Modify the request_module to prefix the file system type with "fs-"
and add aliases to all of the filesystems that can be built as modules
to match.
A common practice is to build all of the kernel code and leave code
that is not commonly needed as modules, with the result that many
users are exposed to any bug anywhere in the kernel.
Looking for filesystems with a fs- prefix limits the pool of possible
modules that can be loaded by mount to just filesystems trivially
making things safer with no real cost.
Using aliases means user space can control the policy of which
filesystem modules are auto-loaded by editing /etc/modprobe.d/*.conf
with blacklist and alias directives. Allowing simple, safe,
well understood work-arounds to known problematic software.
This also addresses a rare but unfortunate problem where the filesystem
name is not the same as it's module name and module auto-loading
would not work. While writing this patch I saw a handful of such
cases. The most significant being autofs that lives in the module
autofs4.
This is relevant to user namespaces because we can reach the request
module in get_fs_type() without having any special permissions, and
people get uncomfortable when a user specified string (in this case
the filesystem type) goes all of the way to request_module.
After having looked at this issue I don't think there is any
particular reason to perform any filtering or permission checks beyond
making it clear in the module request that we want a filesystem
module. The common pattern in the kernel is to call request_module()
without regards to the users permissions. In general all a filesystem
module does once loaded is call register_filesystem() and go to sleep.
Which means there is not much attack surface exposed by loading a
filesytem module unless the filesystem is mounted. In a user
namespace filesystems are not mounted unless .fs_flags = FS_USERNS_MOUNT,
which most filesystems do not set today.
Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
Acked-by: Kees Cook <keescook@chromium.org>
Reported-by: Kees Cook <keescook@google.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Pull Xen bug-fixes from Konrad Rzeszutek Wilk:
- Update the Xen ACPI memory and CPU hotplug locking mechanism.
- Fix PAT issues wherein various applications would not start
- Fix handling of multiple MSI as AHCI now does it.
- Fix ARM compile failures.
* tag 'stable/for-linus-3.9-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen:
xenbus: fix compile failure on ARM with Xen enabled
xen/pci: We don't do multiple MSI's.
xen/pat: Disable PAT using pat_enabled value.
xen/acpi: xen cpu hotplug minor updates
xen/acpi: xen memory hotplug minor updates
Adding an include of linux/mm.h resolves this:
drivers/xen/xenbus/xenbus_client.c: In function ‘xenbus_map_ring_valloc_hvm’:
drivers/xen/xenbus/xenbus_client.c:532:66: error: implicit declaration of function ‘page_to_section’ [-Werror=implicit-function-declaration]
CC: stable@vger.kernel.org
Signed-off-by: Steven Noonan <steven@uplinklabs.net>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Pull vfs pile (part one) from Al Viro:
"Assorted stuff - cleaning namei.c up a bit, fixing ->d_name/->d_parent
locking violations, etc.
The most visible changes here are death of FS_REVAL_DOT (replaced with
"has ->d_weak_revalidate()") and a new helper getting from struct file
to inode. Some bits of preparation to xattr method interface changes.
Misc patches by various people sent this cycle *and* ocfs2 fixes from
several cycles ago that should've been upstream right then.
PS: the next vfs pile will be xattr stuff."
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (46 commits)
saner proc_get_inode() calling conventions
proc: avoid extra pde_put() in proc_fill_super()
fs: change return values from -EACCES to -EPERM
fs/exec.c: make bprm_mm_init() static
ocfs2/dlm: use GFP_ATOMIC inside a spin_lock
ocfs2: fix possible use-after-free with AIO
ocfs2: Fix oops in ocfs2_fast_symlink_readpage() code path
get_empty_filp()/alloc_file() leave both ->f_pos and ->f_version zero
target: writev() on single-element vector is pointless
export kernel_write(), convert open-coded instances
fs: encode_fh: return FILEID_INVALID if invalid fid_type
kill f_vfsmnt
vfs: kill FS_REVAL_DOT by adding a d_weak_revalidate dentry op
nfsd: handle vfs_getattr errors in acl protocol
switch vfs_getattr() to struct path
default SET_PERSONALITY() in linux/elf.h
ceph: prepopulate inodes only when request is aborted
d_hash_and_lookup(): export, switch open-coded instances
9p: switch v9fs_set_create_acl() to inode+fid, do it before d_instantiate()
9p: split dropping the acls from v9fs_set_create_acl()
...
Recently at native Rafael did some cleanup for acpi, say, drop
acpi_bus_add, remove unnecessary argument of acpi_bus_scan,
and run acpi_bus_scan under acpi_scan_lock.
This patch does similar cleanup for xen cpu hotplug, removing
redundant logic, and adding lock.
Signed-off-by: Liu Jinsong <jinsong.liu@intel.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Dan Carpenter found current xen memory hotplug logic
has potential issue: at func acpi_memory_get_device()
*mem_device = acpi_driver_data(device);
while the device may be NULL and then dereference.
At native side, Rafael recently updated acpi_memory_get_device(),
dropping acpi_bus_add, adding lock, and avoiding above issue.
This patch updates xen memory hotplug logic accordingly, removing
redundant logic, adding lock, and avoiding dereference.
Signed-off-by: Liu Jinsong <jinsong.liu@intel.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Pull Xen update from Konrad Rzeszutek Wilk:
"This has two new ACPI drivers for Xen - a physical CPU offline/online
and a memory hotplug. The way this works is that ACPI kicks the
drivers and they make the appropiate hypercall to the hypervisor to
tell it that there is a new CPU or memory. There also some changes to
the Xen ARM ABIs and couple of fixes. One particularly nasty bug in
the Xen PV spinlock code was fixed by Stefan Bader - and has been
there since the 2.6.32!
Features:
- Xen ACPI memory and CPU hotplug drivers - allowing Xen hypervisor
to be aware of new CPU and new DIMMs
- Cleanups
Bug-fixes:
- Fixes a long-standing bug in the PV spinlock wherein we did not
kick VCPUs that were in a tight loop.
- Fixes in the error paths for the event channel machinery"
Fix up a few semantic conflicts with the ACPI interface changes in
drivers/xen/xen-acpi-{cpu,mem}hotplug.c.
* tag 'stable/for-linus-3.9-rc0-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen:
xen: event channel arrays are xen_ulong_t and not unsigned long
xen: Send spinlock IPI to all waiters
xen: introduce xen_remap, use it instead of ioremap
xen: close evtchn port if binding to irq fails
xen-evtchn: correct comment and error output
xen/tmem: Add missing %s in the printk statement.
xen/acpi: move xen_acpi_get_pxm under CONFIG_XEN_DOM0
xen/acpi: ACPI cpu hotplug
xen/acpi: Move xen_acpi_get_pxm to Xen's acpi.h
xen/stub: driver for CPU hotplug
xen/acpi: ACPI memory hotplug
xen/stub: driver for memory hotplug
xen: implement updated XENMEM_add_to_physmap_range ABI
xen/smp: Move the common CPU init code a bit to prep for PVH patch.
Pull x86 mm changes from Peter Anvin:
"This is a huge set of several partly interrelated (and concurrently
developed) changes, which is why the branch history is messier than
one would like.
The *really* big items are two humonguous patchsets mostly developed
by Yinghai Lu at my request, which completely revamps the way we
create initial page tables. In particular, rather than estimating how
much memory we will need for page tables and then build them into that
memory -- a calculation that has shown to be incredibly fragile -- we
now build them (on 64 bits) with the aid of a "pseudo-linear mode" --
a #PF handler which creates temporary page tables on demand.
This has several advantages:
1. It makes it much easier to support things that need access to data
very early (a followon patchset uses this to load microcode way
early in the kernel startup).
2. It allows the kernel and all the kernel data objects to be invoked
from above the 4 GB limit. This allows kdump to work on very large
systems.
3. It greatly reduces the difference between Xen and native (Xen's
equivalent of the #PF handler are the temporary page tables created
by the domain builder), eliminating a bunch of fragile hooks.
The patch series also gets us a bit closer to W^X.
Additional work in this pull is the 64-bit get_user() work which you
were also involved with, and a bunch of cleanups/speedups to
__phys_addr()/__pa()."
* 'x86-mm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (105 commits)
x86, mm: Move reserving low memory later in initialization
x86, doc: Clarify the use of asm("%edx") in uaccess.h
x86, mm: Redesign get_user with a __builtin_choose_expr hack
x86: Be consistent with data size in getuser.S
x86, mm: Use a bitfield to mask nuisance get_user() warnings
x86/kvm: Fix compile warning in kvm_register_steal_time()
x86-32: Add support for 64bit get_user()
x86-32, mm: Remove reference to alloc_remap()
x86-32, mm: Remove reference to resume_map_numa_kva()
x86-32, mm: Rip out x86_32 NUMA remapping code
x86/numa: Use __pa_nodebug() instead
x86: Don't panic if can not alloc buffer for swiotlb
mm: Add alloc_bootmem_low_pages_nopanic()
x86, 64bit, mm: hibernate use generic mapping_init
x86, 64bit, mm: Mark data/bss/brk to nx
x86: Merge early kernel reserve for 32bit and 64bit
x86: Add Crash kernel low reservation
x86, kdump: Remove crashkernel range find limit for 64bit
memblock: Add memblock_mem_size()
x86, boot: Not need to check setup_header version for setup_data
...
Pull ACPI and power management updates from Rafael Wysocki:
- Rework of the ACPI namespace scanning code from Rafael J. Wysocki
with contributions from Bjorn Helgaas, Jiang Liu, Mika Westerberg,
Toshi Kani, and Yinghai Lu.
- ACPI power resources handling and ACPI device PM update from Rafael
J Wysocki.
- ACPICA update to version 20130117 from Bob Moore and Lv Zheng with
contributions from Aaron Lu, Chao Guan, Jesper Juhl, and Tim Gardner.
- Support for Intel Lynxpoint LPSS from Mika Westerberg.
- cpuidle update from Len Brown including Intel Haswell support, C1
state for intel_idle, removal of global pm_idle.
- cpuidle fixes and cleanups from Daniel Lezcano.
- cpufreq fixes and cleanups from Viresh Kumar and Fabio Baltieri with
contributions from Stratos Karafotis and Rickard Andersson.
- Intel P-states driver for Sandy Bridge processors from Dirk
Brandewie.
- cpufreq driver for Marvell Kirkwood SoCs from Andrew Lunn.
- cpufreq fixes related to ordering issues between acpi-cpufreq and
powernow-k8 from Borislav Petkov and Matthew Garrett.
- cpufreq support for Calxeda Highbank processors from Mark Langsdorf
and Rob Herring.
- cpufreq driver for the Freescale i.MX6Q SoC and cpufreq-cpu0 update
from Shawn Guo.
- cpufreq Exynos fixes and cleanups from Jonghwan Choi, Sachin Kamat,
and Inderpal Singh.
- Support for "lightweight suspend" from Zhang Rui.
- Removal of the deprecated power trace API from Paul Gortmaker.
- Assorted updates from Andreas Fleig, Colin Ian King, Davidlohr Bueso,
Joseph Salisbury, Kees Cook, Li Fei, Nishanth Menon, ShuoX Liu,
Srinivas Pandruvada, Tejun Heo, Thomas Renninger, and Yasuaki
Ishimatsu.
* tag 'pm+acpi-3.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (267 commits)
PM idle: remove global declaration of pm_idle
unicore32 idle: delete stray pm_idle comment
openrisc idle: delete pm_idle
mn10300 idle: delete pm_idle
microblaze idle: delete pm_idle
m32r idle: delete pm_idle, and other dead idle code
ia64 idle: delete pm_idle
cris idle: delete idle and pm_idle
ARM64 idle: delete pm_idle
ARM idle: delete pm_idle
blackfin idle: delete pm_idle
sparc idle: rename pm_idle to sparc_idle
sh idle: rename global pm_idle to static sh_idle
x86 idle: rename global pm_idle to static x86_idle
APM idle: register apm_cpu_idle via cpuidle
cpufreq / intel_pstate: Add kernel command line option disable intel_pstate.
cpufreq / intel_pstate: Change to disallow module build
tools/power turbostat: display SMI count by default
intel_idle: export both C1 and C1E
ACPI / hotplug: Fix concurrency issues and memory leaks
...
Pull x86/hyperv changes from Ingo Molnar:
"The biggest change is support for Windows 8's improved hypervisor
interrupt model on the Linux Hyper-V guest subsystem code side.
Smallish fixes otherwise."
* 'x86-hyperv-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86, hyperv: HYPERV depends on X86_LOCAL_APIC
X86: Handle Hyper-V vmbus interrupts as special hypervisor interrupts
X86: Add a check to catch Xen emulation of Hyper-V
x86: Hyper-V: register clocksource only if its advertised
ioremap can't be used to map ring pages on ARM because it uses device
memory caching attributes (MT_DEVICE*).
Introduce a Xen specific abstraction to map ring pages, called
xen_remap, that is defined as ioremap on x86 (no behavioral changes).
On ARM it explicitly calls __arm_ioremap with the right caching
attributes: MT_MEMORY.
Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
The evtchn device has been moved to /dev/xen. Also change log level to
KERN_ERR as other xen drivers.
Signed-off-by: Wei Liu <wei.liu2@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
This patch implement real Xen ACPI cpu hotplug driver as module.
When loaded, it replaces Xen stub driver.
For booting existed cpus, the driver enumerates them.
For hotadded cpus, which added at runtime and notify OS via
device or container event, the driver is invoked to add them,
parsing cpu information, hypercalling to Xen hypervisor to add
them, and finally setting up new /sys interface for them.
Signed-off-by: Liu Jinsong <jinsong.liu@intel.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Add Xen stub driver for CPU hotplug, early occupy to block native,
will be replaced later by real Xen processor driver module.
Signed-off-by: Liu Jinsong <jinsong.liu@intel.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
This patch implements real Xen acpi memory hotplug driver as module.
When loaded, it replaces Xen stub driver.
When an acpi memory device hotadd event occurs, it notifies OS and
invokes notification callback, adding related memory device and parsing
memory information, finally hypercall to xen hypervisor to add memory.
Signed-off-by: Liu Jinsong <jinsong.liu@intel.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
This patch create a file (xen-stub.c) for Xen stub drivers.
Xen stub drivers are used to reserve space for Xen drivers, i.e.
memory hotplug and cpu hotplug, and to block native drivers loaded,
so that real Xen drivers can be modular and loaded on demand.
This patch is specific for Xen memory hotplug (other Xen logic
can add stub drivers on their own). The xen stub driver will
occupied earlier via subsys_initcall (than native memory hotplug
driver via module_init and so blocking native). Later real Xen
memory hotplug logic will unregister the stub driver and register
itself to take effect on demand.
Signed-off-by: Liu Jinsong <jinsong.liu@intel.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Pull xen fixes from Konrad Rzeszutek Wilk:
"Two fixes:
- A simple bug-fix for redundant NULL check.
- CVE-2013-0228/XSA-42: x86/xen: don't assume %ds is usable in
xen_iret for 32-bit PVOPS
and two reverts:
- Revert the PVonHVM kexec. The patch introduces a regression with
older hypervisor stacks, such as Xen 4.1."
* tag 'stable/for-linus-3.8-rc7-tag-two' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen:
Revert "xen PVonHVM: use E820_Reserved area for shared_info"
Revert "xen/PVonHVM: fix compile warning in init_hvm_pv_info"
xen: remove redundant NULL check before unregister_and_remove_pcpu().
x86/xen: don't assume %ds is usable in xen_iret for 32-bit PVOPS.
* acpi-cleanup: (21 commits)
ACPI / hotplug: Fix concurrency issues and memory leaks
ACPI: Remove the use of CONFIG_ACPI_CONTAINER_MODULE
ACPI / scan: Full transition to D3cold in acpi_device_unregister()
ACPI / scan: Make acpi_bus_hot_remove_device() acquire the scan lock
ACPI: Drop the container.h header file
ACPI / Documentation: refer to correct file for acpi_platform_device_ids[] table
ACPI / scan: Make container driver use struct acpi_scan_handler
ACPI / scan: Remove useless #ifndef from acpi_eject_store()
ACPI: Unbind ACPI drv when probe failed
ACPI: sysfs eject support for ACPI scan handlers
ACPI / scan: Follow priorities of IDs when matching scan handlers
ACPI / PCI: pci_slot: replace printk(KERN_xxx) with pr_xxx()
ACPI / dock: Fix acpi_bus_get_device() check in drivers/acpi/dock.c
ACPI / scan: Clean up acpi_bus_get_parent()
ACPI / platform: Use struct acpi_scan_handler for creating devices
ACPI / PCI: Make PCI IRQ link driver use struct acpi_scan_handler
ACPI / PCI: Make PCI root driver use struct acpi_scan_handler
ACPI / scan: Introduce struct acpi_scan_handler
ACPI / scan: Make scanning of fixed devices follow the general scheme
ACPI: Drop device start operation that is not used
...
unregister_and_remove_pcpu on a NULL pointer is a no-op, so the NULL check in
sync_pcpu can be removed.
Signed-off-by: Cyril Roelandt <tipecaml@gmail.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Starting with win8, vmbus interrupts can be delivered on any VCPU in the guest
and furthermore can be concurrently active on multiple VCPUs. Support this
interrupt delivery model by setting up a separate IDT entry for Hyper-V vmbus.
interrupts. I would like to thank Jan Beulich <JBeulich@suse.com> and
Thomas Gleixner <tglx@linutronix.de>, for their help.
In this version of the patch, based on the feedback, I have merged the IDT
vector for Xen and Hyper-V and made the necessary adjustments. Furhermore,
based on Jan's feedback I have added the necessary compilation switches.
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Link: http://lkml.kernel.org/r/1359940959-32168-3-git-send-email-kys@microsoft.com
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Eric W. Biederman
Linus Torvalds
Steven Noonan
Liu Jinsong
Al Viro
Ian Campbell
Stefano Stabellini
Wei Liu
Konrad Rzeszutek Wilk
Rafael J. Wysocki
Cyril Roelandt
K. Y. Srinivasan