linux_dsm_epyc7002/security/selinux
Thiébaud Weksteen dd8166212d selinux: add tracepoint on audited events
The audit data currently captures which process and which target
is responsible for a denial. There is no data on where exactly in the
process that call occurred. Debugging can be made easier by being able to
reconstruct the unified kernel and userland stack traces [1]. Add a
tracepoint on the SELinux denials which can then be used by userland
(i.e. perf).

Although this patch could manually be added by each OS developer to
trouble shoot a denial, adding it to the kernel streamlines the
developers workflow.

It is possible to use perf for monitoring the event:
  # perf record -e avc:selinux_audited -g -a
  ^C
  # perf report -g
  [...]
      6.40%     6.40%  audited=800000 tclass=4
               |
                  __libc_start_main
                  |
                  |--4.60%--__GI___ioctl
                  |          entry_SYSCALL_64
                  |          do_syscall_64
                  |          __x64_sys_ioctl
                  |          ksys_ioctl
                  |          binder_ioctl
                  |          binder_set_nice
                  |          can_nice
                  |          capable
                  |          security_capable
                  |          cred_has_capability.isra.0
                  |          slow_avc_audit
                  |          common_lsm_audit
                  |          avc_audit_post_callback
                  |          avc_audit_post_callback
                  |

It is also possible to use the ftrace interface:
  # echo 1 > /sys/kernel/debug/tracing/events/avc/selinux_audited/enable
  # cat /sys/kernel/debug/tracing/trace
  tracer: nop
  entries-in-buffer/entries-written: 1/1   #P:8
  [...]
  dmesg-3624  [001] 13072.325358: selinux_denied: audited=800000 tclass=4

The tclass value can be mapped to a class by searching
security/selinux/flask.h. The audited value is a bit field of the
permissions described in security/selinux/av_permissions.h for the
corresponding class.

[1] https://source.android.com/devices/tech/debug/native_stack_dump

Signed-off-by: Thiébaud Weksteen <tweek@google.com>
Suggested-by: Joel Fernandes <joelaf@google.com>
Reviewed-by: Peter Enderborg <peter.enderborg@sony.com>
Acked-by: Stephen Smalley <stephen.smalley.work@gmail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2020-08-21 17:05:22 -04:00
..
include selinux: move policy commit after updating selinuxfs 2020-08-17 20:50:22 -04:00
ss selinux: fix memdup.cocci warnings 2020-08-20 08:39:05 -04:00
.gitignore .gitignore: add SPDX License Identifier 2020-03-25 11:50:48 +01:00
avc.c selinux: add tracepoint on audited events 2020-08-21 17:05:22 -04:00
hooks.c selinux: permit removing security.selinux xattr before policy load 2020-08-20 21:55:31 -04:00
ibpkey.c selinux: clean up selinux_enabled/disabled/enforcing_boot 2019-12-18 21:22:46 -05:00
Kconfig Documentation,selinux: deprecate setting checkreqprot to 1 2020-02-10 10:49:01 -05:00
Makefile selinux: hash context structure directly 2020-04-17 16:04:34 -04:00
netif.c selinux: Fix spelling mistakes in the comments 2020-07-08 12:15:52 -04:00
netlabel.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 13 2019-05-21 11:28:45 +02:00
netlink.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
netnode.c selinux: Fix spelling mistakes in the comments 2020-07-08 12:15:52 -04:00
netport.c selinux: Fix spelling mistakes in the comments 2020-07-08 12:15:52 -04:00
nlmsgtab.c net: bridge: vlan: add rtm definitions and dump support 2020-01-15 13:48:17 +01:00
selinuxfs.c selinux: Create new booleans and class dirs out of tree 2020-08-21 09:41:31 -04:00
status.c selinux: move status variables out of selinux_ss 2020-02-10 10:49:01 -05:00
xfrm.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00