%PDF-
%PDF-
Mini Shell
Mini Shell
Demonstrations of capable, the Linux bpftrace/eBPF version.
capable traces calls to the kernel cap_capable() function, which does security
capability checks, and prints details for each call. For example:
# ./capable.bt
TIME UID PID COMM CAP NAME AUDIT
22:11:23 114 2676 snmpd 12 CAP_NET_ADMIN 1
22:11:23 0 6990 run 24 CAP_SYS_RESOURCE 1
22:11:23 0 7003 chmod 3 CAP_FOWNER 1
22:11:23 0 7003 chmod 4 CAP_FSETID 1
22:11:23 0 7005 chmod 4 CAP_FSETID 1
22:11:23 0 7005 chmod 4 CAP_FSETID 1
22:11:23 0 7006 chown 4 CAP_FSETID 1
22:11:23 0 7006 chown 4 CAP_FSETID 1
22:11:23 0 6990 setuidgid 6 CAP_SETGID 1
22:11:23 0 6990 setuidgid 6 CAP_SETGID 1
22:11:23 0 6990 setuidgid 7 CAP_SETUID 1
22:11:24 0 7013 run 24 CAP_SYS_RESOURCE 1
22:11:24 0 7026 chmod 3 CAP_FOWNER 1
22:11:24 0 7026 chmod 4 CAP_FSETID 1
22:11:24 0 7028 chmod 4 CAP_FSETID 1
22:11:24 0 7028 chmod 4 CAP_FSETID 1
22:11:24 0 7029 chown 4 CAP_FSETID 1
22:11:24 0 7029 chown 4 CAP_FSETID 1
22:11:24 0 7013 setuidgid 6 CAP_SETGID 1
22:11:24 0 7013 setuidgid 6 CAP_SETGID 1
22:11:24 0 7013 setuidgid 7 CAP_SETUID 1
22:11:25 0 7036 run 24 CAP_SYS_RESOURCE 1
22:11:25 0 7049 chmod 3 CAP_FOWNER 1
22:11:25 0 7049 chmod 4 CAP_FSETID 1
22:11:25 0 7051 chmod 4 CAP_FSETID 1
22:11:25 0 7051 chmod 4 CAP_FSETID 1
[...]
This can be useful for general debugging, and also security enforcement:
determining a whitelist of capabilities an application needs.
The output above includes various capability checks: snmpd checking
CAP_NET_ADMIN, run checking CAP_SYS_RESOURCES, then some short-lived processes
checking CAP_FOWNER, CAP_FSETID, etc.
To see what each of these capabilities does, check the capabilities(7) man
page and the kernel source.
There is another version of this tool in bcc: https://github.com/iovisor/bcc
The bcc version provides options to customize the output.
Zerion Mini Shell 1.0