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 17967 invoked from network); 10 Jun 2020 10:31:18 -0000 Received: from mother.openwall.net (195.42.179.200) by inbox.vuxu.org with ESMTPUTF8; 10 Jun 2020 10:31:18 -0000 Received: (qmail 20249 invoked by uid 550); 10 Jun 2020 10:31:14 -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 20228 invoked from network); 10 Jun 2020 10:31:14 -0000 Date: Wed, 10 Jun 2020 12:31:02 +0200 From: Szabolcs Nagy To: Norbert Lange Cc: musl@lists.openwall.com Message-ID: <20200610103102.GF871552@port70.net> Mail-Followup-To: Norbert Lange , musl@lists.openwall.com References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Subject: Re: [musl] Mark stack as non-executable in asm * Norbert Lange [2020-06-10 11:24:04 +0200]: > I did borrow some assembler files to avoid having to link against > (any) libc. That was for building a DSO, ultimately loaded via glibc. > The effect was that glibc did change the protection of all stacks to > be executable. > > Would you consider adding the line [1] > .section .note.GNU-stack, "", %progbits > to assembly files? > > I know this is not a musl bug, and I can easily add the lines myself. musl build system (just like other libcs i know of) pass -noexecstack to the assembler so if you build the asm files as part of libc the object files should have the marking, if you build outside of libc i think it's your responsibility to add the note (either to the asm or via the -Wa,-noexecstack flag) readelf -lW libfoo.so | grep GNU_STACK is one way to verify that everything has the note. > > regards, Norbert > > [1] - https://wiki.ubuntu.com/SecurityTeam/Roadmap/ExecutableStacks