fscrypt: add FS_IOC_ADD_ENCRYPTION_KEY ioctl

Add a new fscrypt ioctl, FS_IOC_ADD_ENCRYPTION_KEY. This ioctl adds an
encryption key to the filesystem's fscrypt keyring ->s_master_keys,
making any fi

fscrypt: add FS_IOC_ADD_ENCRYPTION_KEY ioctl

Add a new fscrypt ioctl, FS_IOC_ADD_ENCRYPTION_KEY. This ioctl adds an
encryption key to the filesystem's fscrypt keyring ->s_master_keys,
making any files encrypted with that key appear "unlocked".

Why we need this
~~~~~~~~~~~~~~~~

The main problem is that the "locked/unlocked" (ciphertext/plaintext)
status of encrypted files is global, but the fscrypt keys are not.
fscrypt only looks for keys in the keyring(s) the process accessing the
filesystem is subscribed to: the thread keyring, process keyring, and
session keyring, where the session keyring may contain the user keyring.

Therefore, userspace has to put fscrypt keys in the keyrings for
individual users or sessions. But this means that when a process with a
different keyring tries to access encrypted files, whether they appear
"unlocked" or not is nondeterministic. This is because it depends on
whether the files are currently present in the inode cache.

Fixing this by consistently providing each process its own view of the
filesystem depending on whether it has the key or not isn't feasible due
to how the VFS caches work. Furthermore, while sometimes users expect
this behavior, it is misguided for two reasons. First, it would be an
OS-level access control mechanism largely redundant with existing access
control mechanisms such as UNIX file permissions, ACLs, LSMs, etc.
Encryption is actually for protecting the data at rest.

Second, almost all users of fscrypt actually do need the keys to be
global. The largest users of fscrypt, Android and Chromium OS, achieve
this by having PID 1 create a "session keyring" that is inherited by
every process. This works, but it isn't scalable because it prevents
session keyrings from being used for any other purpose.

On general-purpose Linux distros, the 'fscrypt' userspace tool [1] can't
similarly abuse the session keyring, so to make 'sudo' work on all
systems it has to link all the user keyrings into root's user keyring
[2]. This is ugly and raises security concerns. Moreover it can't make
the keys available to system services, such as sshd trying to access the
user's '~/.ssh' directory (see [3], [4]) or NetworkManager trying to
read certificates from the user's home directory (see [5]); or to Docker
containers (see [6], [7]).

By having an API to add a key to the *filesystem* we'll be able to fix
the above bugs, remove userspace workarounds, and clearly express the
intended semantics: the locked/unlocked status of an encrypted directory
is global, and encryption is orthogonal to OS-level access control.

Why not use the add_key() syscall
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We use an ioctl for this API rather than the existing add_key() system
call because the ioctl gives us the flexibility needed to implement
fscrypt-specific semantics that will be introduced in later patches:

- Supporting key removal with the semantics such that the secret is
removed immediately and any unused inodes using the key are evicted;
also, the eviction of any in-use inodes can be retried.

- Calculating a key-dependent cryptographic identifier and returning it
to userspace.

- Allowing keys to be added and removed by non-root users, but only keys
for v2 encryption policies; and to prevent denial-of-service attacks,
users can only remove keys they themselves have added, and a key is
only really removed after all users who added it have removed it.

Trying to shoehorn these semantics into the keyrings syscalls would be
very difficult, whereas the ioctls make things much easier.

However, to reuse code the implementation still uses the keyrings
service internally. Thus we get lockless RCU-mode key lookups without
having to re-implement it, and the keys automatically show up in
/proc/keys for debugging purposes.

References:

[1] https://github.com/google/fscrypt
[2] https://goo.gl/55cCrI#heading=h.vf09isp98isb
[3] https://github.com/google/fscrypt/issues/111#issuecomment-444347939
[4] https://github.com/google/fscrypt/issues/116
[5] https://bugs.launchpad.net/ubuntu/+source/fscrypt/+bug/1770715
[6] https://github.com/google/fscrypt/issues/128
[7] https://askubuntu.com/questions/1130306/cannot-run-docker-on-an-encrypted-filesystem

Reviewed-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Eric Biggers <ebiggers@google.com>

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fscrypt: rename keyinfo.c to keysetup.c

Rename keyinfo.c to keysetup.c since this better describes what the file
does (sets up the key), and it matches the new file keysetup_v1.c.

Reviewed-by: Theo

fscrypt: rename keyinfo.c to keysetup.c

Rename keyinfo.c to keysetup.c since this better describes what the file
does (sets up the key), and it matches the new file keysetup_v1.c.

Reviewed-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Eric Biggers <ebiggers@google.com>

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fscrypt: move v1 policy key setup to keysetup_v1.c

In preparation for introducing v2 encryption policies which will find
and derive encryption keys differently from the current v1 encryption
policie

fscrypt: move v1 policy key setup to keysetup_v1.c

In preparation for introducing v2 encryption policies which will find
and derive encryption keys differently from the current v1 encryption
policies, move the v1 policy-specific key setup code from keyinfo.c into
keysetup_v1.c.

Reviewed-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Eric Biggers <ebiggers@google.com>

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Merge branch 'next' into for-linus

Prepare second round of input updates for 5.3 merge window.

Merge tag 'v5.2' into next

Sync up with mainline to resolve conflicts in iforce driver.

Merge branches 'for-5.2/fixes', 'for-5.3/doc', 'for-5.3/ish', 'for-5.3/logitech' and 'for-5.3/wacom' into for-linus

Merge tag 'asoc-v5.3' of https://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound into for-linus

ASoC: Updates for v5.3

This is a very big update, mainly thanks to Morimoto-san's refactoring
w

Merge tag 'asoc-v5.3' of https://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound into for-linus

ASoC: Updates for v5.3

This is a very big update, mainly thanks to Morimoto-san's refactoring
work and some fairly large new drivers.

- Lots more work on moving towards a component based framework from
Morimoto-san.
- Support for force disconnecting muxes from Jerome Brunet.
- New drivers for Cirrus Logic CS47L35, CS47L85 and CS47L90, Conexant
CX2072X, Realtek RT1011 and RT1308.

Signed-off-by: Takashi Iwai <tiwai@suse.de>

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Merge tag 'nand/for-5.3' of git://git.kernel.org/pub/scm/linux/kernel/git/mtd/linux into mtd/next

NAND core changes:
- use longest matching pattern in ->exec_op() default parser
- export NAND operat

Merge tag 'nand/for-5.3' of git://git.kernel.org/pub/scm/linux/kernel/git/mtd/linux into mtd/next

NAND core changes:
- use longest matching pattern in ->exec_op() default parser
- export NAND operation tracer
- add flag to indicate panic_write in MTD
- use kzalloc() instead of kmalloc() and memset()

Raw NAND controller drivers changes:
- brcmnand:
* fix BCH ECC layout for large page NAND parts
* fallback to detected ecc-strength, ecc-step-size
* when oops in progress use pio and interrupt polling
* code refactor code to introduce helper functions
* add support for v7.3 controller
- FSMC:
* use nand_op_trace for operation tracing
- GPMI:
* move all driver code into single file
* various cleanups (including dmaengine changes)
* use runtime PM to manage clocks
* implement exec_op
- MTK:
* correct low level time calculation of r/w cycle
* improve data sampling timing for read cycle
* add validity check for CE# pin setting
* fix wrongly assigned OOB buffer pointer issue
* re-license MTK NAND driver as Dual MIT/GPL
- STM32:
* manage the get_irq error case
* increase DMA completion timeouts

Raw NAND chips drivers changes:
- Macronix: add read-retry support

Onenand driver changes:
- add support for 8Gb datasize chips
- avoid fall-through warnings

SPI-NAND changes:
- define macros for page-read ops with three-byte addresses
- add support for two-byte device IDs and then for GigaDevice
GD5F1GQ4UFxxG
- add initial support for Paragon PN26G0xA
- handle the case where the last page read has bitflips

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Merge tag 'v5.2-rc6' into rdma.git for-next

For dependencies in next patches.

Resolve conflicts:
- Use uverbs_get_cleared_udata() with new cq allocation flow
- Continue to delete nes despite SPDX c

Merge tag 'v5.2-rc6' into rdma.git for-next

For dependencies in next patches.

Resolve conflicts:
- Use uverbs_get_cleared_udata() with new cq allocation flow
- Continue to delete nes despite SPDX conflict
- Resolve list appends in mlx5_command_str()
- Use u16 for vport_rule stuff
- Resolve list appends in struct ib_client

Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

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Merge tag 'v5.2-rc6' into asoc-5.3

Linux 5.2-rc6

Merge remote-tracking branch 'drm/drm-next' into drm-misc-next-fixes

Some fixes have been accidentally pushed to this, so I cannot fost-forward.
Required to pull in the remove-fbcon-notifiers fixes.

Merge remote-tracking branch 'drm/drm-next' into drm-misc-next-fixes

Some fixes have been accidentally pushed to this, so I cannot fost-forward.
Required to pull in the remove-fbcon-notifiers fixes.

Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>

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Merge tag 'topic/remove-fbcon-notifiers-2019-06-14-1' of git://anongit.freedesktop.org/drm/drm-misc into fbdev-for-next

topic/remove-fbcon-notifiers:
- remove fbdev notifier usage for fbcon, as prep

Merge tag 'topic/remove-fbcon-notifiers-2019-06-14-1' of git://anongit.freedesktop.org/drm/drm-misc into fbdev-for-next

topic/remove-fbcon-notifiers:
- remove fbdev notifier usage for fbcon, as prep work to clean up the fbcon locking
- assorted locking checks in vt/console code
- assorted notifier and cleanups in fbdev and backlight code

One trivial merge conflict fixed.

Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>

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Merge tag 'v5.2-rc4' into regulator-5.3

Linux 5.2-rc4

Merge tag 'v5.2-rc4' into mauro

We need to pick up post-rc1 changes to various document files so they don't
get lost in Mauro's massive RST conversion push.

Merge tag 'v5.2-rc4' into spi-5.3

Linux 5.2-rc4

Merge 5.2-rc4 into char-misc-next

We want the char/misc driver fixes in here as well.

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Merge 5.2-rc3 into tty-next

We want the tty/serial fixes in here as well.

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Merge tag 'v5.2-rc3' into perf/core, to pick up fixes

Signed-off-by: Ingo Molnar <mingo@kernel.org>

Merge 5.2-rc3 into staging-next

We need the staging fixes in here as well.

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Merge 5.2-rc3 into usb-next

we want the USB fixes in here as well.

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux

Merge tag 'kvm-ppc-fixes-5.2-1' of git://git.kernel.org/pub/scm/linux/kernel/git/paulus/powerpc into kvm-master

PPC KVM fixes for 5.2

- Several bug fixes for the new XIVE-native code.
- Replace kvm

Merge tag 'kvm-ppc-fixes-5.2-1' of git://git.kernel.org/pub/scm/linux/kernel/git/paulus/powerpc into kvm-master

PPC KVM fixes for 5.2

- Several bug fixes for the new XIVE-native code.
- Replace kvm->lock by other mutexes in several places where we hold a
vcpu mutex, to avoid lock order inversions.
- Fix a lockdep warning on guest entry for radix-mode guests.
- Fix a bug causing user-visible corruption of SPRG3 on the host.

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Merge tag 'v5.2-rc2' into patchwork

Merge back from upstream into media tree, as there are some
patches merged upstream that has pontential of causing
conflicts (one actually rised a conflict alread

Merge tag 'v5.2-rc2' into patchwork

Merge back from upstream into media tree, as there are some
patches merged upstream that has pontential of causing
conflicts (one actually rised a conflict already).

Linux 5.2-rc2

* tag 'v5.2-rc2': (377 commits)
Linux 5.2-rc2
random: fix soft lockup when trying to read from an uninitialized blocking pool
tracing: Silence GCC 9 array bounds warning
ext4: fix dcache lookup of !casefolded directories
locking/lock_events: Use this_cpu_add() when necessary
KVM: x86: fix return value for reserved EFER
tools/kvm_stat: fix fields filter for child events
KVM: selftests: Wrap vcpu_nested_state_get/set functions with x86 guard
kvm: selftests: aarch64: compile with warnings on
kvm: selftests: aarch64: fix default vm mode
kvm: selftests: aarch64: dirty_log_test: fix unaligned memslot size
KVM: s390: fix memory slot handling for KVM_SET_USER_MEMORY_REGION
KVM: x86/pmu: do not mask the value that is written to fixed PMUs
KVM: x86/pmu: mask the result of rdpmc according to the width of the counters
x86/kvm/pmu: Set AMD's virt PMU version to 1
KVM: x86: do not spam dmesg with VMCS/VMCB dumps
kvm: Check irqchip mode before assign irqfd
kvm: svm/avic: fix off-by-one in checking host APIC ID
KVM: selftests: do not blindly clobber registers in guest asm
KVM: selftests: Remove duplicated TEST_ASSERT in hyperv_cpuid.c
...

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Merge drm/drm-next into drm-intel-next-queued

Get the HDR dependencies originally merged via drm-misc. Sync up all
i915 changes applied via other trees. And get v5.2-rc2 as the baseline.

Signed-off

Merge drm/drm-next into drm-intel-next-queued

Get the HDR dependencies originally merged via drm-misc. Sync up all
i915 changes applied via other trees. And get v5.2-rc2 as the baseline.

Signed-off-by: Jani Nikula <jani.nikula@intel.com>

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Merge remote-tracking branch 'drm/drm-next' into drm-misc-next

This picks up rc2 for us as well.

Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>