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From: "Hou Wenlong" <houwenlong.hwl@antgroup.com>
To: linux-kernel@vger.kernel.org
Cc: "Thomas Garnier" <thgarnie@chromium.org>,
"Lai Jiangshan" <jiangshan.ljs@antgroup.com>,
"Kees Cook" <keescook@chromium.org>,
"Hou Wenlong" <houwenlong.hwl@antgroup.com>,
"Thomas Gleixner" <tglx@linutronix.de>, "Ingo Molnar" <mingo@redhat.com>,
"Borislav Petkov" <bp@alien8.de>,
"Dave Hansen" <dave.hansen@linux.intel.com>, <x86@kernel.org>,
"H. Peter Anvin" <hpa@zytor.com>, "Masahiro Yamada" <masahiroy@kernel.org>,
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"Nick Desaulniers" <ndesaulniers@google.com>,
"Nicolas Schier" <nicolas@fjasle.eu>, "Josh Poimboeuf" <jpoimboe@kernel.org>,
"Peter Zijlstra" <peterz@infradead.org>,
"Christophe Leroy" <christophe.leroy@csgroup.eu>,
"Sathvika Vasireddy" <sv@linux.ibm.com>,
" =?utf-8?q?Thomas_Wei=C3=9Fschuh?= " <linux@weissschuh.net>,
<linux-kbuild@vger.kernel.org>
Subject: [PATCH RFC 33/43] objtool: Add validation for x86 PIE support
Date: Fri, 28 Apr 2023 17:51:13 +0800
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| Series |
x86/pie: Make kernel image's virtual address flexible
|
|
Commit Message
Hou Wenlong
April 28, 2023, 9:51 a.m. UTC
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@antgroup.com>
Signed-off-by: Hou Wenlong <houwenlong.hwl@antgroup.com>
Cc: Thomas Garnier <thgarnie@chromium.org>
Cc: Kees Cook <keescook@chromium.org>
---
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(-)
Comments
Le 28/04/2023 à 11:51, Hou Wenlong a écrit : > [Vous ne recevez pas souvent de courriers de houwenlong.hwl@antgroup.com. 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@antgroup.com> > Signed-off-by: Hou Wenlong <houwenlong.hwl@antgroup.com> > Cc: Thomas Garnier <thgarnie@chromium.org> > Cc: Kees Cook <keescook@chromium.org> > --- > 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 >
On Fri, Apr 28, 2023 at 10:28:19AM +0000, Christophe Leroy wrote: > > 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; > > +} Urgh, this is horrendous crap. Yes you're only using it in case of a warning, but adding a function like this makes it appear like it's actually sane to use. A far better implementation -- but still not stellar -- would be something like: sym = find_symbol_containing(sec, offset); if (!sym) // fail sym_for_each_insn(file, sym, insn) { ... } But given insn_hash uses sec_offset_hash() you can do something similar to find_reloc_by_dest_range() start = offset - (INSN_MAX_SIZE - 1); for_offset_range(o, start, start + INSN_MAX_SIZE) { hash_for_each_possible(file->insn_hash, insn, hash, sec_offset_hash(sec, o)) { if (insn->sec != sec) continue; if (insn->offset <= offset && insn->offset + inns->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") ? Yes, this should be something like arch_PIE_reloc() or so. Similar to arch_pc_relative_reloc().
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@antgroup.com. 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@antgroup.com> > > Signed-off-by: Hou Wenlong <houwenlong.hwl@antgroup.com> > > Cc: Thomas Garnier <thgarnie@chromium.org> > > Cc: Kees Cook <keescook@chromium.org> > > --- > > 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 > >
On Fri, Apr 28, 2023 at 07:43:38PM +0800, Peter Zijlstra wrote: > On Fri, Apr 28, 2023 at 10:28:19AM +0000, Christophe Leroy wrote: > > > > > 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; > > > +} > > Urgh, this is horrendous crap. Yes you're only using it in case of a > warning, but adding a function like this makes it appear like it's > actually sane to use. > > A far better implementation -- but still not stellar -- would be > something like: > > sym = find_symbol_containing(sec, offset); > if (!sym) > // fail > sym_for_each_insn(file, sym, insn) { > ... > } > > But given insn_hash uses sec_offset_hash() you can do something similar > to find_reloc_by_dest_range() > > start = offset - (INSN_MAX_SIZE - 1); > for_offset_range(o, start, start + INSN_MAX_SIZE) { > hash_for_each_possible(file->insn_hash, insn, hash, sec_offset_hash(sec, o)) { > if (insn->sec != sec) > continue; > > if (insn->offset <= offset && > insn->offset + inns->len > offset) > return insn; > } > } > return NULL; > Thanks for your suggestion, I'll pick it in the next version. > > > + > > > + > > > 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") ? > > Yes, this should be something like arch_PIE_reloc() or so. Similar to > arch_pc_relative_reloc().
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: + 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;