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Konrad Witaszczyk 480f31c214 Add support for encrypted kernel crash dumps.
Changes include modifications in kernel crash dump routines, dumpon(8) and
savecore(8). A new tool called decryptcore(8) was added.

A new DIOCSKERNELDUMP I/O control was added to send a kernel crash dump
configuration in the diocskerneldump_arg structure to the kernel.
The old DIOCSKERNELDUMP I/O control was renamed to DIOCSKERNELDUMP_FREEBSD11 for
backward ABI compatibility.

dumpon(8) generates an one-time random symmetric key and encrypts it using
an RSA public key in capability mode. Currently only AES-256-CBC is supported
but EKCD was designed to implement support for other algorithms in the future.
The public key is chosen using the -k flag. The dumpon rc(8) script can do this
automatically during startup using the dumppubkey rc.conf(5) variable.  Once the
keys are calculated dumpon sends them to the kernel via DIOCSKERNELDUMP I/O
control.

When the kernel receives the DIOCSKERNELDUMP I/O control it generates a random
IV and sets up the key schedule for the specified algorithm. Each time the
kernel tries to write a crash dump to the dump device, the IV is replaced by
a SHA-256 hash of the previous value. This is intended to make a possible
differential cryptanalysis harder since it is possible to write multiple crash
dumps without reboot by repeating the following commands:
# sysctl debug.kdb.enter=1
db> call doadump(0)
db> continue
# savecore

A kernel dump key consists of an algorithm identifier, an IV and an encrypted
symmetric key. The kernel dump key size is included in a kernel dump header.
The size is an unsigned 32-bit integer and it is aligned to a block size.
The header structure has 512 bytes to match the block size so it was required to
make a panic string 4 bytes shorter to add a new field to the header structure.
If the kernel dump key size in the header is nonzero it is assumed that the
kernel dump key is placed after the first header on the dump device and the core
dump is encrypted.

Separate functions were implemented to write the kernel dump header and the
kernel dump key as they need to be unencrypted. The dump_write function encrypts
data if the kernel was compiled with the EKCD option. Encrypted kernel textdumps
are not supported due to the way they are constructed which makes it impossible
to use the CBC mode for encryption. It should be also noted that textdumps don't
contain sensitive data by design as a user decides what information should be
dumped.

savecore(8) writes the kernel dump key to a key.# file if its size in the header
is nonzero. # is the number of the current core dump.

decryptcore(8) decrypts the core dump using a private RSA key and the kernel
dump key. This is performed by a child process in capability mode.
If the decryption was not successful the parent process removes a partially
decrypted core dump.

Description on how to encrypt crash dumps was added to the decryptcore(8),
dumpon(8), rc.conf(5) and savecore(8) manual pages.

EKCD was tested on amd64 using bhyve and i386, mipsel and sparc64 using QEMU.
The feature still has to be tested on arm and arm64 as it wasn't possible to run
FreeBSD due to the problems with QEMU emulation and lack of hardware.

Designed by:	def, pjd
Reviewed by:	cem, oshogbo, pjd
Partial review:	delphij, emaste, jhb, kib
Approved by:	pjd (mentor)
Differential Revision:	https://reviews.freebsd.org/D4712
2016-12-10 16:20:39 +00:00
bin Capsicum support for dd(1) 2016-12-09 14:51:05 +00:00
cddl err.D_PROC_CREATEFAIL.many.d passes, so remove the EFAIL annotation. 2016-12-08 18:56:35 +00:00
contrib Perl is not available in base fix scripts depending on it to use 2016-12-10 12:02:32 +00:00
crypto MFV r308196: 2016-11-02 06:49:25 +00:00
etc Add support for encrypted kernel crash dumps. 2016-12-10 16:20:39 +00:00
gnu Add WITH_LLD_AS_LD build knob 2016-11-25 13:15:28 +00:00
include Create the /usr/lib/include symlink as relative. 2016-12-03 05:29:12 +00:00
kerberos5 DIRDEPS_BUILD: Update dependencies 2016-06-14 16:55:05 +00:00
lib More debugging code I missed in r309051. 2016-12-09 16:14:55 +00:00
libexec Retire long-broken/unused static rtld support 2016-12-02 14:23:26 +00:00
release Revert r309314, which breaks installing ports. 2016-11-30 22:00:25 +00:00
rescue DIRDEPS_BUILD: Update dependencies. 2016-11-13 00:11:30 +00:00
sbin Add support for encrypted kernel crash dumps. 2016-12-10 16:20:39 +00:00
secure Prefer ACFLAGS over CFLAGS for compiling aarch64 assembly files. 2016-10-26 20:12:30 +00:00
share Add support for encrypted kernel crash dumps. 2016-12-10 16:20:39 +00:00
sys Add support for encrypted kernel crash dumps. 2016-12-10 16:20:39 +00:00
targets Merge ^/head r308491 through r308841. 2016-11-19 16:05:55 +00:00
tests coredump_phnum_test: Make expected pheader count more flexible 2016-12-04 03:50:57 +00:00
tools Respect WITHOUT_FINGER in src.conf when running make delete-old 2016-12-10 12:28:43 +00:00
usr.bin Export the whole thread name in kinfo_proc 2016-12-07 15:04:22 +00:00
usr.sbin Fix pkg groupshow <gid> 2016-12-10 12:48:48 +00:00
.arcconfig callsign isn't required anymore 2016-09-29 06:19:45 +00:00
.arclint phabricator related changes: 2015-04-20 20:33:22 +00:00
COPYRIGHT Bump copyright year. 2015-12-31 11:21:45 +00:00
LOCKS
MAINTAINERS Remove myself from kern_timeout.c yeah! 2016-07-27 20:37:32 +00:00
Makefile Add full softfloat and hardfloat support for RISC-V. 2016-11-16 15:21:32 +00:00
Makefile.inc1 dd is currently a bootstrap tool. It really doesn't have any business 2016-12-02 14:44:38 +00:00
Makefile.libcompat Fix in-tree GCC builds after r304681. 2016-08-23 19:29:37 +00:00
ObsoleteFiles.inc Bump the libproc library version. 2016-12-06 04:23:32 +00:00
README README: remove nonexistent 'games' directory. 2016-05-18 10:43:13 +00:00
UPDATING Add UPDATING entry for clang/llvm 3.9.0 import. 2016-11-24 22:18:55 +00:00

This is the top level of the FreeBSD source directory.  This file
was last revised on:
$FreeBSD$

For copyright information, please see the file COPYRIGHT in this
directory (additional copyright information also exists for some
sources in this tree - please see the specific source directories for
more information).

The Makefile in this directory supports a number of targets for
building components (or all) of the FreeBSD source tree.  See build(7)
and http://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/makeworld.html
for more information, including setting make(1) variables.

The `buildkernel` and `installkernel` targets build and install
the kernel and the modules (see below).  Please see the top of
the Makefile in this directory for more information on the
standard build targets and compile-time flags.

Building a kernel is a somewhat more involved process.  See build(7), config(8),
and http://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/kernelconfig.html
for more information.

Note: If you want to build and install the kernel with the
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world before.  More information is available in the handbook.

The kernel configuration files reside in the sys/<arch>/conf
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NOTES contains entries and documentation for all possible
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Source Roadmap:
---------------

bin		System/user commands.

cddl		Various commands and libraries under the Common Development
		and Distribution License.

contrib		Packages contributed by 3rd parties.

crypto		Cryptography stuff (see crypto/README).

etc		Template files for /etc.

gnu		Various commands and libraries under the GNU Public License.
		Please see gnu/COPYING* for more information.

include		System include files.

kerberos5	Kerberos5 (Heimdal) package.

lib		System libraries.

libexec		System daemons.

release		Release building Makefile & associated tools.

rescue		Build system for statically linked /rescue utilities.

sbin		System commands.

secure		Cryptographic libraries and commands.

share		Shared resources.

sys		Kernel sources.

tests		Regression tests which can be run by Kyua.  See tests/README
		for additional information.

tools		Utilities for regression testing and miscellaneous tasks.

usr.bin		User commands.

usr.sbin	System administration commands.


For information on synchronizing your source tree with one or more of
the FreeBSD Project's development branches, please see:

  http://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/synching.html