From patchwork Fri Jul 17 17:00:03 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kristen Carlson Accardi X-Patchwork-Id: 11670839 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 29DBB913 for ; Fri, 17 Jul 2020 17:01:30 +0000 (UTC) Received: from mother.openwall.net (mother.openwall.net [195.42.179.200]) by mail.kernel.org (Postfix) with SMTP id 66CA120775 for ; Fri, 17 Jul 2020 17:01:29 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 66CA120775 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.intel.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kernel-hardening-return-19380-patchwork-kernel-hardening=patchwork.kernel.org@lists.openwall.com Received: (qmail 9820 invoked by uid 550); 17 Jul 2020 17:01:07 -0000 Mailing-List: contact kernel-hardening-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-ID: Delivered-To: mailing list kernel-hardening@lists.openwall.com Received: (qmail 9725 invoked from network); 17 Jul 2020 17:01:05 -0000 IronPort-SDR: M18F+T7J7/isnirAqdXffSa+L38X8TGwUSVDwnFmAfQn3ttvxcya038uX/r383L64P2D8DoT/W rnPIorsZbPHg== X-IronPort-AV: E=McAfee;i="6000,8403,9685"; a="137748230" X-IronPort-AV: E=Sophos;i="5.75,362,1589266800"; d="scan'208";a="137748230" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False IronPort-SDR: NWj7oLgSmlwHYacGEeXpVk//kBB+ogD+RefXmM+m9lS+AvKxLZXdjbQVYXvBKDxa2dGtBMrDoq JQ3NHH5ZmRiA== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.75,362,1589266800"; d="scan'208";a="270862125" From: Kristen Carlson Accardi To: keescook@chromium.org, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, x86@kernel.org, "H. Peter Anvin" Cc: arjan@linux.intel.com, linux-kernel@vger.kernel.org, kernel-hardening@lists.openwall.com, rick.p.edgecombe@intel.com, Kristen Carlson Accardi , Tony Luck Subject: [PATCH v4 06/10] x86/tools: Add relative relocs for randomized functions Date: Fri, 17 Jul 2020 10:00:03 -0700 Message-Id: <20200717170008.5949-7-kristen@linux.intel.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20200717170008.5949-1-kristen@linux.intel.com> References: <20200717170008.5949-1-kristen@linux.intel.com> MIME-Version: 1.0 When reordering functions, the relative offsets for relocs that are either in the randomized sections, or refer to the randomized sections will need to be adjusted. Add code to detect whether a reloc satisfies these cases, and if so, add them to the appropriate reloc list. Signed-off-by: Kristen Carlson Accardi Reviewed-by: Tony Luck Tested-by: Tony Luck Reviewed-by: Kees Cook --- 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 7619742f91c9..c17b1c8ec82c 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 31b2d151aa63..e0665038742e 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 fgkaslr_mode; + 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 (!fgkaslr_mode) + 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 (!fgkaslr_mode) + 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) { + fgkaslr_mode = 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..f582895c04dd 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 fgkaslr); 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 fgkaslr); #endif /* RELOCS_H */ diff --git a/arch/x86/tools/relocs_common.c b/arch/x86/tools/relocs_common.c index 6634352a20bc..a80efa2f53ff 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, fgkaslr_opt; 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; + fgkaslr_opt = 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) { + fgkaslr_opt = 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, fgkaslr_opt); else process_32(fp, use_real_mode, as_text, show_absolute_syms, show_absolute_relocs, - show_reloc_info); + show_reloc_info, fgkaslr_opt); fclose(fp); return 0; }