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  1. Dec 15, 2020
    • Dmitry Safonov's avatar
      vm_ops: rename .split() callback to .may_split() · dd3b614f
      Dmitry Safonov authored 
      Rename the callback to reflect that it's not called *on* or *after* split,
but rather some time before the splitting to check if it's possible.

Link: https://lkml.kernel.org/r/20201013013416.390574-5-dima@arista.com


Signed-off-by: default avatarDmitry Safonov <dima@arista.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Brian Geffon <bgeffon@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      dd3b614f
  3. Aug 23, 2020
  5. Aug 12, 2020
  7. Aug 07, 2020
  9. Jun 09, 2020
  11. Apr 07, 2020
  13. Jan 25, 2019
    • Arnd Bergmann's avatar
      ipc: rename old-style shmctl/semctl/msgctl syscalls · 275f2214
      Arnd Bergmann authored 
      The behavior of these system calls is slightly different between
architectures, as determined by the CONFIG_ARCH_WANT_IPC_PARSE_VERSION
symbol. Most architectures that implement the split IPC syscalls don't set
that symbol and only get the modern version, but alpha, arm, microblaze,
mips-n32, mips-n64 and xtensa expect the caller to pass the IPC_64 flag.

For the architectures that so far only implement sys_ipc(), i.e. m68k,
mips-o32, powerpc, s390, sh, sparc, and x86-32, we want the new behavior
when adding the split syscalls, so we need to distinguish between the
two groups of architectures.

The method I picked for this distinction is to have a separate system call
entry point: sys_old_*ctl() now uses ipc_parse_version, while sys_*ctl()
does not. The system call tables of the five architectures are changed
accordingly.

As an additional benefit, we no longer need the configuration specific
definition for ipc_parse_version(), it always does the same th...
      275f2214
  15. Oct 05, 2018
  17. Sep 04, 2018
  19. Aug 27, 2018
    • Arnd Bergmann's avatar
      y2038: globally rename compat_time to old_time32 · 9afc5eee
      Arnd Bergmann authored 
      
Christoph Hellwig suggested a slightly different path for handling
backwards compatibility with the 32-bit time_t based system calls:

Rather than simply reusing the compat_sys_* entry points on 32-bit
architectures unchanged, we get rid of those entry points and the
compat_time types by renaming them to something that makes more sense
on 32-bit architectures (which don't have a compat mode otherwise),
and then share the entry points under the new name with the 64-bit
architectures that use them for implementing the compatibility.

The following types and interfaces are renamed here, and moved
from linux/compat_time.h to linux/time32.h:

old				new
---				---
compat_time_t			old_time32_t
struct compat_timeval		struct old_timeval32
struct compat_timespec		struct old_timespec32
struct compat_itimerspec	struct old_itimerspec32
ns_to_compat_timeval()		ns_to_old_timeval32()
get_compat_itimerspec64()	get_old_itimerspec32()
put_compat_itimerspec64()	put_old_itimerspec32()
compat_get_timespec64()		get_old_timespec32()
compat_put_timespec64()		put_old_timespec32()

As we already have aliases in place, this patch addresses only the
instances that are relevant to the system call interface in particular,
not those that occur in device drivers and other modules. Those
will get handled separately, while providing the 64-bit version
of the respective interfaces.

I'm not renaming the timex, rusage and itimerval structures, as we are
still debating what the new interface will look like, and whether we
will need a replacement at all.

This also doesn't change the names of the syscall entry points, which can
be done more easily when we actually switch over the 32-bit architectures
to use them, at that point we need to change COMPAT_SYSCALL_DEFINEx to
SYSCALL_DEFINEx with a new name, e.g. with a _time32 suffix.

Suggested-by: default avatarChristoph Hellwig <hch@infradead.org>
Link: https://lore.kernel.org/lkml/20180705222110.GA5698@infradead.org/


Signed-off-by: default avatarArnd Bergmann <arnd@arndb.de>
      9afc5eee
  21. Aug 22, 2018
  23. Aug 02, 2018
    • Jane Chu's avatar
      ipc/shm.c add ->pagesize function to shm_vm_ops · eec3636a
      Jane Chu authored 
      Commit 05ea8860 ("mm, hugetlbfs: introduce ->pagesize() to
vm_operations_struct") adds a new ->pagesize() function to
hugetlb_vm_ops, intended to cover all hugetlbfs backed files.

With System V shared memory model, if "huge page" is specified, the
"shared memory" is backed by hugetlbfs files, but the mappings initiated
via shmget/shmat have their original vm_ops overwritten with shm_vm_ops,
so we need to add a ->pagesize function to shm_vm_ops.  Otherwise,
vma_kernel_pagesize() returns PAGE_SIZE given a hugetlbfs backed vma,
result in below BUG:

  fs/hugetlbfs/inode.c
        443             if (unlikely(page_mapped(page))) {
        444                     BUG_ON(truncate_op);

resulting in

  hugetlbfs: oracle (4592): Using mlock ulimits for SHM_HUGETLB is deprecated
  ------------[ cut here ]------------
  kernel BUG at fs/hugetlbfs/inode.c:444!
  Modules linked in: nfsv3 rpcsec_gss_krb5 nfsv4 ...
  CPU: 35 PID: 5583 Comm: oracle_5583_sbt Not tainted 4.14.35-1829.el7uek.x86_64 #2
  RIP: 0010:remove_inode_hugepages+0x3db/0x3e2
  ....
  Call Trace:
    hugetlbfs_evict_inode+0x1e/0x3e
    evict+0xdb/0x1af
    iput+0x1a2/0x1f7
    dentry_unlink_inode+0xc6/0xf0
    __dentry_kill+0xd8/0x18d
    dput+0x1b5/0x1ed
    __fput+0x18b/0x216
    ____fput+0xe/0x10
    task_work_run+0x90/0xa7
    exit_to_usermode_loop+0xdd/0x116
    do_syscall_64+0x187/0x1ae
    entry_SYSCALL_64_after_hwframe+0x150/0x0

[jane.chu@oracle.com: relocate comment]
  Link: http://lkml.kernel.org/r/20180731044831.26036-1-jane.chu@oracle.com
Link: http://lkml.kernel.org/r/20180727211727.5020-1-jane.chu@oracle.com


Fixes: 05ea8860 ("mm, hugetlbfs: introduce ->pagesize() to vm_operations_struct")
Signed-off-by: default avatarJane Chu <jane.chu@oracle.com>
Suggested-by: default avatarMike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: default avatarMike Kravetz <mike.kravetz@oracle.com>
Acked-by: default avatarDavidlohr Bueso <dave@stgolabs.net>
Acked-by: default avatarMichal Hocko <mhocko@suse.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jérôme Glisse <jglisse@redhat.com>
Cc: Manfred Spraul <manfred@colorfullife.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      eec3636a
  25. Jul 12, 2018
  27. Jun 22, 2018
    • NeilBrown's avatar
      rhashtable: split rhashtable.h · 0eb71a9d
      NeilBrown authored 
      
Due to the use of rhashtables in net namespaces,
rhashtable.h is included in lots of the kernel,
so a small changes can required a large recompilation.
This makes development painful.

This patch splits out rhashtable-types.h which just includes
the major type declarations, and does not include (non-trivial)
inline code.  rhashtable.h is no longer included by anything
in the include/ directory.
Common include files only include rhashtable-types.h so a large
recompilation is only triggered when that changes.

Acked-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: default avatarNeilBrown <neilb@suse.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      0eb71a9d
  29. Jun 14, 2018
  31. May 26, 2018
  33. Apr 20, 2018
    • Arnd Bergmann's avatar
      y2038: ipc: Report long times to user space · c2ab975c
      Arnd Bergmann authored 
      
The shmid64_ds/semid64_ds/msqid64_ds data structures have been extended
to contain extra fields for storing the upper bits of the time stamps,
this patch does the other half of the job and and fills the new fields on
32-bit architectures as well as 32-bit tasks running on a 64-bit kernel
in compat mode.

There should be no change for native 64-bit tasks.

Signed-off-by: default avatarArnd Bergmann <arnd@arndb.de>
      c2ab975c
  35. Apr 14, 2018
    • Eric Biggers's avatar
      ipc/shm: fix use-after-free of shm file via remap_file_pages() · 3f05317d
      Eric Biggers authored 
      syzbot reported a use-after-free of shm_file_data(file)->file->f_op in
shm_get_unmapped_area(), called via sys_remap_file_pages().

Unfortunately it couldn't generate a reproducer, but I found a bug which
I think caused it.  When remap_file_pages() is passed a full System V
shared memory segment, the memory is first unmapped, then a new map is
created using the ->vm_file.  Between these steps, the shm ID can be
removed and reused for a new shm segment.  But, shm_mmap() only checks
whether the ID is currently valid before calling the underlying file's
->mmap(); it doesn't check whether it was reused.  Thus it can use the
wrong underlying file, one that was already freed.

Fix this by making the "outer" shm file (the one that gets put in
->vm_file) hold a reference to the real shm file, and by making
__shm_open() require that the file associated with the shm ID matches
the one associated with the "outer" file.

Taking the reference to the real shm file is needed to fully solve the
problem, since otherwise sfd->file could point to a freed file, which
then could be reallocated for the reused shm ID, causing the wrong shm
segment to be mapped (and without the required permission checks).

Commit 1ac0b6de ("ipc/shm: handle removed segments gracefully in
shm_mmap()") almost fixed this bug, but it didn't go far enough because
it didn't consider the case where the shm ID is reused.

The following program usually reproduces this bug:

	#include <stdlib.h>
	#include <sys/shm.h>
	#include <sys/syscall.h>
	#include <unistd.h>

	int main()
	{
		int is_parent = (fork() != 0);
		srand(getpid());
		for (;;) {
			int id = shmget(0xF00F, 4096, IPC_CREAT|0700);
			if (is_parent) {
				void *addr = shmat(id, NULL, 0);
				usleep(rand() % 50);
				while (!syscall(__NR_remap_file_pages, addr, 4096, 0, 0, 0));
			} else {
				usleep(rand() % 50);
				shmctl(id, IPC_RMID, NULL);
			}
		}
	}

It causes the following NULL pointer dereference due to a 'struct file'
being used while it's being freed.  (I couldn't actually get a KASAN
use-after-free splat like in the syzbot report.  But I think it's
possible with this bug; it would just take a more extraordinary race...)

	BUG: unable to handle kernel NULL pointer dereference at 0000000000000058
	PGD 0 P4D 0
	Oops: 0000 [#1] SMP NOPTI
	CPU: 9 PID: 258 Comm: syz_ipc Not tainted 4.16.0-05140-gf8cf2f16a7c95 #189
	Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.11.0-20171110_100015-anatol 04/01/2014
	RIP: 0010:d_inode include/linux/dcache.h:519 [inline]
	RIP: 0010:touch_atime+0x25/0xd0 fs/inode.c:1724
	[...]
	Call Trace:
	 file_accessed include/linux/fs.h:2063 [inline]
	 shmem_mmap+0x25/0x40 mm/shmem.c:2149
	 call_mmap include/linux/fs.h:1789 [inline]
	 shm_mmap+0x34/0x80 ipc/shm.c:465
	 call_mmap include/linux/fs.h:1789 [inline]
	 mmap_region+0x309/0x5b0 mm/mmap.c:1712
	 do_mmap+0x294/0x4a0 mm/mmap.c:1483
	 do_mmap_pgoff include/linux/mm.h:2235 [inline]
	 SYSC_remap_file_pages mm/mmap.c:2853 [inline]
	 SyS_remap_file_pages+0x232/0x310 mm/mmap.c:2769
	 do_syscall_64+0x64/0x1a0 arch/x86/entry/common.c:287
	 entry_SYSCALL_64_after_hwframe+0x42/0xb7

[ebiggers@google.com: add comment]
  Link: http://lkml.kernel.org/r/20180410192850.235835-1-ebiggers3@gmail.com
Link: http://lkml.kernel.org/r/20180409043039.28915-1-ebiggers3@gmail.com


Reported-by: default avatar <syzbot+d11f321e7f1923157eac80aa990b446596f46439@syzkaller.appspotmail.com>
Fixes: c8d78c18 ("mm: replace remap_file_pages() syscall with emulation")
Signed-off-by: default avatarEric Biggers <ebiggers@google.com>
Acked-by: default avatarKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: default avatarDavidlohr Bueso <dbueso@suse.de>
Cc: Manfred Spraul <manfred@colorfullife.com>
Cc: "Eric W . Biederman" <ebiederm@xmission.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      3f05317d
  37. Apr 11, 2018
    • Andrew Morton's avatar
      ipc/shm.c: shm_split(): remove unneeded test for NULL shm_file_data.vm_ops · a61fc2cb
      Andrew Morton authored 
      
This was added by the recent "ipc/shm.c: add split function to
shm_vm_ops", but it is not necessary.

Reviewed-by: default avatarMike Kravetz <mike.kravetz@oracle.com>
Cc: Laurent Dufour <ldufour@linux.vnet.ibm.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Manfred Spraul <manfred@colorfullife.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      a61fc2cb
    • Davidlohr Bueso's avatar
      ipc/shm: introduce shmctl(SHM_STAT_ANY) · c21a6970
      Davidlohr Bueso authored 
      Patch series "sysvipc: introduce STAT_ANY commands", v2.

The following patches adds the discussed (see [1]) new command for shm
as well as for sems and msq as they are subject to the same
discrepancies for ipc object permission checks between the syscall and
via procfs.  These new commands are justified in that (1) we are stuck
with this semantics as changing syscall and procfs can break userland;
and (2) some users can benefit from performance (for large amounts of
shm segments, for example) from not having to parse the procfs
interface.

Once merged, I will submit the necesary manpage updates.  But I'm thinking
something like:

: diff --git a/man2/shmctl.2 b/man2/shmctl.2
: index 7bb503999941..bb00bbe21a57 100644
: --- a/man2/shmctl.2
: +++ b/man2/shmctl.2
: @@ -41,6 +41,7 @@
:  .\" 2005-04-25, mtk -- noted aberrant Linux behavior w.r.t. new
:  .\"	attaches to a segment that has already been marked for deletion.
:  .\" 2005-08-02, mtk: Added IPC_INFO, SHM_INFO, SHM_STAT descriptions.
: +.\" 2018-02-13, dbueso: Added SHM_STAT_ANY description.
:  .\"
:  .TH SHMCTL 2 2017-09-15 "Linux" "Linux Programmer's Manual"
:  .SH NAME
: @@ -242,6 +243,18 @@ However, the
:  argument is not a segment identifier, but instead an index into
:  the kernel's internal array that maintains information about
:  all shared memory segments on the system.
: +.TP
: +.BR SHM_STAT_ANY " (Linux-specific)"
: +Return a
: +.I shmid_ds
: +structure as for
: +.BR SHM_STAT .
: +However, the
: +.I shm_perm.mode
: +is not checked for read access for
: +.IR shmid ,
: +resembing the behaviour of
: +/proc/sysvipc/shm.
:  .PP
:  The caller can prevent or allow swapping of a shared
:  memory segment with the following \fIcmd\fP values:
: @@ -287,7 +300,7 @@ operation returns the index of the highest used entry in the
:  kernel's internal array recording information about all
:  shared memory segments.
:  (This information can be used with repeated
: -.B SHM_STAT
: +.B SHM_STAT/SHM_STAT_ANY
:  operations to obtain information about all shared memory segments
:  on the system.)
:  A successful
: @@ -328,7 +341,7 @@ isn't accessible.
:  \fIshmid\fP is not a valid identifier, or \fIcmd\fP
:  is not a valid command.
:  Or: for a
: -.B SHM_STAT
: +.B SHM_STAT/SHM_STAT_ANY
:  operation, the index value specified in
:  .I shmid
:  referred to an array slot that is currently unused.

This patch (of 3):

There is a permission discrepancy when consulting shm ipc object metadata
between /proc/sysvipc/shm (0444) and the SHM_STAT shmctl command.  The
later does permission checks for the object vs S_IRUGO.  As such there can
be cases where EACCESS is returned via syscall but the info is displayed
anyways in the procfs files.

While this might have security implications via info leaking (albeit no
writing to the shm metadata), this behavior goes way back and showing all
the objects regardless of the permissions was most likely an overlook - so
we are stuck with it.  Furthermore, modifying either the syscall or the
procfs file can cause userspace programs to break (ie ipcs).  Some
applications require getting the procfs info (without root privileges) and
can be rather slow in comparison with a syscall -- up to 500x in some
reported cases.

This patch introduces a new SHM_STAT_ANY command such that the shm ipc
object permissions are ignored, and only audited instead.  In addition,
I've left the lsm security hook checks in place, as if some policy can
block the call, then the user has no other choice than just parsing the
procfs file.

[1] https://lkml.org/lkml/2017/12/19/220

Link: http://lkml.kernel.org/r/20180215162458.10059-2-dave@stgolabs.net


Signed-off-by: default avatarDavidlohr Bueso <dbueso@suse.de>
Acked-by: default avatarMichal Hocko <mhocko@suse.com>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Manfred Spraul <manfred@colorfullife.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Robert Kettler <robert.kettler@outlook.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      c21a6970
  39. Apr 02, 2018
  41. Mar 28, 2018
    • Mike Kravetz's avatar
      ipc/shm.c: add split function to shm_vm_ops · 3d942ee0
      Mike Kravetz authored 
      If System V shmget/shmat operations are used to create a hugetlbfs
backed mapping, it is possible to munmap part of the mapping and split
the underlying vma such that it is not huge page aligned.  This will
untimately result in the following BUG:

  kernel BUG at /build/linux-jWa1Fv/linux-4.15.0/mm/hugetlb.c:3310!
  Oops: Exception in kernel mode, sig: 5 [#1]
  LE SMP NR_CPUS=2048 NUMA PowerNV
  Modules linked in: kcm nfc af_alg caif_socket caif phonet fcrypt
  CPU: 18 PID: 43243 Comm: trinity-subchil Tainted: G         C  E 4.15.0-10-generic #11-Ubuntu
  NIP:  c00000000036e764 LR: c00000000036ee48 CTR: 0000000000000009
  REGS: c000003fbcdcf810 TRAP: 0700   Tainted: G         C  E (4.15.0-10-generic)
  MSR:  9000000000029033 <SF,HV,EE,ME,IR,DR,RI,LE>  CR: 24002222  XER: 20040000
  CFAR: c00000000036ee44 SOFTE: 1
  NIP __unmap_hugepage_range+0xa4/0x760
  LR __unmap_hugepage_range_final+0x28/0x50
  Call Trace:
    0x7115e4e00000 (unreliable)
    __unmap_hugepage_range_final+0x28/0x50
    unmap_single_vma+0x11c/0x190
    unmap_vmas+0x94/0x140
    exit_mmap+0x9c/0x1d0
    mmput+0xa8/0x1d0
    do_exit+0x360/0xc80
    do_group_exit+0x60/0x100
    SyS_exit_group+0x24/0x30
    system_call+0x58/0x6c
  ---[ end trace ee88f958a1c62605 ]---

This bug was introduced by commit 31383c68 ("mm, hugetlbfs:
introduce ->split() to vm_operations_struct").  A split function was
added to vm_operations_struct to determine if a mapping can be split.
This was mostly for device-dax and hugetlbfs mappings which have
specific alignment constraints.

Mappings initiated via shmget/shmat have their original vm_ops
overwritten with shm_vm_ops.  shm_vm_ops functions will call back to the
original vm_ops if needed.  Add such a split function to shm_vm_ops.

Link: http://lkml.kernel.org/r/20180321161314.7711-1-mike.kravetz@oracle.com


Fixes: 31383c68 ("mm, hugetlbfs: introduce ->split() to vm_operations_struct")
Signed-off-by: default avatarMike Kravetz <mike.kravetz@oracle.com>
Reported-by: default avatarLaurent Dufour <ldufour@linux.vnet.ibm.com>
Reviewed-by: default avatarLaurent Dufour <ldufour@linux.vnet.ibm.com>
Tested-by: default avatarLaurent Dufour <ldufour@linux.vnet.ibm.com>
Reviewed-by: default avatarDan Williams <dan.j.williams@intel.com>
Acked-by: default avatarMichal Hocko <mhocko@suse.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Manfred Spraul <manfred@colorfullife.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      3d942ee0
    • Eric W. Biederman's avatar
      ipc/shm: Fix pid freeing. · 2236d4d3
      Eric W. Biederman authored 
      
The 0day kernel test build report reported an oops:
>
>  IP: put_pid+0x22/0x5c
>  PGD 19efa067 P4D 19efa067 PUD 0
>  Oops: 0000 [#1]
>  CPU: 0 PID: 727 Comm: trinity Not tainted 4.16.0-rc2-00010-g98f929b #1
>  RIP: 0010:put_pid+0x22/0x5c
>  RSP: 0018:ffff986719f73e48 EFLAGS: 00010202
>  RAX: 00000006d765f710 RBX: ffff98671a4fa4d0 RCX: ffff986719f73d40
>  RDX: 000000006f6e6125 RSI: 0000000000000000 RDI: ffffffffa01e6d21
>  RBP: ffffffffa0955fe0 R08: 0000000000000020 R09: 0000000000000000
>  R10: 0000000000000078 R11: ffff986719f73e76 R12: 0000000000001000
>  R13: 00000000ffffffea R14: 0000000054000fb0 R15: 0000000000000000
>  FS:  00000000028c2880(0000) GS:ffffffffa06ad000(0000) knlGS:0000000000000000
>  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
>  CR2: 0000000677846439 CR3: 0000000019fc1005 CR4: 00000000000606b0
>  Call Trace:
>   ? ipc_update_pid+0x36/0x3e
>   ? newseg+0x34c/0x3a6
>   ? ipcget+0x5d/0x528
>   ? entry_SYSCALL_64_after_hwframe+0x52/0xb7
>   ? SyS_shmget+0x5a/0x84
>   ? do_syscall_64+0x194/0x1b3
>   ? entry_SYSCALL_64_after_hwframe+0x42/0xb7
>  Code: ff 05 e7 20 9b 03 58 c9 c3 48 ff 05 85 21 9b 03 48 85 ff 74 4f 8b 47 04 8b 17 48 ff 05 7c 21 9b 03 48 83 c0 03 48 c1 e0 04 ff ca <48> 8b 44 07 08 74 1f 48 ff 05 6c 21 9b 03 ff 0f 0f 94 c2 48 ff
>  RIP: put_pid+0x22/0x5c RSP: ffff986719f73e48
>  CR2: 0000000677846439
>  ---[ end trace ab8c5cb4389d37c5 ]---
>  Kernel panic - not syncing: Fatal exception

In newseg when changing shm_cprid and shm_lprid from pid_t to struct
pid* I misread the kvmalloc as kvzalloc and thought shp was
initialized to 0.  As that is not the case it is not safe to for the
error handling to address shm_cprid and shm_lprid before they are
initialized.

Therefore move the cleanup of shm_cprid and shm_lprid from the no_file
error cleanup path to the no_id error cleanup path.  Ensuring that an
early error exit won't cause the oops above.

Reported-by: default avatarkernel test robot <fengguang.wu@intel.com>
Reviewed-by: default avatarNagarathnam Muthusamy <nagarathnam.muthusamy@oracle.com>
Signed-off-by: default avatarEric W. Biederman <ebiederm@xmission.com>
      2236d4d3
  43. Mar 27, 2018
    • Eric W. Biederman's avatar
      ipc: Directly call the security hook in ipc_ops.associate · 50ab44b1
      Eric W. Biederman authored 
      
After the last round of cleanups the shm, sem, and msg associate
operations just became trivial wrappers around the appropriate security
method.  Simplify things further by just calling the security method
directly.

Signed-off-by: default avatar"Eric W. Biederman" <ebiederm@xmission.com>
      50ab44b1
    • Eric W. Biederman's avatar
      ipc/shm: Fix shmctl(..., IPC_STAT, ...) between pid namespaces. · 98f929b1
      Eric W. Biederman authored 
      
Today shm_cpid and shm_lpid are remembered in the pid namespace of the
creator and the processes that last touched a sysvipc shared memory
segment.   If you have processes in multiple pid namespaces that
is just wrong, and I don't know how this has been over-looked for
so long.

As only creation and shared memory attach and shared memory detach
update the pids I do not expect there to be a repeat of the issues
when struct pid was attached to each af_unix skb, which in some
notable cases cut the performance in half.  The problem was threads of
the same process updating same struct pid from different cpus causing
the cache line to be highly contended and bounce between cpus.

As creation, attach, and detach are expected to be rare operations for
sysvipc shared memory segments I do not expect that kind of cache line
ping pong to cause probems.  In addition because the pid is at a fixed
location in the structure instead of being dynamic on a skb, the
reference count of the pid does not need to be updated on each
operation if the pid is the same.  This ability to simply skip the pid
reference count changes if the pid is unchanging further reduces the
likelihood of the a cache line holding a pid reference count
ping-ponging between cpus.

Fixes: b488893a ("pid namespaces: changes to show virtual ids to user")
Reviewed-by: default avatarNagarathnam Muthusamy <nagarathnam.muthusamy@oracle.com>
Signed-off-by: default avatar"Eric W. Biederman" <ebiederm@xmission.com>
      98f929b1
  45. Mar 24, 2018
  47. Mar 23, 2018
  49. Feb 07, 2018
  51. Nov 18, 2017
  53. Nov 02, 2017
    • Greg Kroah-Hartman's avatar
      License cleanup: add SPDX GPL-2.0 license identifier to files with no license · b2441318
      Greg Kroah-Hartman authored 
      
Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.

By default all files without license information are under the default
license of the kernel, which is GPL version 2.

Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier.  The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.

This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.

How this work was done:

Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
 - file had no licensing information it it.
 - file was a */uapi/* one with no licensing information in it,
 - file was a */uapi/* one with existing licensing information,

Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.

The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne.  Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.

The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed.  Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.

Criteria used to select files for SPDX license identifier tagging was:
 - Files considered eligible had to be source code files.
 - Make and config files were included as candidates if they contained >5
   lines of source
 - File already had some variant of a license header in it (even if <5
   lines).

All documentation files were explicitly excluded.

The following heuristics were used to determine which SPDX license
identifiers to apply.

 - when both scanners couldn't find any license traces, file was
   considered to have no license information in it, and the top level
   COPYING file license applied.

   For non */uapi/* files that summary was:

   SPDX license identifier                            # files
   ---------------------------------------------------|-------
   GPL-2.0                                              11139

   and resulted in the first patch in this series.

   If that file was a */uapi/* path one, it was "GPL-2.0 WITH
   Linux-syscall-note" otherwise it was "GPL-2.0".  Results of that was:

   SPDX license identifier                            # files
   ---------------------------------------------------|-------
   GPL-2.0 WITH Linux-syscall-note                        930

   and resulted in the second patch in this series.

 - if a file had some form of licensing information in it, and was one
   of the */uapi/* ones, it was denoted with the Linux-syscall-note if
   any GPL family license was found in the file or had no licensing in
   it (per prior point).  Results summary:

   SPDX license identifier                            # files
   ---------------------------------------------------|------
   GPL-2.0 WITH Linux-syscall-note                       270
   GPL-2.0+ WITH Linux-syscall-note                      169
   ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause)    21
   ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause)    17
   LGPL-2.1+ WITH Linux-syscall-note                      15
   GPL-1.0+ WITH Linux-syscall-note                       14
   ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause)    5
   LGPL-2.0+ WITH Linux-syscall-note                       4
   LGPL-2.1 WITH Linux-syscall-note                        3
   ((GPL-2.0 WITH Linux-syscall-note) OR MIT)              3
   ((GPL-2.0 WITH Linux-syscall-note) AND MIT)             1

   and that resulted in the third patch in this series.

 - when the two scanners agreed on the detected license(s), that became
   the concluded license(s).

 - when there was disagreement between the two scanners (one detected a
   license but the other didn't, or they both detected different
   licenses) a manual inspection of the file occurred.

 - In most cases a manual inspection of the information in the file
   resulted in a clear resolution of the license that should apply (and
   which scanner probably needed to revisit its heuristics).

 - When it was not immediately clear, the license identifier was
   confirmed with lawyers working with the Linux Foundation.

 - If there was any question as to the appropriate license identifier,
   the file was flagged for further research and to be revisited later
   in time.

In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.

Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights.  The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.

Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.

In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.

Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
 - a full scancode scan run, collecting the matched texts, detected
   license ids and scores
 - reviewing anything where there was a license detected (about 500+
   files) to ensure that the applied SPDX license was correct
 - reviewing anything where there was no detection but the patch license
   was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
   SPDX license was correct

This produced a worksheet with 20 files needing minor correction.  This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.

These .csv files were then reviewed by Greg.  Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected.  This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.)  Finally Greg ran the script using the .csv files to
generate the patches.

Reviewed-by: default avatarKate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: default avatarPhilippe Ombredanne <pombredanne@nexb.com>
Reviewed-by: default avatarThomas Gleixner <tglx@linutronix.de>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      b2441318