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Fix linux personality syscall wrapper 

The personality system call, starting with linux kernel commit
v2.6.29-6609-g11d06b2a1e5658f448a308aa3beb97bacd64a940, always
successfully changes the personality if requested.  The syscall
wrapper, however, still can return an error in the following cases:
- the value returned by the system call looks like an error
due to architecture limitations of 32-bit kernels;
- a personality greater than 0xffffffff is passed to the system call,
and the 64-bit kernel does not have commit
v2.6.35-rc1-372-g485d527686850d68a0e9006dd9904f19f122485e
that would truncate this value to unsigned int;
- on sparc64, the value returned by the system call looks like an error
due to sparc64 kernel sign extension bug.

The solution is three-fold:
- move generic syscalls.list personality entry to generic 64-bit
syscalls.list file;
- for each 32-bit architecture that use negated errno semantics,
add a NOERRNO personality entry to their syscalls.list file;
- for sparc64 and 32-bit architectures that use dedicated registers
to flag syscall errors, add a wrapper around personality syscall;
if the system call return value is flagged as an error, this wrapper
returns the negated "would be errno" value, otherwise it returns
the system call return value; on sparc64, it also truncates the
personality argument to unsigned int before passing it to the kernel.

[BZ #19408]
* sysdeps/unix/sysv/linux/personality.c: New file.
* sysdeps/unix/sysv/linux/sparc/sparc64/personality.c: Likewise.
* sysdeps/unix/sysv/linux/tst-personality.c: Likewise.
* sysdeps/unix/sysv/linux/Makefile [$(subdir) == misc]
(sysdep_routines): Add personality.
(tests): Add tst-personality.
* sysdeps/unix/sysv/linux/syscalls.list (personality): Move ...
* sysdeps/unix/sysv/linux/wordsize-64/syscalls.list: ... here.
* sysdeps/unix/sysv/linux/arm/syscalls.list (personality): New entry.
* sysdeps/unix/sysv/linux/hppa/syscalls.list (personality): Likewise.
* sysdeps/unix/sysv/linux/i386/syscalls.list (personality): Likewise.
* sysdeps/unix/sysv/linux/m68k/syscalls.list (personality): Likewise.
* sysdeps/unix/sysv/linux/microblaze/syscalls.list (personality):
Likewise.
* sysdeps/unix/sysv/linux/mips/mips64/n32/syscalls.list (personality):
Likewise.
* sysdeps/unix/sysv/linux/s390/s390-32/syscalls.list (personality):
Likewise.
* sysdeps/unix/sysv/linux/sh/syscalls.list (personality): Likewise.
* sysdeps/unix/sysv/linux/x86_64/x32/syscalls.list (personality):
Likewise.
This commit is contained in:
Dmitry V. Levin 2015-12-27 16:30:02 +00:00
parent cc42170ef6
commit e0043e17df
16 changed files with 139 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

25
ChangeLog
View File

@ -1,3 +1,28 @@
2015-12-30 Dmitry V. Levin <ldv@altlinux.org>
[BZ #19408]
* sysdeps/unix/sysv/linux/personality.c: New file.
* sysdeps/unix/sysv/linux/sparc/sparc64/personality.c: Likewise.
* sysdeps/unix/sysv/linux/tst-personality.c: Likewise.
* sysdeps/unix/sysv/linux/Makefile [$(subdir) == misc]
(sysdep_routines): Add personality.
(tests): Add tst-personality.
* sysdeps/unix/sysv/linux/syscalls.list (personality): Move ...
* sysdeps/unix/sysv/linux/wordsize-64/syscalls.list: ... here.
* sysdeps/unix/sysv/linux/arm/syscalls.list (personality): New entry.
* sysdeps/unix/sysv/linux/hppa/syscalls.list (personality): Likewise.
* sysdeps/unix/sysv/linux/i386/syscalls.list (personality): Likewise.
* sysdeps/unix/sysv/linux/m68k/syscalls.list (personality): Likewise.
* sysdeps/unix/sysv/linux/microblaze/syscalls.list (personality):
Likewise.
* sysdeps/unix/sysv/linux/mips/mips64/n32/syscalls.list (personality):
Likewise.
* sysdeps/unix/sysv/linux/s390/s390-32/syscalls.list (personality):
Likewise.
* sysdeps/unix/sysv/linux/sh/syscalls.list (personality): Likewise.
* sysdeps/unix/sysv/linux/x86_64/x32/syscalls.list (personality):
Likewise.
2015-12-30 Aurelien Jarno <aurelien@aurel32.net>
* sysdeps/unix/sysv/linux/arm/ioperm.c: Do not include <string.h>.

5
sysdeps/unix/sysv/linux/Makefile
View File

@ -16,7 +16,8 @@ include $(firstword $(wildcard $(sysdirs:=/sysctl.mk)))
sysdep_routines += clone llseek umount umount2 readahead \
setfsuid setfsgid makedev epoll_pwait signalfd \
eventfd eventfd_read eventfd_write prlimit
eventfd eventfd_read eventfd_write prlimit \
personality
CFLAGS-gethostid.c = -fexceptions
CFLAGS-tst-writev.c += "-DARTIFICIAL_LIMIT=0x80000000-__getpagesize()"
@ -41,7 +42,7 @@ sysdep_headers += sys/mount.h sys/acct.h sys/sysctl.h \
bits/socket_type.h bits/syscall.h bits/sysctl.h \
bits/mman-linux.h
tests += tst-clone tst-fanotify
tests += tst-clone tst-fanotify tst-personality
# Generate the list of SYS_* macros for the system calls (__NR_* macros).

2
sysdeps/unix/sysv/linux/arm/syscalls.list
View File

@ -19,6 +19,8 @@ prlimit64 EXTRA prlimit64 i:iipp prlimit64
fanotify_mark EXTRA fanotify_mark i:iiiiis fanotify_mark
personality EXTRA personality Ei:i __personality personality
# Semaphore and shm system calls. msgctl, shmctl, and semctl have C
# wrappers (to set __IPC_64).
msgget - msgget i:ii __msgget msgget

1
sysdeps/unix/sysv/linux/hppa/syscalls.list
View File

@ -37,3 +37,4 @@ setrlimit - setrlimit i:ip __setrlimit setrlimit
getrlimit - getrlimit i:ip __getrlimit getrlimit
prlimit64 EXTRA prlimit64 i:iipp __prlimit64 prlimit64@@GLIBC_2.17
fanotify_mark EXTRA fanotify_mark i:iiiiis __fanotify_mark fanotify_mark@@GLIBC_2.19
personality EXTRA personality Ei:i __personality personality

2
sysdeps/unix/sysv/linux/i386/syscalls.list
View File

@ -25,3 +25,5 @@ waitpid - waitpid Ci:ipi __waitpid waitpid
prlimit64 EXTRA prlimit64 i:iipp prlimit64
fanotify_mark EXTRA fanotify_mark i:iiiiis fanotify_mark
personality EXTRA personality Ei:i __personality personality

1
sysdeps/unix/sysv/linux/m68k/syscalls.list
View File

@ -19,3 +19,4 @@ setfsuid - setfsuid32 Ei:i setfsuid
cacheflush EXTRA cacheflush i:iiii __cacheflush cacheflush
prlimit64 EXTRA prlimit64 i:iipp prlimit64
fanotify_mark EXTRA fanotify_mark i:iiiiis fanotify_mark
personality EXTRA personality Ei:i __personality personality

1
sysdeps/unix/sysv/linux/microblaze/syscalls.list
View File

@ -4,6 +4,7 @@ cacheflush EXTRA cacheflush i:iiii __cacheflush cacheflush
prlimit64 EXTRA prlimit64 i:iipp prlimit64
fanotify_mark EXTRA fanotify_mark i:iiiiis fanotify_mark
personality EXTRA personality Ei:i __personality personality
# Semaphore and shm system calls. msgctl, shmctl, and semctl have C
# wrappers (to set __IPC_64).

2
sysdeps/unix/sysv/linux/mips/mips64/n32/syscalls.list
View File

@ -6,3 +6,5 @@ sync_file_range - sync_file_range Ci:iiii sync_file_range
prlimit64 EXTRA prlimit64 i:iipp prlimit64
fanotify_mark EXTRA fanotify_mark i:iiiis fanotify_mark
personality EXTRA personality Ei:i __personality personality

49
sysdeps/unix/sysv/linux/personality.c Normal file
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@ -0,0 +1,49 @@
/* Copyright (C) 2015 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 <sys/personality.h>
#include <sysdep.h>
extern __typeof (personality) __personality;
int
__personality (unsigned long persona)
{
#ifdef PERSONALITY_TRUNCATE_ARGUMENT
/* Starting with kernel commit v2.6.21-3117-g97dc32c, the type of
task_struct->pesonality is "unsigned int".
Starting with kernel commit v2.6.35-rc1-372-g485d527, the personality
syscall accepts "unsigned int" instead of "long unsigned int".
Inbetween, a personality argument that does not fit into "unsigned int"
would result to system call returning -EINVAL.
We explicitly truncate the personality argument to "unsigned int"
to eliminate the uncertainty. */
persona = (unsigned int) persona;
#endif
INTERNAL_SYSCALL_DECL (err);
long ret = INTERNAL_SYSCALL (personality, err, 1, persona);
/* Starting with kernel commit v2.6.29-6609-g11d06b2, the personality syscall
never fails. However, 32-bit kernels might flag valid values as errors, so
we need to reverse the error setting. We can't use the raw result as some
arches split the return/error values. */
if (__glibc_unlikely (INTERNAL_SYSCALL_ERROR_P (ret, err)))
ret = -INTERNAL_SYSCALL_ERRNO (ret, err);
return ret;
}
weak_alias (__personality, personality)

1
sysdeps/unix/sysv/linux/s390/s390-32/syscalls.list
View File

@ -20,3 +20,4 @@ setrlimit - setrlimit i:ip __setrlimit setrlimit@GLIBC_2.0 setrlimit@@GLIBC_2.2
prlimit64 EXTRA prlimit64 i:iipp prlimit64
fanotify_mark EXTRA fanotify_mark i:iiiiis fanotify_mark
personality EXTRA personality Ei:i __personality personality

2
sysdeps/unix/sysv/linux/sh/syscalls.list
View File

@ -20,3 +20,5 @@ waitpid - waitpid Ci:ipi __waitpid waitpid
prlimit64 EXTRA prlimit64 i:iipp prlimit64
fanotify_mark EXTRA fanotify_mark i:iiiiis __fanotify_mark fanotify_mark@@GLIBC_2.16
personality EXTRA personality Ei:i __personality personality

3
sysdeps/unix/sysv/linux/sparc/sparc64/personality.c Normal file
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@ -0,0 +1,3 @@
/* Work around sign extension bug in the kernel. */
#define PERSONALITY_TRUNCATE_ARGUMENT
#include <sysdeps/unix/sysv/linux/personality.c>

1
sysdeps/unix/sysv/linux/syscalls.list
View File

@ -46,7 +46,6 @@ munlockall - munlockall i: munlockall
nanosleep - nanosleep Ci:pp __nanosleep nanosleep
nfsservctl EXTRA nfsservctl i:ipp nfsservctl
pause - pause Ci: __libc_pause pause
personality EXTRA personality i:i __personality personality
pipe - pipe i:f __pipe pipe
pipe2 - pipe2 i:fi __pipe2 pipe2
pivot_root EXTRA pivot_root i:ss pivot_root

45
sysdeps/unix/sysv/linux/tst-personality.c Normal file
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@ -0,0 +1,45 @@
/* BZ #19408 linux personality syscall wrapper test.
Copyright (C) 2015 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 <errno.h>
#include <sys/personality.h>
static int
do_test (void)
{
int rc = 0;
unsigned int test_persona = -EINVAL;
unsigned int saved_persona;
errno = 0xdefaced;
saved_persona = personality (0xffffffff);
if (personality (test_persona) != saved_persona ||
personality (0xffffffff) == -1 ||
personality (PER_LINUX) == -1 ||
personality (0xffffffff) != PER_LINUX ||
0xdefaced != errno)
rc = 1;
(void) personality (saved_persona);
return rc;
}
#define TEST_FUNCTION do_test ()
#include "../test-skeleton.c"

1
sysdeps/unix/sysv/linux/wordsize-64/syscalls.list
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@ -20,3 +20,4 @@ open - open Ci:siv __libc_open __open open __open64 open64
prlimit EXTRA prlimit64 i:iipp prlimit prlimit64
fanotify_mark EXTRA fanotify_mark i:iiiis fanotify_mark
personality EXTRA personality i:i __personality personality

1
sysdeps/unix/sysv/linux/x86_64/x32/syscalls.list
View File

@ -2,6 +2,7 @@
fallocate - fallocate Ci:iiii fallocate fallocate64
gettimeofday - gettimeofday:__vdso_gettimeofday@LINUX_2.6 i:pP __gettimeofday gettimeofday
personality EXTRA personality Ei:i __personality personality
posix_fadvise - fadvise64 Vi:iiii posix_fadvise posix_fadvise64
preadv - preadv Ci:ipii preadv preadv64
pwritev - pwritev Ci:ipii pwritev pwritev64