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 73638C433E0 for ; Thu, 21 May 2020 16:57:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4477F207F7 for ; Thu, 21 May 2020 16:57:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730136AbgEUQ5M (ORCPT ); Thu, 21 May 2020 12:57:12 -0400 Received: from mga02.intel.com ([134.134.136.20]:46206 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729787AbgEUQ5L (ORCPT ); Thu, 21 May 2020 12:57:11 -0400 IronPort-SDR: kjF61sP2qM8ZuLUGmRs4D8KNmS8vNci+g5JUDB9rUIRjgnQ0bK9zikt8LQHrHXefYQdgMORqa0 Cp/XNYGIY9lA== X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga003.fm.intel.com ([10.253.24.29]) by orsmga101.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 21 May 2020 09:57:10 -0700 IronPort-SDR: TeipsK/N9HFpFReQGpALhDkmQ7gbrf5yJhKh+2sZ8PgWZ6NiphMk8urCwhS9X04rZD18VqS5Cs cQRRsz8zTzQA== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.73,418,1583222400"; d="scan'208";a="309094697" Received: from kcaccard-mobl.amr.corp.intel.com (HELO kcaccard-mobl1.jf.intel.com) ([10.212.147.236]) by FMSMGA003.fm.intel.com with ESMTP; 21 May 2020 09:57:08 -0700 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 v2 2/9] x86: tools/relocs: Support >64K section headers Date: Thu, 21 May 2020 09:56:33 -0700 Message-Id: <20200521165641.15940-3-kristen@linux.intel.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20200521165641.15940-1-kristen@linux.intel.com> References: <20200521165641.15940-1-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 While the relocs tool already supports finding the total number of section headers if vmlinux exceeds 64K sections, it fails to read the extended symbol table to get section header indexes for symbols, causing incorrect symbol table indexes to be used when there are > 64K symbols. Parse the elf file to read the extended symbol table info, and then replace all direct references to st_shndx with calls to sym_index(), which will determine whether the value can be read directly or whether the value should be pulled out of the extended table. Signed-off-by: Kristen Carlson Accardi Reviewed-by: Kees Cook Reviewed-by: Tony Luck Tested-by: Tony Luck --- arch/x86/tools/relocs.c | 104 ++++++++++++++++++++++++++++++---------- 1 file changed, 78 insertions(+), 26 deletions(-) diff --git a/arch/x86/tools/relocs.c b/arch/x86/tools/relocs.c index ce7188cbdae5..a00dc133f109 100644 --- a/arch/x86/tools/relocs.c +++ b/arch/x86/tools/relocs.c @@ -14,6 +14,10 @@ static Elf_Ehdr ehdr; static unsigned long shnum; static unsigned int shstrndx; +static unsigned int shsymtabndx; +static unsigned int shxsymtabndx; + +static int sym_index(Elf_Sym *sym); struct relocs { uint32_t *offset; @@ -32,6 +36,7 @@ struct section { Elf_Shdr shdr; struct section *link; Elf_Sym *symtab; + Elf32_Word *xsymtab; Elf_Rel *reltab; char *strtab; }; @@ -265,7 +270,7 @@ static const char *sym_name(const char *sym_strtab, Elf_Sym *sym) name = sym_strtab + sym->st_name; } else { - name = sec_name(sym->st_shndx); + name = sec_name(sym_index(sym)); } return name; } @@ -335,6 +340,23 @@ static uint64_t elf64_to_cpu(uint64_t val) #define elf_xword_to_cpu(x) elf32_to_cpu(x) #endif +static int sym_index(Elf_Sym *sym) +{ + Elf_Sym *symtab = secs[shsymtabndx].symtab; + Elf32_Word *xsymtab = secs[shxsymtabndx].xsymtab; + unsigned long offset; + int index; + + if (sym->st_shndx != SHN_XINDEX) + return sym->st_shndx; + + /* calculate offset of sym from head of table. */ + offset = (unsigned long) sym - (unsigned long) symtab; + index = offset/sizeof(*sym); + + return elf32_to_cpu(xsymtab[index]); +} + static void read_ehdr(FILE *fp) { if (fread(&ehdr, sizeof(ehdr), 1, fp) != 1) { @@ -468,31 +490,60 @@ static void read_strtabs(FILE *fp) static void read_symtabs(FILE *fp) { int i,j; + for (i = 0; i < shnum; i++) { struct section *sec = &secs[i]; - if (sec->shdr.sh_type != SHT_SYMTAB) { + int num_syms; + + switch (sec->shdr.sh_type) { + case SHT_SYMTAB_SHNDX: + sec->xsymtab = malloc(sec->shdr.sh_size); + if (!sec->xsymtab) { + die("malloc of %d bytes for xsymtab failed\n", + sec->shdr.sh_size); + } + if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) { + die("Seek to %d failed: %s\n", + sec->shdr.sh_offset, strerror(errno)); + } + if (fread(sec->xsymtab, 1, sec->shdr.sh_size, fp) + != sec->shdr.sh_size) { + die("Cannot read extended symbol table: %s\n", + strerror(errno)); + } + shxsymtabndx = i; + continue; + + case SHT_SYMTAB: + num_syms = sec->shdr.sh_size/sizeof(Elf_Sym); + + sec->symtab = malloc(sec->shdr.sh_size); + if (!sec->symtab) { + die("malloc of %d bytes for symtab failed\n", + sec->shdr.sh_size); + } + if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) { + die("Seek to %d failed: %s\n", + sec->shdr.sh_offset, strerror(errno)); + } + if (fread(sec->symtab, 1, sec->shdr.sh_size, fp) + != sec->shdr.sh_size) { + die("Cannot read symbol table: %s\n", + strerror(errno)); + } + for (j = 0; j < num_syms; j++) { + Elf_Sym *sym = &sec->symtab[j]; + + sym->st_name = elf_word_to_cpu(sym->st_name); + sym->st_value = elf_addr_to_cpu(sym->st_value); + sym->st_size = elf_xword_to_cpu(sym->st_size); + sym->st_shndx = elf_half_to_cpu(sym->st_shndx); + } + shsymtabndx = i; + continue; + + default: continue; - } - sec->symtab = malloc(sec->shdr.sh_size); - if (!sec->symtab) { - die("malloc of %d bytes for symtab failed\n", - sec->shdr.sh_size); - } - if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) { - die("Seek to %d failed: %s\n", - sec->shdr.sh_offset, strerror(errno)); - } - if (fread(sec->symtab, 1, sec->shdr.sh_size, fp) - != sec->shdr.sh_size) { - die("Cannot read symbol table: %s\n", - strerror(errno)); - } - for (j = 0; j < sec->shdr.sh_size/sizeof(Elf_Sym); j++) { - Elf_Sym *sym = &sec->symtab[j]; - sym->st_name = elf_word_to_cpu(sym->st_name); - sym->st_value = elf_addr_to_cpu(sym->st_value); - sym->st_size = elf_xword_to_cpu(sym->st_size); - sym->st_shndx = elf_half_to_cpu(sym->st_shndx); } } } @@ -759,13 +810,14 @@ static void percpu_init(void) */ static int is_percpu_sym(ElfW(Sym) *sym, const char *symname) { - return (sym->st_shndx == per_cpu_shndx) && + int shndx = sym_index(sym); + + return (shndx == per_cpu_shndx) && strcmp(symname, "__init_begin") && strcmp(symname, "__per_cpu_load") && strncmp(symname, "init_per_cpu_", 13); } - static int do_reloc64(struct section *sec, Elf_Rel *rel, ElfW(Sym) *sym, const char *symname) { @@ -1088,7 +1140,7 @@ static int do_reloc_info(struct section *sec, Elf_Rel *rel, ElfW(Sym) *sym, sec_name(sec->shdr.sh_info), rel_type(ELF_R_TYPE(rel->r_info)), symname, - sec_name(sym->st_shndx)); + sec_name(sym_index(sym))); return 0; } -- 2.20.1