3 Process switch
5.2.4 Kernel threads
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5.2.5 Scheduling
Figure 5-13: O(1) scheduling
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5.2.6 Kernel preemption
Figure 5-14: Hyperthreaded scheduling
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5.3 Inter-process communication
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5.3.1 Pipes
Figure 5-15: Pipes Implementation
5.3.1.1 Data structures and algorithms
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5.3.2 First-In First-Out Named pipes
5.3.2.1 FIFO creation
5.3.2.2 FIFO open
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5.3.3 System V IPC
5.3.3.1 Common data structures
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5.3.3.2 Common functions
5.3.3.2.1 ipc_alloc()
5.3.3.2.2 ipcperms()
5.3.3.3 Message queues
5.3.3.3.1 msg_queue
5.3.3.3.2 msg_msg
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5.3.4 Signals
5.3.4.1 Data structures
5.3.4.2 Algorithms
5.3.5 Sockets
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5.4 Network subsystem
Figure 5-16: Object reuse handling in socket allocation
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5.4.1 Overview of the network protocol stack
Figure 5-17: Network subsystem and its interaction with other subsystems
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Figure 5-18: How data travels through the Network protocol stack
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5.4.2 Transport layer protocols
5.4.2.1 TCP
5.4.2.2 UDP
5.4.3 Network layer protocols
5.4.3.1 Internet Protocol Version 4 (IPv4)
5.4.3.2 Internet Protocol Version 6 (IPv6)
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5.4.3.2.1 Addressing
5.4.3.2.2 IPv6 Header
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5.4.3.2.3 Flow Labels
5.4.3.2.4 Security
5.4.3.3 Transition between IPv4 and IPv6
5.4.3.4 IP Security (IPsec)
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5.4.3.4.1 Functional Description of IPsec
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5.4.4 Internet Control Message Protocol (ICMP)
5.4.4.1 Link layer protocols
5.4.4.1.1 Address Resolution Protocol (ARP)
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5.4.5 Network services interface
Figure 5-19: Server and client operations using socket interface
5.4.5.1 socket()
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Figure 5-20: bind() function for internet domain TCP socket
5.4.5.2 bind()
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Figure 5-21: bind() function for UNIX domain TCP socket
5.4.5.3 listen()
5.4.5.4 accept()
5.4.5.5 connect()
5.4.5.6 Generic calls
5.4.5.7 Access control
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5.5 Memory management
Figure 5-22: Mapping read, write and close calls for sockets
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Figure 5-23: Memory subsystem and its interaction with other subsystems
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5.5.1 Four-Level Page Tables
Figure 5-24: Previous three-level page-tables architecture
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5.5.2 Memory addressing
5.5.2.1 System x
Figure 5-25: New page-table implementation: the four-level page-table architecture
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Figure 5-26: System x virtual addressing space
Figure 5-27: Logical Address Translation
5.5.2.1.1 Segmentation
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Figure 5-28: Access control through segmentation
5.5.2.1.2 Paging
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Figure 5-29: Contiguous linear addresses map to contiguous physical addresses
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Figure 5-32: Access control through paging
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Figure 5-33: Paging data structures
5.5.2.2 System p
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Figure 5-34: Logical partitions
Figure 5-35: Machine state register
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5.5.2.2.1 Address Translation on LPARs
5.5.2.2.2 Hypervisor
5.5.2.2.3 Real mode addressing
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5.5.2.2.4 Virtual mode addressing
5.5.2.2.5 Access to I/O address space
5.5.2.2.6 Direct Memory Access addressing
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Figure 5-38: DMA addressing
5.5.2.2.7 Run-Time Abstraction Services
5.5.2.2.8 Preventing denial of service
5.5.2.3 System p native mode
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Figure 5-39: Effective address
Figure 5-40: Virtual address
5.5.2.3.1 Machine State Register
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Figure 5-41: Block address
Figure 5-42: Machine state register
5.5.2.3.2 Page descriptor
5.5.2.3.3 Segment descriptor
5.5.2.3.4 Block descriptor
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Figure 5-43: Page table entry
Figure 5-44: Segment Table Entry
5.5.2.3.5 Address translation mechanisms
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Figure 5-46: Address translation method selection
Figure 5-45: Block Address Translation entry
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Figure 5-47: Block Address Translation access control
5.5.2.3.6 Page Address Translation and access control
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5.5.2.4 System z
5.5.2.4.1 Native hardware mode
5.5.2.4.2 LPAR mode
5.5.2.4.3 z/VM Guest mode
5.5.2.4.4 Address types
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5.5.2.4.5 Address sizes
5.5.2.4.6 Address spaces
5.5.2.4.7 Address translations
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Figure 5-51: Address translation modes
5.5.2.4.8 Memory protection mechanisms
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Figure 5-53: Low-address protection on effective address
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Figure 5-56: Key match logic for key-controlled protection
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Figure 5-57: Fetch protection override for key-controlled
5.5.2.5 eServer 326
5.5.2.5.1 Logical address
5.5.2.5.2 Effective address
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Figure 5-58: eServer 326 address types and their conversion units
5.5.2.5.3 Linear address
5.5.2.5.4 Physical address
5.5.2.5.5 Segmentation
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Figure 5-59: Data access privilege checks
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5.5.2.5.6 Paging
5.5.2.5.7 Translation Lookaside Buffers
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5.5.3 Kernel memory management
5.5.3.1 Support for NUMA servers
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Figure 5-64: NUMA Design
5.5.3.2 Reverse map Virtual Memory
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Figure 5-65: Rmap VM
5.5.3.3 Huge Translation Lookaside Buffers
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Figure 5-66: TLB Operation
5.5.3.4 Remap_file_pages
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Figure 5-67: Remap_ file_ pages for database applications
5.5.3.5 Page frame management
5.5.3.6 Memory area management
5.5.3.7 Noncontiguous memory area management
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5.5.4 Process address space
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Figure 5-68: Object reuse handling while allocating new linear address
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5.5.5 Symmetric multiprocessing and synchronization
5.5.5.1 Atomic operations
5.5.5.2 Memory barriers
5.5.5.3 Spin locks
5.5.5.4 Kernel semaphores
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5.6 Audit subsystem
5.6.1 Audit components
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Figure 5-69: Audit framework components
5.6.1.1 Audit kernel components
5.6.1.1.1 Kernel-userspace interface
5.6.1.1.2 Syscall auditing
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Figure 5-70: Audit Kernel Components
5.6.1.1.3 Filesystem watches
5.6.1.1.4 Task structure
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Figure 5-71: Task Structure
5.6.1.1.5 Audit context fields
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5.6.1.2 File system audit components
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5.6.1.3 User space audit components
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5.6.2 Audit operation and configuration options
Figure 5-72: Audit User Space Components
5.6.2.1 Configuration
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5.6.2.2 Operation
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5.6.3 Audit records
5.6.3.1 Audit record generation
5.6.3.1.1 Kernel record generation
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Figure 5-73: Audit Record Generation
5.6.3.1.2 Syscall audit record generation
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Figure 5-74: Extension to system calls interface
5.6.3.1.3 File system audit record generation
5.6.3.1.4 Socket call and IPC audit record generation
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Figure 5-75: User Space Record Generation
5.6.3.1.5 Record generation by trusted programs
5.6.3.2 Audit record format
158
5.6.4 Audit tools
5.6.4.1 auditctl
5.6.4.2 ausearch
5.6.5 Login uid association
5.7 Kernel modules
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5.7.1 Linux Security Module framework
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5.7.2 LSM capabilities module
Figure 5-76: LSM hook architecture
5.7.3 LSM AppArmor module
5.8 AppArmor
162
5.8.1 AppArmor administrative utilities
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5.8.2 AppArmor access control functions
5.8.3 securityfs
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5.9 Device drivers
5.9.1 I/O virtualization on System z
5.9.1.1 Interpretive-execution facility
165
5.9.1.2 State description
5.9.1.3 Hardware virtualization and simulation
166
5.9.2 Character device driver
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5.9.3 Block device driver
Figure 5-77: Setup of f_op for character device specific file operations
168
5.10 System initialization
Figure 5-78: Setup of f_op for block device specific file operations
5.10.1 init
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5.10.2 System x
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5.10.2.1 Boot methods
5.10.2.2 Boot loader
5.10.2.3 Boot process
173
5.10.3 System p
5.10.3.1 Boot methods
5.10.3.2 Boot loader
5.10.3.3 Boot process
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5.10.4.1 Boot process
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5.10.5 System z
5.10.5.1 Boot methods
5.10.5.2 Control program
5.10.5.3 Boot process
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5.10.6 eServer 326
Figure 5-82: System z SLES boot sequence
5.10.6.1 Boot methods
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5.10.6.2 Boot loader
5.10.6.3 Boot process
183
5.11 Identification and authentication
Figure 5-83: eServer 326 SLES boot sequence
184
5.11.1 Pluggable Authentication Module
5.11.1.1 Overview
185
5.11.1.2 Configuration terminology
5.11.1.3 Modules
187
5.11.2 Protected databases
5.11.2.1 Access control rules 5.11.2.1.1 DAC
5.11.2.1.2 Software privilege
188
5.11.3 Trusted commands and trusted processes
5.11.3.1 agetty
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5.11.3.2 gpasswd
5.11.3.3 login
190
5.11.3.4 mingetty
5.11.3.5 newgrp
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5.11.3.6 passwd
5.11.3.7 su
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5.11.4 Interaction with audit
5.12 Network applications
5.12.1 OpenSSL Secure socket-layer interface
193
Figure 5-84: SSL location in the network stack
5.12.1.1 Concepts
5.12.1.1.1 Encryption
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Figure 5-86: Decryption
Figure 5-85: Encryption
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Figure 5-87: Encryption Algorithm and Key
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5.12.1.1.2 Message digest
5.12.1.1.3 Message Authentication Code (MAC)
5.12.1.1.4 Digital certificates and certificate authority
5.12.1.2 SSL architecture
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Figure 5-90: SSL Protocol
5.12.1.2.1 SSL handshake protocol
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Figure 5-92: SSL protocol action
5.12.1.3 OpenSSL algorithms
5.12.1.4 Symmetric ciphers
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5.12.1.4.1 Asymmetric ciphers
5.12.1.4.2 Certificates
5.12.1.4.3 Hash functions
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5.12.2 Secure Shell
203
5.12.2.1 SSH client
5.12.2.2 SSH server daemon
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5.12.3 Very Secure File Transfer Protocol daemon
5.12.4 CUPS
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5.12.4.1 cupsd
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5.12.4.2 ping
5.12.4.3 ping6
5.12.4.4 openssl
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5.12.4.5 stunnel
5.12.4.6 xinetd
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5.13 System management 5.13.1 Account Management
5.13.1.1 chage
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5.13.1.2 chfn
5.13.1.3 chsh
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5.13.2 User management
5.13.2.1 useradd
5.13.2.2 usermod
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5.13.2.3 userdel
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5.13.3 Group management
5.13.3.1 groupadd
213
5.13.3.2 groupmod
5.13.3.3 groupdel
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5.13.4 System Time management
5.13.4.1 date
5.13.4.2 hwclock
5.13.5 Other System Management
5.13.5.1 AMTU
216
5.13.5.1.1 Memory
5.13.5.1.2 Memory separation
5.13.5.1.3 I/O controller and network
5.13.5.1.4 I/O controller and disk
5.13.5.1.5 Supervisor mode instructions
218
5.13.5.1.6 AMTU output
5.13.5.2 star
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5.13.6 I&A support
5.13.6.1 pam_tally
5.13.6.2 unix_chkpwd
5.14 Batch processing
5.14.1 Batch processing user commands
5.14.1.1 crontab
221
5.14.1.2 at
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5.14.2 Batch processing daemons
5.14.2.1 cron
5.14.2.2 atd
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5.15 User-level audit subsystem
5.15.1 Audit daemon
5.15.2 Audit utilities
5.15.2.1 aureport
5.15.2.2 ausearch
5.15.2.3 autrace
224
5.15.3 Audit configuration files
5.15.4 Audit logs
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5.16 Supporting functions
5.16.1 TSF libraries
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Library Description
227
5.16.2 Library linking mechanism
5.16.3 System call linking mechanism
5.16.3.1 System x
5.16.3.2 System p
5.16.3.3 System z
5.16.3.4 eServer 326
228
5.16.4 System call argument verification
230
6 Mapping the TOE summary specification to the High-Level Design
233
6.7.4 Trusted processes (TP.4)
6.7.5 TSF Databases (TP.5)
6.7.6 Internal TOE protection mechanisms (TP.6)
6.7.7 Testing the TOE protection mechanisms (TP.7)
6.8 Security enforcing interfaces between subsystems
234
6.8.1 Summary of kernel subsystem interfaces
6.8.1.1 Kernel subsystem file and I/O
6.8.1.1.1 External Interfaces
235
6.8.1.1.2 Internal Interfaces 6.8.1.1.3
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6.8.1.1.4 Data Structures
6.8.1.2 Kernel subsystem process control and management
6.8.1.2.1 External interfaces (system calls)
237
6.8.1.2.2 Internal Interfaces
6.8.1.2.3 Data Structures
6.8.1.3 Kernel subsystem inter-process communication
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6.8.1.3.1 External interfaces (system calls)
6.8.1.3.2 Internal Interfaces
6.8.1.3.3 Data Structures
239
6.8.1.4 Kernel subsystem networking
6.8.1.4.1 External interfaces (system calls)
6.8.1.4.2 Internal interfaces
6.8.1.4.3 Data Structures
6.8.1.5 Kernel subsystem memory management
6.8.1.5.1 External interfaces (system calls)
240
6.8.1.5.2 Internal interfaces
6.8.1.5.3 Data Structures
6.8.1.6 Kernel subsystem audit
6.8.1.6.1 External interfaces
6.8.1.6.2 Internal interfaces
241
6.8.1.6.3 Data structures
6.8.1.7 Kernel subsystem device drivers 6.8.1.7.1 External interfaces (system calls)
6.8.1.7.2 Internal interfaces
243
6.8.2 Summary of trusted processes interfaces
244
7 References