On Fri, Apr 28, 2023 at 06:28:19PM +0800, Christophe Leroy wrote: > > > Le 28/04/2023 à 11:51, Hou Wenlong a écrit : > > [Vous ne recevez pas souvent de courriers de houwenlong.hwl@xxxxxxxxxxxx. Découvrez pourquoi ceci est important à https://aka.ms/LearnAboutSenderIdentification ] > > > > For x86 PIE binary, only RIP-relative addressing is allowed, however, > > there are still a little absolute references of R_X86_64_64 relocation > > type for data section and a little absolute references of R_X86_64_32S > > relocation type in pvh_start_xen() function. > > > > Suggested-by: Lai Jiangshan <jiangshan.ljs@xxxxxxxxxxxx> > > Signed-off-by: Hou Wenlong <houwenlong.hwl@xxxxxxxxxxxx> > > Cc: Thomas Garnier <thgarnie@xxxxxxxxxxxx> > > Cc: Kees Cook <keescook@xxxxxxxxxxxx> > > --- > > arch/x86/Kconfig | 1 + > > scripts/Makefile.lib | 1 + > > tools/objtool/builtin-check.c | 4 +- > > tools/objtool/check.c | 82 +++++++++++++++++++++++++ > > tools/objtool/include/objtool/builtin.h | 1 + > > 5 files changed, 88 insertions(+), 1 deletion(-) > > > > diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig > > index 715f0734d065..b753a54e5ea7 100644 > > --- a/arch/x86/Kconfig > > +++ b/arch/x86/Kconfig > > @@ -2224,6 +2224,7 @@ config RELOCATABLE > > config X86_PIE > > def_bool n > > depends on X86_64 > > + select OBJTOOL if HAVE_OBJTOOL > > > > config RANDOMIZE_BASE > > bool "Randomize the address of the kernel image (KASLR)" > > diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib > > index 100a386fcd71..e3c804fbc421 100644 > > --- a/scripts/Makefile.lib > > +++ b/scripts/Makefile.lib > > @@ -270,6 +270,7 @@ objtool-args-$(CONFIG_HAVE_STATIC_CALL_INLINE) += --static-call > > objtool-args-$(CONFIG_HAVE_UACCESS_VALIDATION) += --uaccess > > objtool-args-$(CONFIG_GCOV_KERNEL) += --no-unreachable > > objtool-args-$(CONFIG_PREFIX_SYMBOLS) += --prefix=$(CONFIG_FUNCTION_PADDING_BYTES) > > +objtool-args-$(CONFIG_X86_PIE) += --pie > > > > objtool-args = $(objtool-args-y) \ > > $(if $(delay-objtool), --link) \ > > diff --git a/tools/objtool/builtin-check.c b/tools/objtool/builtin-check.c > > index 7c175198d09f..1cf1d00464e0 100644 > > --- a/tools/objtool/builtin-check.c > > +++ b/tools/objtool/builtin-check.c > > @@ -81,6 +81,7 @@ static const struct option check_options[] = { > > OPT_BOOLEAN('t', "static-call", &opts.static_call, "annotate static calls"), > > OPT_BOOLEAN('u', "uaccess", &opts.uaccess, "validate uaccess rules for SMAP"), > > OPT_BOOLEAN(0 , "cfi", &opts.cfi, "annotate kernel control flow integrity (kCFI) function preambles"), > > + OPT_BOOLEAN(0, "pie", &opts.pie, "validate addressing rules for PIE"), > > OPT_CALLBACK_OPTARG(0, "dump", NULL, NULL, "orc", "dump metadata", parse_dump), > > > > OPT_GROUP("Options:"), > > @@ -137,7 +138,8 @@ static bool opts_valid(void) > > opts.sls || > > opts.stackval || > > opts.static_call || > > - opts.uaccess) { > > + opts.uaccess || > > + opts.pie) { > > if (opts.dump_orc) { > > ERROR("--dump can't be combined with other options"); > > return false; > > diff --git a/tools/objtool/check.c b/tools/objtool/check.c > > index 5b600bbf2389..d67b80251eec 100644 > > --- a/tools/objtool/check.c > > +++ b/tools/objtool/check.c > > @@ -131,6 +131,27 @@ static struct instruction *prev_insn_same_sym(struct objtool_file *file, > > for (insn = next_insn_same_sec(file, insn); insn; \ > > insn = next_insn_same_sec(file, insn)) > > > > +static struct instruction *find_insn_containing(struct objtool_file *file, > > + struct section *sec, > > + unsigned long offset) > > +{ > > + struct instruction *insn; > > + > > + insn = find_insn(file, sec, 0); > > + if (!insn) > > + return NULL; > > + > > + sec_for_each_insn_from(file, insn) { > > + if (insn->offset > offset) > > + return NULL; > > + if (insn->offset <= offset && (insn->offset + insn->len) > offset) > > + return insn; > > + } > > + > > + return NULL; > > +} > > + > > + > > static inline struct symbol *insn_call_dest(struct instruction *insn) > > { > > if (insn->type == INSN_JUMP_DYNAMIC || > > @@ -4529,6 +4550,61 @@ static int validate_reachable_instructions(struct objtool_file *file) > > return 0; > > } > > > > +static int is_in_pvh_code(struct instruction *insn) > > +{ > > + struct symbol *sym = insn->sym; > > + > > + return sym && !strcmp(sym->name, "pvh_start_xen"); > > +} > > + > > +static int validate_pie(struct objtool_file *file) > > +{ > > + struct section *sec; > > + struct reloc *reloc; > > + struct instruction *insn; > > + int warnings = 0; > > + > > + for_each_sec(file, sec) { > > + if (!sec->reloc) > > + continue; > > + if (!(sec->sh.sh_flags & SHF_ALLOC)) > > + continue; > > + > > + list_for_each_entry(reloc, &sec->reloc->reloc_list, list) { > > + switch (reloc->type) { > > + case R_X86_64_NONE: > > + case R_X86_64_PC32: > > + case R_X86_64_PLT32: > > + case R_X86_64_64: > > + case R_X86_64_PC64: > > + case R_X86_64_GOTPCREL: > > + break; > > + case R_X86_64_32: > > + case R_X86_64_32S: > > That looks very specific to X86, should it go at another place ? > > If it can work for any architecture, can you add generic macros, just > like commit c1449735211d ("objtool: Use macros to define arch specific > reloc types") then commit c984aef8c832 ("objtool/powerpc: Add --mcount > specific implementation") ? > Get it, I'll refactor it and move code into X86 directory. Thanks. > > + insn = find_insn_containing(file, sec, reloc->offset); > > + if (!insn) { > > + WARN("can't find relocate insn near %s+0x%lx", > > + sec->name, reloc->offset); > > + } else { > > + if (is_in_pvh_code(insn)) > > + break; > > + WARN("insn at %s+0x%lx is not compatible with PIE", > > + sec->name, insn->offset); > > + } > > + warnings++; > > + break; > > + default: > > + WARN("unexpected relocation type %d at %s+0x%lx", > > + reloc->type, sec->name, reloc->offset); > > + warnings++; > > + break; > > + } > > + } > > + } > > + > > + return warnings; > > +} > > + > > int check(struct objtool_file *file) > > { > > int ret, warnings = 0; > > @@ -4673,6 +4749,12 @@ int check(struct objtool_file *file) > > warnings += ret; > > } > > > > + if (opts.pie) { > > + ret = validate_pie(file); > > + if (ret < 0) > > + return ret; > > + warnings += ret; > > + } > > > > if (opts.stats) { > > printf("nr_insns_visited: %ld\n", nr_insns_visited); > > diff --git a/tools/objtool/include/objtool/builtin.h b/tools/objtool/include/objtool/builtin.h > > index 2a108e648b7a..1151211a5cea 100644 > > --- a/tools/objtool/include/objtool/builtin.h > > +++ b/tools/objtool/include/objtool/builtin.h > > @@ -26,6 +26,7 @@ struct opts { > > bool uaccess; > > int prefix; > > bool cfi; > > + bool pie; > > > > /* options: */ > > bool backtrace; > > -- > > 2.31.1 > >
