NAME¶

capable.bt - Trace security capability checks (cap_capable()).

SYNOPSIS¶

capable.bt

DESCRIPTION¶

This traces security capability checks in the kernel, and prints details for each call. This can be useful for general debugging, and also security enforcement: determining a white list of capabilities an application needs.

Since this uses BPF, only the root user can use this tool.

REQUIREMENTS¶

CONFIG_BPF, bpftrace.

EXAMPLES¶

Trace all capability checks system-wide:

# capable.bt

FIELDS¶

TIME(s)

Time of capability check: HH:MM:SS.

UID

User ID.

PID

Process ID.

COMM

Process name. CAP Capability number. NAME Capability name. See capabilities(7) for descriptions.

AUDIT

Whether this was an audit event.

OVERHEAD¶

This adds low-overhead instrumentation to capability checks, which are expected to be low frequency, however, that depends on the application. Test in a lab environment before use.

SOURCE¶

This is from bpftrace.

https://github.com/iovisor/bpftrace

Also look in the bpftrace distribution for a companion _examples.txt file containing example usage, output, and commentary for this tool.

This is a bpftrace version of the bcc tool of the same name. The bcc tool provides options to customize the output.

https://github.com/iovisor/bcc

OS¶

Linux

STABILITY¶

Unstable - in development.

AUTHOR¶

Brendan Gregg

SEE ALSO¶

capabilities(7)