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") ? > + 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 >
