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37 .Nd Capability mode system calls
45 .Fn cap_getmode "u_int *modep"
48 places the current process into capability mode, a mode of execution in which
49 processes may only issue system calls operating on file descriptors or
50 reading limited global system state.
51 Access to global name spaces, such as file system or IPC name spaces, is
53 If the process is already in a capability mode sandbox, the system call is a
55 Future process descendants created with
59 will be placed in capability mode from inception.
62 .Xr cap_rights_limit 2 ,
63 .Xr cap_ioctls_limit 2 ,
64 .Xr cap_fcntls_limit 2 ,
66 may be used to create kernel-enforced sandboxes in which
67 appropriately-crafted applications or application components may be run.
70 returns a flag indicating whether or not the process is in a capability mode
73 Creating effective process sandboxes is a tricky process that involves
74 identifying the least possible rights required by the process and then
75 passing those rights into the process in a safe manner.
78 should also be aware of other inherited rights, such as access to VM
79 resources, memory contents, and other process properties that should be
81 It is advisable to use
83 to create a runtime environment inside the sandbox that has as few implicitly
84 acquired rights as possible.
86 .Rv -std cap_enter cap_getmode
96 The kernel is compiled without:
98 .Cd "options CAPABILITY_MODE"
103 system call may also return the following error:
108 points outside the process's allocated address space.
111 .Xr cap_fcntls_limit 2 ,
112 .Xr cap_ioctls_limit 2 ,
113 .Xr cap_rights_limit 2 ,
115 .Xr cap_sandboxed 3 ,
118 Support for capabilities and capabilities mode was developed as part of the
122 These functions and the capability facility were created by
123 .An "Robert N. M. Watson"
124 at the University of Cambridge Computer Laboratory with support from a grant