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SubjectRe: [PATCH v3 0/4] Better integrate seccomp logging and auditing
On Sun, May 6, 2018 at 7:36 PM, Kees Cook <keescook@chromium.org> wrote:
> On Sun, May 6, 2018 at 2:31 PM, Paul Moore <paul@paul-moore.com> wrote:
>> On Thu, May 3, 2018 at 9:08 PM, Tyler Hicks <tyhicks@canonical.com> wrote:
>>> Seccomp received improved logging controls in v4.14. Applications can opt into
>>> logging of "handled" actions (SECCOMP_RET_TRAP, SECCOMP_RET_TRACE,
>>> SECCOMP_RET_ERRNO) using the SECCOMP_FILTER_FLAG_LOG bit when loading filters.
>>> They can also debug filter matching with the new SECCOMP_RET_LOG action.
>>> Administrators can prevent specific actions from being logged using the
>>> kernel.seccomp.actions_logged sysctl.
>>>
>>> However, one corner case intentionally wasn't addressed in those v4.14 changes.
>>> When a process is being inspected by the audit subsystem, seccomp's decision
>>> making for logging ignores the new controls and unconditionally logs every
>>> action taken except for SECCOMP_RET_ALLOW. This isn't particularly useful since
>>> many existing applications don't intend to log handled actions due to them
>>> occurring very frequently. This amount of logging fills the audit logs without
>>> providing many benefits now that application authors have fine grained controls
>>> at their disposal.
>>>
>>> This patch set aligns the seccomp logging behavior for both audited and
>>> non-audited processes. It also emits an audit record, if auditing is enabled,
>>> when the kernel.seccomp.actions_logged sysctl is written to so that there's a
>>> paper trail when entire actions are quieted.
>>>
>>> Changes in v3:
>>> * Patch 3
>>> - Never drop a field when emitting the audit record
>>> - Use the value "?" for the actions field when an error occurred while
>>> writing to the sysctl
>>> - Use the value "?" for the actions and/or old-actions fields when a failure
>>> to translate actions to names
>>> - Use the value "(none)" for the actions and/or old-actions fields when no
>>> actions are specified
>>> + This is possible when writing an empty string to the sysctl
>>> - Update the commit message to note the new values and give an example of
>>> when an empty string is written
>>> * Patch 4
>>> - Adjust the control flow of seccomp_log() to exit early if nothing should be
>>> logged
>>>
>>> Changes in v2:
>>> * Patch 2
>>> - New patch, allowing for a configurable separator between action names
>>> * Patch 3
>>> - The value of the actions field in the audit record now uses a comma instead
>>> of a space
>>> - The value of the actions field in the audit record is no longer enclosed in
>>> quotes
>>> - audit_log_start() is called with the current processes' audit_context in
>>> audit_seccomp_actions_logged()
>>> - audit_seccomp_actions_logged() no longer records the pid, uid, auid, tty,
>>> ses, task context, comm, or executable path
>>> - The new and old value of seccomp_actions_logged is recorded in the
>>> AUDIT_CONFIG_CHANGE record
>>> - The value of the "res" field in the CONFIG_CHANGE audit record is corrected
>>> (1 indicates success, 0 failure)
>>> - Updated patch 3's commit message to reflect the updated audit record format
>>> in the examples
>>> * Patch 4
>>> - A function comment for audit_seccomp() was added to explain, among other
>>> things, that event filtering is performed in seccomp_log()
>>
>> Kees, are you still okay with v3? Also, are you okay with these
>> patches going in via the audit tree, or would you prefer to take them
>> via seccomp? I've got a slight preference for the audit tree myself,
>> but as I said before, as long as it hits Linus' tree I'm happy.
>
> Yup, it looks good. I have no tree preference, so you win! :) Please
> consider the whole series:
>
> Acked-by: Kees Cook <keescook@chromium.org>

Merged into audit/next, thanks guys.

--
paul moore
www.paul-moore.com

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