From 7c21383f3429dd70da39c0c7f1efa12377a47ab6 Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Thu, 4 Apr 2019 14:40:27 -0700 Subject: x86/build: Keep local relocations with ld.lld The LLVM linker (ld.lld) defaults to removing local relocations, which causes KASLR boot failures. ld.bfd and ld.gold already handle this correctly. This adds the explicit instruction "--discard-none" during the link phase. There is no change in output for ld.bfd and ld.gold, but ld.lld now produces an image with all the needed relocations. Signed-off-by: Kees Cook Signed-off-by: Borislav Petkov Cc: "H. Peter Anvin" Cc: Ingo Molnar Cc: Nick Desaulniers Cc: Thomas Gleixner Cc: clang-built-linux@googlegroups.com Cc: x86-ml Link: https://lkml.kernel.org/r/20190404214027.GA7324@beast Link: https://github.com/ClangBuiltLinux/linux/issues/404 --- arch/x86/Makefile | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'arch') diff --git a/arch/x86/Makefile b/arch/x86/Makefile index a587805c6687..56e748a7679f 100644 --- a/arch/x86/Makefile +++ b/arch/x86/Makefile @@ -47,7 +47,7 @@ export REALMODE_CFLAGS export BITS ifdef CONFIG_X86_NEED_RELOCS - LDFLAGS_vmlinux := --emit-relocs + LDFLAGS_vmlinux := --emit-relocs --discard-none endif # -- cgit v1.2.3 From 93ddedaa5c9cb828d39a19b5d6e7e1939393085a Mon Sep 17 00:00:00 2001 From: "Ahmed S. Darwish" Date: Wed, 6 Mar 2019 01:44:25 +0100 Subject: x86/defconfig: Remove archaic partition tables support On x86 systems, only MSDOS and GPT partition tables are typically encountered. Remove all the rest. Note, CONFIG_EFI_PARTITION is also removed since it defaults to `y'. Signed-off-by: Ahmed S. Darwish Cc: Borislav Petkov Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/20190306004425.GA30537@darwi-home-pc Signed-off-by: Ingo Molnar --- arch/x86/configs/i386_defconfig | 12 ------------ arch/x86/configs/x86_64_defconfig | 12 ------------ 2 files changed, 24 deletions(-) (limited to 'arch') diff --git a/arch/x86/configs/i386_defconfig b/arch/x86/configs/i386_defconfig index 9f908112bbb9..2b2481acc661 100644 --- a/arch/x86/configs/i386_defconfig +++ b/arch/x86/configs/i386_defconfig @@ -25,18 +25,6 @@ CONFIG_JUMP_LABEL=y CONFIG_MODULES=y CONFIG_MODULE_UNLOAD=y CONFIG_MODULE_FORCE_UNLOAD=y -CONFIG_PARTITION_ADVANCED=y -CONFIG_OSF_PARTITION=y -CONFIG_AMIGA_PARTITION=y -CONFIG_MAC_PARTITION=y -CONFIG_BSD_DISKLABEL=y -CONFIG_MINIX_SUBPARTITION=y -CONFIG_SOLARIS_X86_PARTITION=y -CONFIG_UNIXWARE_DISKLABEL=y -CONFIG_SGI_PARTITION=y -CONFIG_SUN_PARTITION=y -CONFIG_KARMA_PARTITION=y -CONFIG_EFI_PARTITION=y CONFIG_SMP=y CONFIG_X86_GENERIC=y CONFIG_HPET_TIMER=y diff --git a/arch/x86/configs/x86_64_defconfig b/arch/x86/configs/x86_64_defconfig index 1d3badfda09e..e8829abf063a 100644 --- a/arch/x86/configs/x86_64_defconfig +++ b/arch/x86/configs/x86_64_defconfig @@ -24,18 +24,6 @@ CONFIG_JUMP_LABEL=y CONFIG_MODULES=y CONFIG_MODULE_UNLOAD=y CONFIG_MODULE_FORCE_UNLOAD=y -CONFIG_PARTITION_ADVANCED=y -CONFIG_OSF_PARTITION=y -CONFIG_AMIGA_PARTITION=y -CONFIG_MAC_PARTITION=y -CONFIG_BSD_DISKLABEL=y -CONFIG_MINIX_SUBPARTITION=y -CONFIG_SOLARIS_X86_PARTITION=y -CONFIG_UNIXWARE_DISKLABEL=y -CONFIG_SGI_PARTITION=y -CONFIG_SUN_PARTITION=y -CONFIG_KARMA_PARTITION=y -CONFIG_EFI_PARTITION=y CONFIG_SMP=y CONFIG_CALGARY_IOMMU=y CONFIG_NR_CPUS=64 -- cgit v1.2.3 From f36e7495dd3990d6848e6d6703c78f1f17a97538 Mon Sep 17 00:00:00 2001 From: Artem Savkov Date: Thu, 29 Nov 2018 16:56:15 +0100 Subject: x86/tools/relocs: Fix big section header tables In case when the number of entries in the section header table is larger then or equal to SHN_LORESERVE the size of the table is held in the sh_size member of the initial entry in section header table instead of e_shnum. Same with the string table index which is located in sh_link instead of e_shstrndx. This case is easily reproducible with KCFLAGS="-ffunction-sections", bzImage build fails with "String table index out of bounds" error. Signed-off-by: Artem Savkov Reviewed-by: Josh Poimboeuf Acked-by: Joe Lawrence Cc: Eric W . Biederman Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/20181129155615.2594-1-asavkov@redhat.com [ Simplify the die() lines. ] Signed-off-by: Ingo Molnar --- arch/x86/tools/relocs.c | 74 ++++++++++++++++++++++++++++++------------------- 1 file changed, 45 insertions(+), 29 deletions(-) (limited to 'arch') diff --git a/arch/x86/tools/relocs.c b/arch/x86/tools/relocs.c index b629f6992d9f..f345586f5e50 100644 --- a/arch/x86/tools/relocs.c +++ b/arch/x86/tools/relocs.c @@ -11,7 +11,9 @@ #define Elf_Shdr ElfW(Shdr) #define Elf_Sym ElfW(Sym) -static Elf_Ehdr ehdr; +static Elf_Ehdr ehdr; +static unsigned long shnum; +static unsigned int shstrndx; struct relocs { uint32_t *offset; @@ -241,9 +243,9 @@ static const char *sec_name(unsigned shndx) { const char *sec_strtab; const char *name; - sec_strtab = secs[ehdr.e_shstrndx].strtab; + sec_strtab = secs[shstrndx].strtab; name = ""; - if (shndx < ehdr.e_shnum) { + if (shndx < shnum) { name = sec_strtab + secs[shndx].shdr.sh_name; } else if (shndx == SHN_ABS) { @@ -271,7 +273,7 @@ static const char *sym_name(const char *sym_strtab, Elf_Sym *sym) static Elf_Sym *sym_lookup(const char *symname) { int i; - for (i = 0; i < ehdr.e_shnum; i++) { + for (i = 0; i < shnum; i++) { struct section *sec = &secs[i]; long nsyms; char *strtab; @@ -366,27 +368,41 @@ static void read_ehdr(FILE *fp) ehdr.e_shnum = elf_half_to_cpu(ehdr.e_shnum); ehdr.e_shstrndx = elf_half_to_cpu(ehdr.e_shstrndx); - if ((ehdr.e_type != ET_EXEC) && (ehdr.e_type != ET_DYN)) { + shnum = ehdr.e_shnum; + shstrndx = ehdr.e_shstrndx; + + if ((ehdr.e_type != ET_EXEC) && (ehdr.e_type != ET_DYN)) die("Unsupported ELF header type\n"); - } - if (ehdr.e_machine != ELF_MACHINE) { + if (ehdr.e_machine != ELF_MACHINE) die("Not for %s\n", ELF_MACHINE_NAME); - } - if (ehdr.e_version != EV_CURRENT) { + if (ehdr.e_version != EV_CURRENT) die("Unknown ELF version\n"); - } - if (ehdr.e_ehsize != sizeof(Elf_Ehdr)) { + if (ehdr.e_ehsize != sizeof(Elf_Ehdr)) die("Bad Elf header size\n"); - } - if (ehdr.e_phentsize != sizeof(Elf_Phdr)) { + if (ehdr.e_phentsize != sizeof(Elf_Phdr)) die("Bad program header entry\n"); - } - if (ehdr.e_shentsize != sizeof(Elf_Shdr)) { + if (ehdr.e_shentsize != sizeof(Elf_Shdr)) die("Bad section header entry\n"); + + + if (shnum == SHN_UNDEF || shstrndx == SHN_XINDEX) { + Elf_Shdr shdr; + + if (fseek(fp, ehdr.e_shoff, SEEK_SET) < 0) + die("Seek to %d failed: %s\n", ehdr.e_shoff, strerror(errno)); + + if (fread(&shdr, sizeof(shdr), 1, fp) != 1) + die("Cannot read initial ELF section header: %s\n", strerror(errno)); + + if (shnum == SHN_UNDEF) + shnum = elf_xword_to_cpu(shdr.sh_size); + + if (shstrndx == SHN_XINDEX) + shstrndx = elf_word_to_cpu(shdr.sh_link); } - if (ehdr.e_shstrndx >= ehdr.e_shnum) { + + if (shstrndx >= shnum) die("String table index out of bounds\n"); - } } static void read_shdrs(FILE *fp) @@ -394,20 +410,20 @@ static void read_shdrs(FILE *fp) int i; Elf_Shdr shdr; - secs = calloc(ehdr.e_shnum, sizeof(struct section)); + secs = calloc(shnum, sizeof(struct section)); if (!secs) { die("Unable to allocate %d section headers\n", - ehdr.e_shnum); + shnum); } if (fseek(fp, ehdr.e_shoff, SEEK_SET) < 0) { die("Seek to %d failed: %s\n", ehdr.e_shoff, strerror(errno)); } - for (i = 0; i < ehdr.e_shnum; i++) { + for (i = 0; i < shnum; i++) { struct section *sec = &secs[i]; if (fread(&shdr, sizeof(shdr), 1, fp) != 1) die("Cannot read ELF section headers %d/%d: %s\n", - i, ehdr.e_shnum, strerror(errno)); + i, shnum, strerror(errno)); sec->shdr.sh_name = elf_word_to_cpu(shdr.sh_name); sec->shdr.sh_type = elf_word_to_cpu(shdr.sh_type); sec->shdr.sh_flags = elf_xword_to_cpu(shdr.sh_flags); @@ -418,7 +434,7 @@ static void read_shdrs(FILE *fp) sec->shdr.sh_info = elf_word_to_cpu(shdr.sh_info); sec->shdr.sh_addralign = elf_xword_to_cpu(shdr.sh_addralign); sec->shdr.sh_entsize = elf_xword_to_cpu(shdr.sh_entsize); - if (sec->shdr.sh_link < ehdr.e_shnum) + if (sec->shdr.sh_link < shnum) sec->link = &secs[sec->shdr.sh_link]; } @@ -427,7 +443,7 @@ static void read_shdrs(FILE *fp) static void read_strtabs(FILE *fp) { int i; - for (i = 0; i < ehdr.e_shnum; i++) { + for (i = 0; i < shnum; i++) { struct section *sec = &secs[i]; if (sec->shdr.sh_type != SHT_STRTAB) { continue; @@ -452,7 +468,7 @@ static void read_strtabs(FILE *fp) static void read_symtabs(FILE *fp) { int i,j; - for (i = 0; i < ehdr.e_shnum; i++) { + for (i = 0; i < shnum; i++) { struct section *sec = &secs[i]; if (sec->shdr.sh_type != SHT_SYMTAB) { continue; @@ -485,7 +501,7 @@ static void read_symtabs(FILE *fp) static void read_relocs(FILE *fp) { int i,j; - for (i = 0; i < ehdr.e_shnum; i++) { + for (i = 0; i < shnum; i++) { struct section *sec = &secs[i]; if (sec->shdr.sh_type != SHT_REL_TYPE) { continue; @@ -528,7 +544,7 @@ static void print_absolute_symbols(void) printf("Absolute symbols\n"); printf(" Num: Value Size Type Bind Visibility Name\n"); - for (i = 0; i < ehdr.e_shnum; i++) { + for (i = 0; i < shnum; i++) { struct section *sec = &secs[i]; char *sym_strtab; int j; @@ -566,7 +582,7 @@ static void print_absolute_relocs(void) else format = "%08"PRIx32" %08"PRIx32" %10s %08"PRIx32" %s\n"; - for (i = 0; i < ehdr.e_shnum; i++) { + for (i = 0; i < shnum; i++) { struct section *sec = &secs[i]; struct section *sec_applies, *sec_symtab; char *sym_strtab; @@ -650,7 +666,7 @@ static void walk_relocs(int (*process)(struct section *sec, Elf_Rel *rel, { int i; /* Walk through the relocations */ - for (i = 0; i < ehdr.e_shnum; i++) { + for (i = 0; i < shnum; i++) { char *sym_strtab; Elf_Sym *sh_symtab; struct section *sec_applies, *sec_symtab; @@ -706,7 +722,7 @@ static Elf_Addr per_cpu_load_addr; static void percpu_init(void) { int i; - for (i = 0; i < ehdr.e_shnum; i++) { + for (i = 0; i < shnum; i++) { ElfW(Sym) *sym; if (strcmp(sec_name(i), ".data..percpu")) continue; -- cgit v1.2.3