mirror of
https://git.FreeBSD.org/src.git
synced 2024-12-20 11:11:24 +00:00
170 lines
5.0 KiB
Plaintext
170 lines
5.0 KiB
Plaintext
This describes the key/certificate revocation list format for OpenSSH.
|
|
|
|
1. Overall format
|
|
|
|
The KRL consists of a header and zero or more sections. The header is:
|
|
|
|
#define KRL_MAGIC 0x5353484b524c0a00ULL /* "SSHKRL\n\0" */
|
|
#define KRL_FORMAT_VERSION 1
|
|
|
|
uint64 KRL_MAGIC
|
|
uint32 KRL_FORMAT_VERSION
|
|
uint64 krl_version
|
|
uint64 generated_date
|
|
uint64 flags
|
|
string reserved
|
|
string comment
|
|
|
|
Where "krl_version" is a version number that increases each time the KRL
|
|
is modified, "generated_date" is the time in seconds since 1970-01-01
|
|
00:00:00 UTC that the KRL was generated, "comment" is an optional comment
|
|
and "reserved" an extension field whose contents are currently ignored.
|
|
No "flags" are currently defined.
|
|
|
|
Following the header are zero or more sections, each consisting of:
|
|
|
|
byte section_type
|
|
string section_data
|
|
|
|
Where "section_type" indicates the type of the "section_data". An exception
|
|
to this is the KRL_SECTION_SIGNATURE section, that has a slightly different
|
|
format (see below).
|
|
|
|
The available section types are:
|
|
|
|
#define KRL_SECTION_CERTIFICATES 1
|
|
#define KRL_SECTION_EXPLICIT_KEY 2
|
|
#define KRL_SECTION_FINGERPRINT_SHA1 3
|
|
#define KRL_SECTION_SIGNATURE 4
|
|
|
|
2. Certificate section
|
|
|
|
These sections use type KRL_SECTION_CERTIFICATES to revoke certificates by
|
|
serial number or key ID. The consist of the CA key that issued the
|
|
certificates to be revoked and a reserved field whose contents is currently
|
|
ignored.
|
|
|
|
string ca_key
|
|
string reserved
|
|
|
|
Where "ca_key" is the standard SSH wire serialisation of the CA's
|
|
public key. Alternately, "ca_key" may be an empty string to indicate
|
|
the certificate section applies to all CAs (this is most useful when
|
|
revoking key IDs).
|
|
|
|
Followed by one or more sections:
|
|
|
|
byte cert_section_type
|
|
string cert_section_data
|
|
|
|
The certificate section types are:
|
|
|
|
#define KRL_SECTION_CERT_SERIAL_LIST 0x20
|
|
#define KRL_SECTION_CERT_SERIAL_RANGE 0x21
|
|
#define KRL_SECTION_CERT_SERIAL_BITMAP 0x22
|
|
#define KRL_SECTION_CERT_KEY_ID 0x23
|
|
|
|
2.1 Certificate serial list section
|
|
|
|
This section is identified as KRL_SECTION_CERT_SERIAL_LIST. It revokes
|
|
certificates by listing their serial numbers. The cert_section_data in this
|
|
case contains:
|
|
|
|
uint64 revoked_cert_serial
|
|
uint64 ...
|
|
|
|
This section may appear multiple times.
|
|
|
|
2.2. Certificate serial range section
|
|
|
|
These sections use type KRL_SECTION_CERT_SERIAL_RANGE and hold
|
|
a range of serial numbers of certificates:
|
|
|
|
uint64 serial_min
|
|
uint64 serial_max
|
|
|
|
All certificates in the range serial_min <= serial <= serial_max are
|
|
revoked.
|
|
|
|
This section may appear multiple times.
|
|
|
|
2.3. Certificate serial bitmap section
|
|
|
|
Bitmap sections use type KRL_SECTION_CERT_SERIAL_BITMAP and revoke keys
|
|
by listing their serial number in a bitmap.
|
|
|
|
uint64 serial_offset
|
|
mpint revoked_keys_bitmap
|
|
|
|
A bit set at index N in the bitmap corresponds to revocation of a keys with
|
|
serial number (serial_offset + N).
|
|
|
|
This section may appear multiple times.
|
|
|
|
2.4. Revoked key ID sections
|
|
|
|
KRL_SECTION_CERT_KEY_ID sections revoke particular certificate "key
|
|
ID" strings. This may be useful in revoking all certificates
|
|
associated with a particular identity, e.g. a host or a user.
|
|
|
|
string key_id[0]
|
|
...
|
|
|
|
This section must contain at least one "key_id". This section may appear
|
|
multiple times.
|
|
|
|
3. Explicit key sections
|
|
|
|
These sections, identified as KRL_SECTION_EXPLICIT_KEY, revoke keys
|
|
(not certificates). They are less space efficient than serial numbers,
|
|
but are able to revoke plain keys.
|
|
|
|
string public_key_blob[0]
|
|
....
|
|
|
|
This section must contain at least one "public_key_blob". The blob
|
|
must be a raw key (i.e. not a certificate).
|
|
|
|
This section may appear multiple times.
|
|
|
|
4. SHA1 fingerprint sections
|
|
|
|
These sections, identified as KRL_SECTION_FINGERPRINT_SHA1, revoke
|
|
plain keys (i.e. not certificates) by listing their SHA1 hashes:
|
|
|
|
string public_key_hash[0]
|
|
....
|
|
|
|
This section must contain at least one "public_key_hash". The hash blob
|
|
is obtained by taking the SHA1 hash of the public key blob. Hashes in
|
|
this section must appear in numeric order, treating each hash as a big-
|
|
endian integer.
|
|
|
|
This section may appear multiple times.
|
|
|
|
5. KRL signature sections
|
|
|
|
The KRL_SECTION_SIGNATURE section serves a different purpose to the
|
|
preceding ones: to provide cryptographic authentication of a KRL that
|
|
is retrieved over a channel that does not provide integrity protection.
|
|
Its format is slightly different to the previously-described sections:
|
|
in order to simplify the signature generation, it includes as a "body"
|
|
two string components instead of one.
|
|
|
|
byte KRL_SECTION_SIGNATURE
|
|
string signature_key
|
|
string signature
|
|
|
|
The signature is calculated over the entire KRL from the KRL_MAGIC
|
|
to this subsection's "signature_key", including both and using the
|
|
signature generation rules appropriate for the type of "signature_key".
|
|
|
|
This section must appear last in the KRL. If multiple signature sections
|
|
appear, they must appear consecutively at the end of the KRL file.
|
|
|
|
Implementations that retrieve KRLs over untrusted channels must verify
|
|
signatures. Signature sections are optional for KRLs distributed by
|
|
trusted means.
|
|
|
|
$OpenBSD: PROTOCOL.krl,v 1.4 2018/04/10 00:10:49 djm Exp $
|