It was reported in http://lkml.org/lkml/2010/3/8/309 that 32 bit readv and
writev AIO operations were not functioning properly.  It turns out that
the code to convert the 32bit io vectors to 64 bits was never written.
The results of that can be pretty bad, but in my testing, it mostly ended
up in generating EFAULT as we walked off the list of I/O vectors provided.

This patch set fixes the problem in my environment.  are greatly
appreciated.

This patch:

Factor out code that will be used by both compat_do_readv_writev and the
compat aio submission code paths.
Signed-off-by: NJeff Moyer <jmoyer@redhat.com>
Reported-by: NMichael Tokarev <mjt@tls.msk.ru>
Cc: Zach Brown <zach.brown@oracle.com>
Cc: <stable@kernel.org>		[2.6.35.1]
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Originally, commit d899bf7b ("procfs: provide stack information for
threads") attempted to introduce a new feature for showing where the
threadstack was located and how many pages are being utilized by the
stack.

Commit c44972f1 ("procfs: disable per-task stack usage on NOMMU") was
applied to fix the NO_MMU case.

Commit 89240ba0 ("x86, fs: Fix x86 procfs stack information for threads on
64-bit") was applied to fix a bug in ia32 executables being loaded.

Commit 9ebd4eba ("procfs: fix /proc/<pid>/stat stack pointer for kernel
threads") was applied to fix a bug which had kernel threads printing a
userland stack address.

Commit 1306d603 ('proc: partially revert "procfs: provide stack
information for threads"') was then applied to revert the stack pages
being used to solve a significant performance regression.

This patch nearly undoes the effect of all these patches.

The reason for reverting these is it provides an unusable value in
field 28.  For x86_64, a fork will result in the task->stack_start
value being updated to the current user top of stack and not the stack
start address.  This unpredictability of the stack_start value makes
it worthless.  That includes the intended use of showing how much stack
space a thread has.

Other architectures will get different values.  As an example, ia64
gets 0.  The do_fork() and copy_process() functions appear to treat the
stack_start and stack_size parameters as architecture specific.

I only partially reverted c44972f1 ("procfs: disable per-task stack usage
on NOMMU") .  If I had completely reverted it, I would have had to change
mm/Makefile only build pagewalk.o when CONFIG_PROC_PAGE_MONITOR is
configured.  Since I could not test the builds without significant effort,
I decided to not change mm/Makefile.

I only partially reverted 89240ba0 ("x86, fs: Fix x86 procfs stack
information for threads on 64-bit") .  I left the KSTK_ESP() change in
place as that seemed worthwhile.
Signed-off-by: NRobin Holt <holt@sgi.com>
Cc: Stefani Seibold <stefani@seibold.net>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: <stable@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h

percpu.h is included by sched.h and module.h and thus ends up being
included when building most .c files.  percpu.h includes slab.h which
in turn includes gfp.h making everything defined by the two files
universally available and complicating inclusion dependencies.

percpu.h -> slab.h dependency is about to be removed.  Prepare for
this change by updating users of gfp and slab facilities include those
headers directly instead of assuming availability.  As this conversion
needs to touch large number of source files, the following script is
used as the basis of conversion.

  http://userweb.kernel.org/~tj/misc/slabh-sweep.py

The script does the followings.

* Scan files for gfp and slab usages and update includes such that
  only the necessary includes are there.  ie. if only gfp is used,
  gfp.h, if slab is used, slab.h.

* When the script inserts a new include, it looks at the include
  blocks and try to put the new include such that its order conforms
  to its surrounding.  It's put in the include block which contains
  core kernel includes, in the same order that the rest are ordered -
  alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
  doesn't seem to be any matching order.

* If the script can't find a place to put a new include (mostly
  because the file doesn't have fitting include block), it prints out
  an error message indicating which .h file needs to be added to the
  file.

The conversion was done in the following steps.

1. The initial automatic conversion of all .c files updated slightly
   over 4000 files, deleting around 700 includes and adding ~480 gfp.h
   and ~3000 slab.h inclusions.  The script emitted errors for ~400
   files.

2. Each error was manually checked.  Some didn't need the inclusion,
   some needed manual addition while adding it to implementation .h or
   embedding .c file was more appropriate for others.  This step added
   inclusions to around 150 files.

3. The script was run again and the output was compared to the edits
   from #2 to make sure no file was left behind.

4. Several build tests were done and a couple of problems were fixed.
   e.g. lib/decompress_*.c used malloc/free() wrappers around slab
   APIs requiring slab.h to be added manually.

5. The script was run on all .h files but without automatically
   editing them as sprinkling gfp.h and slab.h inclusions around .h
   files could easily lead to inclusion dependency hell.  Most gfp.h
   inclusion directives were ignored as stuff from gfp.h was usually
   wildly available and often used in preprocessor macros.  Each
   slab.h inclusion directive was examined and added manually as
   necessary.

6. percpu.h was updated not to include slab.h.

7. Build test were done on the following configurations and failures
   were fixed.  CONFIG_GCOV_KERNEL was turned off for all tests (as my
   distributed build env didn't work with gcov compiles) and a few
   more options had to be turned off depending on archs to make things
   build (like ipr on powerpc/64 which failed due to missing writeq).

   * x86 and x86_64 UP and SMP allmodconfig and a custom test config.
   * powerpc and powerpc64 SMP allmodconfig
   * sparc and sparc64 SMP allmodconfig
   * ia64 SMP allmodconfig
   * s390 SMP allmodconfig
   * alpha SMP allmodconfig
   * um on x86_64 SMP allmodconfig

8. percpu.h modifications were reverted so that it could be applied as
   a separate patch and serve as bisection point.

Given the fact that I had only a couple of failures from tests on step
6, I'm fairly confident about the coverage of this conversion patch.
If there is a breakage, it's likely to be something in one of the arch
headers which should be easily discoverable easily on most builds of
the specific arch.
Signed-off-by: NTejun Heo <tj@kernel.org>
Guess-its-ok-by: NChristoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>

Add a generic implementation of the old select() syscall, which expects
its argument in a memory block and switch all architectures over to use
it.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Hirokazu Takata <takata@linux-m32r.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@elte.hu>
Reviewed-by: NH. Peter Anvin <hpa@zytor.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: James Morris <jmorris@namei.org>
Acked-by: NAndreas Schwab <schwab@linux-m68k.org>
Acked-by: NRussell King <rmk+kernel@arm.linux.org.uk>
Acked-by: NGreg Ungerer <gerg@uclinux.org>
Acked-by: NDavid Howells <dhowells@redhat.com>
Cc: Andreas Schwab <schwab@linux-m68k.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Two nfsd related headers where included but never actually
used. The linux/nfsd/nfsd.h file will eventually be moved
to fs/nfsd directory as it is only needed by nfsd itself.

There are 3 more compat.c files in the Kernel at other ARCHs
that wrongly #include nfsd headers. Once these are fixed the
headers can be moved.
Signed-off-by: NBoaz Harrosh <bharrosh@panasas.com>
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

This patch fixes two issues in the procfs stack information on
x86-64 linux.

The 32 bit loader compat_do_execve did not store stack
start. (this was figured out by Alexey Dobriyan).

The stack information on a x64_64 kernel always shows 0 kbyte
stack usage, because of a missing implementation of the KSTK_ESP
macro which always returned -1.

The new implementation now returns the right value.
Signed-off-by: NStefani Seibold <stefani@seibold.net>
Cc: Americo Wang <xiyou.wangcong@gmail.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>
LKML-Reference: <1257240160.4889.24.camel@wall-e>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

sys_mount() reads/copies a whole page for its "type" parameter.  When
do_mount_root() passes a kernel address that points to an object which is
smaller than a whole page, copy_mount_options() will happily go past this
memory object, possibly dereferencing "wild" pointers that could be in any
state (hence the kmemcheck warning, which shows that parts of the next
page are not even allocated).

(The likelihood of something going wrong here is pretty low -- first of
all this only applies to kernel calls to sys_mount(), which are mostly
found in the boot code.  Secondly, I guess if the page was not mapped,
exact_copy_from_user() _would_ in fact handle it correctly because of its
access_ok(), etc.  checks.)

But it is much nicer to avoid the dubious reads altogether, by stopping as
soon as we find a NUL byte.  Is there a good reason why we can't do
something like this, using the already existing strndup_from_user()?

[akpm@linux-foundation.org: make copy_mount_string() static]
[AV: fix compat mount breakage, which involves undoing akpm's change above]
Reported-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NVegard Nossum <vegard.nossum@gmail.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: Nal <al@dizzy.pdmi.ras.ru>

Compat utimensat() returns EINVAL when the tv_nsec is one of UTIME_OMIT or
UTIME_NOW and the tv_sec is set to non-zero.  As per man pages, the tv_sec
field should be ignored.

sys_utimensat() works fine in this case.

Test case:

#define _GNU_SOURCE
#define _ATFILE_SOURCE
#include <stdio.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/stat.h>
#include <stdlib.h>

main(int argc, char *argv[])
{
	struct timespec ts[2];
	struct timespec *tsp;

	if (argc < 2) {
		fprintf(stderr, "Usage : %s filename\n", argv[0]);
		exit (-1);
	}

	ts[0].tv_nsec = ts[1].tv_nsec = UTIME_NOW;
	ts[0].tv_sec = ts[1].tv_sec = 1;

	tsp = ts;

	if (utimensat(AT_FDCWD, argv[1],tsp,0) == -1)
		perror("utimensat");
	else
		fprintf(stdout, "utimensat success\n");
	return 0;
}
mjs22lp5:~ # cc -m64 utimensat-test.c -o utimensat_test64
mjs22lp5:~ # cc -m32 utimensat-test.c -o utimensat_test32
mjs22lp5:~ # ./utimensat_test32 /tmp/utimensat_test
utimensat: Invalid argument
mjs22lp5:~ # ./utimensat_test64 /tmp/utimensat_test
utimensat success
mjs22lp5:~ # uname -r
2.6.31-rc8

With the patch :

mjs22lp5:~ # ./utimensat_test64 /tmp/utimensat_test
utimensat success
mjs22lp5:~ # ./utimensat_test32 /tmp/utimensat_test
utimensat success
mjs22lp5:~ # uname -r
2.6.31-rc8utimensat
Signed-off-by: NSuzuki K P <suzuki@in.ibm.com>
Cc: Ulrich Drepper <drepper@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Tom Horsley reports that his debugger hangs when it tries to read
/proc/pid_of_tracee/maps, this happens since

	"mm_for_maps: take ->cred_guard_mutex to fix the race with exec"
	04b836cbf19e885f8366bccb2e4b0474346c02d

commit in 2.6.31.

But the root of the problem lies in the fact that do_execve() path calls
tracehook_report_exec() which can stop if the tracer sets PT_TRACE_EXEC.

The tracee must not sleep in TASK_TRACED holding this mutex.  Even if we
remove ->cred_guard_mutex from mm_for_maps() and proc_pid_attr_write(),
another task doing PTRACE_ATTACH should not hang until it is killed or the
tracee resumes.

With this patch do_execve() does not use ->cred_guard_mutex directly and
we do not hold it throughout, instead:

	- introduce prepare_bprm_creds() helper, it locks the mutex
	  and calls prepare_exec_creds() to initialize bprm->cred.

	- install_exec_creds() drops the mutex after commit_creds(),
	  and thus before tracehook_report_exec()->ptrace_stop().

	  or, if exec fails,

	  free_bprm() drops this mutex when bprm->cred != NULL which
	  indicates install_exec_creds() was not called.
Reported-by: NTom Horsley <tom.horsley@att.net>
Signed-off-by: NOleg Nesterov <oleg@redhat.com>
Acked-by: NDavid Howells <dhowells@redhat.com>
Cc: Roland McGrath <roland@redhat.com>
Cc: James Morris <jmorris@namei.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

* Remove smp_lock.h from files which don't need it (including some headers!)
* Add smp_lock.h to files which do need it
* Make smp_lock.h include conditional in hardirq.h
  It's needed only for one kernel_locked() usage which is under CONFIG_PREEMPT

  This will make hardirq.h inclusion cheaper for every PREEMPT=n config
  (which includes allmodconfig/allyesconfig, BTW)
Signed-off-by: NAlexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

do_execve() and ptrace_attach() return -EINTR if
mutex_lock_interruptible(->cred_guard_mutex) fails.

This is not right, change the code to return ERESTARTNOINTR.

Perhaps we should also change proc_pid_attr_write().
Signed-off-by: NOleg Nesterov <oleg@redhat.com>
Cc: David Howells <dhowells@redhat.com>
Acked-by: NRoland McGrath <roland@redhat.com>
Cc: James Morris <jmorris@namei.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Fix a typo in fs/compat.c
Signed-off-by: NNikanth Karthikesan <knikanth@suse.de>
Signed-off-by: NJiri Kosina <jkosina@suse.cz>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Rename cred_exec_mutex to reflect that it's a guard against foreign
intervention on a process's credential state, such as is made by ptrace().  The
attachment of a debugger to a process affects execve()'s calculation of the new
credential state - _and_ also setprocattr()'s calculation of that state.
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NJames Morris <jmorris@namei.org>

If do_execve() fails after check_unsafe_exec(), it clears fs->in_exec
unconditionally. This is wrong if we race with our sub-thread which
also does do_execve:

	Two threads T1 and T2 and another process P, all share the same
	->fs.

	T1 starts do_execve(BAD_FILE). It calls check_unsafe_exec(), since
	->fs is shared, we set LSM_UNSAFE but not ->in_exec.

	P exits and decrements fs->users.

	T2 starts do_execve(), calls check_unsafe_exec(), now ->fs is not
	shared, we set fs->in_exec.

	T1 continues, open_exec(BAD_FILE) fails, we clear ->in_exec and
	return to the user-space.

	T1 does clone(CLONE_FS /* without CLONE_THREAD */).

	T2 continues without LSM_UNSAFE_SHARE while ->fs is shared with
	another process.

Change check_unsafe_exec() to return res = 1 if we set ->in_exec, and change
do_execve() to clear ->in_exec depending on res.

When do_execve() suceeds, it is safe to clear ->in_exec unconditionally.
It can be set only if we don't share ->fs with another process, and since
we already killed all sub-threads either ->in_exec == 0 or we are the
only user of this ->fs.

Also, we do not need fs->lock to clear fs->in_exec.
Signed-off-by: NOleg Nesterov <oleg@redhat.com>
Acked-by: NRoland McGrath <roland@redhat.com>
Acked-by: NHugh Dickins <hugh@veritas.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

There's really no reason to keep vfs_stat_fd and vfs_lstat_fd with
Oleg's vfs_fstatat.  Use vfs_fstatat for the few cases having the
directory fd, and switch all others to vfs_stat / vfs_lstat.
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

This is a version incorporating Christoph's suggestion.

Separate out common *fstatat functionality into a single function
instead of duplicating it all over the code.
Signed-off-by: NOleg Drokin <green@linuxhacker.ru>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Instead of always splitting the file offset into 32-bit 'high' and 'low'
parts, just split them into the largest natural word-size - which in C
terms is 'unsigned long'.

This allows 64-bit architectures to avoid the unnecessary 32-bit
shifting and masking for native format (while the compat interfaces will
obviously always have to do it).

This also changes the order of 'high' and 'low' to be "low first".  Why?
Because when we have it like this, the 64-bit system calls now don't use
the "pos_high" argument at all, and it makes more sense for the native
system call to simply match the user-mode prototype.

This results in a much more natural calling convention, and allows the
compiler to generate much more straightforward code.  On x86-64, we now
generate

        testq   %rcx, %rcx      # pos_l
        js      .L122   #,
        movq    %rcx, -48(%rbp) # pos_l, pos

from the C source

        loff_t pos = pos_from_hilo(pos_h, pos_l);
	...
        if (pos < 0)
                return -EINVAL;

and the 'pos_h' register isn't even touched.  It used to generate code
like

        mov     %r8d, %r8d      # pos_low, pos_low
        salq    $32, %rcx       #, tmp71
        movq    %r8, %rax       # pos_low, pos.386
        orq     %rcx, %rax      # tmp71, pos.386
        js      .L122   #,
        movq    %rax, -48(%rbp) # pos.386, pos

which isn't _that_ horrible, but it does show how the natural word size
is just a more sensible interface (same arguments will hold in the user
level glibc wrapper function, of course, so the kernel side is just half
of the equation!)

Note: in all cases the user code wrapper can again be the same. You can
just do

	#define HALF_BITS (sizeof(unsigned long)*4)
	__syscall(PWRITEV, fd, iov, count, offset, (offset >> HALF_BITS) >> HALF_BITS);

or something like that.  That way the user mode wrapper will also be
nicely passing in a zero (it won't actually have to do the shifts, the
compiler will understand what is going on) for the last argument.

And that is a good idea, even if nobody will necessarily ever care: if
we ever do move to a 128-bit lloff_t, this particular system call might
be left alone.  Of course, that will be the least of our worries if we
really ever need to care, so this may not be worth really caring about.

[ Fixed for lost 'loff_t' cast noticed by Andrew Morton ]
Acked-by: NGerd Hoffmann <kraxel@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: linux-api@vger.kernel.org
Cc: linux-arch@vger.kernel.org
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Ralf Baechle <ralf@linux-mips.org>>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: <linux-api@vger.kernel.org>
Cc: <linux-arch@vger.kernel.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This patch adds preadv and pwritev system calls.  These syscalls are a
pretty straightforward combination of pread and readv (same for write).
They are quite useful for doing vectored I/O in threaded applications.
Using lseek+readv instead opens race windows you'll have to plug with
locking.

Other systems have such system calls too, for example NetBSD, check
here: http://www.daemon-systems.org/man/preadv.2.html

The application-visible interface provided by glibc should look like
this to be compatible to the existing implementations in the *BSD family:

  ssize_t preadv(int d, const struct iovec *iov, int iovcnt, off_t offset);
  ssize_t pwritev(int d, const struct iovec *iov, int iovcnt, off_t offset);

This prototype has one problem though: On 32bit archs is the (64bit)
offset argument unaligned, which the syscall ABI of several archs doesn't
allow to do.  At least s390 needs a wrapper in glibc to handle this.  As
we'll need a wrappers in glibc anyway I've decided to push problem to
glibc entriely and use a syscall prototype which works without
arch-specific wrappers inside the kernel: The offset argument is
explicitly splitted into two 32bit values.

The patch sports the actual system call implementation and the windup in
the x86 system call tables.  Other archs follow as separate patches.
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: <linux-api@vger.kernel.org>
Cc: <linux-arch@vger.kernel.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Factor out some code from compat_sys_writev() which can be shared with the
upcoming compat_sys_pwritev().
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: <linux-api@vger.kernel.org>
Cc: <linux-arch@vger.kernel.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This patch series:

Implement the preadv() and pwritev() syscalls.  *BSD has this syscall for
quite some time.

Test code:

#if 0
set -x
gcc -Wall -O2 -o preadv $0
exit 0
#endif
/*
 * preadv demo / test
 *
 * (c) 2008 Gerd Hoffmann <kraxel@redhat.com>
 *
 * build with "sh $thisfile"
 */

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <inttypes.h>
#include <sys/uio.h>

/* ----------------------------------------------------------------- */
/* syscall windup                                                    */

#include <sys/syscall.h>
#if 0
/* WARNING: Be sure you know what you are doing if you enable this.
 * linux syscall code isn't upstream yet, syscall numbers are subject
 * to change */
# ifndef __NR_preadv
#  ifdef __i386__
#   define __NR_preadv  333
#   define __NR_pwritev 334
#  endif
#  ifdef __x86_64__
#   define __NR_preadv  295
#   define __NR_pwritev 296
#  endif
# endif
#endif
#ifndef __NR_preadv
# error preadv/pwritev syscall numbers are unknown
#endif

static ssize_t preadv(int fd, const struct iovec *iov, int iovcnt, off_t offset)
{
    uint32_t pos_high = (offset >> 32) & 0xffffffff;
    uint32_t pos_low  =  offset        & 0xffffffff;

    return syscall(__NR_preadv, fd, iov, iovcnt, pos_high, pos_low);
}

static ssize_t pwritev(int fd, const struct iovec *iov, int iovcnt, off_t offset)
{
    uint32_t pos_high = (offset >> 32) & 0xffffffff;
    uint32_t pos_low  =  offset        & 0xffffffff;

    return syscall(__NR_pwritev, fd, iov, iovcnt, pos_high, pos_low);
}

/* ----------------------------------------------------------------- */
/* demo/test app                                                     */

static char filename[] = "/tmp/preadv-XXXXXX";
static char outbuf[11] = "0123456789";
static char inbuf[11]  = "----------";

static struct iovec ovec[2] = {{
        .iov_base = outbuf + 5,
        .iov_len  = 5,
    },{
        .iov_base = outbuf + 0,
        .iov_len  = 5,
    }};

static struct iovec ivec[3] = {{
        .iov_base = inbuf + 6,
        .iov_len  = 2,
    },{
        .iov_base = inbuf + 4,
        .iov_len  = 2,
    },{
        .iov_base = inbuf + 2,
        .iov_len  = 2,
    }};

void cleanup(void)
{
    unlink(filename);
}

int main(int argc, char **argv)
{
    int fd, rc;

    fd = mkstemp(filename);
    if (-1 == fd) {
        perror("mkstemp");
        exit(1);
    }
    atexit(cleanup);

    /* write to file: "56789-01234" */
    rc = pwritev(fd, ovec, 2, 0);
    if (rc < 0) {
        perror("pwritev");
        exit(1);
    }

    /* read from file: "78-90-12" */
    rc = preadv(fd, ivec, 3, 2);
    if (rc < 0) {
        perror("preadv");
        exit(1);
    }

    printf("result  : %s\n", inbuf);
    printf("expected: %s\n", "--129078--");
    exit(0);
}

This patch:

Factor out some code from compat_sys_readv() which can be shared with the
upcoming compat_sys_preadv().
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: <linux-api@vger.kernel.org>
Cc: <linux-arch@vger.kernel.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

* all changes of current->fs are done under task_lock and write_lock of
  old fs->lock
* refcount is not atomic anymore (same protection)
* its decrements are done when removing reference from current; at the
  same time we decide whether to free it.
* put_fs_struct() is gone
* new field - ->in_exec.  Set by check_unsafe_exec() if we are trying to do
  execve() and only subthreads share fs_struct.  Cleared when finishing exec
  (success and failure alike).  Makes CLONE_FS fail with -EAGAIN if set.
* check_unsafe_exec() may fail with -EAGAIN if another execve() from subthread
  is in progress.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Joe Malicki reports that setuid sometimes doesn't: very rarely,
a setuid root program does not get root euid; and, by the way,
they have a health check running lsof every few minutes.

Right, check_unsafe_exec() notes whether the files_struct is being
shared by more threads than will get killed by the exec, and if so
sets LSM_UNSAFE_SHARE to make bprm_set_creds() careful about euid.
But /proc/<pid>/fd and /proc/<pid>/fdinfo lookups make transient
use of get_files_struct(), which also raises that sharing count.

There's a rather simple fix for this: exec's check on files->count
has been redundant ever since 2.6.1 made it unshare_files() (except
while compat_do_execve() omitted to do so) - just remove that check.

[Note to -stable: this patch will not apply before 2.6.29: earlier
releases should just remove the files->count line from unsafe_exec().]
Reported-by: NJoe Malicki <jmalicki@metacarta.com>
Narrowed-down-by: NMichael Itz <mitz@metacarta.com>
Tested-by: NJoe Malicki <jmalicki@metacarta.com>
Signed-off-by: NHugh Dickins <hugh@veritas.com>
Cc: stable@kernel.org
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

2.6.26's commit fd8328be
"sanitize handling of shared descriptor tables in failing execve()"
moved the unshare_files() from flush_old_exec() and several binfmts
to the head of do_execve(); but forgot to make the same change to
compat_do_execve(), leaving a CLONE_FILES files_struct shared across
exec from a 32-bit process on a 64-bit kernel.

It's arguable whether the files_struct really ought to be unshared
across exec; but 2.6.1 made that so to stop the loading binary's fd
leaking into other threads, and a 32-bit process on a 64-bit kernel
ought to behave in the same way as 32 on 32 and 64 on 64.
Signed-off-by: NHugh Dickins <hugh@veritas.com>
Cc: stable@kernel.org
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Due to a different size of ino_t ustat needs a compat handler, but
currently only x86 and mips provide one.  Add a generic compat_sys_ustat
and switch all architectures over to it.  Instead of doing various
user copy hacks compat_sys_ustat just reimplements sys_ustat as
it's trivial.  This was suggested by Arnd Bergmann.

Found by Eric Sandeen when running xfstests/017 on ppc64, which causes
stack smashing warnings on RHEL/Fedora due to the too large amount of
data writen by the syscall.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

This patch allows LSM modules to determine whether current process is in an
execve operation or not so that they can behave differently while an execve
operation is in progress.

This patch is needed by TOMOYO. Please see another patch titled "LSM adapter
functions." for backgrounds.
Signed-off-by: NTetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NJames Morris <jmorris@namei.org>

The patch:

	commit a6f76f23
	CRED: Make execve() take advantage of copy-on-write credentials

moved the place in which the 'safeness' of a SUID/SGID exec was performed to
before de_thread() was called.  This means that LSM_UNSAFE_SHARE is now
calculated incorrectly.  This flag is set if any of the usage counts for
fs_struct, files_struct and sighand_struct are greater than 1 at the time the
determination is made.  All of which are true for threads created by the
pthread library.

However, since we wish to make the security calculation before irrevocably
damaging the process so that we can return it an error code in the case where
we decide we want to reject the exec request on this basis, we have to make the
determination before calling de_thread().

So, instead, we count up the number of threads (CLONE_THREAD) that are sharing
our fs_struct (CLONE_FS), files_struct (CLONE_FILES) and sighand_structs
(CLONE_SIGHAND/CLONE_THREAD) with us.  These will be killed by de_thread() and
so can be discounted by check_unsafe_exec().

We do have to be careful because CLONE_THREAD does not imply FS or FILES.

We _assume_ that there will be no extra references to these structs held by the
threads we're going to kill.

This can be tested with the attached pair of programs.  Build the two programs
using the Makefile supplied, and run ./test1 as a non-root user.  If
successful, you should see something like:

	[dhowells@andromeda tmp]$ ./test1
	--TEST1--
	uid=4043, euid=4043 suid=4043
	exec ./test2
	--TEST2--
	uid=4043, euid=0 suid=0
	SUCCESS - Correct effective user ID

and if unsuccessful, something like:

	[dhowells@andromeda tmp]$ ./test1
	--TEST1--
	uid=4043, euid=4043 suid=4043
	exec ./test2
	--TEST2--
	uid=4043, euid=4043 suid=4043
	ERROR - Incorrect effective user ID!

The non-root user ID you see will depend on the user you run as.

[test1.c]
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <pthread.h>

static void *thread_func(void *arg)
{
	while (1) {}
}

int main(int argc, char **argv)
{
	pthread_t tid;
	uid_t uid, euid, suid;

	printf("--TEST1--\n");
	getresuid(&uid, &euid, &suid);
	printf("uid=%d, euid=%d suid=%d\n", uid, euid, suid);

	if (pthread_create(&tid, NULL, thread_func, NULL) < 0) {
		perror("pthread_create");
		exit(1);
	}

	printf("exec ./test2\n");
	execlp("./test2", "test2", NULL);
	perror("./test2");
	_exit(1);
}

[test2.c]
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>

int main(int argc, char **argv)
{
	uid_t uid, euid, suid;

	getresuid(&uid, &euid, &suid);
	printf("--TEST2--\n");
	printf("uid=%d, euid=%d suid=%d\n", uid, euid, suid);

	if (euid != 0) {
		fprintf(stderr, "ERROR - Incorrect effective user ID!\n");
		exit(1);
	}
	printf("SUCCESS - Correct effective user ID\n");
	exit(0);
}

[Makefile]
CFLAGS = -D_GNU_SOURCE -Wall -Werror -Wunused
all: test1 test2

test1: test1.c
	gcc $(CFLAGS) -o test1 test1.c -lpthread

test2: test2.c
	gcc $(CFLAGS) -o test2 test2.c
	sudo chown root.root test2
	sudo chmod +s test2
Reported-by: NDavid Smith <dsmith@redhat.com>
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Acked-by: NDavid Smith <dsmith@redhat.com>
Signed-off-by: NJames Morris <jmorris@namei.org>

Not a single architecture has wired up sys_pselect7 plus it is the
only system call with seven parameters. Just make it static and
rename it to do_pselect which will do the work for sys_pselect6.
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>

Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>
Cc: Jay Lan <jlan@engr.sgi.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Make execve() take advantage of copy-on-write credentials, allowing it to set
up the credentials in advance, and then commit the whole lot after the point
of no return.

This patch and the preceding patches have been tested with the LTP SELinux
testsuite.

This patch makes several logical sets of alteration:

 (1) execve().

     The credential bits from struct linux_binprm are, for the most part,
     replaced with a single credentials pointer (bprm->cred).  This means that
     all the creds can be calculated in advance and then applied at the point
     of no return with no possibility of failure.

     I would like to replace bprm->cap_effective with:

	cap_isclear(bprm->cap_effective)

     but this seems impossible due to special behaviour for processes of pid 1
     (they always retain their parent's capability masks where normally they'd
     be changed - see cap_bprm_set_creds()).

     The following sequence of events now happens:

     (a) At the start of do_execve, the current task's cred_exec_mutex is
     	 locked to prevent PTRACE_ATTACH from obsoleting the calculation of
     	 creds that we make.

     (a) prepare_exec_creds() is then called to make a copy of the current
     	 task's credentials and prepare it.  This copy is then assigned to
     	 bprm->cred.

  	 This renders security_bprm_alloc() and security_bprm_free()
     	 unnecessary, and so they've been removed.

     (b) The determination of unsafe execution is now performed immediately
     	 after (a) rather than later on in the code.  The result is stored in
     	 bprm->unsafe for future reference.

     (c) prepare_binprm() is called, possibly multiple times.

     	 (i) This applies the result of set[ug]id binaries to the new creds
     	     attached to bprm->cred.  Personality bit clearance is recorded,
     	     but now deferred on the basis that the exec procedure may yet
     	     fail.

         (ii) This then calls the new security_bprm_set_creds().  This should
	     calculate the new LSM and capability credentials into *bprm->cred.

	     This folds together security_bprm_set() and parts of
	     security_bprm_apply_creds() (these two have been removed).
	     Anything that might fail must be done at this point.

         (iii) bprm->cred_prepared is set to 1.

	     bprm->cred_prepared is 0 on the first pass of the security
	     calculations, and 1 on all subsequent passes.  This allows SELinux
	     in (ii) to base its calculations only on the initial script and
	     not on the interpreter.

     (d) flush_old_exec() is called to commit the task to execution.  This
     	 performs the following steps with regard to credentials:

	 (i) Clear pdeath_signal and set dumpable on certain circumstances that
	     may not be covered by commit_creds().

         (ii) Clear any bits in current->personality that were deferred from
             (c.i).

     (e) install_exec_creds() [compute_creds() as was] is called to install the
     	 new credentials.  This performs the following steps with regard to
     	 credentials:

         (i) Calls security_bprm_committing_creds() to apply any security
             requirements, such as flushing unauthorised files in SELinux, that
             must be done before the credentials are changed.

	     This is made up of bits of security_bprm_apply_creds() and
	     security_bprm_post_apply_creds(), both of which have been removed.
	     This function is not allowed to fail; anything that might fail
	     must have been done in (c.ii).

         (ii) Calls commit_creds() to apply the new credentials in a single
             assignment (more or less).  Possibly pdeath_signal and dumpable
             should be part of struct creds.

	 (iii) Unlocks the task's cred_replace_mutex, thus allowing
	     PTRACE_ATTACH to take place.

         (iv) Clears The bprm->cred pointer as the credentials it was holding
             are now immutable.

         (v) Calls security_bprm_committed_creds() to apply any security
             alterations that must be done after the creds have been changed.
             SELinux uses this to flush signals and signal handlers.

     (f) If an error occurs before (d.i), bprm_free() will call abort_creds()
     	 to destroy the proposed new credentials and will then unlock
     	 cred_replace_mutex.  No changes to the credentials will have been
     	 made.

 (2) LSM interface.

     A number of functions have been changed, added or removed:

     (*) security_bprm_alloc(), ->bprm_alloc_security()
     (*) security_bprm_free(), ->bprm_free_security()

     	 Removed in favour of preparing new credentials and modifying those.

     (*) security_bprm_apply_creds(), ->bprm_apply_creds()
     (*) security_bprm_post_apply_creds(), ->bprm_post_apply_creds()

     	 Removed; split between security_bprm_set_creds(),
     	 security_bprm_committing_creds() and security_bprm_committed_creds().

     (*) security_bprm_set(), ->bprm_set_security()

     	 Removed; folded into security_bprm_set_creds().

     (*) security_bprm_set_creds(), ->bprm_set_creds()

     	 New.  The new credentials in bprm->creds should be checked and set up
     	 as appropriate.  bprm->cred_prepared is 0 on the first call, 1 on the
     	 second and subsequent calls.

     (*) security_bprm_committing_creds(), ->bprm_committing_creds()
     (*) security_bprm_committed_creds(), ->bprm_committed_creds()

     	 New.  Apply the security effects of the new credentials.  This
     	 includes closing unauthorised files in SELinux.  This function may not
     	 fail.  When the former is called, the creds haven't yet been applied
     	 to the process; when the latter is called, they have.

 	 The former may access bprm->cred, the latter may not.

 (3) SELinux.

     SELinux has a number of changes, in addition to those to support the LSM
     interface changes mentioned above:

     (a) The bprm_security_struct struct has been removed in favour of using
     	 the credentials-under-construction approach.

     (c) flush_unauthorized_files() now takes a cred pointer and passes it on
     	 to inode_has_perm(), file_has_perm() and dentry_open().
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Acked-by: NJames Morris <jmorris@namei.org>
Acked-by: NSerge Hallyn <serue@us.ibm.com>
Signed-off-by: NJames Morris <jmorris@namei.org>

Some userland apps seem to pass in a "0" for the seconds, and several
seconds worth of usecs to select().  The old kernels accepted this just
fine, so the new kernels must too.

However, due to the upscaling of the microseconds to nanoseconds we had
some cases where we got math overflow, and depending on the GCC version
(due to inlining decisions) that actually resulted in an -EINVAL return.

This patch fixes this by adding the excess microseconds to the seconds
field.

Also with thanks to Marcin Slusarz for spotting some implementation bugs
in the diagnostics patches.
Reported-by: NCarlos R. Mafra <crmafra2@gmail.com>
Signed-off-by: NArjan van de Ven <arjan@linux.intel.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

It's not the final state, but it allows moving ->readdir() instances
to passing filldir return value to caller of vfs_readdir().
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

struct stat / compat_stat is the same on all architectures, so
cp_compat_stat should be, too.

Turns out it is, except that various architectures have slightly and some
high2lowuid/high2lowgid or the direct assignment instead of the
SET_UID/SET_GID that expands to the correct one anyway.

This patch replaces the arch-specific cp_compat_stat implementations with
a common one based on the x86-64 one.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Acked-by: David S. Miller <davem@davemloft.net> [ sparc bits ]
Acked-by: Kyle McMartin <kyle@mcmartin.ca> [ parisc bits ]
Cc: <linux-arch@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

With MAX_ARG_STRINGS set to 0x7FFFFFFF, and being passed to 'count()' and
compat_count(), it would appear that the current max bounds check of
fs/exec.c:394:

	if(++i > max)
		return -E2BIG;

would never trigger. Since 'i' is of type int, so values would wrap and the
function would continue looping.

Simple fix seems to be chaning ++i to i++ and checking for '>='.
Signed-off-by: NJason Baron <jbaron@redhat.com>
Acked-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Cc: "Ollie Wild" <aaw@google.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

With lots of help, input and cleanups from Thomas Gleixner

This patch switches select() and poll() over to hrtimers.

The core of the patch is replacing the "s64 timeout" with a
"struct timespec end_time" in all the plumbing.

But most of the diffstat comes from using the just introduced helpers:
	poll_select_set_timeout
	poll_select_copy_remaining
	timespec_add_safe
which make manipulating the timespec easier and less error-prone.
Signed-off-by: NArjan van de Ven <arjan@linux.intel.com>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

This patch adds 2 helpers that will be used for the hrtimer based select/poll:

poll_select_set_timeout() is a helper that takes a timeout (as a second, nanosecond
pair) and turns that into a "struct timespec" that represents the absolute end time.
This is a common operation in the many select() and poll() variants and needs various,
common, sanity checks.

poll_select_copy_remaining() is a helper that takes care of copying the remaining
time to userspace, as select(), pselect() and ppoll() do. This function comes in
both a natural and a compat implementation (due to datastructure differences).
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NArjan van de Ven <arjan@linux.intel.com>

Handling of -EOVERFLOW.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

* do not pass nameidata; struct path is all the callers want.
* switch to new helpers:
	user_path_at(dfd, pathname, flags, &path)
	user_path(pathname, &path)
	user_lpath(pathname, &path)
	user_path_dir(pathname, &path)  (fail if not a directory)
  The last 3 are trivial macro wrappers for the first one.
* remove nameidata in callers.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

This patch adds the new signalfd4 syscall.  It extends the old signalfd
syscall by one parameter which is meant to hold a flag value.  In this
patch the only flag support is SFD_CLOEXEC which causes the close-on-exec
flag for the returned file descriptor to be set.

A new name SFD_CLOEXEC is introduced which in this implementation must
have the same value as O_CLOEXEC.

The following test must be adjusted for architectures other than x86 and
x86-64 and in case the syscall numbers changed.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
#include <fcntl.h>
#include <signal.h>
#include <stdio.h>
#include <unistd.h>
#include <sys/syscall.h>

#ifndef __NR_signalfd4
# ifdef __x86_64__
#  define __NR_signalfd4 289
# elif defined __i386__
#  define __NR_signalfd4 327
# else
#  error "need __NR_signalfd4"
# endif
#endif

#define SFD_CLOEXEC O_CLOEXEC

int
main (void)
{
  sigset_t ss;
  sigemptyset (&ss);
  sigaddset (&ss, SIGUSR1);
  int fd = syscall (__NR_signalfd4, -1, &ss, 8, 0);
  if (fd == -1)
    {
      puts ("signalfd4(0) failed");
      return 1;
    }
  int coe = fcntl (fd, F_GETFD);
  if (coe == -1)
    {
      puts ("fcntl failed");
      return 1;
    }
  if (coe & FD_CLOEXEC)
    {
      puts ("signalfd4(0) set close-on-exec flag");
      return 1;
    }
  close (fd);

  fd = syscall (__NR_signalfd4, -1, &ss, 8, SFD_CLOEXEC);
  if (fd == -1)
    {
      puts ("signalfd4(SFD_CLOEXEC) failed");
      return 1;
    }
  coe = fcntl (fd, F_GETFD);
  if (coe == -1)
    {
      puts ("fcntl failed");
      return 1;
    }
  if ((coe & FD_CLOEXEC) == 0)
    {
      puts ("signalfd4(SFD_CLOEXEC) does not set close-on-exec flag");
      return 1;
    }
  close (fd);

  puts ("OK");

  return 0;
}
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

[akpm@linux-foundation.org: add sys_ni stub]
Signed-off-by: NUlrich Drepper <drepper@redhat.com>
Acked-by: NDavide Libenzi <davidel@xmailserver.org>
Cc: Michael Kerrisk <mtk.manpages@googlemail.com>
Cc: <linux-arch@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>