SAnon includes channel bindings as part of the key derivation function, so they
cannot be ignored. Always set GSS_C_CHANNEL_BOUND_FLAG in the SAnon acceptor.
In acquire_mech_cred(), treat a credential store with no elements as equivalent
to GSS_C_NO_CRED_STORE, allowing a mechanism's gss_acquire_cred()
implementation to be called.
GM_USE_MG_NAME was not honored in the case where the mechanism emitted a name,
but the caller of gss_accept_sec_context() did not request it be returned. This
would result in m->gm_release_name() being called on the mechglue name, which
would crash either because that function pointer was NULL or because it would
have expected a mechanism name.
To avoid future regressions such as the one corrected in 0dd19003, make
IS_DCE_STYLE() an inline function (rather than a macro) so that its
argument is typed.
4b543b7 introduced a regression in the krb5 mechanism's gss_unwrap for
DCE applications, owing to IS_DCE_STYLE() being called with a krb5
instead of mechanism context handle.
Samba compiles Heimdal internally without HAVE_DLOPEN to keep
to internally supplied mechanisms and plugins.
Samba compiles with strict warning flags and on Ubuntu 20.04
with gcc version 9.3.0 (Ubuntu 9.3.0-17ubuntu1~20.04) we see:
../../source4/heimdal/lib/gssapi/mech/gss_mech_switch.c: In function ‘_gss_load_mech’:
../../source4/heimdal/lib/gssapi/mech/gss_mech_switch.c:462:1: error: label ‘out’ defined but not used [-Werror=unused-label]
462 | out:
| ^~~
cc1: all warnings being treated as errors
Signed-off-by: Andrew Bartlett <abartlet@samba.org>
Some compilers with -Wstring-concatenation enabled warned about a suspicious
concatenation of string literals in the initialization of the GSS-API error
message array.
At the expense of a long line, avoid this warning but explicitly concatenating
the offending string literal.
Fixes: #775
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!
acquire_cred_with_password() must call
krb5_get_init_creds_opt_set_default_flags() to initialize the
krb5_get_init_creds option flags to the values obtained from
the krb5_context.
Change-Id: Icd8c500dd0787a781c2382284f19cef277b1d30b
gss_unwrap_iov() with rc4-hmac (RFC4757) encryption types would fail unless
GSS_C_DCE_STYLE was specified, as an incorrect length was passed to
_gssapi_verify_mech_header(). (The correct length is the header length for
GSS_C_DCE_STYLE, and the wrap token length otherwise.)
RFC 4121/4757 don't require padding as they operate as stream ciphers. Make the
PADDING buffer optional when using these encryption types with gss_wrap_iov()
and gss_unwrap_iov().
Our initiator supports configuration-driven delegation of destination
TGTs.
This commit adds acceptor-side handling of destination TGT policy to
reject storing of non-destination TGTs when destination TGTs are
desired.
Currently we use the same appdefault for this.
Background:
A root TGT is one of the form krbtgt/REALM@SAME-REALM.
A destination TGT is a root TGT for the same realm as the acceptor
service's realm.
Normally clients delegate a root TGT for the client's realm.
In some deployments clients may want to delegate destination TGTs as
a form of constrained delegation: so that the destination service
cannot use the delegated credential to impersonate the client
principal to services in its home realm (due to KDC lineage/transit
checks). In those deployments there may not even be a route back to
the KDCs of the client's realm, and attempting to use a
non-destination TGT might even lead to timeouts.
_gsskrb5_init_sec_context() when called with GSS_C_NO_CREDENTIAL
opens the default ccache and sets the CLOSE_CCACHE flag indicating
that the ccache lifetime is tied to the gsskrb5_ctx. When
_gsskrb5_delete_sec_context() is called, it must close the ccache
if the CLOSE_CCACHE flag is set. Otherwise, the ccache resources
will leak.
Leaked since 39fe446983.
Change-Id: I8d0faab1e844d68fe71b11b715f8d88fcd2f4af7
Seen with Ubuntu 18.04
gcc version 7.5.0 (Ubuntu 7.5.0-3ubuntu1~18.04)
mech/gss_krb5.c: In function ‘gss_krb5_ccache_name’:
mech/gss_krb5.c:501:18: error: the address of ‘buffer’ will always evaluate as ‘true’ [-Werror=address]
_mg_buffer_zero(&buffer);
^
mech/mech_locl.h:72:7: note: in definition of macro ‘_mg_buffer_zero’
if (buffer) { \
^~~~~~
Signed-off-by: Andrew Bartlett <abartlet@samba.org>
This avoids these compiler warnings on Ubuntu 18.04
gcc version 7.5.0 (Ubuntu 7.5.0-3ubuntu1~18.04)
expand_path.c: In function ‘expand_token’:
expand_path.c:493:17: warning: ignoring return value of ‘asprintf’, declared with attribute warn_unused_result [-Wunused-result]
asprintf(&arg, "%.*s", (int)(token_end - colon - 1), colon + 1);
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
log.c: In function ‘fmtkv’:
log.c:646:5: warning: ignoring return value of ‘vasprintf’, declared with attribute warn_unused_result [-Wunused-result]
vasprintf(&buf1, fmt, ap);
^~~~~~~~~~~~~~~~~~~~~~~~~
mech/context.c: In function ‘gss_mg_set_error_string’:
mech/context.c:212:5: warning: ignoring return value of ‘vasprintf’, declared with attribute warn_unused_result [-Wunused-result]
(void) vasprintf(&str, fmt, ap);
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
mech/context.c: In function ‘_gss_mg_log_name’:
mech/context.c:319:6: warning: ignoring return value of ‘vasprintf’, declared with attribute warn_unused_result [-Wunused-result]
(void) vasprintf(&str, fmt, ap);
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
mech/context.c: In function ‘_gss_mg_log_cred’:
mech/context.c:346:5: warning: ignoring return value of ‘vasprintf’, declared with attribute warn_unused_result [-Wunused-result]
(void) vasprintf(&str, fmt, ap);
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
kerberos5.c: In function ‘_kdc_set_e_text’:
kerberos5.c:338:5: warning: ignoring return value of ‘vasprintf’, declared with attribute warn_unused_result [-Wunused-result]
vasprintf(&e_text, fmt, ap);
^~~~~~~~~~~~~~~~~~~~~~~~~~~
Signed-off-by: Andrew Bartlett <abartlet@samba.org>
When a function is assigned to a function pointer that is declared
with a particular calling convention, then the assigned function
must be declared with that calling convention as well. Otherwise,
kaboom!!!
The following functions are fixed by this change:
kuser/kx509.c
validate1()
add1_2chain()
lib/base/log.c
log_syslog()
close_syslog()
log_file()
close_file()
lib/gssapi/mech/context.c
gss_set_log_function()
lib/krb5/kx509.c
certs_export_func()
Change-Id: Ib68abf739e3385e98136fa4e4f5a0240e9fce033
SAnon unconditionally sets the replay, sequence, confidentiality, and integrity
flags on the acceptor; do so on the initiator as well. Some indentation
cleanups are also included in this commit.
In SAnon, the optional flags send in the initial context token are input into
the key derivation function. Mask out the flags we wish to ignore after (not
before) calling the key derivation function, as the initiator may not know
which flags we wish to ignore.
In SAnon:
The is_initiator bitfield must be unsigned to avoid undefined behaviour, as
there is only a single bit defined. Thanks to Nico Williams for explaining
this.
We were passing SANON flags to _gss_mg_import_rfc4121_context(), which
wants GSS flags. Meanwhile, I broke gss_inquire_context() on imported
SAnon contexts when I did my review of SAnon.
This commit fixes both issues and removes SANON_FLAG_*, which were only
ever needed because of a flag to track whether a context was locally
initiated or accepted. Now we use a separate int field of the sanon_ctx
to track whether a context was locally initiated. Once an SAnon context
is fully established, we rely on gss_inquire_context() on the rfc4121
sub-context for all metadata that isn't the initiator and acceptor names
nor the mechanism OID.
Add support for SAnon, a simple key agreement protocol that provides no
authentication of initiator or acceptor using x25519 ECDH key exchange.
See doc/standardization/draft-howard-gss-sanon-xx.txt for a protocol
description.
Fix for issue #486 based on a patch by Nico Williams.
A GSS-API acceptor can return an error token to be sent to the initiator. Our
SPNEGO implementation discarded these when sending a SPNEGO reject response.
This patch fixes the SPNEGO acceptor to convey those in the SPNEGO response.
The SPNEGO initiator is also updated to not bail out early on receiving a
SPNEGO reject response from the acceptor, but instead pass the response token
(if any) to gss_init_sec_context(). A reject response with no response token
will continue to return an error.
