Re: [PATCH] audit: Add cmdline to taskinfo output

On Thu, Oct 31, 2013 at 8:46 AM, Richard Guy Briggs <rgb(a)redhat.com&gt;wrote: > On Thu, Oct 31, 2013 at 08:33:34AM -0700, William Roberts wrote: > > On Thu, Oct 31, 2013 at 8:28 AM, Richard Guy Briggs <rgb(a)redhat.com&gt; > wrote: > > > > > On Thu, Oct 31, 2013 at 08:24:11AM -0700, William Roberts wrote: > > > > On Thu, Oct 31, 2013 at 7:36 AM, Steve Grubb <sgrubb(a)redhat.com&gt; > wrote: > > > > > On Wednesday, October 30, 2013 01:18:13 PM William Roberts wrote: > > > > > > On Wed, Oct 30, 2013 at 12:42 PM, Steve Grubb < > sgrubb(a)redhat.com&gt; wrote: > > > > > > I have compiled kernels in the past with custom COMM widths, but > > > > > > the memory footprint goes up, at least here were not keeping a > > > > > > bunch of possibly unused data around in the kernel plus we're > not > > > > > > allocating anything on the common case of it being turned off. > > > > > > > > > > I don't like the idea of fields appearing and disappearing. The > > > > > complaint is "comm" is meaningless. Let's fix that. > > > > > > > > Its not that the field is disappearing, its just whether or not you > > > > want the value printed out. cmdline=(null) vs cmdline="something". > > > > That's a trivial change of not making it dynamic which is what my > > > > first patch did but Richard Briggs suggested making it a dynamic > > > > feature and I was pretty ok with that. > > > > > > Ok, so how about both fields are always present, but have some keyword > > > that is printed that indicates it is a duplicate of the other field? > > > > > > Something like cmdline=(comm) > > > > How are you going to detect that cmdlne has changed, its a region of > > memory in userspace? We would have to cmp the values, and if we cannot > > detect the transition, this gets more expensive. Also, I have yet to > > see a case where the above statement is true, so it would be a very > > infrequent event. > > Is it likely that those two point to the same region of memory? If so, > just compare the pointers. > no cmdline is mapped into the user process, cmdline is mapped into the kernel, so their virtual addresses and pa's are different (hopefully or I don't understand mmu based memory management)

> > However, their is a condition in my patch where an error will cause > > comm=(null) not to be printed, which could be > > viewed as a disappearing field. > > Would it be useful if this condition were changed to print instead > comm=(error)? > It could be, but ideally we should printk the error too.... someone can arbitrarily set their proc cmdline entry or tsk comm to something "reserved" > > > > > William C Roberts > > > > > > - RGB > > > > William C Roberts > > - RGB > > -- > Richard Guy Briggs <rbriggs(a)redhat.com&gt; > Senior Software Engineer > Kernel Security > AMER ENG Base Operating Systems > Remote, Ottawa, Canada > Voice: +1.647.777.2635 > Internal: (81) 32635 > Alt: +1.613.693.0684x3545 > -- Respectfully, William C Roberts