glibc/sysdeps/unix/sysv/linux/x86/setjmpP.h

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x86: Make a space in jmpbuf for shadow stack pointer To support Shadow Stack (SHSTK) in Intel Control-flow Enforcement Technology (CET) in setjmp/longjmp, we need to save shadow stack pointer in jmp_buf. The __saved_mask field in jmp_buf has type of __sigset_t. On Linux, __sigset_t is defined as #define _SIGSET_NWORDS (1024 / (8 * sizeof (unsigned long int))) typedef struct { unsigned long int __val[_SIGSET_NWORDS]; } __sigset_t; which is much bigger than expected by the __sigprocmask system call, which has typedef struct { unsigned long sig[_NSIG_WORDS]; } sigset_t; For Linux/x86, we can shrink __sigset_t used by __saved_mask in jmp_buf to add paddings for shadow stack pointer. As long as the new __sigset_t is not smaller than sigset_t expected by the __sigprocmask system call, it should work correctly. This patch adds an internal header file, <setjmpP.h>, to define __jmp_buf_sigset_t for __saved_mask in jmp_buf for Linux/x86 with a space to store shadow stack pointer. It verifies __jmp_buf_sigset_t has the suitable size for the __sigprocmask system call. A run-time test, tst-saved_mask-1.c, is added to verify that size of __jmp_buf_sigset_t is sufficient. If its size is too small, the test fails with rt_sigprocmask(SIG_SETMASK, strace: umoven: short read (4 < 8) @0x7fa8aa28effc 0x7fa8aa28effc, NULL, 8) = -1 EFAULT (Bad address) rt_sigprocmask(SIG_SETMASK, strace: umoven: short read (4 < 8) @0x7fa8aa28effc 0x7fa8aa28effc, NULL, 8) = -1 EFAULT (Bad address) rt_sigprocmask(SIG_SETMASK, NULL, 0x7fa8aa28effc, 8) = -1 EFAULT (Bad address) exit_group(1) = ? Tested with build-many-glibcs.py. * debug/longjmp_chk.c: Include <setjmpP.h> instead of <setjmp.h>. * setjmp/longjmp.c: Include <setjmpP.h> instead of <setjmp.h>. (__libc_siglongjmp): Cast &env[0].__saved_mask to "sigset_t *". * setjmp/sigjmp.c: Include <setjmpP.h> instead of <setjmp.h>. (__sigjmp_save): Cast &env[0].__saved_mask to "sigset_t *". * sysdeps/generic/setjmpP.h: New file. * sysdeps/unix/sysv/linux/x86/jmp_buf-ssp.sym: Likewise. * sysdeps/unix/sysv/linux/x86/setjmpP.h: Likewise. * sysdeps/unix/sysv/linux/x86/tst-saved_mask-1.c: Likewise. * sysdeps/unix/sysv/linux/x86/Makefile (gen-as-const-headers): Add jmp_buf-ssp.sym. (tests): Add tst-saved_mask-1.
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/* Internal header file for <setjmp.h>. Linux/x86 version.
Copyright (C) 2017-2019 Free Software Foundation, Inc.
x86: Make a space in jmpbuf for shadow stack pointer To support Shadow Stack (SHSTK) in Intel Control-flow Enforcement Technology (CET) in setjmp/longjmp, we need to save shadow stack pointer in jmp_buf. The __saved_mask field in jmp_buf has type of __sigset_t. On Linux, __sigset_t is defined as #define _SIGSET_NWORDS (1024 / (8 * sizeof (unsigned long int))) typedef struct { unsigned long int __val[_SIGSET_NWORDS]; } __sigset_t; which is much bigger than expected by the __sigprocmask system call, which has typedef struct { unsigned long sig[_NSIG_WORDS]; } sigset_t; For Linux/x86, we can shrink __sigset_t used by __saved_mask in jmp_buf to add paddings for shadow stack pointer. As long as the new __sigset_t is not smaller than sigset_t expected by the __sigprocmask system call, it should work correctly. This patch adds an internal header file, <setjmpP.h>, to define __jmp_buf_sigset_t for __saved_mask in jmp_buf for Linux/x86 with a space to store shadow stack pointer. It verifies __jmp_buf_sigset_t has the suitable size for the __sigprocmask system call. A run-time test, tst-saved_mask-1.c, is added to verify that size of __jmp_buf_sigset_t is sufficient. If its size is too small, the test fails with rt_sigprocmask(SIG_SETMASK, strace: umoven: short read (4 < 8) @0x7fa8aa28effc 0x7fa8aa28effc, NULL, 8) = -1 EFAULT (Bad address) rt_sigprocmask(SIG_SETMASK, strace: umoven: short read (4 < 8) @0x7fa8aa28effc 0x7fa8aa28effc, NULL, 8) = -1 EFAULT (Bad address) rt_sigprocmask(SIG_SETMASK, NULL, 0x7fa8aa28effc, 8) = -1 EFAULT (Bad address) exit_group(1) = ? Tested with build-many-glibcs.py. * debug/longjmp_chk.c: Include <setjmpP.h> instead of <setjmp.h>. * setjmp/longjmp.c: Include <setjmpP.h> instead of <setjmp.h>. (__libc_siglongjmp): Cast &env[0].__saved_mask to "sigset_t *". * setjmp/sigjmp.c: Include <setjmpP.h> instead of <setjmp.h>. (__sigjmp_save): Cast &env[0].__saved_mask to "sigset_t *". * sysdeps/generic/setjmpP.h: New file. * sysdeps/unix/sysv/linux/x86/jmp_buf-ssp.sym: Likewise. * sysdeps/unix/sysv/linux/x86/setjmpP.h: Likewise. * sysdeps/unix/sysv/linux/x86/tst-saved_mask-1.c: Likewise. * sysdeps/unix/sysv/linux/x86/Makefile (gen-as-const-headers): Add jmp_buf-ssp.sym. (tests): Add tst-saved_mask-1.
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This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
Prefer https to http for gnu.org and fsf.org URLs Also, change sources.redhat.com to sourceware.org. This patch was automatically generated by running the following shell script, which uses GNU sed, and which avoids modifying files imported from upstream: sed -ri ' s,(http|ftp)(://(.*\.)?(gnu|fsf|sourceware)\.org($|[^.]|\.[^a-z])),https\2,g s,(http|ftp)(://(.*\.)?)sources\.redhat\.com($|[^.]|\.[^a-z]),https\2sourceware.org\4,g ' \ $(find $(git ls-files) -prune -type f \ ! -name '*.po' \ ! -name 'ChangeLog*' \ ! -path COPYING ! -path COPYING.LIB \ ! -path manual/fdl-1.3.texi ! -path manual/lgpl-2.1.texi \ ! -path manual/texinfo.tex ! -path scripts/config.guess \ ! -path scripts/config.sub ! -path scripts/install-sh \ ! -path scripts/mkinstalldirs ! -path scripts/move-if-change \ ! -path INSTALL ! -path locale/programs/charmap-kw.h \ ! -path po/libc.pot ! -path sysdeps/gnu/errlist.c \ ! '(' -name configure \ -execdir test -f configure.ac -o -f configure.in ';' ')' \ ! '(' -name preconfigure \ -execdir test -f preconfigure.ac ';' ')' \ -print) and then by running 'make dist-prepare' to regenerate files built from the altered files, and then executing the following to cleanup: chmod a+x sysdeps/unix/sysv/linux/riscv/configure # Omit irrelevant whitespace and comment-only changes, # perhaps from a slightly-different Autoconf version. git checkout -f \ sysdeps/csky/configure \ sysdeps/hppa/configure \ sysdeps/riscv/configure \ sysdeps/unix/sysv/linux/csky/configure # Omit changes that caused a pre-commit check to fail like this: # remote: *** error: sysdeps/powerpc/powerpc64/ppc-mcount.S: trailing lines git checkout -f \ sysdeps/powerpc/powerpc64/ppc-mcount.S \ sysdeps/unix/sysv/linux/s390/s390-64/syscall.S # Omit change that caused a pre-commit check to fail like this: # remote: *** error: sysdeps/sparc/sparc64/multiarch/memcpy-ultra3.S: last line does not end in newline git checkout -f sysdeps/sparc/sparc64/multiarch/memcpy-ultra3.S
2019-09-07 05:40:42 +00:00
<https://www.gnu.org/licenses/>. */
x86: Make a space in jmpbuf for shadow stack pointer To support Shadow Stack (SHSTK) in Intel Control-flow Enforcement Technology (CET) in setjmp/longjmp, we need to save shadow stack pointer in jmp_buf. The __saved_mask field in jmp_buf has type of __sigset_t. On Linux, __sigset_t is defined as #define _SIGSET_NWORDS (1024 / (8 * sizeof (unsigned long int))) typedef struct { unsigned long int __val[_SIGSET_NWORDS]; } __sigset_t; which is much bigger than expected by the __sigprocmask system call, which has typedef struct { unsigned long sig[_NSIG_WORDS]; } sigset_t; For Linux/x86, we can shrink __sigset_t used by __saved_mask in jmp_buf to add paddings for shadow stack pointer. As long as the new __sigset_t is not smaller than sigset_t expected by the __sigprocmask system call, it should work correctly. This patch adds an internal header file, <setjmpP.h>, to define __jmp_buf_sigset_t for __saved_mask in jmp_buf for Linux/x86 with a space to store shadow stack pointer. It verifies __jmp_buf_sigset_t has the suitable size for the __sigprocmask system call. A run-time test, tst-saved_mask-1.c, is added to verify that size of __jmp_buf_sigset_t is sufficient. If its size is too small, the test fails with rt_sigprocmask(SIG_SETMASK, strace: umoven: short read (4 < 8) @0x7fa8aa28effc 0x7fa8aa28effc, NULL, 8) = -1 EFAULT (Bad address) rt_sigprocmask(SIG_SETMASK, strace: umoven: short read (4 < 8) @0x7fa8aa28effc 0x7fa8aa28effc, NULL, 8) = -1 EFAULT (Bad address) rt_sigprocmask(SIG_SETMASK, NULL, 0x7fa8aa28effc, 8) = -1 EFAULT (Bad address) exit_group(1) = ? Tested with build-many-glibcs.py. * debug/longjmp_chk.c: Include <setjmpP.h> instead of <setjmp.h>. * setjmp/longjmp.c: Include <setjmpP.h> instead of <setjmp.h>. (__libc_siglongjmp): Cast &env[0].__saved_mask to "sigset_t *". * setjmp/sigjmp.c: Include <setjmpP.h> instead of <setjmp.h>. (__sigjmp_save): Cast &env[0].__saved_mask to "sigset_t *". * sysdeps/generic/setjmpP.h: New file. * sysdeps/unix/sysv/linux/x86/jmp_buf-ssp.sym: Likewise. * sysdeps/unix/sysv/linux/x86/setjmpP.h: Likewise. * sysdeps/unix/sysv/linux/x86/tst-saved_mask-1.c: Likewise. * sysdeps/unix/sysv/linux/x86/Makefile (gen-as-const-headers): Add jmp_buf-ssp.sym. (tests): Add tst-saved_mask-1.
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#ifndef _SETJMPP_H
#define _SETJMPP_H 1
#include <bits/types/__sigset_t.h>
x86: Use pad in pthread_unwind_buf to preserve shadow stack register The pad array in struct pthread_unwind_buf is used by setjmp to save shadow stack register. We assert that size of struct pthread_unwind_buf is no less than offset of shadow stack pointer + shadow stack pointer size. Since functions, like LIBC_START_MAIN, START_THREAD_DEFN as well as these with thread cancellation, call setjmp, but never return after __libc_unwind_longjmp, __libc_unwind_longjmp, which is defined as __libc_longjmp on x86, doesn't need to restore shadow stack register. __libc_longjmp, which is a private interface for thread cancellation implementation in libpthread, is changed to call __longjmp_cancel, instead of __longjmp. __longjmp_cancel is a new internal function in libc, which is similar to __longjmp, but doesn't restore shadow stack register. The compatibility longjmp and siglongjmp in libpthread.so are changed to call __libc_siglongjmp, instead of __libc_longjmp, so that they will restore shadow stack register. Tested with build-many-glibcs.py. Signed-off-by: H.J. Lu <hjl.tools@gmail.com> Reviewed-by: Carlos O'Donell <carlos@redhat.com> * nptl/pthread_create.c (START_THREAD_DEFN): Clear previous handlers after setjmp. * setjmp/longjmp.c (__libc_longjmp): Don't define alias if defined. * sysdeps/unix/sysv/linux/x86/setjmpP.h: Include <libc-pointer-arith.h>. (_JUMP_BUF_SIGSET_BITS_PER_WORD): New. (_JUMP_BUF_SIGSET_NSIG): Changed to 96. (_JUMP_BUF_SIGSET_NWORDS): Changed to use ALIGN_UP and _JUMP_BUF_SIGSET_BITS_PER_WORD. * sysdeps/x86/Makefile (sysdep_routines): Add __longjmp_cancel. * sysdeps/x86/__longjmp_cancel.S: New file. * sysdeps/x86/longjmp.c: Likewise. * sysdeps/x86/nptl/pt-longjmp.c: Likewise.
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#include <libc-pointer-arith.h>
x86: Make a space in jmpbuf for shadow stack pointer To support Shadow Stack (SHSTK) in Intel Control-flow Enforcement Technology (CET) in setjmp/longjmp, we need to save shadow stack pointer in jmp_buf. The __saved_mask field in jmp_buf has type of __sigset_t. On Linux, __sigset_t is defined as #define _SIGSET_NWORDS (1024 / (8 * sizeof (unsigned long int))) typedef struct { unsigned long int __val[_SIGSET_NWORDS]; } __sigset_t; which is much bigger than expected by the __sigprocmask system call, which has typedef struct { unsigned long sig[_NSIG_WORDS]; } sigset_t; For Linux/x86, we can shrink __sigset_t used by __saved_mask in jmp_buf to add paddings for shadow stack pointer. As long as the new __sigset_t is not smaller than sigset_t expected by the __sigprocmask system call, it should work correctly. This patch adds an internal header file, <setjmpP.h>, to define __jmp_buf_sigset_t for __saved_mask in jmp_buf for Linux/x86 with a space to store shadow stack pointer. It verifies __jmp_buf_sigset_t has the suitable size for the __sigprocmask system call. A run-time test, tst-saved_mask-1.c, is added to verify that size of __jmp_buf_sigset_t is sufficient. If its size is too small, the test fails with rt_sigprocmask(SIG_SETMASK, strace: umoven: short read (4 < 8) @0x7fa8aa28effc 0x7fa8aa28effc, NULL, 8) = -1 EFAULT (Bad address) rt_sigprocmask(SIG_SETMASK, strace: umoven: short read (4 < 8) @0x7fa8aa28effc 0x7fa8aa28effc, NULL, 8) = -1 EFAULT (Bad address) rt_sigprocmask(SIG_SETMASK, NULL, 0x7fa8aa28effc, 8) = -1 EFAULT (Bad address) exit_group(1) = ? Tested with build-many-glibcs.py. * debug/longjmp_chk.c: Include <setjmpP.h> instead of <setjmp.h>. * setjmp/longjmp.c: Include <setjmpP.h> instead of <setjmp.h>. (__libc_siglongjmp): Cast &env[0].__saved_mask to "sigset_t *". * setjmp/sigjmp.c: Include <setjmpP.h> instead of <setjmp.h>. (__sigjmp_save): Cast &env[0].__saved_mask to "sigset_t *". * sysdeps/generic/setjmpP.h: New file. * sysdeps/unix/sysv/linux/x86/jmp_buf-ssp.sym: Likewise. * sysdeps/unix/sysv/linux/x86/setjmpP.h: Likewise. * sysdeps/unix/sysv/linux/x86/tst-saved_mask-1.c: Likewise. * sysdeps/unix/sysv/linux/x86/Makefile (gen-as-const-headers): Add jmp_buf-ssp.sym. (tests): Add tst-saved_mask-1.
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x86: Use pad in pthread_unwind_buf to preserve shadow stack register The pad array in struct pthread_unwind_buf is used by setjmp to save shadow stack register. We assert that size of struct pthread_unwind_buf is no less than offset of shadow stack pointer + shadow stack pointer size. Since functions, like LIBC_START_MAIN, START_THREAD_DEFN as well as these with thread cancellation, call setjmp, but never return after __libc_unwind_longjmp, __libc_unwind_longjmp, which is defined as __libc_longjmp on x86, doesn't need to restore shadow stack register. __libc_longjmp, which is a private interface for thread cancellation implementation in libpthread, is changed to call __longjmp_cancel, instead of __longjmp. __longjmp_cancel is a new internal function in libc, which is similar to __longjmp, but doesn't restore shadow stack register. The compatibility longjmp and siglongjmp in libpthread.so are changed to call __libc_siglongjmp, instead of __libc_longjmp, so that they will restore shadow stack register. Tested with build-many-glibcs.py. Signed-off-by: H.J. Lu <hjl.tools@gmail.com> Reviewed-by: Carlos O'Donell <carlos@redhat.com> * nptl/pthread_create.c (START_THREAD_DEFN): Clear previous handlers after setjmp. * setjmp/longjmp.c (__libc_longjmp): Don't define alias if defined. * sysdeps/unix/sysv/linux/x86/setjmpP.h: Include <libc-pointer-arith.h>. (_JUMP_BUF_SIGSET_BITS_PER_WORD): New. (_JUMP_BUF_SIGSET_NSIG): Changed to 96. (_JUMP_BUF_SIGSET_NWORDS): Changed to use ALIGN_UP and _JUMP_BUF_SIGSET_BITS_PER_WORD. * sysdeps/x86/Makefile (sysdep_routines): Add __longjmp_cancel. * sysdeps/x86/__longjmp_cancel.S: New file. * sysdeps/x86/longjmp.c: Likewise. * sysdeps/x86/nptl/pt-longjmp.c: Likewise.
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/* <setjmp/setjmp.h> has
struct __jmp_buf_tag
{
__jmp_buf __jmpbuf;
int __mask_was_saved;
__sigset_t __saved_mask;
};
struct __jmp_buf_tag is 32 bits aligned on i386 and is 64 bits
aligned on x32 and x86-64. __saved_mask is aligned to 32 bits
on i386/x32 without padding and is aligned to 64 bits on x86-64
with 32 bit padding.
and <nptl/descr.h> has
struct pthread_unwind_buf
{
struct
{
__jmp_buf jmp_buf;
int mask_was_saved;
} cancel_jmp_buf[1];
union
{
void *pad[4];
struct
{
struct pthread_unwind_buf *prev;
struct _pthread_cleanup_buffer *cleanup;
int canceltype;
} data;
} priv;
};
struct pthread_unwind_buf is 32 bits aligned on i386 and 64 bits
aligned on x32/x86-64. cancel_jmp_buf is aligned to 32 bits on
i386 and is aligned to 64 bits on x32/x86-64.
The pad array in struct pthread_unwind_buf is used by setjmp to save
shadow stack register. The usable space in __saved_mask for sigset
and shadow stack pointer:
1. i386: The 4x4 byte pad array which can be used for 4 byte shadow
stack pointer and maximum 12 byte sigset.
2. x32: 4 byte padding + the 4x4 byte pad array which can be used
for 8 byte shadow stack pointer and maximum 12 byte sigset.
3. x86-64: The 4x8 byte pad array which can be used for 8 byte
shadow stack pointer and maximum 24 byte sigset.
NB: We use setjmp in thread cancellation and this saves the shadow
stack register, but __libc_unwind_longjmp doesn't restore the shadow
stack register since cancellation never returns after longjmp. */
/* Number of bits per long. */
#define _JUMP_BUF_SIGSET_BITS_PER_WORD (8 * sizeof (unsigned long int))
/* The biggest signal number. As of kernel 4.14, x86 _NSIG is 64. The
common maximum sigset for i386, x32 and x86-64 is 12 bytes (96 bits).
Define it to 96 to leave some rooms for future use. */
#define _JUMP_BUF_SIGSET_NSIG 96
x86: Make a space in jmpbuf for shadow stack pointer To support Shadow Stack (SHSTK) in Intel Control-flow Enforcement Technology (CET) in setjmp/longjmp, we need to save shadow stack pointer in jmp_buf. The __saved_mask field in jmp_buf has type of __sigset_t. On Linux, __sigset_t is defined as #define _SIGSET_NWORDS (1024 / (8 * sizeof (unsigned long int))) typedef struct { unsigned long int __val[_SIGSET_NWORDS]; } __sigset_t; which is much bigger than expected by the __sigprocmask system call, which has typedef struct { unsigned long sig[_NSIG_WORDS]; } sigset_t; For Linux/x86, we can shrink __sigset_t used by __saved_mask in jmp_buf to add paddings for shadow stack pointer. As long as the new __sigset_t is not smaller than sigset_t expected by the __sigprocmask system call, it should work correctly. This patch adds an internal header file, <setjmpP.h>, to define __jmp_buf_sigset_t for __saved_mask in jmp_buf for Linux/x86 with a space to store shadow stack pointer. It verifies __jmp_buf_sigset_t has the suitable size for the __sigprocmask system call. A run-time test, tst-saved_mask-1.c, is added to verify that size of __jmp_buf_sigset_t is sufficient. If its size is too small, the test fails with rt_sigprocmask(SIG_SETMASK, strace: umoven: short read (4 < 8) @0x7fa8aa28effc 0x7fa8aa28effc, NULL, 8) = -1 EFAULT (Bad address) rt_sigprocmask(SIG_SETMASK, strace: umoven: short read (4 < 8) @0x7fa8aa28effc 0x7fa8aa28effc, NULL, 8) = -1 EFAULT (Bad address) rt_sigprocmask(SIG_SETMASK, NULL, 0x7fa8aa28effc, 8) = -1 EFAULT (Bad address) exit_group(1) = ? Tested with build-many-glibcs.py. * debug/longjmp_chk.c: Include <setjmpP.h> instead of <setjmp.h>. * setjmp/longjmp.c: Include <setjmpP.h> instead of <setjmp.h>. (__libc_siglongjmp): Cast &env[0].__saved_mask to "sigset_t *". * setjmp/sigjmp.c: Include <setjmpP.h> instead of <setjmp.h>. (__sigjmp_save): Cast &env[0].__saved_mask to "sigset_t *". * sysdeps/generic/setjmpP.h: New file. * sysdeps/unix/sysv/linux/x86/jmp_buf-ssp.sym: Likewise. * sysdeps/unix/sysv/linux/x86/setjmpP.h: Likewise. * sysdeps/unix/sysv/linux/x86/tst-saved_mask-1.c: Likewise. * sysdeps/unix/sysv/linux/x86/Makefile (gen-as-const-headers): Add jmp_buf-ssp.sym. (tests): Add tst-saved_mask-1.
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/* Number of longs to hold all signals. */
#define _JUMP_BUF_SIGSET_NWORDS \
x86: Use pad in pthread_unwind_buf to preserve shadow stack register The pad array in struct pthread_unwind_buf is used by setjmp to save shadow stack register. We assert that size of struct pthread_unwind_buf is no less than offset of shadow stack pointer + shadow stack pointer size. Since functions, like LIBC_START_MAIN, START_THREAD_DEFN as well as these with thread cancellation, call setjmp, but never return after __libc_unwind_longjmp, __libc_unwind_longjmp, which is defined as __libc_longjmp on x86, doesn't need to restore shadow stack register. __libc_longjmp, which is a private interface for thread cancellation implementation in libpthread, is changed to call __longjmp_cancel, instead of __longjmp. __longjmp_cancel is a new internal function in libc, which is similar to __longjmp, but doesn't restore shadow stack register. The compatibility longjmp and siglongjmp in libpthread.so are changed to call __libc_siglongjmp, instead of __libc_longjmp, so that they will restore shadow stack register. Tested with build-many-glibcs.py. Signed-off-by: H.J. Lu <hjl.tools@gmail.com> Reviewed-by: Carlos O'Donell <carlos@redhat.com> * nptl/pthread_create.c (START_THREAD_DEFN): Clear previous handlers after setjmp. * setjmp/longjmp.c (__libc_longjmp): Don't define alias if defined. * sysdeps/unix/sysv/linux/x86/setjmpP.h: Include <libc-pointer-arith.h>. (_JUMP_BUF_SIGSET_BITS_PER_WORD): New. (_JUMP_BUF_SIGSET_NSIG): Changed to 96. (_JUMP_BUF_SIGSET_NWORDS): Changed to use ALIGN_UP and _JUMP_BUF_SIGSET_BITS_PER_WORD. * sysdeps/x86/Makefile (sysdep_routines): Add __longjmp_cancel. * sysdeps/x86/__longjmp_cancel.S: New file. * sysdeps/x86/longjmp.c: Likewise. * sysdeps/x86/nptl/pt-longjmp.c: Likewise.
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(ALIGN_UP (_JUMP_BUF_SIGSET_NSIG, _JUMP_BUF_SIGSET_BITS_PER_WORD) \
/ _JUMP_BUF_SIGSET_BITS_PER_WORD)
x86: Make a space in jmpbuf for shadow stack pointer To support Shadow Stack (SHSTK) in Intel Control-flow Enforcement Technology (CET) in setjmp/longjmp, we need to save shadow stack pointer in jmp_buf. The __saved_mask field in jmp_buf has type of __sigset_t. On Linux, __sigset_t is defined as #define _SIGSET_NWORDS (1024 / (8 * sizeof (unsigned long int))) typedef struct { unsigned long int __val[_SIGSET_NWORDS]; } __sigset_t; which is much bigger than expected by the __sigprocmask system call, which has typedef struct { unsigned long sig[_NSIG_WORDS]; } sigset_t; For Linux/x86, we can shrink __sigset_t used by __saved_mask in jmp_buf to add paddings for shadow stack pointer. As long as the new __sigset_t is not smaller than sigset_t expected by the __sigprocmask system call, it should work correctly. This patch adds an internal header file, <setjmpP.h>, to define __jmp_buf_sigset_t for __saved_mask in jmp_buf for Linux/x86 with a space to store shadow stack pointer. It verifies __jmp_buf_sigset_t has the suitable size for the __sigprocmask system call. A run-time test, tst-saved_mask-1.c, is added to verify that size of __jmp_buf_sigset_t is sufficient. If its size is too small, the test fails with rt_sigprocmask(SIG_SETMASK, strace: umoven: short read (4 < 8) @0x7fa8aa28effc 0x7fa8aa28effc, NULL, 8) = -1 EFAULT (Bad address) rt_sigprocmask(SIG_SETMASK, strace: umoven: short read (4 < 8) @0x7fa8aa28effc 0x7fa8aa28effc, NULL, 8) = -1 EFAULT (Bad address) rt_sigprocmask(SIG_SETMASK, NULL, 0x7fa8aa28effc, 8) = -1 EFAULT (Bad address) exit_group(1) = ? Tested with build-many-glibcs.py. * debug/longjmp_chk.c: Include <setjmpP.h> instead of <setjmp.h>. * setjmp/longjmp.c: Include <setjmpP.h> instead of <setjmp.h>. (__libc_siglongjmp): Cast &env[0].__saved_mask to "sigset_t *". * setjmp/sigjmp.c: Include <setjmpP.h> instead of <setjmp.h>. (__sigjmp_save): Cast &env[0].__saved_mask to "sigset_t *". * sysdeps/generic/setjmpP.h: New file. * sysdeps/unix/sysv/linux/x86/jmp_buf-ssp.sym: Likewise. * sysdeps/unix/sysv/linux/x86/setjmpP.h: Likewise. * sysdeps/unix/sysv/linux/x86/tst-saved_mask-1.c: Likewise. * sysdeps/unix/sysv/linux/x86/Makefile (gen-as-const-headers): Add jmp_buf-ssp.sym. (tests): Add tst-saved_mask-1.
2017-11-30 12:49:25 +00:00
typedef struct
{
unsigned long int __val[_JUMP_BUF_SIGSET_NWORDS];
} __jmp_buf_sigset_t;
typedef union
{
__sigset_t __saved_mask_compat;
struct
{
__jmp_buf_sigset_t __saved_mask;
x86: Use pad in pthread_unwind_buf to preserve shadow stack register The pad array in struct pthread_unwind_buf is used by setjmp to save shadow stack register. We assert that size of struct pthread_unwind_buf is no less than offset of shadow stack pointer + shadow stack pointer size. Since functions, like LIBC_START_MAIN, START_THREAD_DEFN as well as these with thread cancellation, call setjmp, but never return after __libc_unwind_longjmp, __libc_unwind_longjmp, which is defined as __libc_longjmp on x86, doesn't need to restore shadow stack register. __libc_longjmp, which is a private interface for thread cancellation implementation in libpthread, is changed to call __longjmp_cancel, instead of __longjmp. __longjmp_cancel is a new internal function in libc, which is similar to __longjmp, but doesn't restore shadow stack register. The compatibility longjmp and siglongjmp in libpthread.so are changed to call __libc_siglongjmp, instead of __libc_longjmp, so that they will restore shadow stack register. Tested with build-many-glibcs.py. Signed-off-by: H.J. Lu <hjl.tools@gmail.com> Reviewed-by: Carlos O'Donell <carlos@redhat.com> * nptl/pthread_create.c (START_THREAD_DEFN): Clear previous handlers after setjmp. * setjmp/longjmp.c (__libc_longjmp): Don't define alias if defined. * sysdeps/unix/sysv/linux/x86/setjmpP.h: Include <libc-pointer-arith.h>. (_JUMP_BUF_SIGSET_BITS_PER_WORD): New. (_JUMP_BUF_SIGSET_NSIG): Changed to 96. (_JUMP_BUF_SIGSET_NWORDS): Changed to use ALIGN_UP and _JUMP_BUF_SIGSET_BITS_PER_WORD. * sysdeps/x86/Makefile (sysdep_routines): Add __longjmp_cancel. * sysdeps/x86/__longjmp_cancel.S: New file. * sysdeps/x86/longjmp.c: Likewise. * sysdeps/x86/nptl/pt-longjmp.c: Likewise.
2018-05-02 13:17:20 +00:00
/* Used for shadow stack pointer. NB: Shadow stack pointer
must have the same alignment as __saved_mask. Otherwise
offset of __saved_mask will be changed. */
x86: Make a space in jmpbuf for shadow stack pointer To support Shadow Stack (SHSTK) in Intel Control-flow Enforcement Technology (CET) in setjmp/longjmp, we need to save shadow stack pointer in jmp_buf. The __saved_mask field in jmp_buf has type of __sigset_t. On Linux, __sigset_t is defined as #define _SIGSET_NWORDS (1024 / (8 * sizeof (unsigned long int))) typedef struct { unsigned long int __val[_SIGSET_NWORDS]; } __sigset_t; which is much bigger than expected by the __sigprocmask system call, which has typedef struct { unsigned long sig[_NSIG_WORDS]; } sigset_t; For Linux/x86, we can shrink __sigset_t used by __saved_mask in jmp_buf to add paddings for shadow stack pointer. As long as the new __sigset_t is not smaller than sigset_t expected by the __sigprocmask system call, it should work correctly. This patch adds an internal header file, <setjmpP.h>, to define __jmp_buf_sigset_t for __saved_mask in jmp_buf for Linux/x86 with a space to store shadow stack pointer. It verifies __jmp_buf_sigset_t has the suitable size for the __sigprocmask system call. A run-time test, tst-saved_mask-1.c, is added to verify that size of __jmp_buf_sigset_t is sufficient. If its size is too small, the test fails with rt_sigprocmask(SIG_SETMASK, strace: umoven: short read (4 < 8) @0x7fa8aa28effc 0x7fa8aa28effc, NULL, 8) = -1 EFAULT (Bad address) rt_sigprocmask(SIG_SETMASK, strace: umoven: short read (4 < 8) @0x7fa8aa28effc 0x7fa8aa28effc, NULL, 8) = -1 EFAULT (Bad address) rt_sigprocmask(SIG_SETMASK, NULL, 0x7fa8aa28effc, 8) = -1 EFAULT (Bad address) exit_group(1) = ? Tested with build-many-glibcs.py. * debug/longjmp_chk.c: Include <setjmpP.h> instead of <setjmp.h>. * setjmp/longjmp.c: Include <setjmpP.h> instead of <setjmp.h>. (__libc_siglongjmp): Cast &env[0].__saved_mask to "sigset_t *". * setjmp/sigjmp.c: Include <setjmpP.h> instead of <setjmp.h>. (__sigjmp_save): Cast &env[0].__saved_mask to "sigset_t *". * sysdeps/generic/setjmpP.h: New file. * sysdeps/unix/sysv/linux/x86/jmp_buf-ssp.sym: Likewise. * sysdeps/unix/sysv/linux/x86/setjmpP.h: Likewise. * sysdeps/unix/sysv/linux/x86/tst-saved_mask-1.c: Likewise. * sysdeps/unix/sysv/linux/x86/Makefile (gen-as-const-headers): Add jmp_buf-ssp.sym. (tests): Add tst-saved_mask-1.
2017-11-30 12:49:25 +00:00
unsigned long int __shadow_stack_pointer;
} __saved;
} __jmpbuf_arch_t;
#undef __sigset_t
#define __sigset_t __jmpbuf_arch_t
#include <setjmp.h>
#undef __saved_mask
#define __saved_mask __saved_mask.__saved.__saved_mask
#include <signal.h>
#define _SIGPROCMASK_NSIG_WORDS (_NSIG / (8 * sizeof (unsigned long int)))
typedef struct
{
unsigned long int __val[_SIGPROCMASK_NSIG_WORDS];
} __sigprocmask_sigset_t;
extern jmp_buf ___buf;
extern __typeof (___buf[0].__saved_mask) ___saved_mask;
_Static_assert (sizeof (___saved_mask) >= sizeof (__sigprocmask_sigset_t),
"size of ___saved_mask < size of __sigprocmask_sigset_t");
#endif /* setjmpP.h */