Various implementation quirks in OCSP servers make it impractical to
use anything other than SHA1 to construct the issuerNameHash and
issuerKeyHash identifiers in the request certID. For example: both
the OpenCA OCSP responder used by ipxe.org and the Boulder OCSP
responder used by LetsEncrypt will fail if SHA256 is used in the
request certID.
As of commit 6ffe28a ("[ocsp] Accept response certID with missing
hashAlgorithm parameters") we rely on asn1_digest_algorithm() to parse
the algorithm identifier in the response certID. This will fail if
SHA1 is disabled via config/crypto.h.
Fix by using a direct ASN.1 object comparison on the OID within the
algorithm identifier.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
There are many ways in which the object for a cryptographic algorithm
may be included, even if not explicitly enabled in config/crypto.h.
For example: the MD5 algorithm is required by TLSv1.1 or earlier, by
iSCSI CHAP authentication, by HTTP digest authentication, and by NTLM
authentication.
In the current implementation, inclusion of an algorithm for any
reason will result in the algorithm's ASN.1 object identifier being
included in the "asn1_algorithms" table, which consequently allows the
algorithm to be used for any ASN1-identified purpose. For example: if
the MD5 algorithm is included in order to support HTTP digest
authentication, then iPXE would accept a (validly signed) TLS
certificate using an MD5 digest.
Split the ASN.1 object identifiers into separate files that are
required only if explicitly enabled in config/crypto.h. This allows
an algorithm to be omitted from the "asn1_algorithms" table even if
the algorithm implementation is dragged in for some other purpose.
The end result is that only the algorithms that are explicitly enabled
in config/crypto.h can be used for ASN1-identified purposes such as
signature verification.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Ensure that the configured RSA digestInfo prefixes are included in any
build that includes rsa.o (rather than relying on x509.o or tls.o also
being present in the final binary).
This allows the RSA self-tests to be run in isolation.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
One of the design goals of ASN.1 DER is to provide a canonical
serialization of a data structure, thereby allowing for equality of
values to be tested by simply comparing the serialized bytes.
Some OCSP servers will modify the request certID to omit the optional
(and null) "parameters" portion of the hashAlgorithm. This is
arguably legal but breaks the ability to perform a straightforward
bitwise comparison on the entire certID field between request and
response.
Fix by comparing the OID-identified hashAlgorithm separately from the
remaining certID fields.
Originally-fixed-by: Thilo Fromm <Thilo@kinvolk.io>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
We currently perform various min-entropy calculations using build-time
floating-point arithmetic. No floating-point code ends up in the
final binary, since the results are eventually converted to integers
and asserted to be compile-time constants.
Though this mechanism is undoubtedly cute, it inhibits us from using
"-mno-sse" to prevent the use of SSE registers by the compiler.
Fix by using fixed-point arithmetic instead.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Allow certificates to be marked as having been added explicitly at run
time. Such certificates will not be discarded via the certificate
store cache discarder.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Enable both IMAGE_DER and IMAGE_PEM by default, and drag in the
relevant objects only when image_asn1() is present in the binary.
This allows "imgverify" to transparently use either DER or PEM
signature files.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Allow code to create a partial ASN.1 cursor containing only the type
and length bytes, so that asn1_start() may be used to determine the
length of a large ASN.1 blob without first allocating memory to hold
the entire blob.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
When building for 64-bit ARM, some symbol references may be resolved
via an "adrp" instruction (to obtain the start of the 4kB page
containing the symbol) and a separate 12-bit offset. For example
(taken from the GNU assembler documentation):
adrp x0, foo
ldr x0, [x0, #:lo12:foo]
We occasionally refer to symbols defined via mechanisms that are not
directly visible to gcc. For example:
extern char some_magic_symbol[];
__asm__ ( ".equ some_magic_symbol, some_magic_expression" );
The subsequent use of the ":lo12:" prefix on such magically-defined
symbols triggers an assertion failure in the assembler.
This problem seems to affect only "private_key_len" in the current
codebase. Fix by storing this value as static data; this avoids the
need to provide the value as a literal within the instruction stream,
and so avoids the problematic use of the ":lo12:" prefix.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
The intention of the existing code (as documented in its own comments)
is that it should be possible to override the list of trusted root
certificates using a "trust" setting held in non-volatile stored
options. However, the rootcert_init() function currently executes
before any devices have been probed, and so will not be able to
retrieve any such non-volatile stored options.
Fix by executing rootcert_init() only after devices have been probed.
Since startup functions may be executed multiple times (unlike
initialisation functions), add an explicit flag to preserve the
property that rootcert_init() should run only once.
As before, if an explicit root of trust is specified at build time,
then any runtime "trust" setting will be ignored.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
On some architectures (such as ARM) the "@" character is used as a
comment delimiter. A section type argument such as "@progbits"
therefore becomes "%progbits".
This is further complicated by the fact that the "%" character has
special meaning for inline assembly when input or output operands are
used, in which cases "@progbits" becomes "%%progbits".
Allow the section type character(s) to be defined via Makefile
variables.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
The assumption in asn1_type() that an ASN.1 cursor will always contain
a type byte is incorrect. A cursor that has been cleanly invalidated
via asn1_invalidate_cursor() will contain a type byte, but there are
other ways in which to arrive at a zero-length cursor.
Fix by explicitly checking the cursor length in asn1_type(). This
allows asn1_invalidate_cursor() to be reduced to simply zeroing the
length field.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
The OCSP responder URI included within an X.509 certificate may or may
not include a trailing slash. We currently rely on the fact that
format_uri() incorrectly inserts an initial slash, which we include
unconditionally within the OCSP request URI.
Switch to using uri_encode() directly, and insert a slash only if the
X.509 certificate's OCSP responder URI does not already include a
trailing slash.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Allow the use of the iPXE DRBG implementation in BSD-licensed
projects.
Requested-by: Sean Davis <dive@hq.endersgame.net>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Allow the use of the iPXE DRBG implementation in BSD-licensed
projects.
Requested-by: Sean Davis <dive@hq.endersgame.net>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Add support for SHA-224, SHA-384, and SHA-512 as digest algorithms in
X.509 certificates, and allow the choice of public-key, cipher, and
digest algorithms to be configured at build time via config/crypto.h.
Originally-implemented-by: Tufan Karadere <tufank@gmail.com>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Remove AXTLS headers now that no AXTLS code remains, with many thanks
to the AXTLS project for use of their cryptography code over the past
several years.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Replace the AES implementation from AXTLS with a dedicated iPXE
implementation which is slightly smaller and around 1000% faster.
This implementation has been verified using the existing self-tests
based on the NIST AES test vectors.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
The current API for Base16 (and Base64) encoding requires the caller
to always provide sufficient buffer space. This prevents the use of
the generic encoding/decoding functionality in some situations, such
as in formatting the hex setting types.
Implement a generic hex_encode() (based on the existing
format_hex_setting()), implement base16_encode() and base16_decode()
in terms of the more generic hex_encode() and hex_decode(), and update
all callers to provide the additional buffer length parameter.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
SHA-512/224 is almost identical to SHA-512, with differing initial
hash values and a truncated output length.
This implementation has been verified using the NIST SHA-512/224 test
vectors.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
SHA-512/256 is almost identical to SHA-512, with differing initial
hash values and a truncated output length.
This implementation has been verified using the NIST SHA-512/256 test
vectors.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
SHA-384 is almost identical to SHA-512, with differing initial hash
values and a truncated output length.
This implementation has been verified using the NIST SHA-384 test
vectors.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
SHA-224 is almost identical to SHA-256, with differing initial hash
values and a truncated output length.
This implementation has been verified using the NIST SHA-224 test
vectors.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
At some point in the past few years, binutils became more aggressive
at removing unused symbols. To function as a symbol requirement, a
relocation record must now be in a section marked with @progbits and
must not be in a section which gets discarded during the link (either
via --gc-sections or via /DISCARD/).
Update REQUIRE_SYMBOL() to generate relocation records meeting these
criteria. To minimise the impact upon the final binary size, we use
existing symbols (specified via the REQUIRING_SYMBOL() macro) as the
relocation targets where possible. We use R_386_NONE or R_X86_64_NONE
relocation types to prevent any actual unwanted relocation taking
place. Where no suitable symbol exists for REQUIRING_SYMBOL() (such
as in config.c), the macro PROVIDE_REQUIRING_SYMBOL() can be used to
generate a one-byte-long symbol to act as the relocation target.
If there are versions of binutils for which this approach fails, then
the fallback will probably involve killing off REQUEST_SYMBOL(),
redefining REQUIRE_SYMBOL() to use the current definition of
REQUEST_SYMBOL(), and postprocessing the linked ELF file with
something along the lines of "nm -u | wc -l" to check that there are
no undefined symbols remaining.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
We currently compare the entirety of the KeyHash object (including the
ASN.1 tag and length byte) against the raw SHA-1 hash of the
certificate's public key. This causes OCSP validation to fail for any
responses which identify the responder by key hash rather than by
name, and hence prevents the use of X.509 certificates where any
certificate in the chain has an OCSP responder which chooses to
identify itself via its key hash.
Fix by adding the missing asn1_enter() required to enter the ASN.1
octet string containing the key hash.
Also add a corresponding test case including an OCSP response where
the responder is identified by key hash, to ensure that this
functionality cannot be broken in future.
Debugged-by: Brian Rak <brak@gameservers.com>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Daniel Johnson
Michael Brown