From: Florian Weimer <fw@deneb.enyo.de>
To: "H.J. Lu via Libc-alpha" <libc-alpha@sourceware.org>
Subject: Re: [PATCH v2] test-strnlen.c: Check that strnlen won't go beyond the maximum length
Date: Sat, 27 Mar 2021 19:34:41 +0100 [thread overview]
Message-ID: <871rc08mym.fsf@mid.deneb.enyo.de> (raw)
In-Reply-To: <CAMe9rOoZ1PtPWdFjEn0uU6BE2haG2frA=rmueYV4cOMk1hhpRw@mail.gmail.com> (H. J. Lu via Libc-alpha's message of "Sat, 27 Mar 2021 11:09:32 -0700")
* 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.
next prev parent reply other threads:[~2021-03-27 18:34 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-27 16:24 [PATCH] " H.J. Lu
2021-03-27 17:51 ` Florian Weimer
2021-03-27 18:09 ` [PATCH v2] test-strnlen.c: " H.J. Lu
2021-03-27 18:34 ` Florian Weimer [this message]
2022-01-27 17:09 ` H.J. Lu
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