Re: [PATCH] sanitize task->comm to avoid leaking escape codes

[Kees Cook <kees.cook@canonical.com>]

On Wed, Jun 23, 2010 at 11:23:35PM +0300, Alexey Dobriyan wrote:
> On Wed, Jun 23, 2010 at 09:41:45PM +0200, Oleg Nesterov wrote:
> > On 06/23, Kees Cook wrote:
>  
> > > -extern char *get_task_comm(char *to, struct task_struct *tsk);
> > > +#define get_task_comm(buf, task) get_task_comm_size(buf, sizeof(buf), task)
> > > +extern char *get_task_comm_size(char *to, size_t len, struct task_struct *tsk);
> > 
> > Oh, but this means that get_task_comm(ptr, task) doesn't work?
> 
> The number of users is so small, and everyone uses TASK_COMM_LEN,
> so maybe nothing should be done or "char buf[TASK_COMM_LEN]"?

I couldn't handle the pathological use of strncpy(dest, src, sizeof(src))
that is currently in get_task_comm; that's just asking for trouble.

If someone wants to use a ptr for get_task_comm, they would get to call
get_task_comm_size() instead?

-Kees

-- 
Kees Cook
Ubuntu Security Team