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Eric Biggers 3b7c17a814 fscrypt: remove kernel-internal constants from UAPI header
commit 3ceb6543e9cf6ed87cc1fbc6f23ca2db903564cd upstream.

There isn't really any valid reason to use __FSCRYPT_MODE_MAX or
FSCRYPT_POLICY_FLAGS_VALID in a userspace program.  These constants are
only meant to be used by the kernel internally, and they are defined in
the UAPI header next to the mode numbers and flags only so that kernel
developers don't forget to update them when adding new modes or flags.

In https://lkml.kernel.org/r/20201005074133.1958633-2-satyat@google.com
there was an example of someone wanting to use __FSCRYPT_MODE_MAX in a
user program, and it was wrong because the program would have broken if
__FSCRYPT_MODE_MAX were ever increased.  So having this definition
available is harmful.  FSCRYPT_POLICY_FLAGS_VALID has the same problem.

So, remove these definitions from the UAPI header.  Replace
FSCRYPT_POLICY_FLAGS_VALID with just listing the valid flags explicitly
in the one kernel function that needs it.  Move __FSCRYPT_MODE_MAX to
fscrypt_private.h, remove the double underscores (which were only
present to discourage use by userspace), and add a BUILD_BUG_ON() and
comments to (hopefully) ensure it is kept in sync.

Keep the old name FS_POLICY_FLAGS_VALID, since it's been around for
longer and there's a greater chance that removing it would break source
compatibility with some program.  Indeed, mtd-utils is using it in
an #ifdef, and removing it would introduce compiler warnings (about
FS_POLICY_FLAGS_PAD_* being redefined) into the mtd-utils build.
However, reduce its value to 0x07 so that it only includes the flags
with old names (the ones present before Linux 5.4), and try to make it
clear that it's now "frozen" and no new flags should be added to it.

Fixes: 2336d0deb2 ("fscrypt: use FSCRYPT_ prefix for uapi constants")
Cc: <stable@vger.kernel.org> # v5.4+
Link: https://lore.kernel.org/r/20201024005132.495952-1-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-12-26 16:02:43 +01:00
arch ARM: dts: exynos: fix USB 3.0 pins supply being turned off on Odroid XU 2020-12-26 16:02:40 +01:00
block block-5.10-2020-12-05 2020-12-05 14:45:30 -08:00
certs .gitignore: add SPDX License Identifier 2020-03-25 11:50:48 +01:00
crypto drivers-5.10-2020-10-12 2020-10-13 13:04:41 -07:00
Documentation USB: UAS: introduce a quirk to set no_write_same 2020-12-21 13:30:08 +01:00
drivers serial_core: Check for port state when tty is in error state 2020-12-26 16:02:43 +01:00
fs fscrypt: remove kernel-internal constants from UAPI header 2020-12-26 16:02:43 +01:00
include fscrypt: remove kernel-internal constants from UAPI header 2020-12-26 16:02:43 +01:00
init initramfs: fix clang build failure 2020-12-11 14:02:14 -08:00
ipc ipc: adjust proc_ipc_sem_dointvec definition to match prototype 2020-09-05 12:14:29 -07:00
kernel A set of x86 and membarrier fixes: 2020-12-13 11:31:19 -08:00
lib selftest/fpu: avoid clang warning 2020-12-11 14:02:14 -08:00
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samples Tracing fixes for 5.10-rc6 2020-12-01 15:30:18 -08:00
scripts Kbuild fixes for v5.10 (2nd) 2020-12-06 10:31:39 -08:00
security selinux/stable-5.10 PR 20201113 2020-11-14 12:04:02 -08:00
sound ALSA: pcm: oss: Fix potential out-of-bounds shift 2020-12-21 13:30:08 +01:00
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usr Merge branch 'work.fdpic' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2020-08-07 13:29:39 -07:00
virt kvm: x86/mmu: Support dirty logging for the TDP MMU 2020-10-23 03:42:13 -04:00
.clang-format RDMA 5.10 pull request 2020-10-17 11:18:18 -07:00
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CREDITS MAINTAINERS: Move Jason Cooper to CREDITS 2020-11-30 10:20:34 +01:00
Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
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MAINTAINERS Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2020-12-10 15:30:13 -08:00
Makefile Linux 5.10.2 2020-12-21 13:30:08 +01:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.