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NAME

     Capability rights — Capsicum capability rights for file descriptors

DESCRIPTION

     When a file descriptor is created by a function such as accept(2), accept4(2), fhopen(2),
     kqueue(2), mq_open(2), open(2), openat(2), pdfork(2), pipe(2), shm_open(2), socket(2) or
     socketpair(2), it is assigned all capability rights.  Those rights can be reduced (but never
     expanded) by using the cap_rights_limit(2), cap_fcntls_limit(2) and cap_ioctls_limit(2)
     system calls.  Once capability rights are reduced, operations on the file descriptor will be
     limited to those permitted by rights.

     The complete list of capability rights is provided below.  The cap_rights_t type is used to
     store list of capability rights.  The cap_rights_init(3) family of functions should be used
     to manage the structure.

RIGHTS

     The following rights may be specified in a rights mask:

     CAP_ACCEPT           Permit accept(2) and accept4(2).

     CAP_ACL_CHECK        Permit acl_valid_fd_np(3).

     CAP_ACL_DELETE       Permit acl_delete_fd_np(3).

     CAP_ACL_GET          Permit acl_get_fd(3) and acl_get_fd_np(3).

     CAP_ACL_SET          Permit acl_set_fd(3) and acl_set_fd_np(3).

     CAP_BIND             When not in capabilities mode, permit bind(2) and bindat(2) with
                          special value AT_FDCWD in the fd parameter.  Note that sockets can also
                          become bound implicitly as a result of connect(2) or send(2), and that
                          socket options set with setsockopt(2) may also affect binding behavior.

     CAP_BINDAT           Permit bindat(2).  This right has to be present on the directory
                          descriptor.  This right includes the CAP_LOOKUP right.

     CAP_CHFLAGSAT        An alias to CAP_FCHFLAGS and CAP_LOOKUP.

     CAP_CONNECT          When not in capabilities mode, permit connect(2) and connectat(2) with
                          special value AT_FDCWD in the fd parameter.  This right is also
                          required for sendto(2) with a non-NULL destination address.

     CAP_CONNECTAT        Permit connectat(2).  This right has to be present on the directory
                          descriptor.  This right includes the CAP_LOOKUP right.

     CAP_CREATE           Permit openat(2) with the O_CREAT flag.

     CAP_EVENT            Permit select(2), poll(2), and kevent(2) to be used in monitoring the
                          file descriptor for events.

     CAP_EXTATTR_DELETE   Permit extattr_delete_fd(2).

     CAP_EXTATTR_GET      Permit extattr_get_fd(2).

     CAP_EXTATTR_LIST     Permit extattr_list_fd(2).

     CAP_EXTATTR_SET      Permit extattr_set_fd(2).

     CAP_FCHDIR           Permit fchdir(2).

     CAP_FCHFLAGS         Permit fchflags(2) and chflagsat(2) if the CAP_LOOKUP right is also
                          present.

     CAP_FCHMOD           Permit fchmod(2) and fchmodat(2) if the CAP_LOOKUP right is also
                          present.

     CAP_FCHMODAT         An alias to CAP_FCHMOD and CAP_LOOKUP.

     CAP_FCHOWN           Permit fchown(2) and fchownat(2) if the CAP_LOOKUP right is also
                          present.

     CAP_FCHOWNAT         An alias to CAP_FCHOWN and CAP_LOOKUP.

     CAP_FCNTL            Permit fcntl(2).  Note that only the F_GETFL, F_SETFL, F_GETOWN and
                          F_SETOWN commands require this capability right.  Also note that the
                          list of permitted commands can be further limited with the
                          cap_fcntls_limit(2) system call.

     CAP_FEXECVE          Permit fexecve(2) and openat(2) with the O_EXEC flag; CAP_READ is also
                          required.

     CAP_FLOCK            Permit flock(2), fcntl(2) (with F_GETLK, F_SETLK, F_SETLKW or
                          F_SETLK_REMOTE flag) and openat(2) (with O_EXLOCK or O_SHLOCK flag).

     CAP_FPATHCONF        Permit fpathconf(2).

     CAP_FSCK             Permit UFS background-fsck operations on the descriptor.

     CAP_FSTAT            Permit fstat(2) and fstatat(2) if the CAP_LOOKUP right is also present.

     CAP_FSTATAT          An alias to CAP_FSTAT and CAP_LOOKUP.

     CAP_FSTATFS          Permit fstatfs(2).

     CAP_FSYNC            Permit aio_fsync(2), fdatasync(2), fsync(2) and openat(2) with O_FSYNC
                          or O_SYNC flag.

     CAP_FTRUNCATE        Permit ftruncate(2) and openat(2) with the O_TRUNC flag.

     CAP_FUTIMES          Permit futimens(2) and futimes(2), and permit futimesat(2) and
                          utimensat(2) if the CAP_LOOKUP right is also present.

     CAP_FUTIMESAT        An alias to CAP_FUTIMES and CAP_LOOKUP.

     CAP_GETPEERNAME      Permit getpeername(2).

     CAP_GETSOCKNAME      Permit getsockname(2).

     CAP_GETSOCKOPT       Permit getsockopt(2).

     CAP_IOCTL            Permit ioctl(2).  Be aware that this system call has enormous scope,
                          including potentially global scope for some objects.  The list of
                          permitted ioctl commands can be further limited with the
                          cap_ioctls_limit(2) system call.

     CAP_KQUEUE           An alias to CAP_KQUEUE_CHANGE and CAP_KQUEUE_EVENT.

     CAP_KQUEUE_CHANGE    Permit kevent(2) on a kqueue(2) descriptor that modifies list of
                          monitored events (the changelist argument is non-NULL).

     CAP_KQUEUE_EVENT     Permit kevent(2) on a kqueue(2) descriptor that monitors events (the
                          eventlist argument is non-NULL).  CAP_EVENT is also required on file
                          descriptors that will be monitored using kevent(2).

     CAP_LINKAT_SOURCE    Permit linkat(2) on the source directory descriptor.  This right
                          includes the CAP_LOOKUP right.

                          Warning: CAP_LINKAT_SOURCE makes it possible to link files in a
                          directory for which file descriptors exist that have additional rights.
                          For example, a file stored in a directory that does not allow CAP_READ
                          may be linked in another directory that does allow CAP_READ, thereby
                          granting read access to a file that is otherwise unreadable.

     CAP_LINKAT_TARGET    Permit linkat(2) on the target directory descriptor.  This right
                          includes the CAP_LOOKUP right.

     CAP_LISTEN           Permit listen(2); not much use (generally) without CAP_BIND.

     CAP_LOOKUP           Permit the file descriptor to be used as a starting directory for calls
                          such as linkat(2), openat(2), and unlinkat(2).

     CAP_MAC_GET          Permit mac_get_fd(3).

     CAP_MAC_SET          Permit mac_set_fd(3).

     CAP_MKDIRAT          Permit mkdirat(2).  This right includes the CAP_LOOKUP right.

     CAP_MKFIFOAT         Permit mkfifoat(2).  This right includes the CAP_LOOKUP right.

     CAP_MKNODAT          Permit mknodat(2).  This right includes the CAP_LOOKUP right.

     CAP_MMAP             Permit mmap(2) with the PROT_NONE protection.

     CAP_MMAP_R           Permit mmap(2) with the PROT_READ protection.  This right includes the
                          CAP_READ and CAP_SEEK rights.

     CAP_MMAP_RW          An alias to CAP_MMAP_R and CAP_MMAP_W.

     CAP_MMAP_RWX         An alias to CAP_MMAP_R, CAP_MMAP_W and CAP_MMAP_X.

     CAP_MMAP_RX          An alias to CAP_MMAP_R and CAP_MMAP_X.

     CAP_MMAP_W           Permit mmap(2) with the PROT_WRITE protection.  This right includes the
                          CAP_WRITE and CAP_SEEK rights.

     CAP_MMAP_WX          An alias to CAP_MMAP_W and CAP_MMAP_X.

     CAP_MMAP_X           Permit mmap(2) with the PROT_EXEC protection.  This right includes the
                          CAP_SEEK right.

     CAP_PDGETPID         Permit pdgetpid(2).

     CAP_PDKILL           Permit pdkill(2).

     CAP_PDWAIT           Permit pdwait4(2).

     CAP_PEELOFF          Permit sctp_peeloff(2).

     CAP_PREAD            An alias to CAP_READ and CAP_SEEK.

     CAP_PWRITE           An alias to CAP_SEEK and CAP_WRITE.

     CAP_READ             Permit aio_read(2) (CAP_SEEK is also required), openat(2) with the
                          O_RDONLY flag, read(2), readv(2), recv(2), recvfrom(2), recvmsg(2),
                          pread(2) (CAP_SEEK is also required), preadv(2) (CAP_SEEK is also
                          required) and related system calls.

     CAP_RECV             An alias to CAP_READ.

     CAP_RENAMEAT_SOURCE  Permit renameat(2) on the source directory descriptor.  This right
                          includes the CAP_LOOKUP right.

                          Warning: CAP_RENAMEAT_SOURCE makes it possible to move files to a
                          directory for which file descriptors exist that have additional rights.
                          For example, a file stored in a directory that does not allow CAP_READ
                          may be moved to another directory that does allow CAP_READ, thereby
                          granting read access to a file that is otherwise unreadable.

     CAP_RENAMEAT_TARGET  Permit renameat(2) on the target directory descriptor.  This right
                          includes the CAP_LOOKUP right.

     CAP_SEEK             Permit operations that seek on the file descriptor, such as lseek(2),
                          but also required for I/O system calls that can read or write at any
                          position in the file, such as pread(2) and pwrite(2).

     CAP_SEM_GETVALUE     Permit sem_getvalue(3).

     CAP_SEM_POST         Permit sem_post(3).

     CAP_SEM_WAIT         Permit sem_wait(3) and sem_trywait(3).

     CAP_SEND             An alias to CAP_WRITE.

     CAP_SETSOCKOPT       Permit setsockopt(2); this controls various aspects of socket behavior
                          and may affect binding, connecting, and other behaviors with global
                          scope.

     CAP_SHUTDOWN         Permit explicit shutdown(2); closing the socket will also generally
                          shut down any connections on it.

     CAP_SYMLINKAT        Permit symlinkat(2).  This right includes the CAP_LOOKUP right.

     CAP_TTYHOOK          Allow configuration of TTY hooks, such as snp(4), on the file
                          descriptor.

     CAP_UNLINKAT         Permit unlinkat(2) and renameat(2).  This right is only required for
                          renameat(2) on the destination directory descriptor if the destination
                          object already exists and will be removed by the rename.  This right
                          includes the CAP_LOOKUP right.

     CAP_WRITE            Allow aio_write(2), openat(2) with O_WRONLY and O_APPEND flags set,
                          send(2), sendmsg(2), sendto(2), write(2), writev(2), pwrite(2),
                          pwritev(2) and related system calls.  For sendto(2) with a non-NULL
                          connection address, CAP_CONNECT is also required.  For openat(2) with
                          the O_WRONLY flag, but without the O_APPEND flag, CAP_SEEK is also
                          required.  For aio_write(2), pwrite(2) and pwritev(2) CAP_SEEK is also
                          required.

SEE ALSO

     accept(2), accept4(2), aio_fsync(2), aio_read(2), aio_write(2), bind(2), bindat(2),
     cap_enter(2), cap_fcntls_limit(2), cap_ioctls_limit(2), cap_rights_limit(2), chflagsat(2),
     connect(2), connectat(2), extattr_delete_fd(2), extattr_get_fd(2), extattr_list_fd(2),
     extattr_set_fd(2), fchflags(2), fchmod(2), fchmodat(2), fchown(2), fchownat(2), fcntl(2),
     fexecve(2), fhopen(2), flock(2), fpathconf(2), fstat(2), fstatat(2), fstatfs(2), fsync(2),
     ftruncate(2), futimes(2), getpeername(2), getsockname(2), getsockopt(2), ioctl(2),
     kevent(2), kqueue(2), linkat(2), listen(2), mmap(2), mq_open(2), open(2), openat(2),
     pdfork(2), pdgetpid(2), pdkill(2), pdwait4(2), pipe(2), poll(2), pread(2), preadv(2),
     pwrite(2), pwritev(2), read(2), readv(2), recv(2), recvfrom(2), recvmsg(2), renameat(2),
     sctp_peeloff(2), select(2), send(2), sendmsg(2), sendto(2), setsockopt(2), shm_open(2),
     shutdown(2), socket(2), socketpair(2), symlinkat(2), unlinkat(2), write(2), writev(2),
     acl_delete_fd_np(3), acl_get_fd(3), acl_get_fd_np(3), acl_set_fd(3), acl_set_fd_np(3),
     acl_valid_fd_np(3), mac_get_fd(3), mac_set_fd(3), sem_getvalue(3), sem_post(3),
     sem_trywait(3), sem_wait(3), capsicum(4), snp(4)

HISTORY

     Support for capabilities and capabilities mode was developed as part of the TrustedBSD
     Project.

AUTHORS

     This manual page was created by Pawel Jakub Dawidek <pawel@dawidek.net> under sponsorship
     from the FreeBSD Foundation based on the cap_new(2) manual page by Robert Watson
     <rwatson@FreeBSD.org>.