On Thu, May 3, 2018 at 9:08 PM, Tyler Hicks <tyhicks@xxxxxxxxxxxxx> 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. -- paul moore www.paul-moore.com -- To unsubscribe from this list: send the line "unsubscribe linux-doc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
