CAPSH

NAME

SYNOPSIS

DESCRIPTION

OPTIONS

--print

Display prevailing capability and related state.

-- [args]

Execute /bin/bash with trailing arguments. Note, you can use -c 'command to execute' for specific commands.

==

Execute capsh again with remaining arguments. Useful for testing exec() behavior.

--caps=cap-set

Set the prevailing process capabilities to those specified by cap-set. Where cap-set is a text-representation of capability state as per cap_from_text(3).

--drop=cap-list

Remove the listed capabilities from the prevailing bounding set. The capabilities are a comma separated list of capabilities as recognized by the cap_from_name(3) function. Use of this feature requires that the capsh program is operating with CAP_SETPCAP in its effective set.

--inh=cap-list

Set the inheritable set of capabilities for the current process to equal those provided in the comma separated list. For this action to succeed, the prevailing process should already have each of these capabilities in the union of the current inheritable and permitted capability sets, or the capsh program is operating with CAP_SETPCAP in its effective set.

--user=username

Assume the identity of the named user. That is, look up the user's uid and gid with getpwuid(3) and their group memberships with getgrouplist(3) and set them all.

--uid=id

Force all uid values to equal id using the setuid(2) system call.

--gid=<id>

Force all gid values to equal id using the setgid(2) system call.

--groups=<id-list>

Set the supplementary groups to the numerical list provided. The groups are set with the setgroups(2) system call.

--keep=<0|1>

In a non-pure capability mode, the kernel provides liberal privilege to the super-user. However, it is normally the case that when the super-user changes uid to some lesser user, then capabilities are dropped. For these situations, the kernel can permit the process to retain its capabilities after a setuid(2) system call. This feature is known as keep-caps support. The way to activate it using this script is with this argument. Setting the value to 1 will cause keep-caps to be active. Setting it to 0 will cause keep-caps to deactivate for the current process. In all cases, keep-caps is deactivated when an exec() is performed. See --secbits for ways to disable this feature.

--secbits=N

XXX - need to document this feature.

--chroot=path

Execute the chroot(2) system call with the new root-directory (/) equal to path. This operation requires CAP_SYS_CHROOT to be in effect.

--forkfor=sec

--killit=sig

--decode=N

This is a convenience feature. If you look at /proc/1/status there are some capability related fields of the following form:

 CapInh:        0000000000000000

 CapPrm:        ffffffffffffffff

 CapEff:        fffffffffffffeff

 CapBnd:        ffffffffffffffff

This option provides a quick way to decode a capability vector represented in this form. For example, the missing capability from this effective set is 0x0100. By running:

 capsh --decode=0x0100

we observe that the missing capability is: cap_setpcap.

--supports=xxx

As the kernel evolves, more capabilities are added. This option can be used to verify the existence of a capability on the system. For example, --supports=cap_syslog will cause capsh to promptly exit with a status of 1 when run on kernel 2.6.27. However, when run on kernel 2.6.38 it will silently succeed.

EXIT STATUS