From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 346A4C55191 for ; Sat, 25 Apr 2020 11:08:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0A64D21835 for ; Sat, 25 Apr 2020 11:08:58 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="diIn7P8W" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726241AbgDYLI5 (ORCPT ); Sat, 25 Apr 2020 07:08:57 -0400 Received: from us-smtp-delivery-1.mimecast.com ([205.139.110.120]:43191 "EHLO us-smtp-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726154AbgDYLI4 (ORCPT ); Sat, 25 Apr 2020 07:08:56 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1587812933; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=mG0Arhf9BVAVDIk0gG0JwBRFn04BBHju3Psf8PqszuA=; b=diIn7P8WVOI7ioOrEnAY5XdagChLCGwwgV/my4Pd4bydBLDokVjPKz64XXr9hr8WkWGJhu l0HArkz83LOf6brispYcamXOo08csiG29Gj7kTAyntqNim75zVgChegI+2oUqZwul3jYbj t+2esgGsghIfn0N+kf/hkLQWzfTSY8I= 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-324-1TKlw0WbMtuAYE05-EIyOA-1; Sat, 25 Apr 2020 07:08:50 -0400 X-MC-Unique: 1TKlw0WbMtuAYE05-EIyOA-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 5BD631800D4A; Sat, 25 Apr 2020 11:08:49 +0000 (UTC) Received: from treble.redhat.com (ovpn-114-29.rdu2.redhat.com [10.10.114.29]) by smtp.corp.redhat.com (Postfix) with ESMTP id 3A4015C1D6; Sat, 25 Apr 2020 11:08:44 +0000 (UTC) From: Josh Poimboeuf To: live-patching@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Peter Zijlstra , Jessica Yu , Joe Lawrence , linux-s390@vger.kernel.org, Gerald Schaefer , Christian Borntraeger Subject: [PATCH v3 06/10] s390/module: Use s390_kernel_write() for late relocations Date: Sat, 25 Apr 2020 06:07:26 -0500 Message-Id: <318ddaed3f4e861dc16d6726d7877e6509c94ad5.1587812518.git.jpoimboe@redhat.com> In-Reply-To: References: MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 Content-Transfer-Encoding: quoted-printable Sender: live-patching-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: live-patching@vger.kernel.org From: Peter Zijlstra Because of late module patching, a livepatch module needs to be able to apply some of its relocations well after it has been loaded. Instead of playing games with module_{dis,en}able_ro(), use existing text poking mechanisms to apply relocations after module loading. So far only x86, s390 and Power have HAVE_LIVEPATCH but only the first two also have STRICT_MODULE_RWX. This will allow removal of the last module_disable_ro() usage in livepatch. The ultimate goal is to completely disallow making executable mappings writable. [ jpoimboe: Split up patches. Use mod state to determine whether memcpy() can be used. Test and add fixes. ] Cc: linux-s390@vger.kernel.org Cc: Heiko Carstens heiko.carstens@de.ibm.com Cc: Gerald Schaefer Cc: Christian Borntraeger Suggested-by: Josh Poimboeuf Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Josh Poimboeuf Acked-by: Peter Zijlstra (Intel) --- arch/s390/kernel/module.c | 147 +++++++++++++++++++++++--------------- 1 file changed, 88 insertions(+), 59 deletions(-) diff --git a/arch/s390/kernel/module.c b/arch/s390/kernel/module.c index ba8f19bb438b..4055f1c49814 100644 --- a/arch/s390/kernel/module.c +++ b/arch/s390/kernel/module.c @@ -19,6 +19,7 @@ #include #include #include +#include #include #include #include @@ -174,10 +175,12 @@ int module_frob_arch_sections(Elf_Ehdr *hdr, Elf_Sh= dr *sechdrs, } =20 static int apply_rela_bits(Elf_Addr loc, Elf_Addr val, - int sign, int bits, int shift) + int sign, int bits, int shift, + void *(*write)(void *dest, const void *src, size_t len)) { unsigned long umax; long min, max; + void *dest =3D (void *)loc; =20 if (val & ((1UL << shift) - 1)) return -ENOEXEC; @@ -194,26 +197,33 @@ static int apply_rela_bits(Elf_Addr loc, Elf_Addr v= al, return -ENOEXEC; } =20 - if (bits =3D=3D 8) - *(unsigned char *) loc =3D val; - else if (bits =3D=3D 12) - *(unsigned short *) loc =3D (val & 0xfff) | + if (bits =3D=3D 8) { + unsigned char tmp =3D val; + write(dest, &tmp, 1); + } else if (bits =3D=3D 12) { + unsigned short tmp =3D (val & 0xfff) | (*(unsigned short *) loc & 0xf000); - else if (bits =3D=3D 16) - *(unsigned short *) loc =3D val; - else if (bits =3D=3D 20) - *(unsigned int *) loc =3D (val & 0xfff) << 16 | - (val & 0xff000) >> 4 | - (*(unsigned int *) loc & 0xf00000ff); - else if (bits =3D=3D 32) - *(unsigned int *) loc =3D val; - else if (bits =3D=3D 64) - *(unsigned long *) loc =3D val; + write(dest, &tmp, 2); + } else if (bits =3D=3D 16) { + unsigned short tmp =3D val; + write(dest, &tmp, 2); + } else if (bits =3D=3D 20) { + unsigned int tmp =3D (val & 0xfff) << 16 | + (val & 0xff000) >> 4 | (*(unsigned int *) loc & 0xf00000ff); + write(dest, &tmp, 4); + } else if (bits =3D=3D 32) { + unsigned int tmp =3D val; + write(dest, &tmp, 4); + } else if (bits =3D=3D 64) { + unsigned long tmp =3D val; + write(dest, &tmp, 8); + } return 0; } =20 static int apply_rela(Elf_Rela *rela, Elf_Addr base, Elf_Sym *symtab, - const char *strtab, struct module *me) + const char *strtab, struct module *me, + void *(*write)(void *dest, const void *src, size_t len)) { struct mod_arch_syminfo *info; Elf_Addr loc, val; @@ -241,17 +251,17 @@ static int apply_rela(Elf_Rela *rela, Elf_Addr base= , Elf_Sym *symtab, case R_390_64: /* Direct 64 bit. */ val +=3D rela->r_addend; if (r_type =3D=3D R_390_8) - rc =3D apply_rela_bits(loc, val, 0, 8, 0); + rc =3D apply_rela_bits(loc, val, 0, 8, 0, write); else if (r_type =3D=3D R_390_12) - rc =3D apply_rela_bits(loc, val, 0, 12, 0); + rc =3D apply_rela_bits(loc, val, 0, 12, 0, write); else if (r_type =3D=3D R_390_16) - rc =3D apply_rela_bits(loc, val, 0, 16, 0); + rc =3D apply_rela_bits(loc, val, 0, 16, 0, write); else if (r_type =3D=3D R_390_20) - rc =3D apply_rela_bits(loc, val, 1, 20, 0); + rc =3D apply_rela_bits(loc, val, 1, 20, 0, write); else if (r_type =3D=3D R_390_32) - rc =3D apply_rela_bits(loc, val, 0, 32, 0); + rc =3D apply_rela_bits(loc, val, 0, 32, 0, write); else if (r_type =3D=3D R_390_64) - rc =3D apply_rela_bits(loc, val, 0, 64, 0); + rc =3D apply_rela_bits(loc, val, 0, 64, 0, write); break; case R_390_PC16: /* PC relative 16 bit. */ case R_390_PC16DBL: /* PC relative 16 bit shifted by 1. */ @@ -260,15 +270,15 @@ static int apply_rela(Elf_Rela *rela, Elf_Addr base= , Elf_Sym *symtab, case R_390_PC64: /* PC relative 64 bit. */ val +=3D rela->r_addend - loc; if (r_type =3D=3D R_390_PC16) - rc =3D apply_rela_bits(loc, val, 1, 16, 0); + rc =3D apply_rela_bits(loc, val, 1, 16, 0, write); else if (r_type =3D=3D R_390_PC16DBL) - rc =3D apply_rela_bits(loc, val, 1, 16, 1); + rc =3D apply_rela_bits(loc, val, 1, 16, 1, write); else if (r_type =3D=3D R_390_PC32DBL) - rc =3D apply_rela_bits(loc, val, 1, 32, 1); + rc =3D apply_rela_bits(loc, val, 1, 32, 1, write); else if (r_type =3D=3D R_390_PC32) - rc =3D apply_rela_bits(loc, val, 1, 32, 0); + rc =3D apply_rela_bits(loc, val, 1, 32, 0, write); else if (r_type =3D=3D R_390_PC64) - rc =3D apply_rela_bits(loc, val, 1, 64, 0); + rc =3D apply_rela_bits(loc, val, 1, 64, 0, write); break; case R_390_GOT12: /* 12 bit GOT offset. */ case R_390_GOT16: /* 16 bit GOT offset. */ @@ -283,33 +293,33 @@ static int apply_rela(Elf_Rela *rela, Elf_Addr base= , Elf_Sym *symtab, case R_390_GOTPLT64: /* 64 bit offset to jump slot. */ case R_390_GOTPLTENT: /* 32 bit rel. offset to jump slot >> 1. */ if (info->got_initialized =3D=3D 0) { - Elf_Addr *gotent; + Elf_Addr *gotent =3D me->core_layout.base + + me->arch.got_offset + + info->got_offset; =20 - gotent =3D me->core_layout.base + me->arch.got_offset + - info->got_offset; - *gotent =3D val; + write(gotent, &val, sizeof(*gotent)); info->got_initialized =3D 1; } val =3D info->got_offset + rela->r_addend; if (r_type =3D=3D R_390_GOT12 || r_type =3D=3D R_390_GOTPLT12) - rc =3D apply_rela_bits(loc, val, 0, 12, 0); + rc =3D apply_rela_bits(loc, val, 0, 12, 0, write); else if (r_type =3D=3D R_390_GOT16 || r_type =3D=3D R_390_GOTPLT16) - rc =3D apply_rela_bits(loc, val, 0, 16, 0); + rc =3D apply_rela_bits(loc, val, 0, 16, 0, write); else if (r_type =3D=3D R_390_GOT20 || r_type =3D=3D R_390_GOTPLT20) - rc =3D apply_rela_bits(loc, val, 1, 20, 0); + rc =3D apply_rela_bits(loc, val, 1, 20, 0, write); else if (r_type =3D=3D R_390_GOT32 || r_type =3D=3D R_390_GOTPLT32) - rc =3D apply_rela_bits(loc, val, 0, 32, 0); + rc =3D apply_rela_bits(loc, val, 0, 32, 0, write); else if (r_type =3D=3D R_390_GOT64 || r_type =3D=3D R_390_GOTPLT64) - rc =3D apply_rela_bits(loc, val, 0, 64, 0); + rc =3D apply_rela_bits(loc, val, 0, 64, 0, write); else if (r_type =3D=3D R_390_GOTENT || r_type =3D=3D R_390_GOTPLTENT) { val +=3D (Elf_Addr) me->core_layout.base - loc; - rc =3D apply_rela_bits(loc, val, 1, 32, 1); + rc =3D apply_rela_bits(loc, val, 1, 32, 1, write); } break; case R_390_PLT16DBL: /* 16 bit PC rel. PLT shifted by 1. */ @@ -320,25 +330,29 @@ static int apply_rela(Elf_Rela *rela, Elf_Addr base= , Elf_Sym *symtab, case R_390_PLTOFF32: /* 32 bit offset from GOT to PLT. */ case R_390_PLTOFF64: /* 16 bit offset from GOT to PLT. */ if (info->plt_initialized =3D=3D 0) { - unsigned int *ip; - ip =3D me->core_layout.base + me->arch.plt_offset + - info->plt_offset; - ip[0] =3D 0x0d10e310; /* basr 1,0 */ - ip[1] =3D 0x100a0004; /* lg 1,10(1) */ + unsigned int insn[5]; + unsigned int *ip =3D me->core_layout.base + + me->arch.plt_offset + + info->plt_offset; + + insn[0] =3D 0x0d10e310; /* basr 1,0 */ + insn[1] =3D 0x100a0004; /* lg 1,10(1) */ if (IS_ENABLED(CONFIG_EXPOLINE) && !nospec_disable) { unsigned int *ij; ij =3D me->core_layout.base + me->arch.plt_offset + me->arch.plt_size - PLT_ENTRY_SIZE; - ip[2] =3D 0xa7f40000 + /* j __jump_r1 */ + insn[2] =3D 0xa7f40000 + /* j __jump_r1 */ (unsigned int)(u16) (((unsigned long) ij - 8 - (unsigned long) ip) / 2); } else { - ip[2] =3D 0x07f10000; /* br %r1 */ + insn[2] =3D 0x07f10000; /* br %r1 */ } - ip[3] =3D (unsigned int) (val >> 32); - ip[4] =3D (unsigned int) val; + insn[3] =3D (unsigned int) (val >> 32); + insn[4] =3D (unsigned int) val; + + write(ip, insn, sizeof(insn)); info->plt_initialized =3D 1; } if (r_type =3D=3D R_390_PLTOFF16 || @@ -357,17 +371,17 @@ static int apply_rela(Elf_Rela *rela, Elf_Addr base= , Elf_Sym *symtab, val +=3D rela->r_addend - loc; } if (r_type =3D=3D R_390_PLT16DBL) - rc =3D apply_rela_bits(loc, val, 1, 16, 1); + rc =3D apply_rela_bits(loc, val, 1, 16, 1, write); else if (r_type =3D=3D R_390_PLTOFF16) - rc =3D apply_rela_bits(loc, val, 0, 16, 0); + rc =3D apply_rela_bits(loc, val, 0, 16, 0, write); else if (r_type =3D=3D R_390_PLT32DBL) - rc =3D apply_rela_bits(loc, val, 1, 32, 1); + rc =3D apply_rela_bits(loc, val, 1, 32, 1, write); else if (r_type =3D=3D R_390_PLT32 || r_type =3D=3D R_390_PLTOFF32) - rc =3D apply_rela_bits(loc, val, 0, 32, 0); + rc =3D apply_rela_bits(loc, val, 0, 32, 0, write); else if (r_type =3D=3D R_390_PLT64 || r_type =3D=3D R_390_PLTOFF64) - rc =3D apply_rela_bits(loc, val, 0, 64, 0); + rc =3D apply_rela_bits(loc, val, 0, 64, 0, write); break; case R_390_GOTOFF16: /* 16 bit offset to GOT. */ case R_390_GOTOFF32: /* 32 bit offset to GOT. */ @@ -375,20 +389,20 @@ static int apply_rela(Elf_Rela *rela, Elf_Addr base= , Elf_Sym *symtab, val =3D val + rela->r_addend - ((Elf_Addr) me->core_layout.base + me->arch.got_offset); if (r_type =3D=3D R_390_GOTOFF16) - rc =3D apply_rela_bits(loc, val, 0, 16, 0); + rc =3D apply_rela_bits(loc, val, 0, 16, 0, write); else if (r_type =3D=3D R_390_GOTOFF32) - rc =3D apply_rela_bits(loc, val, 0, 32, 0); + rc =3D apply_rela_bits(loc, val, 0, 32, 0, write); else if (r_type =3D=3D R_390_GOTOFF64) - rc =3D apply_rela_bits(loc, val, 0, 64, 0); + rc =3D apply_rela_bits(loc, val, 0, 64, 0, write); break; case R_390_GOTPC: /* 32 bit PC relative offset to GOT. */ case R_390_GOTPCDBL: /* 32 bit PC rel. off. to GOT shifted by 1. */ val =3D (Elf_Addr) me->core_layout.base + me->arch.got_offset + rela->r_addend - loc; if (r_type =3D=3D R_390_GOTPC) - rc =3D apply_rela_bits(loc, val, 1, 32, 0); + rc =3D apply_rela_bits(loc, val, 1, 32, 0, write); else if (r_type =3D=3D R_390_GOTPCDBL) - rc =3D apply_rela_bits(loc, val, 1, 32, 1); + rc =3D apply_rela_bits(loc, val, 1, 32, 1, write); break; case R_390_COPY: case R_390_GLOB_DAT: /* Create GOT entry. */ @@ -412,9 +426,10 @@ static int apply_rela(Elf_Rela *rela, Elf_Addr base,= Elf_Sym *symtab, return 0; } =20 -int apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab, +static int __apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab, unsigned int symindex, unsigned int relsec, - struct module *me) + struct module *me, + void *(*write)(void *dest, const void *src, size_t len)) { Elf_Addr base; Elf_Sym *symtab; @@ -430,13 +445,27 @@ int apply_relocate_add(Elf_Shdr *sechdrs, const cha= r *strtab, n =3D sechdrs[relsec].sh_size / sizeof(Elf_Rela); =20 for (i =3D 0; i < n; i++, rela++) { - rc =3D apply_rela(rela, base, symtab, strtab, me); + rc =3D apply_rela(rela, base, symtab, strtab, me, write); if (rc) return rc; } return 0; } =20 +int apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab, + unsigned int symindex, unsigned int relsec, + struct module *me) +{ + bool early =3D me->state =3D=3D MODULE_STATE_UNFORMED; + void *(*write)(void *, const void *, size_t) =3D memcpy; + + if (!early) + write =3D s390_kernel_write; + + return __apply_relocate_add(sechdrs, strtab, symindex, relsec, me, + write); +} + int module_finalize(const Elf_Ehdr *hdr, const Elf_Shdr *sechdrs, struct module *me) --=20 2.21.1