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[Bug dynamic-link/21598] i386 _dl_runtime_resolve/_dl_runtime_profile is incompatible with shadow stack
- From: "cvs-commit at gcc dot gnu.org" <sourceware-bugzilla at sourceware dot org>
- To: glibc-bugs at sourceware dot org
- Date: Wed, 05 Jul 2017 00:46:38 +0000
- Subject: [Bug dynamic-link/21598] i386 _dl_runtime_resolve/_dl_runtime_profile is incompatible with shadow stack
- Auto-submitted: auto-generated
- References: <bug-21598-131@http.sourceware.org/bugzilla/>
https://sourceware.org/bugzilla/show_bug.cgi?id=21598
--- Comment #17 from cvs-commit at gcc dot gnu.org <cvs-commit at gcc dot gnu.org> ---
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The branch, hjl/cet/property has been created
at e04eefe5ee59389a8017e5509c0b1a0d26ced21f (commit)
- Log -----------------------------------------------------------------
https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=e04eefe5ee59389a8017e5509c0b1a0d26ced21f
commit e04eefe5ee59389a8017e5509c0b1a0d26ced21f
Author: H.J. Lu <hjl.tools@gmail.com>
Date: Wed Jun 28 15:16:46 2017 -0700
i386: Add _dl_runtime_resolve_shstk/_dl_runtime_profile_shstk [BZ #21598]
Add SHSTK compatible symbol resolvers to support Shadow Stack in Intel
Control-flow Enforcement Technology (CET) instructions:
https://software.intel.com/sites/default/files/managed/4d/2a/control-flow-enforcement-technology-preview.pdf
Replace _dl_runtime_resolve and _dl_runtime_profile with
_dl_runtime_resolve_shstk and _dl_runtime_profile_shstk, respectively if
SHSTK is enabled.
[BZ #21598]
* sysdeps/i386/dl-trampoline.S (_dl_runtime_resolve_shstk): New.
(_dl_runtime_profile_shstk): Likewise.
* sysdeps/unix/sysv/linux/i386/dl-cet.c: New file.
https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=ec13d7eee49929a7e4e867fcfc30c23930fba5cf
commit ec13d7eee49929a7e4e867fcfc30c23930fba5cf
Author: H.J. Lu <hjl.tools@gmail.com>
Date: Thu Jun 22 04:15:39 2017 -0700
x86: Support IBT and SHSTK from Intel CET
Intel Control-flow Enforcement Technology (CET) instructions:
https://software.intel.com/sites/default/files/managed/4d/2a/control-flow-en
forcement-technology-preview.pdf
includes Indirect Branch Tracking (IBT) and Shadow Stack (SHSTK).
GNU_PROPERTY_X86_FEATURE_1_IBT is added to GNU program property to
indicate that all executable sections are compatible with IBT when
ENDBR instruction starts each valid target where an indirect branch
instruction can land. GNU_PROPERTY_X86_FEATURE_1_IBT is set on output
only if it is set on all relocatable inputs.
On an IBT capable processor, the following steps should be taken:
1. When loading an executable, if GNU_PROPERTY_X86_FEATURE_1_IBT is
set on the executable, enable IBT.
2. If IBT is enabled, when loading a shared object without
GNU_PROPERTY_X86_FEATURE_1_IBT:
a. If legacy interwork is allowed, then mark all pages in executable
PT_LOAD segments in legacy code page bitmap. Failure of legacy code
page bitmap allocation causes an error.
b. If legacy interwork isn't allowed, it causes an error.
GNU_PROPERTY_X86_FEATURE_1_SHSTK is added to GNU program property to
indicate that all executable sections are compatible with SHSTK where
return address popped from shadow stack always matches return address
popped from normal stack. GNU_PROPERTY_X86_FEATURE_1_SHSTK is set on
output only if it is set on all relocatable inputs.
On a SHSTK capable processor, the following steps should be taken:
1. When loading an executable, if GNU_PROPERTY_X86_FEATURE_1_SHSTK is
set on the executable as well as all shared objects loaded via the
DT_NEEDED tag, enable SHSTK.
2. After SHSTK is enabled, it is an error to load a shared object
without GNU_PROPERTY_X86_FEATURE_1_SHSTK.
When glibc is built with a compiler which defines defines__IBT__ and
__SHSTK__, CET is enabled, unless --disable-cet is used to configure
glibc. When CET is enabled, both compiler and assembler must support
CET. Otherwise, it is a configure-time error.
To support CET run-time control,
1. _dl_x86_feature_1 is added to the writable ld.so namespace to indicate
if IBT or SHSTK are enabled at run-time.
2. For dynamic executables:
a. A l_cet field is added to struct link_map to indicate if IBT or
SHSTK is enabled in an ELF module. The optional DL_PROCESS_PT_NOTE
is called to process PT_NOTE segment for GNU program property and
set l_cet.
b. _dl_start_user calls _dl_cet_init, instead of _dl_init, which sets
_dl_x86_feature_1 as well as sets up IBT and SHSTK.
3. For static executables, _dl_setup_cet is called to process PT_NOTE
segment for GNU program property to set _dl_x86_feature_1 as well as set
up IBT and SHSTK.
<sys/cet.h> is added so that it can be included by assembly codes to
add GNU_PROPERTY_X86_FEATURE_1_IBT and GNU_PROPERTY_X86_FEATURE_1_SHSTK
to GNU program property if __IBT__ or __SHSTK__ is defined.
* config.h.in (ENABLE_CET): New #undef.
* configure.ac: Add --enable-cet.
* configure: Regenerated.
* elf/dl-load.c (filebuf): Moved before "dynamic-link.h".
(_dl_map_object_from_fd): Call DL_PROCESS_PT_NOTE on PT_NOTE
segment if DL_PROCESS_PT_NOTE is defined.
* elf/rtld.c (dl_main): Likewise.
* elf/dl-support.c: Include <dl-procruntime.c>.
* include/link.h: Include <link_map.h>.
* sysdeps/generic/dl-procruntime.c: New file.
* sysdeps/generic/link_map.h: Likewise.
* sysdeps/unix/sysv/linux/i386/dl-machine.h: Likewise.
* sysdeps/unix/sysv/linux/x86/configure: Likewise.
* sysdeps/unix/sysv/linux/x86/configure.ac: Likewise.
* sysdeps/unix/sysv/linux/x86/dl-cet-nonshared.c: Likewise.
* sysdeps/unix/sysv/linux/x86/dl-cet.c: Likewise.
* sysdeps/unix/sysv/linux/x86/dl-cet.h: Likewise.
* sysdeps/unix/sysv/linux/x86/dl-procruntime.c: Likewise.
* sysdeps/unix/sysv/linux/x86/libc-start.c: Likewise.
* sysdeps/unix/sysv/linux/x86/link_map.h: Likewise.
* sysdeps/unix/sysv/linux/x86/sys/cet.h: Likewise.
* sysdeps/unix/sysv/linux/x86_64/dl-machine.h: Likewise.
* sysdeps/generic/ldsodefs.h: Include <dl-procruntime.c> in
the writable ld.so namespace.
* sysdeps/i386/dl-machine.h (DL_INIT): New.
(_dl_start_user): Replace _dl_init with DL_INIT.
* sysdeps/unix/sysv/linux/x86/Makefile (sysdep_routines): Add
dl-cet-nonshared if CET is enabled.
(sysdep-dl-routines): Add dl-cet if CET is enabled.
(sysdep_headers): Add sys/cet.h if CET is enabled.
(asm-CPPFLAGS): Include sysdeps/unix/sysv/linux/x86/sys/cet.h
if CET is enabled.
* sysdeps/x86/libc-start.c (ARCH_INIT_CPU_FEATURES): Define
only if it is undefined.
* sysdeps/x86_64/dl-machine.h (DL_INIT): New.
(_dl_start_user): Replace _dl_init with DL_INIT.
https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=31e1594811caf5d87d236cd9f58e84fee92e6714
commit 31e1594811caf5d87d236cd9f58e84fee92e6714
Author: H.J. Lu <hjl.tools@gmail.com>
Date: Thu Jun 22 08:51:42 2017 -0700
x86: Add IBT/SHSTK bits to cpu-features
Add IBT/SHSTK bits to cpu-features for Shadow Stack in Intel Control-flow
Enforcement Technology (CET) instructions:
https://software.intel.com/sites/default/files/managed/4d/2a/control-flow-enforcement-technology-preview.pdf
* sysdeps/x86/cpu-features.h (bit_cpu_BIT): New.
(bit_cpu_SHSTK): Likewise.
(index_cpu_IBT): Likewise.
(index_cpu_SHSTK): Likewise.
(reg_IBT): Likewise.
(reg_SHSTK): Likewise.
https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=40215e85a8f00b85c1e2b96cb4b37c23fc3831cd
commit 40215e85a8f00b85c1e2b96cb4b37c23fc3831cd
Author: H.J. Lu <hjl.tools@gmail.com>
Date: Wed Jun 21 13:07:05 2017 -0700
Add NT_GNU_PROPERTY_TYPE_0 macros
Add macros used in GNU .note.gnu.property notes (NT_GNU_PROPERTY_TYPE_0).
* elf/elf.h (NT_GNU_PROPERTY_TYPE_0): New.
(NOTE_GNU_PROPERTY_SECTION_NAME): Likewise.
(GNU_PROPERTY_STACK_SIZE): Likewie.
(GNU_PROPERTY_NO_COPY_ON_PROTECTED): Likewie.
(GNU_PROPERTY_LOPROC): Likewise.
(GNU_PROPERTY_HIPROC): Likewise.
(GNU_PROPERTY_LOUSER): Likewise.
(GNU_PROPERTY_HIUSER): Likewise.
(GNU_PROPERTY_X86_ISA_1_USED): Likwise.
(GNU_PROPERTY_X86_ISA_1_NEEDED): Likwise.
(GNU_PROPERTY_X86_FEATURE_1_AND): Likwise.
(GNU_PROPERTY_X86_ISA_1_486): Likwise.
(GNU_PROPERTY_X86_ISA_1_586): Likwise.
(GNU_PROPERTY_X86_ISA_1_686): Likwise.
(GNU_PROPERTY_X86_ISA_1_SSE): Likwise.
(GNU_PROPERTY_X86_ISA_1_SSE2): Likwise.
(GNU_PROPERTY_X86_ISA_1_SSE3): Likwise.
(GNU_PROPERTY_X86_ISA_1_SSSE3): Likwise.
(GNU_PROPERTY_X86_ISA_1_SSE4_1): Likwise.
(GNU_PROPERTY_X86_ISA_1_SSE4_2): Likwise.
(GNU_PROPERTY_X86_ISA_1_AVX): Likwise.
(GNU_PROPERTY_X86_ISA_1_AVX2): Likwise.
(GNU_PROPERTY_X86_ISA_1_AVX512F): Likwise.
(GNU_PROPERTY_X86_ISA_1_AVX512CD): Likwise.
(GNU_PROPERTY_X86_ISA_1_AVX512ER): Likwise.
(GNU_PROPERTY_X86_ISA_1_AVX512PF): Likwise.
(GNU_PROPERTY_X86_ISA_1_AVX512VL): Likwise.
(GNU_PROPERTY_X86_ISA_1_AVX512DQ): Likwise.
(GNU_PROPERTY_X86_ISA_1_AVX512BW): Likwise.
(GNU_PROPERTY_X86_FEATURE_1_IBT): Likwise.
(GNU_PROPERTY_X86_FEATURE_1_SHSTK): Likwise.
https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=fd362b682226c8597c1b01a648d1d49423bb8ac3
commit fd362b682226c8597c1b01a648d1d49423bb8ac3
Author: H.J. Lu <hjl.tools@gmail.com>
Date: Fri Jun 16 14:27:02 2017 -0700
Add private_function for private functions within glibc
i386 _dl_runtime_resolve:
movl (%esp), %ecx
movl %eax, (%esp) # Store the function address.
movl 4(%esp), %eax
ret $12 # Jump to function address.
is incompatible with Shadow Stack in Intel Control-flow Enforcement
Technology (CET) instructions:
https://software.intel.com/sites/default/files/managed/4d/2a/control-flow-enforcement-technology-preview.pdf
since shadow stack doesn't match return stack. We need to use register
indirect branch via %ecx. That means only 2 parameters can be passed
in registers for external function calls with lazy binding. However,
internal_function, which should be used only with hidden function, is
defined as
# define internal_function __attribute__ ((regparm (3), stdcall))
and used with private function calls between different shared objects of
glibc. We introduce private_function for such purpose:
# define private_function __attribute__ ((regparm (2), stdcall))
so that %ecx can be used by _dl_runtime_resolve as scratch register.
[BZ #21598]
* config.h.in (USE_REGPARMS): Removed.
(internal_function): Undef.
(private_function): New. Undef.
* debug/fortify_fail.c (__fortify_fail): Replace internal_function
with private_function.
* elf/dl-addr.c (_dl_addr): Likewise.
* elf/dl-error-skeleton.c (_dl_signal_error): Likewise.
(_dl_catch_error): Likewise.
* elf/dl-execstack.c (_dl_make_stack_executable): Likewise.
* elf/dl-load.c (_dl_rtld_di_serinfo): Likewise.
* elf/dl-open.c (_dl_find_dso_for_object): Likewise.
* elf/dl-support.c (_dl_make_stack_executable_hook): Likewise.
* elf/dl-sym.c (_dl_vsym): Likewise.
(_dl_sym): Likewise.
* elf/dl-tls.c (_dl_get_tls_static_info): Likewise.
(_dl_allocate_tls_init): Likewise.
(_dl_allocate_tls): Likewise.
(_dl_deallocate_tls): Likewise.
* grp/grp-merge.c (__copy_grp): Likewise.
(__merge_grp): Likewise.
* grp/grp-merge.h (__copy_grp): Likewise.
(__merge_grp): Likewise.
* include/dlfcn.h (_dl_addr): Likewise.
(_dl_sym): Likewise.
(_dl_vsym): Likewise.
* include/rpc/pmap_clnt.h (__libc_rpc_getport): Likewise.
* include/stdio.h (__fortify_fail): Likewise.
* include/stdlib.h (__strtof_nan): Likewise.
(__strtod_nan): Likewise.
(__strtold_nan): Likewise.
(__wcstof_nan): Likewise.
(__wcstod_nan): Likewise.
(__wcstold_nan): Likewise.
(__strtof128_nan): Likewise.
(__wcstof128_nan): Likewise.
* inet/inet6_scopeid_pton.c (__inet6_scopeid_pton): Likewise.
* inet/net-internal.h (__inet6_scopeid_pton): Likewise.
* nptl/allocatestack.c (__make_stacks_executable): Likewise.
* nptl/libc_pthread_init.c (__libc_pthread_init): Likewise.
* nptl/pthreadP.h (__make_stacks_executable): Likewise.
(__libc_pthread_init): Likewise.
* nss/XXX-lookup.c (DB_LOOKUP_FCT): Likewise.
(DB_COMPAT_FCT): Likewise.
* nss/getXXbyYY_r.c (DB_LOOKUP_FCT): Likewise.
* nss/getXXent_r.c (DB_LOOKUP_FCT): Likewise.
* nss/nsswitch.h (db_lookup_function): Likewise.
* resolv/gai_misc.h (__gai_sigqueue): Likewise.
* resolv/gai_sigqueue.c (__gai_sigqueue): Likewise.
* stdlib/strtod_nan_main.c (STRTOD_NAN): Likewise.
* sunrpc/pm_getport.c (__libc_rpc_getport): Likewise.
* sysdeps/generic/ldsodefs.h (_dl_make_stack_executable_hook):
Likewise.
(_dl_make_stack_executable): Likewise.
(_dl_signal_error): Likewise.
(_dl_catch_error): Likewise.
(_dl_rtld_di_serinfo): Likewise.
(_dl_allocate_tls): Likewise.
(_dl_get_tls_static_info): Likewise.
(_dl_allocate_tls_init): Likewise.
(_dl_deallocate_tls): Likewise.
(_dl_find_dso_for_object): Likewise.
* sysdeps/unix/sysv/linux/dl-execstack.c
(_dl_make_stack_executable): Likewise.
* sysdeps/unix/sysv/linux/gai_sigqueue.c (__gai_sigqueue):
Likewise.
* sysdeps/unix/sysv/linux/netlink_assert_response.c
(__netlink_assert_response): Likewise.
* sysdeps/unix/sysv/linux/netlinkaccess.h
(__netlink_assert_response): Likewise.
* include/libc-symbols.h (private_function): New.
* sysdeps/i386/configure.ac (USE_REGPARMS): Removed.
(internal_function): New AC_DEFINE.
(private_function): Likewise.
* sysdeps/i386/configure: Regenerated.
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