Initialize mutex fileassoc_global.lock.

fileassoc(9): Fast paths to skip global locks when not in use.

PR kern/57552

table can't be NULL here.

branches: 1.35.6; 1.35.20;
fileassoc_file_delete: pre-check whether fileassoc was used and thus avoid
acquiring kernel-lock, which damages sys_unlink() performance.

branches: 1.34.12; 1.34.16;
Oops - unintentional locking bit that's not yet ready.

This subsystem had leftovers from the time it was part of Veriexec, and then
from when I first implemented it as "metahook."

Cleanup a lot of the mess by unifying variable names, add struct member
prefixes, adjust comments, etc.

No functional change intended.

No need for these prototypes here.

- Convert hashinit() to use kmem_alloc(). The hash tables can be large
and it's better to not have them in kmem_map.
- Convert a couple of minor items along the way to kmem_alloc().
- Fix some memory leaks.

branches: 1.30.6; 1.30.8; 1.30.10;
Merge vmlocking2 to head.

branches: 1.29.8; 1.29.14; 1.29.16; 1.29.20;
Some Veriexec stuff that's been rotting in my tree for months.

Bug fixes:
- Fix crash reported by Scott Ellis on current-users@.

- Fix race conditions in enforcing the Veriexec rename and remove
policies. These are NOT security issues.

- Fix memory leak in rename handling when overwriting a monitored
file.

- Fix table deletion logic.

- Don't prevent query requests if not in learning mode.


KPI updates:
- fileassoc_table_run() now takes a cookie to pass to the callback.

- veriexec_table_add() was removed, it is now done internally. As a
result, there's no longer a need for VERIEXEC_TABLESIZE.

- veriexec_report() was removed, it is now internal.

- Perform sanity checks on the entry type, and enforce default type
in veriexec_file_add() rather than in veriexecctl.

- Add veriexec_flush(), used to delete all Veriexec tables, and
veriexec_dump(), used to fill an array with all Veriexec entries.


New features:
- Add a '-k' flag to veriexecctl, to keep the filenames in the kernel
database. This allows Veriexec to produce slightly more accurate
logs under certain circumstances. In the future, this can be either
replaced by vnode->pathname translation, or combined with it.

- Add a VERIEXEC_DUMP ioctl, to dump the entire Veriexec database.
This can be used to recover a database if the file was lost.
Example usage:

# veriexecctl dump > /etc/signatures

Note that only entries with the filename kept (that is, were loaded
with the '-k' flag) will be dumped.

Idea from Brett Lymn.

- Add a VERIEXEC_FLUSH ioctl, to delete all Veriexec entries. Sample
usage:

# veriexecctl flush

- Add a 'veriexec_flags' rc(8) variable, and make its default have
the '-k' flag. On systems using the default signatures file
(generaetd from running 'veriexecgen' with no arguments), this will
use additional 32kb of kernel memory on average.

- Add a '-e' flag to veriexecctl, to evaluate the fingerprint during
load. This is done automatically for files marked as 'untrusted'.


Misc. stuff:
- The code for veriexecctl was massively simplified as a result of
eliminating the need for VERIEXEC_TABLESIZE, and now uses a single
pass of the signatures file, making the loading somewhat faster.

- Lots of minor fixes found using the (still under development)
Veriexec regression testsuite.

- Some of the messages Veriexec prints were improved.

- Various documentation fixes.


All relevant man-pages were updated to reflect the above changes.

Binary compatibility with existing veriexecctl binaries is maintained.

Revert the latest changes back to 1.25 rev.

Fix tbl, which was misstyped as tlb.

fileassoc_file_delete: Handle an error case of fileassoc_table_lookup().
CID: 4431

branches: 1.25.2; 1.25.4;
fileassoc_table_lookup: call fileassoc_init if it has not been done yet.
fixes crashes sys_unlink when there are no users of fileassoc.

branches: 1.24.2;
remove empty line

- Properly autocreate tables,
- Properly track number of used slots in the table,
- Track number of "assocs" per entry.

PR/35253: YAMAMOTO Takashi: fileassoc hash size problem

fileassoc_table_add() was removed from the KPI and made internal. From now
fileassoc(9) will manage the optimal table size internally.

Input from and okay yamt@.

Add missing specificdata_key_delete() in fileassoc_deregister().

Update comment: device -> mount. No functional change.

Remove advertising clause from all of my stuff.

branches: 1.18.2;
Fix a comment. No functional change.

- remove the fileassoc "tabledata" functionality. use mountspecific instead.
- make pax_segvguard_cb static.

tested and ok'ed by elad.

- just associate fileassoc "table" to struct mount.
because the latter is always available during the lifetime of the former,
there is little point to use another global list to keep track of them.
it also allows to remove an #ifdef FILEASSOC.

- avoid some operations (memory allocation and VOP) in fileassoc_file_lookup,
when fileassoc table is not used.

ok'ed by elad.

make fileassoc_tables static.

- remove a static configuration, FILEASSOC_NHOOKS. do it dynamically instead.
- make fileassoc_t a pointer and remove FILEASSOC_INVAL.
- clean up kern_fileassoc.c. unify duplicated code.
- unexport fileassoc_init using RUN_ONCE(9).
- plug memory leaks in fileassoc_file_delete and fileassoc_table_delete.
- always call callbacks, regardless of the value of the associated data.

ok'ed by elad.

don't expose FILEASSOC_NHOOKS.

compare pointer against null, not zero

Don't leak handle.

branches: 1.10.2; 1.10.4;
* Correct hashing macro so it uses FHANDLE_SIZE()
* Stop fhandle memory leaks and use the correct fhandle dealloc routine
(thanks to Elad for these fixes)
* Remove include of kmem.h, it is not required.

branches: 1.9.2;
* Remove "hinted" interface
* Modify fileassoc internals to use fhandle_t instead of fileid

Add functions to the fileassoc interface to allow a "hint" to be provided
instead of performing an implicit VOP_GETATTR() when adding/looking up
fileassoc entries.

Add __KERNEL_RCSID()

Pretending to be Elad's keyboard:

fileassoc.diff adds a fileassoc_table_run() routine that allows you to
pass a callback to be called with every entry on a given mount.

veriexec.diff adds some raw device access policies: if raw disk is
opened at strict level 1, all fingerprints on this disk will be
invalidated as a safety measure. level 2 will not allow opening disk
for raw writing if we monitor it, and prevent raw writes to memory.
level 3 will not allow opening any disk for raw writing.

both update all relevant documentation.

veriexec concept is okay blymn@.

branches: 1.5.2; 1.5.4;
Use the LWP cached credentials where sane.

Fix an obvious overlook (struct fileassoc_hook is not defined in
fileassoc.h anymore). I could say "please compile-test", but then, I'm not
doing it either for that commit.

expose less api; prompted by yamt@.

dont use magic numbers.

okay, since there was no way to divide this to two commits, here it goes..

introduce fileassoc(9), a kernel interface for associating meta-data with
files using in-kernel memory. this is very similar to what we had in
veriexec till now, only abstracted so it can be used more easily by more
consumers.

this also prompted the redesign of the interface, making it work on vnodes
and mounts and not directly on devices and inodes. internally, we still
use file-id but that's gonna change soon... the interface will remain
consistent.

as a result, veriexec went under some heavy changes to conform to the new
interface. since we no longer use device numbers to identify file-systems,
the veriexec sysctl stuff changed too: kern.veriexec.count.dev_N is now
kern.veriexec.tableN.* where 'N' is NOT the device number but rather a
way to distinguish several mounts.

also worth noting is the plugging of unmount/delete operations
wrt/fileassoc and veriexec.

tons of input from yamt@, wrstuden@, martin@, and christos@.