[Bug nptl/22563] __cancel_jmp_buf in __pthread_unwind_buf_t is incompatible with setjmp/longmp

["cvs-commit at gcc dot gnu.org" <sourceware-bugzilla at sourceware dot org>]

https://sourceware.org/bugzilla/show_bug.cgi?id=22563

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- Log -----------------------------------------------------------------
https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=cba595c350e52194e10c0006732e1991e3d0803b

commit cba595c350e52194e10c0006732e1991e3d0803b
Author: H.J. Lu <hjl.tools@gmail.com>
Date:   Tue Dec 19 02:45:16 2017 -0800

    x86: Add feature_1 to tcbhead_t [BZ #22563]

    On x86, padding in struct __jmp_buf_tag is used for shadow stack pointer
    to support Shadow Stack in Intel Control-flow Enforcemen Technology.
    cancel_jmp_buf has been updated to include saved_mask so that it is as
    large as struct __jmp_buf_tag.  We must suport the old cancel_jmp_buf
    in existing binaries.  Since symbol versioning doesn't work on
    cancel_jmp_buf, feature_1 is added to tcbhead_t so that setjmp and
    longjmp can check if shadow stack is enabled.  NB: Shadow stack is
    enabled only if all modules are shadow stack enabled.

        [BZ #22563]
        * sysdeps/i386/nptl/tcb-offsets.sym (FEATURE_1_OFFSET): New.
        * sysdeps/i386/nptl/tls.h (tcbhead_t): Add feature_1.
        * sysdeps/x86_64/nptl/tcb-offsets.sym (FEATURE_1_OFFSET): New.
        * sysdeps/x86_64/nptl/tls.h (tcbhead_t): Rename __glibc_unused1
        to feature_1.

https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=f81ddabffd76ac9dd600b02adbf3e1dac4bb10ec

commit f81ddabffd76ac9dd600b02adbf3e1dac4bb10ec
Author: H.J. Lu <hjl.tools@gmail.com>
Date:   Tue Dec 19 02:43:50 2017 -0800

    Linux/x86: Update cancel_jmp_buf to match __jmp_buf_tag [BZ #22563]

    On x86, padding in struct __jmp_buf_tag is used for shadow stack pointer
    to support shadow stack in Intel Control-flow Enforcemen Technology.
    Since the cancel_jmp_buf array is passed to setjmp and longjmp by
    casting it to pointer to struct __jmp_buf_tag, it should be as large
    as struct __jmp_buf_tag.  Otherwise when shadow stack is enabled,
    setjmp and longjmp will write and read beyond cancel_jmp_buf when saving
    and restoring shadow stack pointer.

    This patch adds bits/types/__cancel_jmp_buf_tag.h to define struct
    __cancel_jmp_buf_tag so that Linux/x86 can add saved_mask to
    cancel_jmp_buf.

    Tested natively on i386, x86_64 and x32.  Tested hppa-linux-gnu with
    build-many-glibcs.py.

        [BZ #22563]
        * bits/types/__cancel_jmp_buf_tag.h: New file.
        * sysdeps/unix/sysv/linux/x86/bits/types/__cancel_jmp_buf_tag.h
        * sysdeps/unix/sysv/linux/x86/pthreaddef.h: Likewise.
        * sysdeps/unix/sysv/linux/x86/nptl/pthreadP.h: Likewise.
        * nptl/Makefile (headers): Add
        bits/types/__cancel_jmp_buf_tag.h.
        * nptl/descr.h [NEED_SAVED_MASK_IN_CANCEL_JMP_BUF]
        (pthread_unwind_buf): Add saved_mask to cancel_jmp_buf.
        * sysdeps/nptl/pthread.h: Include
        <bits/types/__cancel_jmp_buf_tag.h>.
        (__pthread_unwind_buf_t): Use struct __cancel_jmp_buf_tag with
        __cancel_jmp_buf.
        * sysdeps/unix/sysv/linux/hppa/pthread.h: Likewise.

-----------------------------------------------------------------------

Summary of changes:
 ChangeLog                                          |   26 ++++++++++++++
 bits/types/__cancel_jmp_buf_tag.h                  |   28 +++++++++++++++
 nptl/Makefile                                      |    3 +-
 nptl/descr.h                                       |    3 ++
 sysdeps/i386/nptl/tcb-offsets.sym                  |    1 +
 sysdeps/i386/nptl/tls.h                            |    4 ++
 sysdeps/nptl/pthread.h                             |    7 +---
 sysdeps/unix/sysv/linux/hppa/pthread.h             |    7 +---
 .../linux/x86/bits/types/__cancel_jmp_buf_tag.h    |   31 +++++++++++++++++
 sysdeps/unix/sysv/linux/x86/nptl/pthreadP.h        |   36 ++++++++++++++++++++
 sysdeps/unix/sysv/linux/x86/pthreaddef.h           |   22 ++++++++++++
 sysdeps/x86_64/nptl/tcb-offsets.sym                |    1 +
 sysdeps/x86_64/nptl/tls.h                          |    5 ++-
 13 files changed, 162 insertions(+), 12 deletions(-)
 create mode 100644 bits/types/__cancel_jmp_buf_tag.h
 create mode 100644
sysdeps/unix/sysv/linux/x86/bits/types/__cancel_jmp_buf_tag.h
 create mode 100644 sysdeps/unix/sysv/linux/x86/nptl/pthreadP.h
 create mode 100644 sysdeps/unix/sysv/linux/x86/pthreaddef.h

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