NAME
capable - Trace security capability checks (cap_capable()).
SYNOPSIS
capable [-h] [-v] [-p PID] [-K] [-U] [-x] [--cgroupmap MAPPATH]
[--mntnsmap MAPPATH] [--unique]
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, bcc.
OPTIONS
-h USAGE message.
- -v
-
Include non-audit capability checks. These are those deemed not interesting and not necessary to audit, such as CAP_SYS_ADMIN checks on memory allocation to affect the behavior of overcommit.
- -K
-
Include kernel stack traces to the output.
- -U
-
Include user-space stack traces to the output.
- -x
-
Show extra fields in TID and INSETID columns.
- --cgroupmap MAPPATH
-
Trace cgroups in this BPF map only (filtered in-kernel).
- --mntnsmap MAPPATH
-
Trace mount namespaces in this BPF map only (filtered in-kernel).
- --unique
-
Don't repeat stacks for the same PID or cgroup.
EXAMPLES
- Trace all capability checks system-wide:
-
# capable
- Trace capability checks for PID 181:
-
# capable -p 181
- Trace capability checks in a set of cgroups only (see special_filtering.md
-
from bcc sources for more details): # capable --cgroupmap /sys/fs/bpf/test01
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. Use -v to include non-audit events. INSETID Whether the INSETID bit was set (Linux >= 5.1).
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 bcc.
-
https://github.com/iovisor/bcc
Also look in the bcc distribution for a companion _examples.txt file containing example usage, output, and commentary for this tool.
OS
Linux
STABILITY
Unstable - in development.
AUTHOR
Brendan Gregg