This allows for negative lifetimes to be encoded, and fits in better
with our use elsewhere of time_t, which in POSIX is a signed integer
type.
Signed-off-by: Joseph Sutton <josephsutton@catalyst.net.nz>
We introduce a notion of soft vs. hard aliases.
Soft aliases are aliases of WELLKNOWN/REFERRALS/TARGET@$some_realm,
where $some_realm is the realm we want the KDC to issue referrals to.
Hard aliases are all other aliases, where if the client requested
canonicalization then the KDC should update the names in the responses,
or else if the client did not request canonicalization, then the KDC
should treat the alias as a distinct principal with the same keys as the
alias' canonical name.
The logic for dealing with these is entirely located in the HDB
backends.
An HDB backend can implement hard aliases by replacing a found
HDB_entry's principal with the name used to look it up.
An HDB backend can implement soft aliases by returning
HDB_ERR_WRONG_REALM to trigger the AS or TGS to return a referral.
Currently only in-tree HDB backends support this feature that use
_hdb_fetch_kvno() as their hdb_fetch_kvno() method implementation.
That's all HDB backends other than SQLite3.
Out-of-tree backends should be unaffected.
We've added a decoration field to HDB_entry: aliased -- an int
(boolean). This is only used internally in libhdb at this time.
Out-of-tree HDB backends could have a use for this decoration, but we
have not decided whether it is a public interface yet.
In order to resolve some shift/reduce conflicts in the ASn.1 compiler's
grammar we need to be strict about value names starting with lower case
and type names starting with upper-case.
Status:
- And it works!
- We have an extensive test based on decoding a rich EK certficate.
This test exercises all of:
- decoding
- encoding with and without decoded open types
- copying of decoded values with decoded open types
- freeing of decoded values with decoded open types
Valgrind finds no memory errors.
- Added a manual page for the compiler.
- rfc2459.asn1 now has all three primary PKIX types that we care about
defined as in RFC5912, with IOS constraints and parameterization:
- `Extension` (embeds open type in an `OCTET STRING`)
- `OtherName` (embeds open type in an `ANY`-like type)
- `SingleAttribute` (embeds open type in an `ANY`-like type)
- `AttributeSet` (embeds open type in a `SET OF ANY`-like type)
All of these use OIDs as the open type type ID field, but integer
open type type ID fields are also supported (and needed, for
Kerberos).
That will cover every typed hole pattern in all our ASN.1 modules.
With this we'll be able to automatically and recursively decode
through all subject DN attributes even when the subject DN is a
directoryName SAN, and subjectDirectoryAttributes, and all
extensions, and all SANs, and all authorization-data elements, and
PA-data, and...
We're not really using `SingleAttribute` and `AttributeSet` yet
because various changes are needed in `lib/hx509` for that.
- `asn1_compile` builds and recognizes the subset of X.681/682/683 that
we need for, and now use in, rfc2459.asn1. It builds the necessary
AST, generates the correct C types, and generates templating for
object sets and open types!
- See READMEs for details.
- Codegen backend not tested; I won't make it implement automatic open
type handling, but it should at least not crash by substituting
`heim_any` for open types not embedded in `OCTET STRING`.
- We're _really_ starting to have problems with the ITU-T ASN.1
grammar and our version of it...
Type names have to start with upper-case, value names with
lower-case, but it's not enough to disambiguate.
The fact the we've allowed value and type names to violate their
respective start-with case rules is causing us trouble now that we're
adding grammar from X.681/682/683, and we're going to have to undo
that.
In preparation for that I'm capitalizing the `heim_any` and
`heim_any_set` types, and doing some additional cleanup, which
requires changes to other parts of Heimdal (all in this same commit
for now).
Problems we have because of this:
- We cannot IMPORT values into modules because we have no idea if a
symbol being imported refers to a value or a type because the only
clue we would have is the symbol's name, so we assume IMPORTed
symbols are for types.
This means we can't import OIDs, for example, which is super
annoying.
One thing we might be able to do here is mark imported symbols as
being of an undetermined-but-not-undefined type, then coerce the
symbol's type the first time it's used in a context where its type
is inferred as type, value, object, object set, or class. (Though
since we don't generate C symbols for objects or classes, we won't
be able to import them, especially since we need to know them at
compile time and cannot defer their handling to link- or
run-time.)
- The `NULL` type name, and the `NULL` value name now cause two
reduce/reduce conflicts via the `FieldSetting` production.
- Various shift/reduce conflicts involving `NULL` values in
non-top-level contexts (in constraints, for example).
- Currently I have a bug where to disambiguate the grammar I have a
CLASS_IDENTIFIER token that is all caps, while TYPE_IDENTIFIER must
start with a capital but not be all caps, but this breaks Kerberos
since all its types are all capitalized -- oof!
To fix this I made it so class names have to be all caps and
start with an underscore (ick).
TBD:
- Check all the XXX comments and address them
- Apply this treatment to Kerberos! Automatic handling of authz-data
sounds useful :)
- Apply this treatment to PKCS#10 (CSRs) and other ASN.1 modules too.
- Replace various bits of code in `lib/hx509/` with uses of this
feature.
- Add JER.
- Enhance `hxtool` and `asn1_print`.
Getting there!
Checking the error code of decoding a blob as an hdb_entry or
hdb_entry_alias to determine which of those the blob is depends on a
detail of the Heimdal ASN.1 compiler and library that shouldn't be
depended on. Using a CHOICE adds no octets to the encoding:
HDB-EntryOrAlias ::= CHOICE {
entry hdb_entry,
alias hdb_entry_alias
}
since we're adding no additional tags and the two arms of the CHOICE
already differ in tag (hdb_entry's tag is a [UNIVERSAL Sequence] tag,
while hdb_entry_alias's is an [APPLICATION 0] tag).
This is a large commit that adds several features:
- Revamps and moves virtual host-based service principal functionality
from kdc/ to lib/hdb/ so that it may be automatically visible to
lib/kadm5/, as well as kadmin(1)/kadmind(8) and ktutil(1).
The changes are backwards-incompatible.
- Completes support for documenting a service principal's supported
enctypes in its HDB entry independently of its long-term keys. This
will reduce HDB bloat by not requiring that service principals have
more long-term keys than they need just to document the service's
supported enctypes.
- Adds support for storing krb5.conf content in principals' HDB
entries. This may eventually be used for causing Heimdal KDC
services to reconfigure primary/secondary roles automatically by
discovering the configured primary in an HDB entry for the realm.
For now this will be used to help reduce the amount of configuration
needed by clients of an upcoming HTTP binding of the kadmin service.
e11abf41 added support in libhdb for always dereferencing principal aliases
during an AS-REQ (where dereferencing refers to enabling alias lookups, and
rewriting the returned entry with the alias name unless canonicalization was
enabled).
Due to the KDC setting HDB_F_FOR_AS_REQ for all lookups from the AS, this
allowed aliases on the TGS itself to be dereferenced during an AS-REQ; however,
on presenting the TGT, the TGS would fail to resolve. Creating an explicit TGS
principal for the aliased realm would work (at least prior to c555ed6a), but
this could be confusing to deploy.
This commit changes enables alias dereferencing when HDB_F_GET_ANY is set,
which essentially means dereference whenever the request is coming from the KDC
(as opposed to, say, kadmin).
We also backout c555ed6a, which changed the TGS to always canonicalize the
server realm, as this breaks serving multiple realms from a single KDC, where
server principals in different realms share a single canonical entry.
HDB_F_CANON is now passed to the backend as a hint only, and per RFC 6806 the
principal name is never changed in TGS replies. (However, for Samba interop,
backends can override this by setting the force-canonicalize HDB flag.)
ASN.1 INTEGERs will now compile to C int64_t or uint64_t, depending
on whether the constraint ranges include numbers that cannot be
represented in 32-bit ints and whether they include negative
numbers.
Template backend support included. check-template is now built with
--template, so we know we're testing it.
Tests included.
