From owner-svn-src-all@FreeBSD.ORG Fri Oct 14 18:24:48 2011 Return-Path: Delivered-To: svn-src-all@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id DB96E1065673; Fri, 14 Oct 2011 18:24:48 +0000 (UTC) (envelope-from kostikbel@gmail.com) Received: from mail.zoral.com.ua (mx0.zoral.com.ua [91.193.166.200]) by mx1.freebsd.org (Postfix) with ESMTP id 288E88FC0C; Fri, 14 Oct 2011 18:24:47 +0000 (UTC) Received: from alf.home (alf.kiev.zoral.com.ua [10.1.1.177]) by mail.zoral.com.ua (8.14.2/8.14.2) with ESMTP id p9EIOho9043313 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Fri, 14 Oct 2011 21:24:43 +0300 (EEST) (envelope-from kostikbel@gmail.com) Received: from alf.home (kostik@localhost [127.0.0.1]) by alf.home (8.14.5/8.14.5) with ESMTP id p9EIOhi3039738; Fri, 14 Oct 2011 21:24:43 +0300 (EEST) (envelope-from kostikbel@gmail.com) Received: (from kostik@localhost) by alf.home (8.14.5/8.14.5/Submit) id p9EIOhoj039737; Fri, 14 Oct 2011 21:24:43 +0300 (EEST) (envelope-from kostikbel@gmail.com) X-Authentication-Warning: alf.home: kostik set sender to kostikbel@gmail.com using -f Date: Fri, 14 Oct 2011 21:24:43 +0300 From: Kostik Belousov To: Marcel Moolenaar Message-ID: <20111014182443.GP1511@deviant.kiev.zoral.com.ua> References: <201110131620.p9DGKAM2022926@svn.freebsd.org> <20111013190943.GM1511@deviant.kiev.zoral.com.ua> <201110131707.14466.jhb@freebsd.org> <20111013225030.GA75054@zim.MIT.EDU> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="Og0BsOHPNghju9eE" Content-Disposition: inline In-Reply-To: <20111013225030.GA75054@zim.MIT.EDU> User-Agent: Mutt/1.4.2.3i X-Virus-Scanned: clamav-milter 0.95.2 at skuns.kiev.zoral.com.ua X-Virus-Status: Clean X-Spam-Status: No, score=-3.3 required=5.0 tests=ALL_TRUSTED,AWL,BAYES_00, DNS_FROM_OPENWHOIS autolearn=no version=3.2.5 X-Spam-Checker-Version: SpamAssassin 3.2.5 (2008-06-10) on skuns.kiev.zoral.com.ua Cc: svn-src-head@freebsd.org, svn-src-all@freebsd.org, Marcel Moolenaar , src-committers@freebsd.org, John Baldwin Subject: Re: svn commit: r226343 - head/sys/vm X-BeenThere: svn-src-all@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: "SVN commit messages for the entire src tree \(except for " user" and " projects" \)" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 14 Oct 2011 18:24:49 -0000 --Og0BsOHPNghju9eE Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Thu, Oct 13, 2011 at 06:50:30PM -0400, David Schultz wrote: > On Thu, Oct 13, 2011, Marcel Moolenaar wrote: > >=20 > > On Oct 13, 2011, at 2:07 PM, John Baldwin wrote: > > >>=20 > > >> That's really besides the point. ABI changes are made deliberately > > >> and ABIs must be well-documented for anyone to adhere to it. You > > >> can't post hoc wave your hand and say that at some unspecified time > > >> in the past the ABI changed: at what precise time does "supported > > >> by hardware mean" and how does that tie to a major FreeBSD version? > > >>=20 > > >> Point in case: the JDK 1.4.x still works on FreeBSD 9.x (i386), so > > >> the ABI really hasn't changed at all in that respect. > > >=20 > > > I think if you booted a FreeBSD 9.x i386 PAE kernel you'd find that t= he > > > jdk did not work. That will be true for any i386 PAE kernel back to > > > when PG_NX support was introduced. > >=20 > > That's bad. After more thought about the issue, I do not agree with you. Elf specification says about the PF_R flag that only read permission for the memory image of the segment is required, but read and execute is allowed. In other words, it is a bug in the old jre, which is further confirmed by the fact that later jres run with non-executable head. >=20 > Recent binutils support a PT_GNU_HEAP flag in the ELF header that > controls whether heap allocations are executable by default. In > Linux, the flag can be set using an ld option or the execstack(8) > command. That seems like a better way to go than breaking old > JVMs or disabling the security feature. No, recent binutils do not support PT_GNU_HEAD. git grep -e PT_GNU_HEAD on the up to date checkout of binutils head gives zero matches. There are indeed PT_GNU_HEAP patches floating around from some hardening projects. There is indeed PT_GNU_STACK, which we do support. I want to commit the following refinement: diff --git a/sys/compat/freebsd32/freebsd32_misc.c b/sys/compat/freebsd32/f= reebsd32_misc.c index 6638ec8..fc2932b 100644 --- a/sys/compat/freebsd32/freebsd32_misc.c +++ b/sys/compat/freebsd32/freebsd32_misc.c @@ -445,7 +445,7 @@ freebsd32_mprotect(struct thread *td, struct freebsd32_= mprotect_args *uap) ap.len =3D uap->len; ap.prot =3D uap->prot; #if defined(__amd64__) || defined(__ia64__) - if (ap.prot & PROT_READ) + if (i386_read_exec && (ap.prot & PROT_READ) !=3D 0) ap.prot |=3D PROT_EXEC; #endif return (sys_mprotect(td, &ap)); @@ -536,7 +536,7 @@ freebsd32_mmap(struct thread *td, struct freebsd32_mmap= _args *uap) #endif =20 #if defined(__amd64__) || defined(__ia64__) - if (prot & PROT_READ) + if (i386_read_exec && (prot & PROT_READ)) prot |=3D PROT_EXEC; #endif =20 diff --git a/sys/kern/imgact_elf.c b/sys/kern/imgact_elf.c index 669c652..9970386 100644 --- a/sys/kern/imgact_elf.c +++ b/sys/kern/imgact_elf.c @@ -118,11 +118,24 @@ static int elf_legacy_coredump =3D 0; SYSCTL_INT(_debug, OID_AUTO, __elfN(legacy_coredump), CTLFLAG_RW,=20 &elf_legacy_coredump, 0, ""); =20 -static int __elfN(nxstack) =3D 0; +static int __elfN(nxstack) =3D +#if defined(__amd64__) || defined(__powerpc__) /* both 64 and 32 bit */ + 1; +#else + 0; +#endif SYSCTL_INT(__CONCAT(_kern_elf, __ELF_WORD_SIZE), OID_AUTO, nxstack, CTLFLAG_RW, &__elfN(nxstack), 0, __XSTRING(__CONCAT(ELF, __ELF_WORD_SIZE)) ": enable non-executable sta= ck"); =20 +#if __ELF_WORD_SIZE =3D=3D 32 +#if defined(__amd64__) || defined(__ia64__) +int i386_read_exec =3D 0; +SYSCTL_INT(_kern_elf32, OID_AUTO, read_exec, CTLFLAG_RW, &i386_read_exec, = 0, + "enable execution from readable segments"); +#endif +#endif + static Elf_Brandinfo *elf_brand_list[MAX_BRANDS]; =20 #define trunc_page_ps(va, ps) ((va) & ~(ps - 1)) @@ -1666,7 +1679,7 @@ __elfN(trans_prot)(Elf_Word flags) prot |=3D VM_PROT_READ; #if __ELF_WORD_SIZE =3D=3D 32 #if defined(__amd64__) || defined(__ia64__) - if (flags & PF_R) + if (i386_read_exec && (flags & PF_R)) prot |=3D VM_PROT_EXECUTE; #endif #endif diff --git a/sys/sys/sysent.h b/sys/sys/sysent.h index 6a4b485..3694ceb 100644 --- a/sys/sys/sysent.h +++ b/sys/sys/sysent.h @@ -151,6 +152,10 @@ extern struct sysentvec null_sysvec; extern struct sysent sysent[]; extern const char *syscallnames[]; =20 +#if defined(__amd64__) || defined(__ia64__) +extern int i386_read_exec; +#endif + #define NO_SYSCALL (-1) =20 struct module; diff --git a/sys/vm/vm_unix.c b/sys/vm/vm_unix.c index d4ea3b7..253ab77 100644 --- a/sys/vm/vm_unix.c +++ b/sys/vm/vm_unix.c @@ -141,7 +141,7 @@ sys_obreak(td, uap) prot =3D VM_PROT_RW; #ifdef COMPAT_FREEBSD32 #if defined(__amd64__) || defined(__ia64__) - if (SV_PROC_FLAG(td->td_proc, SV_ILP32)) + if (i386_read_exec && SV_PROC_FLAG(td->td_proc, SV_ILP32)) prot |=3D VM_PROT_EXECUTE; #endif #endif --Og0BsOHPNghju9eE Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.18 (FreeBSD) iEYEARECAAYFAk6YfmsACgkQC3+MBN1Mb4hwkACfR9VcAyVfyAMQrr1RxwUeXL72 hpYAoKjzaKTukty46YMvzOOhKjOhBPiu =7Agc -----END PGP SIGNATURE----- --Og0BsOHPNghju9eE--