* Re: [PATCH v2] test-strnlen.c: Check that strnlen won't go beyond the maximum length
[not found] ` <871rc08mym.fsf@mid.deneb.enyo.de>
@ 2022-01-27 17:09 ` H.J. Lu
0 siblings, 0 replies; only message in thread
From: H.J. Lu @ 2022-01-27 17:09 UTC (permalink / raw)
To: Florian Weimer, Libc-stable Mailing List; +Cc: H.J. Lu via Libc-alpha
On Sat, Mar 27, 2021 at 11:34 AM Florian Weimer <fw@deneb.enyo.de> wrote:
>
> * H. J. Lu via Libc-alpha:
>
> > From: "H.J. Lu" <hjl.tools@gmail.com>
> > Date: Sat, 27 Mar 2021 09:06:39 -0700
> > Subject: [PATCH v2] test-strnlen.c: Check that strnlen won't go beyond the
> > maximum length
> >
> > Place strings ending at page boundary without the null byte. If an
> > implementation goes beyond EXP_LEN, it will trigger the segfault.
> > ---
> > string/test-strnlen.c | 30 ++++++++++++++++++++++++++++++
> > 1 file changed, 30 insertions(+)
> >
> > diff --git a/string/test-strnlen.c b/string/test-strnlen.c
> > index 0293acbc71..d70faa26ab 100644
> > --- a/string/test-strnlen.c
> > +++ b/string/test-strnlen.c
> > @@ -198,6 +198,35 @@ do_page_tests (void)
> > }
> > }
> >
> > +/* Tests meant to unveil fail on implementations that access bytes
> > + beyond the maxium length. */
> > +
> > +static void
> > +do_page_2_tests (void)
> > +{
> > + size_t i, exp_len, offset;
> > + size_t last_offset = page_size / sizeof (CHAR);
> > +
> > + CHAR *s = (CHAR *) buf2;
> > + MEMSET (s, 65, last_offset);
> > +
> > + /* Place short strings ending at page boundary without the null
> > + byte. */
> > + offset = last_offset;
> > + for (i = 0; i < 128; i++)
> > + {
> > + /* Decrease offset to stress several sizes and alignments. */
> > + offset--;
> > + exp_len = last_offset - offset;
> > + FOR_EACH_IMPL (impl, 0)
> > + {
> > + /* If an implementation goes beyond EXP_LEN, it will trigger
> > + the segfault. */
> > + do_one_test (impl, (CHAR *) (s + offset), exp_len, exp_len);
> > + }
> > + }
> > +}
>
> Thanks, looks good. The comments and the commit message are much
> clearer now.
I am backporting this to release branches.
--
H.J.
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