From mboxrd@z Thu Jan 1 00:00:00 1970 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on inbox.vuxu.org X-Spam-Level: X-Spam-Status: No, score=-3.3 required=5.0 tests=MAILING_LIST_MULTI, RCVD_IN_DNSWL_MED,RCVD_IN_MSPIKE_H3,RCVD_IN_MSPIKE_WL autolearn=ham autolearn_force=no version=3.4.4 Received: (qmail 24993 invoked from network); 8 Dec 2020 19:42:08 -0000 Received: from mother.openwall.net (195.42.179.200) by inbox.vuxu.org with ESMTPUTF8; 8 Dec 2020 19:42:08 -0000 Received: (qmail 14045 invoked by uid 550); 8 Dec 2020 19:42:05 -0000 Mailing-List: contact musl-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-ID: Reply-To: musl@lists.openwall.com Received: (qmail 12109 invoked from network); 8 Dec 2020 19:39:30 -0000 Date: Tue, 8 Dec 2020 19:39:19 +0000 From: Brooks Davis To: musl@lists.openwall.com Message-ID: <20201208193919.GA5522@spindle.one-eyed-alien.net> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="huq684BweRXVnRxX" Content-Disposition: inline User-Agent: Mutt/1.9.4 (2018-02-28) Subject: [musl] out-of-bounds reads in strstr --huq684BweRXVnRxX Content-Type: text/plain; charset=us-ascii Content-Disposition: inline The strstr implementation contains the following snippet which results in out-of-bounds reads in memchr (we detect them on CHERI because we have byte-granularity bounds of small buffers): /* Fast estimate for MIN(l,63) */ size_t grow = l | 63; const unsigned char *z2 = memchr(z, 0, grow); The use of `|` means this is very much not an approximation of `MIN(l,63)`. What is actually intended here? For CheriBSD (via FreeBSD) I need a way to avoid out-of-bounds reads entirely (`MIN(l,63)` does seem to work in simple system-level testing, but given the mismatch it's unclear that's what was intended). Thanks, Brooks --huq684BweRXVnRxX Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEcBAEBAgAGBQJfz9ZlAAoJEKzQXbSebgfAMkEIAJR7mJhPOUXBuOiE/Hw7u56U mb1Ur77y+u+++ColRmHN+zvQDpEEpCRZ1C7/XX7MOjZxxPFjEzCiDU840+yOkFkL FWBORy2x0nASnQavjb5JDwddPRqoC2Lxzdm+BlX1bbCq/F4U0bwhEqZyrEbqOKrj 9Abwu8pl1vvSkJvzWxVNlCE8yTpAamXbl868ah8LEUZGawUPT1KH5VUs+3gUwhwD 0BEP7u6vneC61FERXaK1jxLwXetzcYVwX5rs0ZLpz3+Yvw9fxWEKF/bMsJekBwoS QwLcT4d9ca9YSl9Ub5qvgLqzdnBgY7eHacQYIPcY0fuHslZjImZQriRHhj8BXgk= =tn7K -----END PGP SIGNATURE----- --huq684BweRXVnRxX--