Re: [PATCH v6 3/3] fanotify,audit: Allow audit to use the full permission event response

On Tue, Jan 17, 2023 at 4:14 PM Richard Guy Briggs <rgb(a)redhat.com&gt; wrote: > > This patch passes the full response so that the audit function can use all > of it. The audit function was updated to log the additional information in > the AUDIT_FANOTIFY record. > > Currently the only type of fanotify info that is defined is an audit > rule number, but convert it to hex encoding to future-proof the field. > Hex encoding suggested by Paul Moore <paul(a)paul-moore.com&gt;. > > The {subj,obj}_trust values are {0,1,2}, corresponding to no, yes, unknown. > > Sample records: > type=FANOTIFY msg=audit(1600385147.372:590): resp=2 fan_type=1 fan_info=3137 subj_trust=3 obj_trust=5 > type=FANOTIFY msg=audit(1659730979.839:284): resp=1 fan_type=0 fan_info=3F subj_trust=2 obj_trust=2 > > Suggested-by: Steve Grubb <sgrubb(a)redhat.com&gt; > Link: https://lore.kernel.org/r/3075502.aeNJFYEL58@x2 > Signed-off-by: Richard Guy Briggs <rgb(a)redhat.com&gt; > --- > fs/notify/fanotify/fanotify.c | 3 ++- > include/linux/audit.h | 9 +++++---- > kernel/auditsc.c | 16 +++++++++++++--- > 3 files changed, 20 insertions(+), 8 deletions(-) ... > diff --git a/kernel/auditsc.c b/kernel/auditsc.c > index d1fb821de104..3133c4175c15 100644 > --- a/kernel/auditsc.c > +++ b/kernel/auditsc.c > @@ -2877,10 +2878,19 @@ void __audit_log_kern_module(char *name) > context->type = AUDIT_KERN_MODULE; > } > > -void __audit_fanotify(u32 response) > +void __audit_fanotify(u32 response, struct fanotify_response_info_audit_rule *friar) > { > - audit_log(audit_context(), GFP_KERNEL, > - AUDIT_FANOTIFY, "resp=%u", response); > + /* {subj,obj}_trust values are {0,1,2}: no,yes,unknown */ > + if (friar->hdr.type == FAN_RESPONSE_INFO_NONE) { > + audit_log(audit_context(), GFP_KERNEL, AUDIT_FANOTIFY, > + "resp=%u fan_type=%u fan_info=3F subj_trust=2 obj_trust=2", > + response, FAN_RESPONSE_INFO_NONE); > + return; > + } > + audit_log(audit_context(), GFP_KERNEL, AUDIT_FANOTIFY, > + "resp=%u fan_type=%u fan_info=%X subj_trust=%u obj_trust=%u", > + response, friar->hdr.type, friar->rule_number, > + friar->subj_trust, friar->obj_trust); > } The only thing that comes to mind might be to convert the if-return into a switch statement to make it a bit cleaner and easier to patch in the future, but that is soooo far removed from any real concern that I debated even mentioning it. I only bring it up in case the "3F" discussion results in a respin, and even then I'm not going to hold my ACK over something as silly as a if-return vs switch. For clarity, this is what I was thinking: void __audit_fanontify(...) { switch (type) { case FAN_RESPONSE_INFO_NONE: audit_log(...); break; default: audit_log(...); } }

paul-moore.com