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=-9.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT 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 3D54CC35247 for ; Wed, 5 Feb 2020 22:39:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 179A322464 for ; Wed, 5 Feb 2020 22:39:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727572AbgBEWjl (ORCPT ); Wed, 5 Feb 2020 17:39:41 -0500 Received: from mga02.intel.com ([134.134.136.20]:60115 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727493AbgBEWji (ORCPT ); Wed, 5 Feb 2020 17:39:38 -0500 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga007.fm.intel.com ([10.253.24.52]) by orsmga101.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 05 Feb 2020 14:39:37 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.70,407,1574150400"; d="scan'208";a="225092456" Received: from unknown (HELO localhost.jf.intel.com) ([10.54.75.26]) by fmsmga007.fm.intel.com with ESMTP; 05 Feb 2020 14:39:36 -0800 From: Kristen Carlson Accardi To: tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, hpa@zytor.com, arjan@linux.intel.com, keescook@chromium.org Cc: rick.p.edgecombe@intel.com, x86@kernel.org, linux-kernel@vger.kernel.org, kernel-hardening@lists.openwall.com, Kristen Carlson Accardi Subject: [RFC PATCH 07/11] x86/tools: Adding relative relocs for randomized functions Date: Wed, 5 Feb 2020 14:39:46 -0800 Message-Id: <20200205223950.1212394-8-kristen@linux.intel.com> X-Mailer: git-send-email 2.24.1 In-Reply-To: <20200205223950.1212394-1-kristen@linux.intel.com> References: <20200205223950.1212394-1-kristen@linux.intel.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org If we are randomizing function sections, we are going to need to recalculate relative offsets for relocs that are either in the randomized sections, or refer to the randomized sections. Add code to detect whether a reloc satisifies these cases, and if so, add them to the appropriate reloc list. Signed-off-by: Kristen Carlson Accardi --- arch/x86/boot/compressed/Makefile | 7 +++++- arch/x86/tools/relocs.c | 41 ++++++++++++++++++++++++++++--- arch/x86/tools/relocs.h | 4 +-- arch/x86/tools/relocs_common.c | 15 +++++++---- 4 files changed, 55 insertions(+), 12 deletions(-) diff --git a/arch/x86/boot/compressed/Makefile b/arch/x86/boot/compressed/Makefile index 1dac210f7d44..b7e5ea757ef4 100644 --- a/arch/x86/boot/compressed/Makefile +++ b/arch/x86/boot/compressed/Makefile @@ -119,6 +119,11 @@ $(obj)/vmlinux: $(vmlinux-objs-y) FORCE $(call if_changed,check-and-link-vmlinux) OBJCOPYFLAGS_vmlinux.bin := -R .comment -S + +ifdef CONFIG_FG_KASLR + RELOCS_ARGS += --fg-kaslr +endif + $(obj)/vmlinux.bin: vmlinux FORCE $(call if_changed,objcopy) @@ -126,7 +131,7 @@ targets += $(patsubst $(obj)/%,%,$(vmlinux-objs-y)) vmlinux.bin.all vmlinux.relo CMD_RELOCS = arch/x86/tools/relocs quiet_cmd_relocs = RELOCS $@ - cmd_relocs = $(CMD_RELOCS) $< > $@;$(CMD_RELOCS) --abs-relocs $< + cmd_relocs = $(CMD_RELOCS) $(RELOCS_ARGS) $< > $@;$(CMD_RELOCS) $(RELOCS_ARGS) --abs-relocs $< $(obj)/vmlinux.relocs: vmlinux FORCE $(call if_changed,relocs) diff --git a/arch/x86/tools/relocs.c b/arch/x86/tools/relocs.c index a00dc133f109..2641eec5f2de 100644 --- a/arch/x86/tools/relocs.c +++ b/arch/x86/tools/relocs.c @@ -42,6 +42,8 @@ struct section { }; static struct section *secs; +static int fg_kaslr; + static const char * const sym_regex_kernel[S_NSYMTYPES] = { /* * Following symbols have been audited. There values are constant and do @@ -818,6 +820,32 @@ static int is_percpu_sym(ElfW(Sym) *sym, const char *symname) strncmp(symname, "init_per_cpu_", 13); } +static int is_function_section(struct section *sec) +{ + const char *name; + + if (!fg_kaslr) + return 0; + + name = sec_name(sec->shdr.sh_info); + + return(!strncmp(name, ".text.", 6)); +} + +static int is_randomized_sym(ElfW(Sym *sym)) +{ + const char *name; + + if (!fg_kaslr) + return 0; + + if (sym->st_shndx > shnum) + return 0; + + name = sec_name(sym_index(sym)); + return(!strncmp(name, ".text.", 6)); +} + static int do_reloc64(struct section *sec, Elf_Rel *rel, ElfW(Sym) *sym, const char *symname) { @@ -842,13 +870,17 @@ static int do_reloc64(struct section *sec, Elf_Rel *rel, ElfW(Sym) *sym, case R_X86_64_PC32: case R_X86_64_PLT32: /* - * PC relative relocations don't need to be adjusted unless - * referencing a percpu symbol. + * we need to keep pc relative relocations for sections which + * might be randomized, and for the percpu section. + * We also need to keep relocations for any offset which might + * reference an address in a section which has been randomized. * * NB: R_X86_64_PLT32 can be treated as R_X86_64_PC32. */ - if (is_percpu_sym(sym, symname)) + if (is_function_section(sec) || is_randomized_sym(sym) || + is_percpu_sym(sym, symname)) add_reloc(&relocs32neg, offset); + break; case R_X86_64_PC64: @@ -1158,8 +1190,9 @@ static void print_reloc_info(void) void process(FILE *fp, int use_real_mode, int as_text, int show_absolute_syms, int show_absolute_relocs, - int show_reloc_info) + int show_reloc_info, int fgkaslr) { + fg_kaslr = fgkaslr; regex_init(use_real_mode); read_ehdr(fp); read_shdrs(fp); diff --git a/arch/x86/tools/relocs.h b/arch/x86/tools/relocs.h index 43c83c0fd22c..05504052c846 100644 --- a/arch/x86/tools/relocs.h +++ b/arch/x86/tools/relocs.h @@ -31,8 +31,8 @@ enum symtype { void process_32(FILE *fp, int use_real_mode, int as_text, int show_absolute_syms, int show_absolute_relocs, - int show_reloc_info); + int show_reloc_info, int fg_kaslr); void process_64(FILE *fp, int use_real_mode, int as_text, int show_absolute_syms, int show_absolute_relocs, - int show_reloc_info); + int show_reloc_info, int fg_kaslr); #endif /* RELOCS_H */ diff --git a/arch/x86/tools/relocs_common.c b/arch/x86/tools/relocs_common.c index 6634352a20bc..f76cd6f53961 100644 --- a/arch/x86/tools/relocs_common.c +++ b/arch/x86/tools/relocs_common.c @@ -12,14 +12,14 @@ void die(char *fmt, ...) static void usage(void) { - die("relocs [--abs-syms|--abs-relocs|--reloc-info|--text|--realmode]" \ - " vmlinux\n"); + die("relocs [--abs-syms|--abs-relocs|--reloc-info|--text|--realmode" + "|--fg-kaslr] vmlinux\n"); } int main(int argc, char **argv) { int show_absolute_syms, show_absolute_relocs, show_reloc_info; - int as_text, use_real_mode; + int as_text, use_real_mode, fg_kaslr; const char *fname; FILE *fp; int i; @@ -30,6 +30,7 @@ int main(int argc, char **argv) show_reloc_info = 0; as_text = 0; use_real_mode = 0; + fg_kaslr = 0; fname = NULL; for (i = 1; i < argc; i++) { char *arg = argv[i]; @@ -54,6 +55,10 @@ int main(int argc, char **argv) use_real_mode = 1; continue; } + if (strcmp(arg, "--fg-kaslr") == 0) { + fg_kaslr = 1; + continue; + } } else if (!fname) { fname = arg; @@ -75,11 +80,11 @@ int main(int argc, char **argv) if (e_ident[EI_CLASS] == ELFCLASS64) process_64(fp, use_real_mode, as_text, show_absolute_syms, show_absolute_relocs, - show_reloc_info); + show_reloc_info, fg_kaslr); else process_32(fp, use_real_mode, as_text, show_absolute_syms, show_absolute_relocs, - show_reloc_info); + show_reloc_info, fg_kaslr); fclose(fp); return 0; } -- 2.24.1