2 .\" Copyright (c) 2011, 2013 Robert N. M. Watson
3 .\" Copyright (c) 2011 Jonathan Anderson
4 .\" All rights reserved.
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7 .\" modification, are permitted provided that the following conditions
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17 .\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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34 .Nd lightweight OS capability and sandbox framework
36 .Cd "options CAPABILITY_MODE"
37 .Cd "options CAPABILITIES"
40 is a lightweight OS capability and sandbox framework implementing a hybrid
41 capability system model.
43 can be used for application and library compartmentalisation, the
44 decomposition of larger bodies of software into isolated (sandboxed)
45 components in order to implement security policies and limit the impact of
46 software vulnerabilities.
49 provides two core kernel primitives:
50 .Bl -tag -width indent
52 A process mode, entered by invoking
54 in which access to global OS namespaces (such as the file system and PID
55 namespaces) is restricted; only explicitly delegated rights, referenced by
56 memory mappings or file descriptors, may be used.
57 Once set, the flag is inherited by future children processes, and may not be
60 Limit operations that can be called on file descriptors.
61 For example, a file descriptor returned by
64 .Xr cap_rights_limit 2
69 can be called, but not
71 The complete list of the capability rights can be found in the
78 requires use of alternatives to traditional POSIX APIs in order to name
79 objects using capabilities rather than global namespaces:
80 .Bl -tag -width indent
81 .It process descriptors
82 File descriptors representing processes, allowing parent processes to manage
83 child processes without requiring access to the PID namespace; described in
86 .It anonymous shared memory
87 An extension to the POSIX shared memory API to support anonymous swap objects
88 associated with file descriptors; described in greater detail in
94 limits the valid values of some parameters to traditional APIs in order to
95 restrict access to global namespaces:
96 .Bl -tag -width indent
98 Processes can only act upon their own process ID with syscalls such as
99 .Xr cpuset_setaffinity 2 .
103 .Xr cap_fcntls_limit 2 ,
105 .Xr cap_ioctls_limit 2 ,
106 .Xr cap_rights_limit 2 ,
116 .Xr cap_rights_get 3 ,
123 and was developed at the University of Cambridge.
128 .An Robert Watson Aq Mt rwatson@FreeBSD.org
130 .An Jonathan Anderson Aq Mt jonathan@FreeBSD.org
131 at the University of Cambridge, and
132 .An Ben Laurie Aq Mt benl@FreeBSD.org
134 .An Kris Kennaway Aq Mt kris@FreeBSD.org
136 .An Pawel Jakub Dawidek Aq Mt pawel@dawidek.net .