[CRIU] Re: [PATCH cr] proc: add a static buffer to prevent segv

[Cyrill Gorcunov]

On Wed, May 02, 2012 at 02:46:10PM +0400, Cyrill Gorcunov wrote:
> On Wed, May 02, 2012 at 02:37:57PM +0400, Andrey Vagin wrote:
> > A few of our functions use buffer and string functions.
> > All these functions require that a string contains '\0' at the end.
> > Before this patch we didn't guarantee that.
> > 
> > I've seen segmentation fault in parse_pid_stat_small.
> > 
> > Signed-off-by: Andrey Vagin <avagin at openvz.org>
> > ---
> >  proc_parse.c |   31 +++++++++++++++++++------------
> >  1 files changed, 19 insertions(+), 12 deletions(-)
> > 
> > diff --git a/proc_parse.c b/proc_parse.c
> > index cd1e7d6..cc67fdc 100644
> > --- a/proc_parse.c
> > +++ b/proc_parse.c
> > @@ -15,11 +15,20 @@
> >  
> >  #include "proc_parse.h"
> >  
> > +struct buffer {
> > +	char buf[PAGE_SIZE];
> > +	char end; /* '\0' */
> > +};
> > +
> 
> No need to define one more struct, just make it simple
> 
> 	static char buf[PAGE_SIZE + 1];
> 
> and never read more than PAGE_SIZE. No?

Actually I've seen sigsegv as well, but it was at

parse_pid_stat
		...
		strncpy(s->comm, tok + 1, sizeof(s->comm) - 1);

	Cyrill