Re: [LTP] [PATCH] syscalls/statvfs01: Correcly zero terminate the strings

[Petr Vorel <pvorel@suse.cz>]

> Hi,

> On 18. 01. 23 14:36, Cyril Hrubis wrote:
> > Fixes random failures caused by the fact that the stack is not
> > guaranteed to be zeroed.

> > Fixes: e305ac4a305f ("statvfs01: Convert to new LTP API")
> > Signed-off-by: Cyril Hrubis <chrubis@suse.cz>
> > CC: Petr Vorel <pvorel@suse.cz>
> > CC: Richard Palethorpe <rpalethorpe@suse.com>
> > CC: Avinesh Kumar <akumar@suse.de>
> > ---
> >   testcases/kernel/syscalls/statvfs/statvfs01.c | 3 +++
> >   1 file changed, 3 insertions(+)

> > diff --git a/testcases/kernel/syscalls/statvfs/statvfs01.c b/testcases/kernel/syscalls/statvfs/statvfs01.c
> > index dd14d6a0e..f17dc4cfa 100644
> > --- a/testcases/kernel/syscalls/statvfs/statvfs01.c
> > +++ b/testcases/kernel/syscalls/statvfs/statvfs01.c
> > @@ -38,6 +38,9 @@ static void run(void)
> >   	memset(valid_fname, 'a', valid_len);
> >   	memset(toolong_fname, 'b', valid_len + 1);
> > +	valid_fname[valid_len] = 0;
> > +	toolong_fname[valid_len+1] = 0;

> Is there a possibility that valid_len could be equal to PATH_MAX-1? I think

PATH_MAX is 4096. statvfs.f_namemax is mostly 255 (only for vfat and exfat is
1530, but that's for multibyte names, the "real" length, when counting
characters is also 255).

> toolong_fname[] size should be bumped to at least PATH_MAX+1.
statvfs01.c:43:22: warning: array subscript 4097 is above array bounds of ‘char[4096]’ [-Warray-bounds]
=> PATH_MAX-1 is the maximum (array size is PATH_MAX).

Kind regards,
Petr

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