RSCRYUTIL(1)RSCRYUTIL(1)NAMErscryutil - Manage Encrypted Log Files
SYNOPSISrscryutil [OPTIONS] [FILE] ...
DESCRIPTION
This tool performs various operations on encrypted log files. Most
importantly, it provides the ability to decrypt them.
OPTIONS-d, --decrypt
Select decryption mode. This is the default mode.
-W,--write-keyfile <file>
Utility function to write a key to a keyfile. The key can be
obtained via any method.
-v, --verbose
Select verbose mode.
-f, --force
Forces operations that otherwise would fail.
-k,--keyfile <file>
Reads the key from <file>. File _must_ contain the key, only, no
headers or other meta information. Keyfiles can be generated via
the --write-keyfile option.
-p,--key-program <path-to-program>
In this mode, the key is provided by a so-called "key program".
This program is executed and must return the key to (as well as
some meta information) via stdout. The core idea of key programs
is that using this interface the user can implement as complex
(and secure) method to obtain keys as desired, all without the
need to make modifications to rsyslog.
-K,--key <KEY>
TESTING AID, NOT FOR PRODUCTION USE. This uses the KEY specified
on the command line. This is the actual key, and as such this
mode is highly insecure. However, it can be useful for intial
testing steps. This option may be removed in the future.
-a,--algo <algo>
Sets the encryption algorightm (cipher) to be used. See below
for supported algorithms. The default is "AES128".
-m,--mode <mode>
Sets the ciphermode to be used. See below for supported modes.
The default is "CBC".
-r,--generate-random-key <bytes>
Generates a random key of length <bytes>. This option is meant
to be used together with --write-keyfile (and it is hard to
envision any other valid use for it).
OPERATION MODES
The operation mode specifies what exactly the tool does with the pro‐
vided files. The default operation mode is "dump", but this may change
in the future. Thus, it is recommended to always set the operations
mode explicitely. If multiple operations mode are set on the command
line, results are unpredictable.
decrypt
The provided log files are decrypted. Note that the .encinfo side files
must exist and be accessible in order for decryption to to work.
write-keyfile
In this mode no log files are processed; thus it is an error to specify
any on the command line. The specified keyfile is written. The key
itself is obtained via the usual key commands. If --keyfile is used,
that file is effectively copied.
For security reasons, existing key files are _not_ overwritten. To per‐
mit this, specify the --force option. When doing so, keep in mind that
lost keys cannot be recovered and data encrypted with them may also be
considered lost.
Keyfiles are always created with 0400 permission, that is read access
for only the user. An exception is when an existing file is overwritten
via the --force option, in which case the former permissions still
apply.
EXIT CODES
The command returns an exit code of 0 if everything went fine, and some
other code in case of failures.
SUPPORTED ALGORITHMS
We basically support what libgcrypt supports. This is:
3DES CAST5 BLOWFISH AES128 AES192 AES256 TWOFISH TWOFISH128 ARCFOUR
DES SERPENT128 SERPENT192 SERPENT256 RFC2268_40 SEED CAMELLIA128
CAMELLIA192 CAMELLIA256
SUPPORTED CIPHER MODES
We basically support what libgcrypt supports. This is:
ECB CFB CBC STREAM OFB CTR AESWRAP
EXAMPLESrscryutil logfile
Decrypts "logfile" and sends data to stdout.
rscryutil--generate-random-key 16 --keyfile /some/secured/path/keyfile
Generates random key and stores it in the specified keyfile.
LOG SIGNATURES
Encrypted log files can be used together with signing. To verify such a
file, it must be decrypted first, and the verification tool rsgtutil(1)
must be run on the decrypted file.
SECURITY CONSIDERATIONS
Specifying keys directly on the command line (--key option) is very
insecure and should not be done, except for testing purposes with test
keys. Even then it is recommended to use keyfiles, which are also easy
to handle during testing. Keep in mind that command history is usally
be kept by bash and can also easily be monitored.
Local keyfiles are also a security risk. At a minimum, they should be
used with very restrictive file permissions. For this reason, the
rscryutil tool creates them with read permissions for the user, only,
no matter what umask is set to.
When selecting cipher algorithms and modes, care needs to be taken. The
defaults should be reasonable safe to use, but this tends to change
over time. Keep up with the most current crypto recommendations.
SEE ALSOrsgtutil(1), rsyslogd(8)COPYRIGHT
This page is part of the rsyslog project, and is available under
LGPLv2.
AUTHOR
Rainer Gerhards <rgerhards@adiscon.com>
2013-04-15 RSCRYUTIL(1)
