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CAPSICUM(4)            FreeBSD Kernel Interfaces Manual            CAPSICUM(4)

NAME
     Capsicum - lightweight OS capability and sandbox framework

SYNOPSIS
     options CAPABILITY_MODE
     options CAPABILITIES
     options PROCDESC

DESCRIPTION
     Capsicum is a lightweight OS capability and sandbox framework
     implementing a hybrid capability system model.  Capsicum can be used for
     application and library compartmentalisation, the decomposition of larger
     bodies of software into isolated (sandboxed) components in order to
     implement security policies and limit the impact of software
     vulnerabilities.

     Capsicum provides two core kernel primitives:

     capability mode
             A process mode, entered by invoking cap_enter(2), in which access
             to global OS namespaces (such as the file system and PID
             namespaces) is restricted; only explicitly delegated rights,
             referenced by memory mappings or file descriptors, may be used.
             Once set, the flag is inherited by future children processes, and
             may not be cleared.

     capabilities
             File descriptors that wrap other file descriptors, masking
             operations that can be called on them; for example, a file
             descriptor returned by open(2) may be refined using cap_new(2) so
             that only read(2) and write(2) can be called, but not fchmod(2).

     In some cases, Capsicum requires use of alternatives to traditional POSIX
     APIs in order to name objects using capabilities rather than global
     namespaces:

     process descriptors
             File descriptors representing processes, allowing parent
             processes to manage child processes without requiring access to
             the PID namespace.

     anonymous shared memory
             An extension to the POSIX shared memory API to support anonymous
             swap objects associated with file descriptors.

SEE ALSO
     cap_enter(2), cap_getmode(2), cap_getrights(2), cap_new(2), fchmod(2),
     open(2), pdfork(2), pdgetpid(2), pdkill(2), pdwait4(2), read(2),
     shm_open(2), write(2)

HISTORY
     Capsicum first appeared in FreeBSD 9.0, and was developed at the
     University of Cambridge.

AUTHORS
     Capsicum was developed by Robert Watson <rwatson@FreeBSD.org> and
     Jonathan Anderson <jonathan@FreeBSD.org> at the University of Cambridge,
     and Ben Laurie <benl@FreeBSD.org> and Kris Kennaway <kris@FreeBSD.org> at
     Google, Inc.

BUGS
     Capsicum is considered experimental in FreeBSD.

FreeBSD 11.0-PRERELEASE       September 20, 2011       FreeBSD 11.0-PRERELEASE

NAME | SYNOPSIS | DESCRIPTION | SEE ALSO | HISTORY | AUTHORS | BUGS

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