From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mout.kundenserver.de (mout.kundenserver.de [217.72.192.74]) by sourceware.org (Postfix) with ESMTPS id 252953858D28 for ; Tue, 7 Dec 2021 20:18:44 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 252953858D28 Authentication-Results: sourceware.org; dmarc=none (p=none dis=none) header.from=towo.net Authentication-Results: sourceware.org; spf=none smtp.mailfrom=towo.net Received: from [192.168.178.72] ([91.65.221.56]) by mrelayeu.kundenserver.de (mreue106 [212.227.15.183]) with ESMTPSA (Nemesis) id 1MulZl-1mc3uL3MMl-00rqsS for ; Tue, 07 Dec 2021 21:18:42 +0100 Message-ID: Date: Tue, 7 Dec 2021 21:18:42 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:91.0) Gecko/20100101 Thunderbird/91.3.2 Subject: Re: [PATCH v2] Cygwin: clipboard: Fix a bug in read(). To: cygwin-patches@cygwin.com References: <20211207140006.912-1-takashi.yano@nifty.ne.jp> From: Thomas Wolff In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Provags-ID: V03:K1:8kybO1O2a6OA+YPphmflF2m35SjE110KInoSewVX426a96JPSmA bOtS6YD9hYKTG8n1ii/dDkYwUbsXszDE2CvWAufPw4OnBcurOToeE5R3nR0X2AKoVwW51AL HMEXoCsWDGAv+ShFJR3MsKnxfIU65YNRoBDjJsnFxPmL+SsffDShzvPDGPxIuqhajLP+u/l pZILmn9H6mAFLiEzuBItw== X-UI-Out-Filterresults: notjunk:1;V03:K0:uNLWLYP+vDI=:CrFlcbglLv5eFlD7U/FCtX TiLcQToDmH/+EQBv6SyMp5yBJtDjxgHYQi19BfqwTnng4dIvvuyh5UCDPcBpNwmnbJFcT+uGg gkYf7AFF75lw1KiGRANawt9vpe0wavEB8EqMCs9igt2o29ZXX+2kZRQD0F+gLFFRVjSPJbzXH 3Uk6FAPlkNC2/55UVO/SJHHfDMm3NwB5nrs9EiV9LDa34SyDY2SNzJsJTzTP/yD4957rmAJHB Ddu1tq0E83X2brzhLVxrkMMf+NONMJdvQ53jcp6R7IvBEIiQzCaoqj2mzY3MFxU+xGUPpNPBQ zF1PLq4EZWL59jnU9oon9ErFD7RXVcIK0zD0a6XvBYgIp9EDjS38Lf7+Y6f4g2SHRA+6JBDaC 8omXACPbESLSEGHs6gBu3lyR0nb9+s5R38jfaw+VGPERpuEVo/Muk173eyCqoV2rqO+aMs5j8 u+jrrtbhNsL9j/SOhXUqZBxO2XEh8RgkBQKJmm3L4s6UKkizR6QOm0ejPERYyqdGvXgXOnHvL 52bc/cOU/TtxCiH4Gz9oILfBK2fG0SSVhugX9EPlL+ewqvvdMHsPW44hjYHieRISx90zK3jg4 e2x38TLeFeesthYqbujGUXKqrUzCW7+i97cS8NDzk8q0Zmx+HEjrFqT7aHKI7T1cAwk8GzVjK 9Xuf3qQbhW2QXugmHug/Zhewt2Uxcpda2g7LR6uESwnbuFwmbwJCi4h3pwsgfxUeYmso= X-Spam-Status: No, score=-9.7 required=5.0 tests=BAYES_00, GIT_PATCH_0, KAM_DMARC_STATUS, KAM_LAZY_DOMAIN_SECURITY, NICE_REPLY_A, RCVD_IN_DNSWL_NONE, RCVD_IN_MSPIKE_H2, SPF_HELO_NONE, SPF_NONE, TXREP autolearn=ham autolearn_force=no version=3.4.4 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on server2.sourceware.org X-BeenThere: cygwin-patches@cygwin.com X-Mailman-Version: 2.1.29 Precedence: list List-Id: Cygwin core component patch submission and discussion List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 07 Dec 2021 20:18:46 -0000 Am 07.12.2021 um 15:23 schrieb Corinna Vinschen: > On Dec 7 23:00, Takashi Yano wrote: >> - Fix a bug in fhandler_dev_clipboard::read() that the second read >> fails with 'Bad address'. >> >> Addresses: >> https://cygwin.com/pipermail/cygwin/2021-December/250141.html >> --- >> winsup/cygwin/fhandler_clipboard.cc | 2 +- >> winsup/cygwin/release/3.3.4 | 6 ++++++ >> 2 files changed, 7 insertions(+), 1 deletion(-) >> create mode 100644 winsup/cygwin/release/3.3.4 >> >> diff --git a/winsup/cygwin/fhandler_clipboard.cc b/winsup/cygwin/fhandler_clipboard.cc >> index 0b87dd352..ae10228a7 100644 >> --- a/winsup/cygwin/fhandler_clipboard.cc >> +++ b/winsup/cygwin/fhandler_clipboard.cc >> @@ -229,7 +229,7 @@ fhandler_dev_clipboard::read (void *ptr, size_t& len) >> if (pos < (off_t) clipbuf->cb_size) >> { >> ret = (len > (clipbuf->cb_size - pos)) ? clipbuf->cb_size - pos : len; >> - memcpy (ptr, &clipbuf[1] + pos , ret); >> + memcpy (ptr, (char *) &clipbuf[1] + pos, ret); > I'm always cringing a bit when I see this kind of expression. Personally > I think (ptr + offset) is easier to read than &ptr[offset], but of course > that's just me. If you agree, would it be ok to change the above to > > (char *) (clipbuf + 1) > > while you're at it? If you like the ampersand expression more, it's ok, > too, of course. Please push. In this specific case I think it's actually more confusing because of the type mangling that's intended in the clipbuf. At quick glance, it looks a bit as if the following were meant: (char *) clipbuf + 1 I'd even make it clearer like + memcpy (ptr, ((char *) &clipbuf[1]) + pos, ret); or even + memcpy (ptr, ((char *) (&clipbuf[1])) + pos, ret); Thomas