From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <fw@deneb.enyo.de>
Received: from albireo.enyo.de (albireo.enyo.de [37.24.231.21])
 by sourceware.org (Postfix) with ESMTPS id C0F64385801A
 for <libc-alpha@sourceware.org>; Sat, 27 Mar 2021 17:51:12 +0000 (GMT)
DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org C0F64385801A
Authentication-Results: sourceware.org;
 dmarc=none (p=none dis=none) header.from=deneb.enyo.de
Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=fw@deneb.enyo.de
Received: from [172.17.203.2] (port=55617 helo=deneb.enyo.de)
 by albireo.enyo.de ([172.17.140.2]) with esmtps
 (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256)
 id 1lQD5b-0002hB-Ew; Sat, 27 Mar 2021 17:51:11 +0000
Received: from fw by deneb.enyo.de with local (Exim 4.92)
 (envelope-from <fw@deneb.enyo.de>)
 id 1lQD5b-0005YQ-D4; Sat, 27 Mar 2021 18:51:11 +0100
From: Florian Weimer <fw@deneb.enyo.de>
To: "H.J. Lu via Libc-alpha" <libc-alpha@sourceware.org>
Subject: Re: [PATCH] Check that strnlen won't go beyond the maximum length
References: <20210327162449.3215538-1-hjl.tools@gmail.com>
Date: Sat, 27 Mar 2021 18:51:11 +0100
In-Reply-To: <20210327162449.3215538-1-hjl.tools@gmail.com> (H. J. Lu via
 Libc-alpha's message of "Sat, 27 Mar 2021 09:24:49 -0700")
Message-ID: <87ft0g8oz4.fsf@mid.deneb.enyo.de>
MIME-Version: 1.0
Content-Type: text/plain
X-Spam-Status: No, score=-12.1 required=5.0 tests=BAYES_00, GIT_PATCH_0,
 KAM_DMARC_STATUS, SPF_HELO_NONE, SPF_PASS,
 TXREP autolearn=ham autolearn_force=no version=3.4.2
X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on
 server2.sourceware.org
X-BeenThere: libc-alpha@sourceware.org
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: Libc-alpha mailing list <libc-alpha.sourceware.org>
List-Unsubscribe: <https://sourceware.org/mailman/options/libc-alpha>,
 <mailto:libc-alpha-request@sourceware.org?subject=unsubscribe>
List-Archive: <https://sourceware.org/pipermail/libc-alpha/>
List-Post: <mailto:libc-alpha@sourceware.org>
List-Help: <mailto:libc-alpha-request@sourceware.org?subject=help>
List-Subscribe: <https://sourceware.org/mailman/listinfo/libc-alpha>,
 <mailto:libc-alpha-request@sourceware.org?subject=subscribe>
X-List-Received-Date: Sat, 27 Mar 2021 17:51:13 -0000

* H. J. Lu via Libc-alpha:

> Run strnlen tests on strings without the null byte around the page
> boundary.
> ---
>  string/test-strnlen.c | 26 ++++++++++++++++++++++++++
>  1 file changed, 26 insertions(+)
>
> diff --git a/string/test-strnlen.c b/string/test-strnlen.c
> index 61eb521dc1..a49d93afa2 100644
> --- a/string/test-strnlen.c
> +++ b/string/test-strnlen.c
> @@ -196,6 +196,31 @@ do_page_tests (void)
>      }
>  }
>  
> +/* Tests meant to unveil fail on implementation that does not access bytes
> +   without the null character around the page boundary accordingly.  */

I don't understand the comment.  Based on it, I would have expected a
null byte at the page boundary, which is incorrectly ignored by the
implementation.

> +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, page_size);

I think this needs to use wmemset for the WIDE case, see
wcsmbs/test-wcsnlen.c.