sys: Automated cleanup of cdefs and other formatting

Apply the following automated changes to try to eliminate
no-longer-needed sys/cdefs.h includes as well as now-empty
blank lines in a row.

Remove /^#if.*\n#endif.*\n#include\s+<sys/cdefs.h>.*\n/
Remove /\n+#include\s+<sys/cdefs.h>.*\n+#if.*\n#endif.*\n+/
Remove /\n+#if.*\n#endif.*\n+/
Remove /^#if.*\n#endif.*\n/
Remove /\n+#include\s+<sys/cdefs.h>\n#include\s+<sys/types.h>/
Remove /\n+#include\s+<sys/cdefs.h>\n#include\s+<sys/param.h>/
Remove /\n+#include\s+<sys/cdefs.h>\n#include\s+<sys/capsicum.h>/

Sponsored by: Netflix

sys: Remove $FreeBSD$: one-line .c pattern

Remove /^[\s*]*__FBSDID\("\$FreeBSD\$"\);?\s*\n/

spdx: The BSD-2-Clause-FreeBSD identifier is obsolete, drop -FreeBSD

The SPDX folks have obsoleted the BSD-2-Clause-FreeBSD identifier. Catch
up to that fact and revert to their recommended match of BSD-2-Clause.

Discussed with: pfg
MFC After: 3 days
Sponsored by: Netflix

Use zfree() instead of explicit_bzero() and free().

In addition to reducing lines of code, this also ensures that the full
allocation is always zeroed avoiding possible bugs with incorrect
lengths passed to explicit_bzero().

Suggested by: cem
Reviewed by: cem, delphij
Approved by: csprng (cem)
Sponsored by: Chelsio Communications
Differential Revision: https://reviews.freebsd.org/D25435

Implement automatic online expansion of GELI providers - if the underlying
provider grows, GELI will expand automatically and will move the metadata
to the new location of the last sector.

This functionality is turned on by default. It can be turned off with the
-R flag, but it is not recommended - if the underlying provider grows and
automatic expansion is turned off, it won't be possible to attach this
provider again, as the metadata is no longer located in the last sector.

If the automatic expansion is turned off and the underlying provider grows,
GELI will only log a message with the previous size of the provider, so
recovery can be easier.

Obtained from: Fudo Security

g_eli_key_cmp is used only in the kernel, so only define it in the
kernel.

sys/geom: adoption of SPDX licensing ID tags.

Mainly focus on files that use BSD 2-Clause license, however the tool I
was using misidentified many licenses so this was mostly a manual - error
prone - task.

The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.

sys/geom/eli: Switch bzero() to explicit_bzero() for sensitive data

In GELI, anywhere we are zeroing out possibly sensitive data, like
the metadata struct, the metadata sector (both contain the encrypted
master key), the user key, or the master key, use explicit_bzero.

Didn't touch the bzero() used to initialize structs.

Reviewed by: delphij, oshogbo
Sponsored by: ScaleEngine Inc.
Differential Revision: https://reviews.freebsd.org/D9809

Make additional parts of sys/geom/eli more usable in userspace

The upcoming GELI support in the loader reuses parts of this code
Some ifdefs are added, and some code is moved outside of existing ifdefs

The HMAC parts of GELI are broken out into their own file, to separate
them from the kernel crypto/openssl dependant parts that are replaced
in the boot code.

Passed the GELI regression suite (tools/regression/geom/eli)
Files=20 Tests=14996
Result: PASS

Reviewed by: pjd, delphij
MFC after: 1 week
Sponsored by: ScaleEngine Inc.
Differential Revision: https://reviews.freebsd.org/D4699

Pull in r267961 and r267973 again. Fix for issues reported will follow.

Revert r267961, r267973:

These changes prevent sysctl(8) from returning proper output,
such as:

1) no output from sysctl(8)
2) erroneously returning ENOMEM with tools like truss(1)
or uname(1)
truss: can not get etype: Cannot allocate memory

Extend the meaning of the CTLFLAG_TUN flag to automatically check if
there is an environment variable which shall initialize the SYSCTL
during early boot. This works for all SYSCTL types both statically and
dynamically created ones, except for the SYSCTL NODE type and SYSCTLs
which belong to VNETs. A new flag, CTLFLAG_NOFETCH, has been added to
be used in the case a tunable sysctl has a custom initialisation
function allowing the sysctl to still be marked as a tunable. The
kernel SYSCTL API is mostly the same, with a few exceptions for some
special operations like iterating childrens of a static/extern SYSCTL
node. This operation should probably be made into a factored out
common macro, hence some device drivers use this. The reason for
changing the SYSCTL API was the need for a SYSCTL parent OID pointer
and not only the SYSCTL parent OID list pointer in order to quickly
generate the sysctl path. The motivation behind this patch is to avoid
parameter loading cludges inside the OFED driver subsystem. Instead of
adding special code to the OFED driver subsystem to post-load tunables
into dynamically created sysctls, we generalize this in the kernel.

Other changes:
- Corrected a possibly incorrect sysctl name from "hw.cbb.intr_mask"
to "hw.pcic.intr_mask".
- Removed redundant TUNABLE statements throughout the kernel.
- Some minor code rewrites in connection to removing not needed
TUNABLE statements.
- Added a missing SYSCTL_DECL().
- Wrapped two very long lines.
- Avoid malloc()/free() inside sysctl string handling, in case it is
called to initialize a sysctl from a tunable, hence malloc()/free() is
not ready when sysctls from the sysctl dataset are registered.
- Bumped FreeBSD version to indicate SYSCTL API change.

MFC after: 2 weeks
Sponsored by: Mellanox Technologies

Always initialize sc_ekey, because as of r238116 it is always used.

If GELI provider was created on FreeBSD HEAD r238116 or later (but before this
change), it is using very weak keys and the data is not protected.
The bug was introduced on 4th July 2012.

One can verify if its provider was created with weak keys by running:

# geli dump <provider> | grep version

If the version is 7 and the system didn't include this fix when provider was
initialized, then the data has to be backed up, underlying provider overwritten
with random data, system upgraded and provider recreated.

Reported by: Fabian Keil <fk@fabiankeil.de>
Tested by: Fabian Keil <fk@fabiankeil.de>
Discussed with: so
MFC after: 3 days

Use correct part of the Master-Key for generating encryption keys.
Before this change the IV-Key was used to generate encryption keys,
which was incorrect, but safe - for the XTS mode this key was unused
anyway and for CBC mode it was used differently to generate IV
vectors, so there is no risk that IV vector collides with encryption
key somehow.

Bump version number and keep compatibility for older versions.

MFC after: 2 weeks

Correct comment.

MFC after: 3 days

Fix a memory leak possible in g_eli_key_allocate() if the key with the
same keyno is added while we aren't holding the lock.

Approved by: pjd (mentor)
MFC after: 1 week

Add magic field to the g_eli_key structure to detect if we are really
operating on proper structures.

MFC after: 1 week

One key is expected from providers smaller than or equal to (2^20)*sectorsize
bytes. Remove bogus assertion and while here remove another too obvious
assertion.

Reported by: Fabian Keil <freebsd-listen@fabiankeil.de>
MFC after: 2 weeks

If number of keys for the given provider doesn't exceed the limit,
allocate all of them at attach time. This allows to avoid moving
keys around in the most-recently-used queue and needs no mutex
synchronization nor refcounting.

MFC after: 2 weeks

Instead of allocating memory for all the keys at device attach,
create reasonably large cache for the keys that is filled when
needed. The previous version was problematic for very large providers
(hundreds of terabytes or serval petabytes). Every terabyte of data
needs around 256kB for keys. Make the default cache limit big enough
to fit all the keys needed for 4TB providers, which will eat at most
1MB of memory.

MFC after: 2 weeks