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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, 20 Dec 2017 15:49:51 +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 #74 from cvs-commit at gcc dot gnu.org <cvs-commit at gcc dot gnu.org> ---
This is an automated email from the git hooks/post-receive script. It was
generated because a ref change was pushed to the repository containing
the project "GNU C Library master sources".
The branch, hjl/cet/master has been created
at ec58375a3f96a0d89b60f24cbbe8ec8b99291a0e (commit)
- Log -----------------------------------------------------------------
https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=ec58375a3f96a0d89b60f24cbbe8ec8b99291a0e
commit ec58375a3f96a0d89b60f24cbbe8ec8b99291a0e
Author: H.J. Lu <hjl.tools@gmail.com>
Date: Wed Dec 20 06:38:42 2017 -0800
Disallow -fcf-protection -mshstk with <ucontext.h>
-fcf-protection -mshstk is incompatible with makecontext family functions
since they can't properly set up and destroy shadow stack pointer. It is
an error when -fcf-protection -mshstk is used with <ucontext.h>. When
<ucontext.h> is used, GNU_PROPERTY_X86_FEATURE_1_SHSTK shouldn't be set
on the program.
* bits/ucontext.h: New file.
* sysdeps/unix/sysv/linux/x86/bits/ucontext.h: Likewise.
* sysdeps/unix/sysv/linux/x86/tst-setcontext3-shstk.sh: Likewise.
* sysdeps/unix/sysv/linux/x86/tst-ucontext-1.c: Likewise.
* sysdeps/unix/sysv/linux/x86/tst-ucontext-1.sh: Likewise.
* stdlib/Makefile (headers): Add bits/ucontext.h.
* stdlib/ucontext.h: Include <bits/ucontext.h>.
* sysdeps/unix/sysv/linux/x86/Makefile (tests-special): Add
$(objpfx)tst-setcontext3-shstk.out.
($(objpfx)tst-setcontext3-shstk.out): New target.
(tests-special): Add $(objpfx)tst-ucontext-1.out if CET is
enabled.
($(objpfx)tst-ucontext-1.out): New target if CET is enabled.
(asm-CPPFLAGS): Add -fcf-protection -mcet -include cet.h if CET
is enabled.
(CFLAGS-tst-context1.c): Add -fcf-protection=branch -mno-shstk
-mibt.
(CFLAGS-bug-getcontext.c): Likewise.
(CFLAGS-tst-makecontext.c): Likewise.
(CFLAGS-tst-makecontext2.c): Likewise.
(CFLAGS-tst-makecontext3.c): Likewise.
(CFLAGS-tst-setcontext.c): Likewise.
(CFLAGS-tst-setcontext2.c): Likewise.
(CFLAGS-tst-setcontext3.c): Likewise.
(CFLAGS-tst-xbzero-opt.c): Likewise.
https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=184a125710029031572171d1bcea6bc1650ad638
commit 184a125710029031572171d1bcea6bc1650ad638
Author: H.J. Lu <hjl.tools@gmail.com>
Date: Thu Jun 22 04:15:39 2017 -0700
x86: Support IBT and SHSTK in Intel CET [BZ #21598]
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. Linker sets GNU_PROPERTY_X86_FEATURE_1_IBT 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 without an interpreter, enable IBT and
lock IBT if GNU_PROPERTY_X86_FEATURE_1_IBT is set on the executable.
2. When loading an executable with an interpreter, enable IBT if
GNU_PROPERTY_X86_FEATURE_1_IBT is set on the interpreter.
a. If GNU_PROPERTY_X86_FEATURE_1_IBT isn't set on the executable,
disable IBT.
b. Lock IBT.
3. 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. Linker sets GNU_PROPERTY_X86_FEATURE_1_SHSTK
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 without an interpreter, enable SHSTK if
GNU_PROPERTY_X86_FEATURE_1_SHSTK is set on the executable.
2. When loading an executable with an interpreter, enable SHSTK if
GNU_PROPERTY_X86_FEATURE_1_SHSTK is set on interpreter.
a. If GNU_PROPERTY_X86_FEATURE_1_SHSTK isn't set on the executable
or any shared objects loaded via the DT_NEEDED tag, disable SHSTK.
b. Otherwise lock SHSTK.
3. After SHSTK is enabled, it is an error to load a shared object
without GNU_PROPERTY_X86_FEATURE_1_SHSTK.
To enable CET support in glibc, --enable-cet is required 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. It should be initialized by
init_cpu_features.
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
up IBT and SHSTK.
c. DL_OPEN_CHECK is added to check IBT and SHSTK compatibilty when
dlopening a shared object.
3. Replace i386 _dl_runtime_resolve and _dl_runtime_profile with
_dl_runtime_resolve_shstk and _dl_runtime_profile_shstk, respectively if
SHSTK is enabled.
<cet.h> from CET-enabled GCC is automatically included by assembly codes
to add GNU_PROPERTY_X86_FEATURE_1_IBT and GNU_PROPERTY_X86_FEATURE_1_SHSTK
to GNU program property. _CET_ENDBR is added at the entrance of all
assembly functions whose address may be taken.
[BZ #21598]
* 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-open.c (dl_open_worker): Call DL_OPEN_CHECK if it is
defined.
* sysdeps/unix/sysv/linux/i386/dl-cet.c: New file.
* sysdeps/unix/sysv/linux/i386/dl-machine.h: Likewise.
* sysdeps/unix/sysv/linux/x86/check-cet.awk: Likewise.
* sysdeps/unix/sysv/linux/x86/configure: Likewise.
* sysdeps/unix/sysv/linux/x86/configure.ac: 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/ldsodefs.h: Likewise.
* sysdeps/unix/sysv/linux/x86/link_map.h: Likewise.
* sysdeps/unix/sysv/linux/x86_64/dl-machine.h: Likewise.
* sysdeps/i386/dl-machine.h (DL_INIT): New.
(_dl_start_user): Replace _dl_init with DL_INIT.
* sysdeps/i386/dl-trampoline.S (_dl_runtime_resolve): Add
_CET_ENDBR.
(_dl_runtime_profile): Likewise.
(_dl_runtime_resolve_shstk): New.
(_dl_runtime_profile_shstk): Likewise.
* sysdeps/unix/sysv/linux/x86/Makefile (sysdep-dl-routines): Add
dl-cet if CET is enabled.
(CFLAGS-.o): Add -fcf-protection -mcet if CET is enabled.
(CFLAGS-.os): Likewise.
(CFLAGS-.op): Likewise.
(CFLAGS-.oS): Likewise.
(asm-CPPFLAGS): Add -fcf-protection -mcet -include cet.h if CET
is enabled.
(tests-special): Add $(objpfx)check-cet.out.
(cet-built-dso): New.
(+$(cet-built-dso:=.note)): Likewise.
(common-generated): Add $(cet-built-dso:$(common-objpfx)%=%.note).
($(objpfx)check-cet.out): New.
(generated): Add check-cet.out.
* sysdeps/x86/sysdep.h (_CET_ENDBR): Define if not defined.
(ENTRY): Add _CET_ENDBR.
* sysdeps/x86_64/dl-machine.h (DL_INIT): New.
(_dl_start_user): Replace _dl_init with DL_INIT.
* sysdeps/x86_64/x32/dl-machine.h (_dl_start_user): Likewise.
* sysdeps/x86_64/dl-trampoline.h (_dl_runtime_resolve): Add
_CET_ENDBR.
(_dl_runtime_profile): Likewise.
https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=80dc4376f88f1228e4456a93a7c2cffec8e7ae12
commit 80dc4376f88f1228e4456a93a7c2cffec8e7ae12
Author: H.J. Lu <hjl.tools@gmail.com>
Date: Tue Dec 5 11:58:23 2017 -0800
x86: Support shadow stack pointer in setjmp/longjmp
Save and restore shadow stack pointer in setjmp and longjmp to support
shadow stack in Intel CET. Use feature_1 in tcbhead_t to check if
shadow stack is enabled before saving and restoring shadow stack
pointer so that it works with the old smaller cancel_jmp_buf which
doesn't have space for shadow stack pointer.
2017-12-07 Igor Tsimbalist <igor.v.tsimbalist@intel.com>
H.J. Lu <hongjiu.lu@intel.com>
* sysdeps/i386/__longjmp.S: Include <jmp_buf-ssp.h>. Restore
shadow stack pointer if shadow stack is enabled and
SHADOW_STACK_POINTER_OFFSET is defined.
* sysdeps/i386/bsd-_setjmp.S: Likewise.
* sysdeps/i386/bsd-setjmp.S: Likewise.
* sysdeps/i386/setjmp.S: Likewise.
* sysdeps/x86_64/__longjmp.S: Likewise.
* sysdeps/x86_64/setjmp.S: Likewise.
* sysdeps/unix/sysv/linux/i386/____longjmp_chk.S: Include
shadow stack pointer if shadow stack is enabled.
* sysdeps/unix/sysv/linux/x86_64/____longjmp_chk.S: Likewise.
* sysdeps/unix/sysv/linux/x86/Makefile (gen-as-const-headers):
Remove jmp_buf-ssp.sym.
* sysdeps/x86/Makefile (gen-as-const-headers): Add
jmp_buf-ssp.sym.
* sysdeps/x86/jmp_buf-ssp.sym: New dummy file.
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