Pull namespace bugfixes from Eric Biederman:
"This is three simple fixes against 3.9-rc1. I have tested each of
these fixes and verified they work correctly.
The userns oops in key_change_session_keyring and the BUG_ON triggered
by proc_ns_follow_link were found by Dave Jones.
I am including the enhancement for mount to only trigger requests of
filesystem modules here instead of delaying this for the 3.10 merge
window because it is both trivial and the kind of change that tends to
bit-rot if left untouched for two months."
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace:
proc: Use nd_jump_link in proc_ns_follow_link
fs: Limit sys_mount to only request filesystem modules (Part 2).
fs: Limit sys_mount to only request filesystem modules.
userns: Stop oopsing in key_change_session_keyring
Joseph was hitting a failure case when mounting efivarfs which
resulted in an incorrect error message,
$ sudo mount -v /sys/firmware/efi/efivars mount: Cannot allocate memory
triggered when efivarfs_valid_name() returned -EINVAL.
Make sure we pass accurate return values up the stack if
efivarfs_fill_super() fails to build inodes for EFI variables.
Reported-by: Joseph Yasi <joe.yasi@gmail.com>
Reported-by: Lingzhu Xiang <lxiang@redhat.com>
Cc: Josh Boyer <jwboyer@redhat.com>
Cc: Jeremy Kerr <jk@ozlabs.org>
Cc: Matthew Garrett <mjg59@srcf.ucam.org>
Cc: <stable@vger.kernel.org> # v3.8
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
Stricter validation was introduced with commit da27a24383
("efivarfs: guid part of filenames are case-insensitive") and commit
47f531e8ba ("efivarfs: Validate filenames much more aggressively"),
which is necessary for the guid portion of efivarfs filenames, but we
don't need to be so strict with the first part, the variable name. The
UEFI specification doesn't impose any constraints on variable names
other than they be a NULL-terminated string.
The above commits caused a regression that resulted in users seeing
the following message,
$ sudo mount -v /sys/firmware/efi/efivars mount: Cannot allocate memory
whenever pstore EFI variables were present in the variable store,
since their variable names failed to pass the following check,
/* GUID should be right after the first '-' */
if (s - 1 != strchr(str, '-'))
as a typical pstore filename is of the form, dump-type0-10-1-<guid>.
The fix is trivial since the guid portion of the filename is GUID_LEN
bytes, we can use (len - GUID_LEN) to ensure the '-' character is
where we expect it to be.
(The bogus ENOMEM error value will be fixed in a separate patch.)
Reported-by: Joseph Yasi <joe.yasi@gmail.com>
Tested-by: Joseph Yasi <joe.yasi@gmail.com>
Reported-by: Lingzhu Xiang <lxiang@redhat.com>
Cc: Josh Boyer <jwboyer@redhat.com>
Cc: Jeremy Kerr <jk@ozlabs.org>
Cc: Matthew Garrett <mjg59@srcf.ucam.org>
Cc: <stable@vger.kernel.org> # v3.8
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
UEFI variables are typically stored in flash. For various reasons, avaiable
space is typically not reclaimed immediately upon the deletion of a
variable - instead, the system will garbage collect during initialisation
after a reboot.
Some systems appear to handle this garbage collection extremely poorly,
failing if more than 50% of the system flash is in use. This can result in
the machine refusing to boot. The safest thing to do for the moment is to
forbid writes if they'd end up using more than half of the storage space.
We can make this more finegrained later if we come up with a method for
identifying the broken machines.
Signed-off-by: Matthew Garrett <matthew.garrett@nebula.com>
Cc: Josh Boyer <jwboyer@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
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 x86/EFI changes from Peter Anvin:
- Improve the initrd handling in the EFI boot stub by allowing forward
slashes in the pathname - from Chun-Yi Lee.
- Cleanup code duplication in the EFI mixed kernel/firmware code - from
Satoru Takeuchi.
- efivarfs bug fixes for more strict filename validation, with lots of
input from Al Viro.
* 'x86-efi-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86, efi: remove duplicate code in setup_arch() by using, efi_is_native()
efivarfs: guid part of filenames are case-insensitive
efivarfs: Validate filenames much more aggressively
efivarfs: Use sizeof() instead of magic number
x86, efi: Allow slash in file path of initrd
a system in the crash path. Plus a new mountpoint
(/sys/fs/pstore ... makes more sense then /dev/pstore).
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Merge tag 'please-pull-pstore' of git://git.kernel.org/pub/scm/linux/kernel/git/aegl/linux
Pull pstore patches from Tony Luck:
"A few fixes to reduce places where pstore might hang a system in the
crash path. Plus a new mountpoint (/sys/fs/pstore ... makes more
sense then /dev/pstore)."
Fix up trivial conflict in drivers/firmware/efivars.c
* tag 'please-pull-pstore' of git://git.kernel.org/pub/scm/linux/kernel/git/aegl/linux:
pstore: Create a convenient mount point for pstore
efi_pstore: Introducing workqueue updating sysfs
efivars: Disable external interrupt while holding efivars->lock
efi_pstore: Avoid deadlock in non-blocking paths
pstore: Avoid deadlock in panic and emergency-restart path
[Problem]
efi_pstore creates sysfs entries, which enable users to access to NVRAM,
in a write callback. If a kernel panic happens in an interrupt context,
it may fail because it could sleep due to dynamic memory allocations during
creating sysfs entries.
[Patch Description]
This patch removes sysfs operations from a write callback by introducing
a workqueue updating sysfs entries which is scheduled after the write
callback is called.
Also, the workqueue is kicked in a just oops case.
A system will go down in other cases such as panic, clean shutdown and emergency
restart. And we don't need to create sysfs entries because there is no chance for
users to access to them.
efi_pstore will be robust against a kernel panic in an interrupt context with this patch.
Signed-off-by: Seiji Aguchi <seiji.aguchi@hds.com>
Acked-by: Matt Fleming <matt.fleming@intel.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
[Problem]
There is a scenario which efi_pstore fails to log messages in a panic case.
- CPUA holds an efi_var->lock in either efivarfs parts
or efi_pstore with interrupt enabled.
- CPUB panics and sends IPI to CPUA in smp_send_stop().
- CPUA stops with holding the lock.
- CPUB kicks efi_pstore_write() via kmsg_dump(KSMG_DUMP_PANIC)
but it returns without logging messages.
[Patch Description]
This patch disables an external interruption while holding efivars->lock
as follows.
In efi_pstore_write() and get_var_data(), spin_lock/spin_unlock is
replaced by spin_lock_irqsave/spin_unlock_irqrestore because they may
be called in an interrupt context.
In other functions, they are replaced by spin_lock_irq/spin_unlock_irq.
because they are all called from a process context.
By applying this patch, we can avoid the problem above with
a following senario.
- CPUA holds an efi_var->lock with interrupt disabled.
- CPUB panics and sends IPI to CPUA in smp_send_stop().
- CPUA receives the IPI after releasing the lock because it is
disabling interrupt while holding the lock.
- CPUB waits for one sec until CPUA releases the lock.
- CPUB kicks efi_pstore_write() via kmsg_dump(KSMG_DUMP_PANIC)
And it can hold the lock successfully.
Signed-off-by: Seiji Aguchi <seiji.aguchi@hds.com>
Acked-by: Mike Waychison <mikew@google.com>
Acked-by: Matt Fleming <matt.fleming@intel.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
It makes no sense to treat the following filenames as unique,
VarName-abcdefab-abcd-abcd-abcd-abcdefabcdef
VarName-ABCDEFAB-ABCD-ABCD-ABCD-ABCDEFABCDEF
VarName-ABcDEfAB-ABcD-ABcD-ABcD-ABcDEfABcDEf
VarName-aBcDEfAB-aBcD-aBcD-aBcD-aBcDEfaBcDEf
... etc ...
since the guid will be converted into a binary representation, which
has no case.
Roll our own dentry operations so that we can treat the variable name
part of filenames ("VarName" in the above example) as case-sensitive,
but the guid portion as case-insensitive. That way, efivarfs will
refuse to create the above files if any one already exists.
Reported-by: Lingzhu Xiang <lxiang@redhat.com>
Cc: Matthew Garrett <mjg59@srcf.ucam.org>
Cc: Jeremy Kerr <jeremy.kerr@canonical.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
The only thing that efivarfs does to enforce a valid filename is
ensure that the name isn't too short. We need to strongly sanitise any
filenames, not least because variable creation is delayed until
efivarfs_file_write(), which means we can't rely on the firmware to
inform us of an invalid name, because if the file is never written to
we'll never know it's invalid.
Perform a couple of steps before agreeing to create a new file,
* hex_to_bin() returns a value indicating whether or not it was able
to convert its arguments to a binary representation - we should
check it.
* Ensure that the GUID portion of the filename is the correct length
and format.
* The variable name portion of the filename needs to be at least one
character in size.
Reported-by: Lingzhu Xiang <lxiang@redhat.com>
Cc: Matthew Garrett <mjg59@srcf.ucam.org>
Cc: Jeremy Kerr <jeremy.kerr@canonical.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
Instead of adding a magic 4 to the variable size, use sizeof() to make
it explicitly clear what the quantity represents (the variable's
attributes).
CC: Jeremy Kerr <jeremy.kerr@canonical.com>
Cc: Chun-Yi Lee <joeyli.kernel@gmail.com>
Cc: Andy Whitcroft <apw@canonical.com>
Reported-by: Lingzhu Xiang <lxiang@redhat.com>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
Pull x86 EFI fixes from Peter Anvin:
"This is a collection of fixes for the EFI support. The controversial
bit here is a set of patches which bumps the boot protocol version as
part of fixing some serious problems with the EFI handover protocol,
used when booting under EFI using a bootloader as opposed to directly
from EFI. These changes should also make it a lot saner to support
cross-mode 32/64-bit EFI booting in the future. Getting these changes
into 3.8 means we avoid presenting an inconsistent ABI to bootloaders.
Other changes are display detection and fixing efivarfs."
* 'x86-efi-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86, efi: remove attribute check from setup_efi_pci
x86, build: Dynamically find entry points in compressed startup code
x86, efi: Fix PCI ROM handing in EFI boot stub, in 32-bit mode
x86, efi: Fix 32-bit EFI handover protocol entry point
x86, efi: Fix display detection in EFI boot stub
x86, boot: Define the 2.12 bzImage boot protocol
x86/boot: Fix minor fd leakage in tools/relocs.c
x86, efi: Set runtime_version to the EFI spec revision
x86, efi: fix 32-bit warnings in setup_efi_pci()
efivarfs: Delete dentry from dcache in efivarfs_file_write()
efivarfs: Never return ENOENT from firmware
efi, x86: Pass a proper identity mapping in efi_call_phys_prelog
efivarfs: Drop link count of the right inode
Originally 'efi_enabled' indicated whether a kernel was booted from
EFI firmware. Over time its semantics have changed, and it now
indicates whether or not we are booted on an EFI machine with
bit-native firmware, e.g. 64-bit kernel with 64-bit firmware.
The immediate motivation for this patch is the bug report at,
https://bugs.launchpad.net/ubuntu-cdimage/+bug/1040557
which details how running a platform driver on an EFI machine that is
designed to run under BIOS can cause the machine to become
bricked. Also, the following report,
https://bugzilla.kernel.org/show_bug.cgi?id=47121
details how running said driver can also cause Machine Check
Exceptions. Drivers need a new means of detecting whether they're
running on an EFI machine, as sadly the expression,
if (!efi_enabled)
hasn't been a sufficient condition for quite some time.
Users actually want to query 'efi_enabled' for different reasons -
what they really want access to is the list of available EFI
facilities.
For instance, the x86 reboot code needs to know whether it can invoke
the ResetSystem() function provided by the EFI runtime services, while
the ACPI OSL code wants to know whether the EFI config tables were
mapped successfully. There are also checks in some of the platform
driver code to simply see if they're running on an EFI machine (which
would make it a bad idea to do BIOS-y things).
This patch is a prereq for the samsung-laptop fix patch.
Cc: David Airlie <airlied@linux.ie>
Cc: Corentin Chary <corentincj@iksaif.net>
Cc: Matthew Garrett <mjg59@srcf.ucam.org>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: Olof Johansson <olof@lixom.net>
Cc: Peter Jones <pjones@redhat.com>
Cc: Colin Ian King <colin.king@canonical.com>
Cc: Steve Langasek <steve.langasek@canonical.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Konrad Rzeszutek Wilk <konrad@kernel.org>
Cc: Rafael J. Wysocki <rjw@sisk.pl>
Cc: <stable@vger.kernel.org>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Files are created in efivarfs_create() before a corresponding variable
is created in the firmware. This leads to users being able to
read/write to the file without the variable existing in the
firmware. Reading a non-existent variable currently returns -ENOENT,
which is confusing because the file obviously *does* exist.
Convert EFI_NOT_FOUND into -EIO which is the closest thing to "error
while interacting with firmware", and should hopefully indicate to the
caller that the variable is in some uninitialised state.
Cc: Josh Boyer <jwboyer@redhat.com>
Acked-by: Jeremy Kerr <jeremy.kerr@canonical.com>
Cc: Lee, Chun-Yi <jlee@suse.com>
Cc: Andy Whitcroft <apw@canonical.com>
Reported-by: Lingzhu Xiang <lxiang@redhat.com>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
efivarfs_unlink() should drop the file's link count, not the directory's.
Signed-off-by: Lingzhu Xiang <lxiang@redhat.com>
Cc: Jeremy Kerr <jeremy.kerr@canonical.com>
Tested-by: Lee, Chun-Yi <jlee@suse.com>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
[Issue]
There is a scenario which efi_pstore may hang up:
- cpuA grabs efivars->lock
- cpuB panics and calls smp_send_stop
- smp_send_stop sends IRQ to cpuA
- after 1 second, cpuB gives up on cpuA and sends an NMI instead
- cpuA is now in an NMI handler while still holding efivars->lock
- cpuB is deadlocked
This case may happen if a firmware has a bug and
cpuA is stuck talking with it.
[Solution]
This patch changes a spin_lock to a spin_trylock in non-blocking paths.
and if the spin_lock has already taken by another cpu,
it returns without accessing to a firmware to avoid the deadlock.
Signed-off-by: Seiji Aguchi <seiji.aguchi@hds.com>
Acked-by: Don Zickus <dzickus@redhat.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
When compiling efivars.c the build fails with:
CC drivers/firmware/efivars.o
drivers/firmware/efivars.c: In function ‘efivarfs_get_inode’:
drivers/firmware/efivars.c:886:31: error: incompatible types when assigning to type ‘kgid_t’ from type ‘int’
make[2]: *** [drivers/firmware/efivars.o] Error 1
make[1]: *** [drivers/firmware/efivars.o] Error 2
Fix the build error by removing the duplicate initialization of i_uid and
i_gid inode_init_always has already initialized them to 0.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull x86 EFI update from Peter Anvin:
"EFI tree, from Matt Fleming. Most of the patches are the new efivarfs
filesystem by Matt Garrett & co. The balance are support for EFI
wallclock in the absence of a hardware-specific driver, and various
fixes and cleanups."
* 'core-efi-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (24 commits)
efivarfs: Make efivarfs_fill_super() static
x86, efi: Check table header length in efi_bgrt_init()
efivarfs: Use query_variable_info() to limit kmalloc()
efivarfs: Fix return value of efivarfs_file_write()
efivarfs: Return a consistent error when efivarfs_get_inode() fails
efivarfs: Make 'datasize' unsigned long
efivarfs: Add unique magic number
efivarfs: Replace magic number with sizeof(attributes)
efivarfs: Return an error if we fail to read a variable
efi: Clarify GUID length calculations
efivarfs: Implement exclusive access for {get,set}_variable
efivarfs: efivarfs_fill_super() ensure we clean up correctly on error
efivarfs: efivarfs_fill_super() ensure we free our temporary name
efivarfs: efivarfs_fill_super() fix inode reference counts
efivarfs: efivarfs_create() ensure we drop our reference on inode on error
efivarfs: efivarfs_file_read ensure we free data in error paths
x86-64/efi: Use EFI to deal with platform wall clock (again)
x86/kernel: remove tboot 1:1 page table creation code
x86, efi: 1:1 pagetable mapping for virtual EFI calls
x86, mm: Include the entire kernel memory map in trampoline_pgd
...
[Issue]
a format of variable name has been updated to type, id, count and ctime
to support holding multiple logs.
Format of current variable name
dump-type0-1-2-12345678
type:0
id:1
count:2
ctime:12345678
On the other hand, if an old variable name before being updated
remains, users can't erase it via /dev/pstore.
Format of old variable name
dump-type0-1-12345678
type:0
id:1
ctime:12345678
[Solution]
This patch add a format check for the old variable name in a erase callback to make it erasable.
Signed-off-by: Seiji Aguchi <seiji.aguchi@hds.com>
Acked-by: Mike Waychison <mikew@google.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
[Issue]
a format of variable name has been updated to type, id, count and ctime
to support holding multiple logs.
Format of current variable name
dump-type0-1-2-12345678
type:0
id:1
count:2
ctime:12345678
On the other hand, if an old variable name before being updated
remains, users can't read it via /dev/pstore.
Format of old variable name
dump-type0-1-12345678
type:0
id:1
ctime:12345678
[Solution]
This patch add a format check for the old variable name in a read callback
to make it readable.
Signed-off-by: Seiji Aguchi <seiji.aguchi@hds.com>
Acked-by: Mike Waychison <mikew@google.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
[Issue]
Currently, a variable name, which identifies each entry, consists of type, id and ctime.
But if multiple events happens in a short time, a second/third event may fail to log because
efi_pstore can't distinguish each event with current variable name.
[Solution]
A reasonable way to identify all events precisely is introducing a sequence counter to
the variable name.
The sequence counter has already supported in a pstore layer with "oopscount".
So, this patch adds it to a variable name.
Also, it is passed to read/erase callbacks of platform drivers in accordance with
the modification of the variable name.
<before applying this patch>
a variable name of first event: dump-type0-1-12345678
a variable name of second event: dump-type0-1-12345678
type:0
id:1
ctime:12345678
If multiple events happen in a short time, efi_pstore can't distinguish them because
variable names are same among them.
<after applying this patch>
it can be distinguishable by adding a sequence counter as follows.
a variable name of first event: dump-type0-1-1-12345678
a variable name of Second event: dump-type0-1-2-12345678
type:0
id:1
sequence counter: 1(first event), 2(second event)
ctime:12345678
In case of a write callback executed in pstore_console_write(), "0" is added to
an argument of the write callback because it just logs all kernel messages and
doesn't need to care about multiple events.
Signed-off-by: Seiji Aguchi <seiji.aguchi@hds.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Mike Waychison <mikew@google.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
[Issue]
Currently, a variable name, which is used to identify each log entry, consists of type,
id and ctime. But an erase callback does not use ctime.
If efi_pstore supported just one log, type and id were enough.
However, in case of supporting multiple logs, it doesn't work because
it can't distinguish each entry without ctime at erasing time.
<Example>
As you can see below, efi_pstore can't differentiate first event from second one without ctime.
a variable name of first event: dump-type0-1-12345678
a variable name of second event: dump-type0-1-23456789
type:0
id:1
ctime:12345678, 23456789
[Solution]
This patch adds ctime to an argument of an erase callback.
It works across reboots because ctime of pstore means the date that the record was originally stored.
To do this, efi_pstore saves the ctime to variable name at writing time and passes it to pstore
at reading time.
Signed-off-by: Seiji Aguchi <seiji.aguchi@hds.com>
Acked-by: Mike Waychison <mikew@google.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
[Issue]
Currently, efi_pstore driver simply overwrites existing panic messages in NVRAM.
So, in the following scenario, we will lose 1st panic messages.
1. kernel panics.
2. efi_pstore is kicked and writes panic messages to NVRAM.
3. system reboots.
4. kernel panics again before a user checks the 1st panic messages in NVRAM.
[Solution]
A reasonable solution to fix the issue is just holding multiple logs without erasing
existing entries.
This patch removes a logic erasing existing entries in a write callback
because the logic is not needed in the write callback to support holding multiple logs.
Signed-off-by: Seiji Aguchi <seiji.aguchi@hds.com>
Acked-by: Mike Waychison <mikew@google.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
[Issue]
Currently, efi_pstore driver simply overwrites existing panic messages in NVRAM.
So, in the following scenario, we will lose 1st panic messages.
1. kernel panics.
2. efi_pstore is kicked and writes panic messages to NVRAM.
3. system reboots.
4. kernel panics again before a user checks the 1st panic messages in NVRAM.
[Solution]
A reasonable solution to fix the issue is just holding multiple logs without erasing
existing entries.
This patch freshly adds a logic erasing existing entries, which shared with a write callback,
to an erase callback.
To support holding multiple logs, the write callback doesn't need to erase any entries and
it will be removed in a subsequent patch.
Signed-off-by: Seiji Aguchi <seiji.aguchi@hds.com>
Acked-by: Mike Waychison <mikew@google.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
[Issue]
As discussed in a thread below, Running out of space in EFI isn't a well-tested scenario.
And we wouldn't expect all firmware to handle it gracefully.
http://marc.info/?l=linux-kernel&m=134305325801789&w=2
On the other hand, current efi_pstore doesn't check a remaining space of storage at writing time.
Therefore, efi_pstore may not work if it tries to write a large amount of data.
[Patch Description]
To avoid handling the situation above, this patch checks if there is a space enough to log with
QueryVariableInfo() before writing data.
Signed-off-by: Seiji Aguchi <seiji.aguchi@hds.com>
Acked-by: Mike Waychison <mikew@google.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
sparse is complaining that efivarfs_fill_super() doesn't have a
prototype. Make it static to avoid the warning.
Cc: Xie ChanglongX <changlongx.xie@intel.com>
Cc: Matthew Garrett <mjg@redhat.com>
Cc: Jeremy Kerr <jeremy.kerr@canonical.com>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
We don't want someone who can write EFI variables to be able to
allocate arbitrarily large amounts of memory, so cap it to something
sensible like the amount of free space for EFI variables.
Acked-by: Jeremy Kerr <jeremy.kerr@canonical.com>
Cc: Matthew Garrett <mjg@redhat.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
We're stuffing a variable of type size_t (unsigned) into a ssize_t
(signed) which, even though both types should be the same number of
bits, it's just asking for sign issues to be introduced.
Cc: Jeremy Kerr <jeremy.kerr@canonical.com>
Reported-by: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
Instead of returning -ENOSPC if efivarfs_get_inode() fails we should
be returning -ENOMEM, since running out of memory is the only reason
it can fail. Furthermore, that's the error value used everywhere else
in this file. It's also less likely to confuse users that hit this
error case.
Acked-by: Jeremy Kerr <jeremy.kerr@canonical.com>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
There's no reason to declare 'datasize' as an int, since the majority
of the functions it's passed to expect an unsigned long anyway. Plus,
this way we avoid any sign problems during arithmetic.
Acked-by: Jeremy Kerr <jeremy.kerr@canonical.com>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
Using pstore's superblock magic number is no doubt going to cause
problems in the future. Give efivarfs its own magic number.
Acked-by: Jeremy Kerr <jeremy.kerr@canonical.com>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
Seeing "+ 4" littered throughout the functions gets a bit
confusing. Use "sizeof(attributes)" which clearly explains what
quantity we're adding.
Acked-by: Jeremy Kerr <jeremy.kerr@canonical.com>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
Instead of always returning 0 in efivarfs_file_read(), even when we
fail to successfully read the variable, convert the EFI status to
something meaningful and return that to the caller. This way the user
will have some hint as to why the read failed.
Acked-by: Jeremy Kerr <jeremy.kerr@canonical.com>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
At present, the handling of GUIDs in efivar file names isn't consistent.
We use GUID_LEN in some places, and 38 in others (GUID_LEN plus
separator), and implicitly use the presence of the trailing NUL.
This change removes the trailing NUL from GUID_LEN, so that we're
explicitly adding it when required. We also replace magic numbers
with GUID_LEN, and clarify the comments where appropriate.
We also fix the allocation size in efivar_create_sysfs_entry, where
we're allocating one byte too much, due to counting the trailing NUL
twice - once when calculating short_name_size, and once in the kzalloc.
Signed-off-by: Jeremy Kerr <jeremy.kerr@canonical.com>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
Currently, efivarfs does not enforce exclusion over the get_variable and
set_variable operations. Section 7.1 of UEFI requires us to only allow a
single processor to enter {get,set}_variable services at once.
This change acquires the efivars->lock over calls to these operations
from the efivarfs paths.
Signed-off-by: Jeremy Kerr <jeremy.kerr@canonical.com>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
Ensure we free both the name and inode on error when building the
individual variables.
Signed-off-by: Andy Whitcroft <apw@canonical.com>
Acked-by: Matthew Garrett <mjg@redhat.com>
Acked-by: Jeremy Kerr <jeremy.kerr@canonical.com>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
d_alloc_name() copies the passed name to new storage, once complete we
no longer need our name.
Signed-off-by: Andy Whitcroft <apw@canonical.com>
Acked-by: Matthew Garrett <mjg@redhat.com>
Acked-by: Jeremy Kerr <jeremy.kerr@canonical.com>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
When d_make_root() fails it will automatically drop the reference
on the root inode. We should not be doing so as well.
Signed-off-by: Andy Whitcroft <apw@canonical.com>
Acked-by: Matthew Garrett <mjg@redhat.com>
Acked-by: Jeremy Kerr <jeremy.kerr@canonical.com>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
Signed-off-by: Andy Whitcroft <apw@canonical.com>
Acked-by: Matthew Garrett <mjg@redhat.com>
Acked-by: Jeremy Kerr <jeremy.kerr@canonical.com>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
Signed-off-by: Andy Whitcroft <apw@canonical.com>
Acked-by: Matthew Garrett <mjg@redhat.com>
Acked-by: Jeremy Kerr <jeremy.kerr@canonical.com>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
UEFI variable filesystem need a new mount point, so this patch add
efivars kobject to efi_kobj for create a /sys/firmware/efi/efivars
folder.
Cc: Matthew Garrett <mjg@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Lee, Chun-Yi <jlee@suse.com>
Signed-off-by: Jeremy Kerr <jeremy.kerr@canonical.com>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
A write to an efivarfs file will not always result in a variable of
'count' size after the EFI SetVariable() call. We may have appended to
the existing data (ie, with the EFI_VARIABLE_APPEND_WRITE attribute), or
even have deleted the variable (with an authenticated variable update,
with a zero datasize).
This change re-reads the updated variable from firmware, to check for
size changes and deletions. In the latter case, we need to drop the
dentry.
Signed-off-by: Jeremy Kerr <jeremy.kerr@canonical.com>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
The existing EFI variables code only supports variables of up to 1024
bytes. This limitation existed in version 0.99 of the EFI specification,
but was removed before any full releases. Since variables can now be
larger than a single page, sysfs isn't the best interface for this. So,
instead, let's add a filesystem. Variables can be read, written and
created, with the first 4 bytes of each variable representing its UEFI
attributes. The create() method doesn't actually commit to flash since
zero-length variables can't exist per-spec.
Updates from Jeremy Kerr <jeremy.kerr@canonical.com>.
Signed-off-by: Matthew Garrett <mjg@redhat.com>
Signed-off-by: Jeremy Kerr <jeremy.kerr@canonical.com>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
Some of the EFI variable attributes are missing from print out from
/sys/firmware/efi/vars/*/attributes. This patch adds those in. It also
updates code to use pre-defined constants for masking current value
of attributes.
Signed-off-by: Khalid Aziz <khalid.aziz@hp.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: Matthew Garrett <mjg@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Ben Hutchings pointed out that the validation in efivars was inadequate -
most obviously, an entry with size 0 would server as a DoS against the
kernel. Improve this based on his suggestions.
Signed-off-by: Matthew Garrett <mjg@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
A common flaw in UEFI systems is a refusal to POST triggered by a malformed
boot variable. Once in this state, machines may only be restored by
reflashing their firmware with an external hardware device. While this is
obviously a firmware bug, the serious nature of the outcome suggests that
operating systems should filter their variable writes in order to prevent
a malicious user from rendering the machine unusable.
Signed-off-by: Matthew Garrett <mjg@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
In the case where CONFIG_PSTORE=n, the function efi_pstore_read() doesn't
have the correct list of parameters. This patch provides a definition
of efi_pstore_read() with 'char **buf' added to fix this warning:
"drivers/firmware/efivars.c:609: warning: initialization from".
problem introduced in commit f6f8285132
Signed-off-by: Christoph Fritz <chf.fritz@googlemail.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Linus Torvalds