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Nikolaus Voss 5adedd4224 KEYS: encrypted: fix key instantiation with user-provided data 
Commit cd3bc044af ("KEYS: encrypted: Instantiate key with
user-provided decrypted data") added key instantiation with user
provided decrypted data.  The user data is hex-ascii-encoded but was
just memcpy'ed to the binary buffer. Fix this to use hex2bin instead.

Old keys created from user provided decrypted data saved with "keyctl
pipe" are still valid, however if the key is recreated from decrypted
data the old key must be converted to the correct format. This can be
done with a small shell script, e.g.:

BROKENKEY=abcdefABCDEF1234567890aaaaaaaaaa
NEWKEY=$(echo -ne $BROKENKEY | xxd -p -c32)
keyctl add user masterkey "$(cat masterkey.bin)" @u
keyctl add encrypted testkey "new user:masterkey 32 $NEWKEY" @u

However, NEWKEY is still broken: If for BROKENKEY 32 bytes were
specified, a brute force attacker knowing the key properties would only
need to try at most 2^(16*8) keys, as if the key was only 16 bytes long.

The security issue is a result of the combination of limiting the input
range to hex-ascii and using memcpy() instead of hex2bin(). It could
have been fixed either by allowing binary input or using hex2bin() (and
doubling the ascii input key length). This patch implements the latter.

The corresponding test for the Linux Test Project ltp has also been
fixed (see link below).

Fixes: cd3bc044af ("KEYS: encrypted: Instantiate key with user-provided decrypted data")
Cc: stable@kernel.org
Link: https://lore.kernel.org/ltp/20221006081709.92303897@mail.steuer-voss.de/
Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
Signed-off-by: Nikolaus Voss <nikolaus.voss@haag-streit.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2022-10-19 13:01:23 -04:00
arch Random number generator fixes for Linux 6.1-rc1. 2022-10-16 15:27:07 -07:00
block Random number generator fixes for Linux 6.1-rc1. 2022-10-16 15:27:07 -07:00
certs certs: make system keyring depend on built-in x509 parser 2022-09-24 04:31:18 +09:00
crypto treewide: use get_random_bytes() when possible 2022-10-11 17:42:58 -06:00
Documentation KEYS: encrypted: fix key instantiation with user-provided data 2022-10-19 13:01:23 -04:00
drivers Random number generator fixes for Linux 6.1-rc1. 2022-10-16 15:27:07 -07:00
fs Random number generator fixes for Linux 6.1-rc1. 2022-10-16 15:27:07 -07:00
include Random number generator fixes for Linux 6.1-rc1. 2022-10-16 15:27:07 -07:00
init - hfs and hfsplus kmap API modernization from Fabio Francesco 2022-10-12 11:00:22 -07:00
io_uring io_uring/rw: ensure kiocb_end_write() is always called 2022-10-12 16:30:56 -06:00
ipc - hfs and hfsplus kmap API modernization from Fabio Francesco 2022-10-12 11:00:22 -07:00
kernel Random number generator fixes for Linux 6.1-rc1. 2022-10-16 15:27:07 -07:00
lib Random number generator fixes for Linux 6.1-rc1. 2022-10-16 15:27:07 -07:00
LICENSES LICENSES/LGPL-2.1: Add LGPL-2.1-or-later as valid identifiers 2021-12-16 14:33:10 +01:00
mm Random number generator fixes for Linux 6.1-rc1. 2022-10-16 15:27:07 -07:00
net Random number generator fixes for Linux 6.1-rc1. 2022-10-16 15:27:07 -07:00
rust Kbuild: add Rust support 2022-09-28 09:02:20 +02:00
samples VFIO updates for v6.1-rc1 2022-10-12 14:46:48 -07:00
scripts Kbuild fixes for v6.1 2022-10-16 11:12:22 -07:00
security KEYS: encrypted: fix key instantiation with user-provided data 2022-10-19 13:01:23 -04:00
sound sound fixes for 6.1-rc1 2022-10-14 13:22:14 -07:00
tools perf tools changes for v6.1: 2nd batch 2022-10-16 15:14:29 -07:00
usr usr/gen_init_cpio.c: remove unnecessary -1 values from int file 2022-10-03 14:21:44 -07:00
virt VFIO updates for v6.1-rc1 2022-10-12 14:46:48 -07:00
.clang-format PCI/DOE: Add DOE mailbox support functions 2022-07-19 15:38:04 -07:00
.cocciconfig
.get_maintainer.ignore get_maintainer: add Alan to .get_maintainer.ignore 2022-08-20 15:17:44 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore Kbuild: add Rust support 2022-09-28 09:02:20 +02:00
.mailmap - hfs and hfsplus kmap API modernization from Fabio Francesco 2022-10-12 11:00:22 -07:00
.rustfmt.toml rust: add .rustfmt.toml 2022-09-28 09:02:20 +02:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS drm for 5.20/6.0 2022-08-03 19:52:08 -07:00
Kbuild Kbuild updates for v6.1 2022-10-10 12:00:45 -07:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS OpenRISC 6.1 Updates 2022-10-15 16:47:33 -07:00
Makefile Linux 6.1-rc1 2022-10-16 15:36:24 -07:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

README 

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.