From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [63.128.21.124]) by sourceware.org (Postfix) with ESMTP id A4B2F389041C for ; Fri, 22 Jan 2021 12:50:08 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org A4B2F389041C Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-590--j4B8oB3OjuiOKWAV0kkHQ-1; Fri, 22 Jan 2021 07:50:04 -0500 X-MC-Unique: -j4B8oB3OjuiOKWAV0kkHQ-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 0B7C0801817; Fri, 22 Jan 2021 12:50:03 +0000 (UTC) Received: from oldenburg.str.redhat.com (ovpn-113-35.ams2.redhat.com [10.36.113.35]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 166A861F55; Fri, 22 Jan 2021 12:50:00 +0000 (UTC) From: Florian Weimer To: Adhemerval Zanella via Libc-alpha Cc: Florian Weimer , Andreas Schwab , Adhemerval Zanella Subject: Re: [PATCH] linux: mips: Fix getdents64 fallback on mips64-n32 References: <20201116211743.2228063-1-adhemerval.zanella@linaro.org> <873619gfo2.fsf@mid.deneb.enyo.de> <08cc387e-e0ec-7242-fdc6-a9b163331986@linaro.org> Date: Fri, 22 Jan 2021 13:49:59 +0100 In-Reply-To: <08cc387e-e0ec-7242-fdc6-a9b163331986@linaro.org> (Adhemerval Zanella via Libc-alpha's message of "Tue, 17 Nov 2020 10:19:09 -0300") Message-ID: <87a6t1p24o.fsf@oldenburg.str.redhat.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/27.1 (gnu/linux) MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain X-Spam-Status: No, score=-6.3 required=5.0 tests=BAYES_00, DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, KAM_NUMSUBJECT, RCVD_IN_DNSWL_LOW, RCVD_IN_MSPIKE_H4, RCVD_IN_MSPIKE_WL, 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 List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 22 Jan 2021 12:50:09 -0000 * Adhemerval Zanella via Libc-alpha: > Would it be more in line of what you have suggested? Yes, thanks. > while ((char *) kdp < (char *) skdp + r) > { > + > + /* Obtain the d_ino, d_off, and d_reclen from kernel filled buffer. */ > + struct kernel_dirent kdirent; > + memcpy (&kdirent, kdp, sizeof (struct kernel_dirent)); I believe this should use offsetof (struct kernel_dirent, d_name) for the size of the copy. Technically, the padding at the end of the struct may not be present in the buffer. > @@ -118,19 +115,19 @@ __getdents64 (int fd, void *buf, size_t nbytes) > } > nb += new_reclen; > > + struct dirent64 d64; > + d64.d_ino = kdirent.d_ino; > + d64.d_off = kdirent.d_off; > + d64.d_reclen = new_reclen; > + d64.d_type = *((char *) kdp + kdirent.d_reclen - 1); > + memcpy (d64.d_name, kdp->d_name, > + kdirent.d_reclen - offsetof (struct kernel_dirent, d_name)); > + > + memcpy (dp, &d64, new_reclen); > + last_offset = kdirent.d_off; > > dp = (struct dirent64 *) ((char *) dp + new_reclen); > + kdp = (struct kernel_dirent *) (((char *) kdp) + kdirent.d_reclen); > } I think the first memcpy is wrong: It has to go into the result buffer because only that will be large enough. 256 bytes for d_name may not be enough. The second memcpy should only copy the header (before d_name). Thanks, Florian -- Red Hat GmbH, https://de.redhat.com/ , Registered seat: Grasbrunn, Commercial register: Amtsgericht Muenchen, HRB 153243, Managing Directors: Charles Cachera, Brian Klemm, Laurie Krebs, Michael O'Neill