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Revert Intel CET changes to __jmp_buf_tag (Bug 22743)

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In commit cba595c350 and commit
f81ddabffd, ABI compatibility with
applications was broken by increasing the size of the on-stack
allocated __pthread_unwind_buf_t beyond the oringal size.
Applications only have the origianl space available for
__pthread_unwind_register, and __pthread_unwind_next to use,
any increase in the size of __pthread_unwind_buf_t causes these
functions to write beyond the original structure into other
on-stack variables leading to segmentation faults in common
applications like vlc. The only workaround is to version those
functions which operate on the old sized objects, but this must
happen in glibc 2.28.

Thank you to Andrew Senkevich, H.J. Lu, and Aurelien Jarno, for
submitting reports and tracking the issue down.

The commit reverts the above mentioned commits and testing on
x86_64 shows that the ABI compatibility is restored. A tst-cleanup1
regression test linked with an older glibc now passes when run
with the newly built glibc. Previously a tst-cleanup1 linked with
an older glibc would segfault when run with an affected glibc build.

Tested on x86_64 with no regressions.

Signed-off-by: Carlos O'Donell <carlos@redhat.com>
This commit is contained in:
Carlos O'Donell 2018-01-24 20:35:22 -08:00
parent 47c4b4b060
commit 2ec0e7eade
13 changed files with 42 additions and 136 deletions
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30
ChangeLog
View File

@ -1,3 +1,33 @@
2018-01-24 Carlos O'Donll <carlos@redhat.com>
Revert:
2017-12-19 H.J. Lu <hongjiu.lu@intel.com>
[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.
2017-12-19 H.J. Lu <hongjiu.lu@intel.com>
[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.
2018-01-25 Rafal Luzynski <digitalfreak@lingonborough.com>
[BZ #10871]

28
bits/types/__cancel_jmp_buf_tag.h
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@ -1,28 +0,0 @@
/* Define struct __cancel_jmp_buf_tag.
Copyright (C) 2017-2018 Free Software Foundation, Inc.
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
<http://www.gnu.org/licenses/>. */
#ifndef ____cancel_jmp_buf_tag_defined
#define ____cancel_jmp_buf_tag_defined 1
struct __cancel_jmp_buf_tag
{
__jmp_buf __cancel_jmp_buf;
int __mask_was_saved;
};
#endif

3
nptl/Makefile
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@ -22,8 +22,7 @@ subdir := nptl
include ../Makeconfig
headers := pthread.h semaphore.h bits/semaphore.h \
bits/types/__cancel_jmp_buf_tag.h
headers := pthread.h semaphore.h bits/semaphore.h
extra-libs := libpthread
extra-libs-others := $(extra-libs)

3
nptl/descr.h
View File

@ -65,9 +65,6 @@ struct pthread_unwind_buf
{
__jmp_buf jmp_buf;
int mask_was_saved;
#ifdef NEED_SAVED_MASK_IN_CANCEL_JMP_BUF
__sigset_t saved_mask;
#endif
} cancel_jmp_buf[1];
union

1
sysdeps/i386/nptl/tcb-offsets.sym
View File

@ -15,4 +15,3 @@ POINTER_GUARD offsetof (tcbhead_t, pointer_guard)
#ifndef __ASSUME_PRIVATE_FUTEX
PRIVATE_FUTEX offsetof (tcbhead_t, private_futex)
#endif
FEATURE_1_OFFSET offsetof (tcbhead_t, feature_1)

4
sysdeps/i386/nptl/tls.h
View File

@ -50,10 +50,6 @@ typedef struct
void *__private_tm[4];
/* GCC split stack support. */
void *__private_ss;
/* Bit 0: IBT.
Bit 1: SHSTK.
*/
unsigned int feature_1;
} tcbhead_t;
# define TLS_MULTIPLE_THREADS_IN_TCB 1

7
sysdeps/nptl/pthread.h
View File

@ -27,7 +27,6 @@
#include <bits/setjmp.h>
#include <bits/wordsize.h>
#include <bits/types/struct_timespec.h>
#include <bits/types/__cancel_jmp_buf_tag.h>
/* Detach state. */
@ -524,7 +523,11 @@ extern void pthread_testcancel (void);
typedef struct
{
struct __cancel_jmp_buf_tag __cancel_jmp_buf[1];
struct
{
__jmp_buf __cancel_jmp_buf;
int __mask_was_saved;
} __cancel_jmp_buf[1];
void *__pad[4];
} __pthread_unwind_buf_t __attribute__ ((__aligned__));

7
sysdeps/unix/sysv/linux/hppa/pthread.h
View File

@ -27,7 +27,6 @@
#include <bits/setjmp.h>
#include <bits/wordsize.h>
#include <bits/types/struct_timespec.h>
#include <bits/types/__cancel_jmp_buf_tag.h>
/* Detach state. */
@ -500,7 +499,11 @@ extern void pthread_testcancel (void);
typedef struct
{
struct __cancel_jmp_buf_tag __cancel_jmp_buf[1];
struct
{
__jmp_buf __cancel_jmp_buf;
int __mask_was_saved;
} __cancel_jmp_buf[1];
void *__pad[4];
} __pthread_unwind_buf_t __attribute__ ((__aligned__));

31
sysdeps/unix/sysv/linux/x86/bits/types/__cancel_jmp_buf_tag.h
View File

@ -1,31 +0,0 @@
/* Define struct __cancel_jmp_buf_tag.
Copyright (C) 2017-2018 Free Software Foundation, Inc.
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
<http://www.gnu.org/licenses/>. */
#ifndef ____cancel_jmp_buf_tag_defined
#define ____cancel_jmp_buf_tag_defined 1
#include <bits/types/__sigset_t.h>
struct __cancel_jmp_buf_tag
{
__jmp_buf __cancel_jmp_buf;
int __mask_was_saved;
__sigset_t __saved_mask;
};
#endif

36
sysdeps/unix/sysv/linux/x86/nptl/pthreadP.h
View File

@ -1,36 +0,0 @@
/* Internal pthread header. Linux/x86 version.
Copyright (C) 2017-2018 Free Software Foundation, Inc.
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
<http://www.gnu.org/licenses/>. */
#include_next <nptl/pthreadP.h>
#ifndef _PTHREADP_H_X86
#define _PTHREADP_H_X86 1
extern struct pthread_unwind_buf ____pthread_unwind_buf_private;
_Static_assert (sizeof (____pthread_unwind_buf_private.cancel_jmp_buf)
>= sizeof (struct __jmp_buf_tag),
"size of cancel_jmp_buf < sizeof __jmp_buf_tag");
extern __pthread_unwind_buf_t ____pthread_unwind_buf;
_Static_assert (sizeof (____pthread_unwind_buf.__cancel_jmp_buf)
>= sizeof (struct __jmp_buf_tag),
"size of __cancel_jmp_buf < sizeof __jmp_buf_tag");
#endif

22
sysdeps/unix/sysv/linux/x86/pthreaddef.h
View File

@ -1,22 +0,0 @@
/* Pthread macros. Linux/x86 version.
Copyright (C) 2017-2018 Free Software Foundation, Inc.
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
<http://www.gnu.org/licenses/>. */
#include_next <pthreaddef.h>
/* Need saved_mask in cancel_jmp_buf. */
#define NEED_SAVED_MASK_IN_CANCEL_JMP_BUF 1

1
sysdeps/x86_64/nptl/tcb-offsets.sym
View File

@ -15,7 +15,6 @@ VGETCPU_CACHE_OFFSET offsetof (tcbhead_t, vgetcpu_cache)
#ifndef __ASSUME_PRIVATE_FUTEX
PRIVATE_FUTEX offsetof (tcbhead_t, private_futex)
#endif
FEATURE_1_OFFSET offsetof (tcbhead_t, feature_1)
-- Not strictly offsets, but these values are also used in the TCB.
TCB_CANCELSTATE_BITMASK CANCELSTATE_BITMASK

5
sysdeps/x86_64/nptl/tls.h
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@ -56,10 +56,7 @@ typedef struct
# else
int __glibc_reserved1;
# endif
/* Bit 0: IBT.
Bit 1: SHSTK.
*/
unsigned int feature_1;
int __glibc_unused1;
/* Reservation of some values for the TM ABI. */
void *__private_tm[4];
/* GCC split stack support. */