MFC r323314, r323338, r328849

r323314:
Audit userspace geom code for leaking memory to disk

Any geom class using g_metadata_store, as well as geom_virstor which
duplicated g_metadata_store internally, would dump sectorsize - mdsize bytes
of userspace memory following the metadata block stored. This is most or all
geom classes (gcache, gconcat, geli, gjournal, glabel, gmirror, gmultipath,
graid3, gshsec, gstripe, and geom_virstor).

PR: 222077 (comment #3)
Reported by: Maxim Khitrov <max AT mxcrypt.com>
Reviewed by: des
Security: yes
Sponsored by: Dell EMC Isilon
Differential Revision: https://reviews.freebsd.org/D12269

r323338:
Fix information leak in geli(8) integrity mode

In integrity mode, a larger logical sector (e.g., 4096 bytes) spans several
physical sectors (e.g., 512 bytes) on the backing device. Due to hash
overhead, a 4096 byte logical sector takes 8.5625 512-byte physical sectors.
This means that only 288 bytes (256 data + 32 hash) of the last 512 byte
sector are used.

The memory allocation used to store the encrypted data to be written to the
physical sectors comes from malloc(9) and does not use M_ZERO.

Previously, nothing initialized the final physical sector backing each
logical sector, aside from the hash + encrypted data portion. So 224 bytes
of kernel heap memory was leaked to every block :-(.

This patch addresses the issue by initializing the trailing portion of the
physical sector in every logical sector to zeros before use. A much simpler
but higher overhead fix would be to tag the entire allocation M_ZERO.

PR: 222077
Reported by: Maxim Khitrov <max AT mxcrypt.com>
Reviewed by: emaste
Security: yes
Sponsored by: Dell EMC Isilon
Differential Revision: https://reviews.freebsd.org/D12272

r328849:
geom: don't write stack garbage in disk labels

Most consumers of g_metadata_store were passing in partially unallocated
memory, resulting in stack garbage being written to disk labels. Fix them by
zeroing the memory first.

gvirstor repeated the same mistake, but in the kernel.

Also, glabel's label contained a fixed-size string that wasn't
initialized to zero.

PR: 222077
Reported by: Maxim Khitrov <max@mxcrypt.com>
Reviewed by: cem
X-MFC-With: 323314
X-MFC-With: 323338
Differential Revision: https://reviews.freebsd.org/D14164

Copy head (r256279) to stable/10 as part of the 10.0-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

- Remove gc_argname field. It was introduced for gpart(8), but if I
understand everything correctly, we don't really need it.
- Provide default numeric value as strings. This allows to simplify
a lot of code.
- Bump version number.

Replace checks for RESCUE in sources with checks for STATIC_GEOM_CLASSES
and define STATIC_GEOM_CLASSES when building the rescue binary. This way
geom can more easily be part of other crunched binaries, as it requires
only a Makefile change.

Make it possible to build glabel into rescue geom(8) utility.

Ok'ed by: marcel
No objection: -current@

Add gpart(8).

In order to support gpart(8), geom(8) needs to support a named
argument. Also, optional string parameters are a requirement.
Both have been added to the infrastructure. The former required
all existing classes to be adjusted.

MFp4: G_TYPE_BOOL sounds much better than G_TYPE_NONE.

Changes: 98722

Remove trailing spaces.

- The geom(8) utility only uses three types of arguments: string (char *),
value (intmax_t) and boolean (int).
Based on that provide three functions:
- gctl_get_ascii()
- gctl_get_int()
- gctl_get_intmax()
- Hide gctl_get_param() function, as it is only used internally in
subr.c.
- Allow to provide argument name as (fmt, ...).
- Assert geom(8) bugs (missing argument is a geom(8) bug).

- Clean-up and simplify the code by using new functions and assumtions
(no more checking for missing argument).

Tested by: regression tests

Define subcommands' usage inside g_command structure.

MFC after: 1 week

- Add md_provsize field to metadata, which will help with
shared-last-sector problem.
After this change, even if there is more than one provider with the same
last sector, the proper one will be chosen based on its size.
It still doesn't fix the 'c' partition problem (when da0s1 can be confused
with da0s1c) and situation when 'a' partition starts at offset 0
(then da0s1a can be confused with da0s1 and da0s1c). One can use '-h'
option there, when creating device or avoid sharing last sector.
Actually, when providers share the same last sector and their size is equal,
they provide exactly the same data, so the name (da0s1, da0s1a, da0s1c)
isn't important at all.
- Provide backward compatibility.
- Update copyright's year.

MFC after: 1 week

Fix arguments syntax.

Manual pages fixes by: ru
MFC after: 3 days

MFp4: Add 'dump' command to gconcat(8), glabel(8) and gstripe(8) which allow
to dump metadata from given components.

- Add 'stop' command, which works just like 'destroy' command, but sounds
less dangerous.
- Update manual pages and extend examples.
- Bump versions.

Introduce GEOM_LABEL class.
This class is used for detecting volume labels on file systems:
UFS, MSDOSFS (FAT12, FAT16, FAT32) and ISO9660.
It also provide native labelization (there is no need for file system).

g_label_ufs.c is based on geom_vol_ffs from Gordon Tetlow.
g_label_msdos.c and g_label_iso9660.c are probably hacks, I just found
where volume labels are stored and I use those offsets here,
but with this class it should be easy to do it as it should be done by
someone who know how.
Implementing volume labels detection for other file systems also should
be trivial.

New providers are created in those directories:
/dev/ufs/ (UFS1, UFS2)
/dev/msdosfs/ (FAT12, FAT16, FAT32)
/dev/iso9660/ (ISO9660)
/dev/label/ (native labels, configured with glabel(8))

Manual page cleanups and some comments inside were submitted by
Simon L. Nielsen, who was, as always, very helpful. Thanks!